Jon D Pelletier

Interests

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Courses

Scholarly Contributions

Chapters

• Komatsu, G., Goto, K., Baker, V. R., Oguchi, T., Hayakawa, Y. S., Saito, H., Pelletier, J. D., McGuire, L., & Iijima, Y. (2014). Effects of tsunami wave erosion on natural landscapes: examples from the 2011 Tohoku-oki Tsunami. In Tsunami Events and Lessons Learned(pp 243--253). Springer, Dordrecht.
• Pelletier, J. (2013). Fundamental principles and techniques of landscape evolution modeling. In Treatise on geomorphology(pp 29--43). Elsevier Inc.
• Pelletier, J. D., & Turcotte, D. L. (1999). Self-affine time series: II. Applications and models. In Advances in Geophysics(pp 91--166). Elsevier.

Journals/Publications

• Doane, T. H., Pelletier, J. D., & Nichols, M. H. (2020). How Hack distributions of rill networks contribute to nonlinear slope length--soil loss relationships. Earth Surface Dynamics Discussions, 1--23.
• Moravec, B. G., White, A. M., Root, R. A., Sanchez, A., Olshansky, Y., Paras, B. K., Carr, B., McIntosh, J., Pelletier, J. D., Rasmussen, C., & others, . (2020). Resolving deep critical zone architecture in complex volcanic terrain. Journal of Geophysical Research: Earth Surface, 125(1), e2019JF005189.
• Pelletier, J. D. (2020). Controls on the hydraulic geometry of alluvial channels: bank stability to gravitational failure, the critical-flow hypothesis, and conservation of mass and energy. Earth Surface Dynamics Discussions, 1--18.
• Fan, Y., Clark, M., Lawrence, D. M., Swenson, S., Band, L. E., Brantley, S. L., Brooks, P. D., Dietrich, W. E., Flores, A., Grant, G., & others, . (2019). Hillslope hydrology in global change research and Earth system modeling. Water Resources Research, 55(2), 1737--1772.
• Lawrence, D. M., Fisher, R. A., Koven, C. D., Oleson, K. W., Swenson, S. C., Bonan, G., Collier, N., Ghimire, B., Kampenhout, L., Kennedy, D., & others, . (2019). The Community Land Model version 5: Description of new features, benchmarking, and impact of forcing uncertainty. Journal of Advances in Modeling Earth Systems, 11(12), 4245--4287.
• Luo, W., Smith, T. J., Whalley, K., Darling, A., Ormand, C., Hung, W., Chiang, J., Pelletier, J., & Duffin, K. (2019). Earth surface modeling for education: How effective is it? Four semesters of classroom tests with WILSIM-GC. British Journal of Educational Technology, 50(3), 1462--1481.
• Chang, L., Dwivedi, R., Knowles, J. F., Fang, Y., Niu, G., Pelletier, J. D., Rasmussen, C., Durcik, M., Barron-Gafford, G. A., & Meixner, T. (2018). Why do large-scale land surface models produce a low ratio of transpiration to evapotranspiration?. Journal of Geophysical Research: Atmospheres, 123(17), 9109--9130.
• Meixner, T., Barron-Gafford, G. A., Durcik, M., Rasmussen, C., Pelletier, J. D., Niu, G., Fang, Y., Knowles, J. F., Dwivedi, R., & Chang, L. (2018). Why Do Large‐Scale Land Surface Models Produce a Low Ratio of Transpiration to Evapotranspiration?. Journal of Geophysical Research: Atmospheres, 123(17), 9109-9130. doi:10.1029/2018JD029159
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  Most land surface models (LSMs) used in Earth System Models produce a lower ratio of transpiration (T) to evapotranspiration (ET) than field observations, degrading the credibility of Earth System Model‐projected ecosystem responses and feedbacks to climate change. To interpret this model deficiency, we conducted a pair of model experiments using a three‐dimensional, process‐based ecohydrological model in a subhumid, mountainous catchment. One experiment (CTRL) describes lateral water flow, topographic shading, leaf dynamics, and water vapor diffusion in the soil, while the other (LSM like) does not explicitly describe these processes to mimic a conventional LSM using artificially flattened terrain. Averaged over the catchment, CTRL produced a higher T/ET ratio (72%) than LSM like (55%) and agreed better with an independent estimate (79.79 ± 27%) based on rainfall and stream water isotopes. To discern the exact causes, we conducted additional model experiments, each reverting only one process described in CTRL to that of LSM like. These experiments revealed that the enhanced T/ET ratio was mostly caused by lateral water flow and water vapor diffusion within the soil. In particular, terrain‐driven lateral water flows spread out soil moisture to a wider range along hillslopes with an optimum subrange from the middle to upper slopes, where evaporation (E) was more suppressed by the drier surface than T due to plant uptake of deep soil water, thereby enhancing T/ET. A more elaborate representation of water vapor diffusion from a dynamically changing evaporating surface to the height of the surface roughness length reduced E and increased the T/ET ratio.
• Pelletier, J. D. (2018). Controls on yardang development and morphology: 2. Numerical modeling. Journal of Geophysical Research: Earth Surface, 123(4), 723--743.
• Pelletier, J. D., Barron-Gafford, G. A., Guti\'errez-Jurado, H., Hinckley, E. S., Istanbulluoglu, E., McGuire, L. A., Niu, G., Poulos, M. J., Rasmussen, C., Richardson, P., & others, . (2018). Which way do you lean? Using slope aspect variations to understand Critical Zone processes and feedbacks. Earth Surface Processes and Landforms, 43(5), 1133--1154.
• Pelletier, J. D., Kapp, P. A., Abell, J., Field, J. P., Williams, Z. C., & Dorsey, R. J. (2018). Controls on yardang development and morphology: 1. Field observations and measurements at Ocotillo Wells, California. Journal of Geophysical Research: Earth Surface, 123(4), 694--722.
• Perdrial, J., Brooks, P. D., Swetnam, T., Lohse, K. A., Rasmussen, C., Litvak, M., Harpold, A. A., Zapata-Rios, X., Broxton, P., Mitra, B., & others, . (2018). A net ecosystem carbon budget for snow dominated forested headwater catchments: linking water and carbon fluxes to critical zone carbon storage. Biogeochemistry, 138(3), 225--243.
• Shepard, C., Pelletier, J. D., Schaap, M. G., & Rasmussen, C. (2018). Signatures of obliquity and eccentricity in soil chronosequences. Geophysical Research Letters, 45(20), 11--147.
• Volkmann, T. H., Sengupta, A., Pangle, L. A., Dontsova, K., Barron-Gafford, G. A., Harman, C. J., Niu, G., Meredith, L. K., Abramson, N., Neto, A., & others, . (2018). Controlled experiments of hillslope coevolution at the Biosphere 2 Landscape Evolution Observatory: Toward prediction of coupled hydrological, biogeochemical, and ecological change. Hydrology of Artificial and Controlled Experiments, 25.
• Campisano, C., Campisano, C., Cohen, A. S., Cohen, A. S., Arrowsmith, J. R., Arrowsmith, J. R., Asrat, A., Asrat, A., Behrensmeyer, A. K., Behrensmeyer, A. K., Brown, E., Brown, E., Deino, A., Deino, A., Deocampo, D., Deocampo, D., Feibel, C., Feibel, C., Kingston, J., , Kingston, J., et al. (2017). The Hominin Sites and Paleolakes Drilling Project: Acquiring High-Resolution Paleoclimate Records from the East African Rift System and Their Implications for Understanding the Environmental Context of Hominin Evolution. Paleoanthropology, 2017, 1-43. doi:10.4207/PA.2017.ART104
• Campisano, C., Cohen, A. S., Arrowsmith, J. R., Asrat, A., Behrensmeyer, A. K., Brown, E. T., Deino, A. L., Deocampo, D. M., Feibel, C. S., Kingston, J. D., & others, . (2017). The Hominin Sites and Paleolakes Drilling Project: High-resolution paleoclimate records from the East African Rift System and their implications for understanding the environmental context of hominin evolution. PaleoAnthropology, 1--43.
• Haren, J., Dontsova, K., Barron-Gafford, G. A., Troch, P. A., Chorover, J., Delong, S. B., Breshears, D. D., Huxman, T. E., Pelletier, J. D., Saleska, S. R., & others, . (2017). CO2 diffusion into pore spaces limits weathering rate of an experimental basalt landscape. Geology, 45(3), 203--206.
• McIntosh, J. C., Schaumberg, C., Perdrial, J., Harpold, A., V\'azquez-Ortega, A., Rasmussen, C., Vinson, D., Zapata-Rios, X., Brooks, P. D., Meixner, T., & others, . (2017). Geochemical evolution of the Critical Zone across variable time scales informs concentration-discharge relationships: Jemez River Basin Critical Zone Observatory. Water Resources Research, 53(5), 4169--4196.
• Norman, L. M., Sankey, J. B., Dean, D., Caster, J., DeLong, S., DeLong, W., & Pelletier, J. D. (2017). Quantifying geomorphic change at ephemeral stream restoration sites using a coupled-model approach. Geomorphology, 283, 1--16.
• Pelletier, J. D. (2017). Quantifying the controls on potential soil production rates: a case study of the San Gabriel Mountains, California. Earth Surface Dynamics, 5(3), 479--492.
• Pelletier, J. D., & Swetnam, T. L. (2017). Asymmetry of weathering-limited hillslopes: the importance of diurnal covariation in solar insolation and temperature. Earth Surface Processes and Landforms, 42(9), 1408--1418.
• Rasmussen, C., McGuire, L., Dhakal, P., & Pelletier, J. D. (2017). Coevolution of soil and topography across a semiarid cinder cone chronosequence. Catena, 156, 338--352.
• Shepard, C., Schaap, M. G., Pelletier, J. D., & Rasmussen, C. (2017). A probabilistic approach to quantifying soil physical properties via time-integrated energy and mass input. Soil, 3(1), 67--82.
• Shepard, C., Schaap, M. G., Pelletier, J. D., & Rasmussen, C. (2017). A probabilistic approach to quantifying soil property change through time integration of energy and mass input. SOIL, 3, 67--82.
• Brunke, M. A., Broxton, P., Pelletier, J., Gochis, D., Hazenberg, P., Lawrence, D. M., Leung, L. R., Niu, G., Troch, P. A., & Zeng, X. (2016). Implementing and evaluating variable soil thickness in the Community Land Model, version 4.5 (CLM4. 5). Journal of Climate, 29(9), 3441--3461.
• Field, J. P., Breshears, D. D., Law, D. J., Villegas, J. C., L\'opez-Hoffman, L., Brooks, P. D., Chorover, J., & Pelletier, J. D. (2016). Understanding ecosystem services from a geosciences perspective. Eos, 97(5), 10--11.
• Luo, W., Pelletier, J., Duffin, K., Ormand, C., Hung, W., Shernoff, D. J., Zhai, X., Iverson, E., Whalley, K., Gallaher, C., & others, . (2016). Advantages of computer simulation in enhancing students' learning about landform evolution: A case study using the grand canyon. Journal of Geoscience Education, 64(1), 60--73.
• McGuire, L. A., & Pelletier, J. D. (2016). Controls on valley spacing in landscapes subject to rapid base-level fall. Earth Surface Processes and Landforms, 41(4), 460--472.
• Olyphant, J., Pelletier, J. D., & Johnson, R. (2016). Topographic correlations with soil and regolith thickness from shallow-seismic refraction constraints across upland hillslopes in the Valles Caldera, New Mexico. Earth Surface Processes and Landforms, 41(12), 1684--1696.
• Orem, C. A., & Pelletier, J. D. (2016). Constraining frequency--magnitude--area relationships for rainfall and flood discharges using radar-derived precipitation estimates: example applications in the Upper and Lower Colorado River basins, USA. Hydrology and Earth System Sciences, 20(11), 4483--4501.
• Orem, C. A., & Pelletier, J. D. (2016). The predominance of post-wildfire erosion in the long-term denudation of the Valles Caldera, New Mexico. Journal of Geophysical Research: Earth Surface, 121(5), 843--864.
• Pelletier, J. D., & Field, J. P. (2016). Predicting the roughness length of turbulent flows over landscapes with multi-scale microtopography. Earth Surface Dynamics, 4(2), 391--405.
• Pelletier, J. D., Broxton, P. D., Hazenberg, P., Zeng, X., Troch, P. A., Niu, G., Williams, Z., Brunke, M. A., & Gochis, D. (2016). A gridded global data set of soil, intact regolith, and sedimentary deposit thicknesses for regional and global land surface modeling. Journal of Advances in Modeling Earth Systems, 8(1), 41--65.
• Pelletier, J. D., Nichols, M. H., & Nearing, M. A. (2016). The influence of Holocene vegetation changes on topography and erosion rates: A case study at Walnut Gulch Experimental Watershed, Arizona. Earth Surface Dynamics, 4(2), 471--488.
• Trostle, K. D., Runyon, J. R., Pohlmann, M. A., Redfield, S. E., Pelletier, J., McIntosh, J., & Chorover, J. (2016). Colloids and organic matter complexation control trace metal concentration-discharge relationships in Marshall Gulch stream waters. Water Resources Research, 52(10), 7931--7944.
• Campisano, C., Cohen, A. S., Arrowsmith, J. R., Asrat, A., Behrensmeyer, A. K., Brown, E., Deino, A., Deocampo, D., Feibel, C., Kingston, J., Lamb, H., Lowenstein, T., Noren, A., Olago, D., Owen, R. B., Pelletier, J. D., Potts, R., Reed, K., Renaut, R., , Russell, J., et al. (2017). The Hominin Sites and Paleolakes Drilling Project: Acquiring High-Resolution Paleoclimate Records from the East African Rift System and Their Implications for Understanding the Environmental Context of Hominin Evolution. Paleoanthropology, 2017, 1-43. doi:doi: 10.4207/PA.2017.ART104
  More info

  The possibility of a causal relationship between Earth history processes and hominin evolution in Africa has been the subject of intensive paleoanthropological research for the last 25 years. One fundamental question is: can any geohistorical processes, in particular, climatic ones, be characterized with sufficient precision to enable temporal correlation with events in hominin evolution and provide support for a possible causal mechanism for evolutionary changes? Previous attempts to link paleoclimate and hominin evolution have centered on evidence from the outcrops where the hominin fossils are found, as understanding whether and how hominin populations responded to habitat change must be examined at the local basinal scale. However, these outcrop records typically provide incomplete, low-resolution climate and environmental histories, and surface weathering often precludes the application of highly sensitive, state-of-the-art paleoenvironmental methods. Continuous and well-preserved deep-sea drill core records have provided an alternative approach to reconstructing the context of hominin evolution, but have been collected at great distances from hominin sites and typically integrate information over vast spatial scales. The goal of the Hominin Sites and Paleolakes Drilling Project (HSPDP) is to analyze climate and other Earth system dynamics using detailed paleoenvironmental data acquired through scientific drilling of lacustrine depocenters at or near six key paleoanthropological sites in Kenya and Ethiopia. This review provides an overview of a unique collaboration of paleoanthropologists and earth scientists who have joined together to explicitly explore key hypotheses linking environmental history and mammalian (including hominin) evolution and potentially develop new testable hypotheses. With a focus on continuous, high-resolution proxies at timescales relevant to both biological and cultural evolution, the HSPDP aims to dramatically expand our understanding of the environmental history of eastern Africa during a significant portion of the Late Neogene and Quaternary, and to generate useful models of long-term environmental dynamics in the region.
• Crouvi, O., Polyakov, V. O., Pelletier, J. D., & Rasmussen, C. (2015). Decadal-scale soil redistribution along hillslopes in the Mojave Desert. Earth Surface Dynamics, 3(2), 251--264.
• Crouvi, O., Polyakov, V., Pelletier, J., & Rasmussen, C. (2015). Decadal-scale soil redistribution along hillslopes in the Mojave Desert. Earth Surface Dynamics, 3, 251.
• Engelder, T. M., & Pelletier, J. D. (2015). Simulating foreland basin response to mountain belt kinematics and climate change in the Eastern Cordillera and Subandes: An analysis of the Chaco foreland basin in southern Bolivia. Geodynamics of a Cordilleran Orogenic System: the Central Andes of Argentina and Northern Chile. Geological Society of America, Boulder, 337--357.
• Field, J. P., Breshears, D. D., Law, D. J., Lopez Hoffman, L. -., Brooks, P. D., Chorover, J., Barron-Gafford, G. A., Gallery, R. E., Litvak, M. E., Lybrand, R., Mcintosh, J. C., Meixner, T. -., Niu, Y. -., Papuga, S. A., Pelletier, J. D., Rasmussen, C. -., & Troch, P. A. (2015). Critical zone services: Expanding context, constraints, and curency beyond ecosystem services.. Vadose Zone Journal, 1-7.
• Field, J. P., Breshears, D. D., Law, D. J., Villegas, J. C., L\'opez-Hoffman, L., Brooks, P. D., Chorover, J., Barron-Gafford, G. A., Gallery, R. E., Litvak, M. E., & others, . (2015). Critical zone services: Expanding context, constraints, and currency beyond ecosystem services. Vadose Zone Journal, 14(1), 1--7.
• Harpold, A. A., Marshall, J. A., Lyon, S. W., Barnhart, T. B., Fisher, B. A., Donovan, M., Brubaker, K. M., Crosby, C. J., Glenn, N. F., Glennie, C. L., & others, . (2015). Laser vision: lidar as a transformative tool to advance critical zone science. Hydrology and Earth System Sciences, 19(6), 2881--2897.
• Harpold, A., Marshall, J., Lyon, S., Barnhart, T., Fisher, B., Donovan, M., Brubaker, K., Crosby, C., Glenn, N., Glennie, C., & others, . (2015). Laser vision: lidar as a transformative tool to advance critical zone science. Hydrology and Earth System Sciences Discussions, 12(1), 1017--1058.
• Hayakawa, Y. S., Oguchi, T., Saito, H., Kobayashi, A., Baker, V. R., Pelletier, J. D., McGuire, L. A., Komatsu, G., & Goto, K. (2015). Geomorphic imprints of repeated tsunami waves in a coastal valley in northeastern Japan. Geomorphology, 242, 3--10.
• Hazenberg, P., Fang, Y., Broxton, P., Gochis, D., Niu, G., Pelletier, J. D., Troch, P. A., & Zeng, X. (2015). A hybrid-3D hillslope hydrological model for use in E arth system models. Water Resources Research, 51(10), 8218--8239.
• Hazenberg, P., Fang, Y., Broxton, P., Gochis, D., Niu, G., Pelletier, J., Troch, P., & Zeng, X. (2015). A hybrid-3D hillslope hydrological model for use in Earth system models. Water Resources Research, 51, 8218--8239.
• Kapp, P., Kapp, P., Pullen, A., Pullen, A., Pelletier, J. D., Pelletier, J. D., Russell, J., Russell, J., Goodman, P., Goodman, P., Cai, F., & Cai, F. (2015). From dust to dust: Quaternary wind erosion of the Mu Us Desert and Loess Plateau, China. Geology, 43, 835--838.
• McGuire, L. A., & Pelletier, J. D. (2015). Controls on valley spacing in landscapes subject to rapid base-level fall. Earth Surface Processes and Landforms.
• Orem, C. A., & Pelletier, J. D. (2015). Quantifying the time scale of elevated geomorphic response following wildfires using multi-temporal LiDAR data: An example from the Las Conchas fire, Jemez Mountains, New Mexico. Geomorphology, 232, 224--238.
• Orem, C., Orem, C. A., Pelletier, J., & Pelletier, J. D. (2015). Constraining frequency-magnitude-area relationships for precipitation and flood discharges using radar-derived precipitation estimates: example applications in the Upper and Lower Colorado River Basins, USA.. Hydrology \& Earth System Sciences Discussions, 12.
• Pangle, L. A., DeLong, S. B., Abramson, N., Adams, J., Barron-Gafford, G. A., Breshears, D. D., Brooks, P. D., Chorover, J., Dietrich, W. E., Dontsova, K., & others, . (2015). The Landscape Evolution Observatory: A large-scale controllable infrastructure to study coupled Earth-surface processes. Geomorphology, 244, 190--203.
• Pangle, L. A., DeLong, S. B., Abramson, N., Adams, J., Barron-Gafford, G., Breshears, D. D., Brooks, P., Chorover, J., Dietrich, W. E., Dontsova, K., & others, . (2015). The Landscape Evolution Observatory: A large-scale controllable infrastructure to study coupled Earth-surface processes. Geomorphology.
• Pelletier, J. D. (2015). Controls on the large-scale spatial variations of dune field properties in the barchanoid portion of White Sands dune field, New Mexico. Journal of Geophysical Research: Earth Surface, 120(3), 453--473.
• Pelletier, J. D. (2015). Controls on the large-scale spatial variations of dune-field properties in the barchanoid portion of White Sands dune field, New Mexico. Journal of Geophysical Research: Earth Surface.
• Pelletier, J. D. (2015). Quantifying topographic and vegetation effects on the transfer of energy and mass to the critical zone. Vadose Zone Journal.
• Pelletier, J. D., Broxton, P. D., Hazenberg, P., Zeng, X., Troch, P. A., Niu, G., Williams, Z., Brunke, M. A., & Gochis, D. (2015). A gridded global data set of soil, immobile regolith, and sedimentary deposit thicknesses for regional and global land surface modeling. Journal of Advances in Modeling Earth Systems.
• Pelletier, J. D., Pelletier, J. D., Brad Murray, A., Brad Murray, A., Pierce, J. L., Pierce, J. L., Bierman, P. R., Bierman, P. R., Breshears, D. D., Breshears, D. D., Crosby, B. T., Crosby, B. T., Ellis, M., Ellis, M., Foufoula-Georgiou, E., Foufoula-Georgiou, E., Heimsath, A. M., Heimsath, A. M., Houser, C., , Houser, C., et al. (2015). Forecasting the response of Earth's surface to future climatic and land use changes: A review of methods and research needs. Earth's Future, 3, 220--251.
• Pelletier, J. D., Pelletier, J. D., Sherman, D. J., Sherman, D. J., Ellis, J. T., Ellis, J. T., Farrell, E. J., Farrell, E. J., Jackson, N. L., Jackson, N. L., Li, B., Li, B., Nordstrom, K. F., Nordstrom, K. F., Maia, L. P., Maia, L. P., Omidyeganeh, M., & Omidyeganeh, M. (2015). Dynamics of sediment storage and release on aeolian dune slip faces: A field study in Jericoacoara, Brazil. Journal of Geophysical Research: Earth Surface, 120, 1911--1934.
• Pelletier, J. D., Pelletier, J. D., Sweeney, K. E., Sweeney, K. E., Roering, J. J., Roering, J. J., Finnegan, N. J., & Finnegan, N. J. (2015). Controls on the geometry of potholes in bedrock channels. Geophysical Research Letters, 42, 797--803.
• Pelletier, J., Pelletier, J. D., Field, J., & Field, J. P. (2015). Predicting the roughness length of turbulent flows over landscapes with multi-scale microtopography. Earth Surface Dynamics Discussions, 3, 1107--1142.
• Rasmussen, C., Pelletier, J. D., Troch, P. A., Swetnam, T. L., & Chorover, J. (2015). Quantifying topographic and vegetation effects on the transfer of energy and mass to the critical zone. Vadose Zone Journal, 14(11), 1--16.
• V\'azquez-Ortega, A., Perdrial, J., Harpold, A., Zapata-R\'\ios, X., Rasmussen, C., McIntosh, J., Schaap, M., Pelletier, J. D., Brooks, P. D., Amistadi, M. K., & others, . (2015). Rare earth elements as reactive tracers of biogeochemical weathering in forested rhyolitic terrain. Chemical Geology, 391, 19--32.
• Williams, Z. C., Williams, Z. C., Pelletier, J. D., & Pelletier, J. D. (2015). Self-affinity and surface-area-dependent fluctuations of lake-level time series. Water Resources Research, 51, 7258--7269.
• Becerra, P., Byrne, S., Mattson, S., Pelletier, J., Herkenhoff, K., & Team, H. (2014). Polar Stratigraphy from HiRISE Stereo Topography. LPI Contributions, 1791, 1183.
• Becerra, P., Byrne, S., Mattson, S., Pelletier, J., Herkenhoff, K., & others, . (2014). Martian Polar Stratigraphy from Stereo Topography. European Planetary Science Congress 2014, EPSC Abstracts, Vol. 9, id. EPSC2014-647, 9, 647.
• Chorover, J. D., Gavaert, A., Tueling, A. J., Uijlenhoet, R., DeLong, S. B., Huxman, T. E., Pangle, L., Brashears, D. D., Pelletier, J. D., Saleska, S. R., Zeng, X., & Troch, P. A. (2014). Hillslope-scale experiment demonstrates the role of convergence during two-step saturation. Hydrol. Earth Syst. Sci., 18, 1-12.
• Chorover, J. D., Vazquez-Ortega, A., Perdrial, J., Harpold, A., Zapata-Rios, X., McIntosh, J., Rasmussen, C., Schaap, M. G., Pelletier, J. D., Brooks, P. D., & Amistadi, M. K. (2014). Rare earth elements as reactive tracers of biogeochemical weathering in forested rhyolitic terrain. Chem. Geol., 391, 19-32.
• Crouvi, O., Polyakov, V., Pelletier, J., & Rasmussen, C. (2014). Controls on slope-wash erosion rates in the Mojave Desert. Earth Surface Dynamics Discussions, 2(1), 535--574.
• Engelder, T. M., & Pelletier, J. D. (2014). Simulating foreland basin response to mountain belt kinematics and climate change in the Eastern Cordillera and Subandes: An analysis of the Chaco foreland basin in southern Bolivia. Geological Society of America Memoirs, 212, MWR212--17.
• Field, J. P., Breshears, D. D., Law, D. J., Villegas, J. C., L\'opez-Hoffman, L., Brooks, P. D., Chorover, J., Barron-Gafford, G. A., Gallery, R. E., Litvak, M. E., & others, . (2014). Critical Zone Services: Expanding Context, Constraints, and Currency beyond Ecosystem Services. Vadose Zone Journal.
• Gevaert, A. I., Teuling, A. J., Uijlenhoet, R., DeLong, S. B., Huxman, T. E., Pangle, L. A., Breshears, D. D., Chorover, J., Pelletier, J. D., Saleska SR, ., & others, . (2014). Hillslope-scale experiment demonstrates the role of convergence during two-step saturation. Hydrology and Earth System Sciences, 18(9), 3681--3692.
• Hazenberg, P., Broxton, P., Gochis, D., Niu, G., Pelletier, J., Troch, P., & Zeng, X. (2014). An effective hyper-resolution pseudo-3D implementation of small scale hydrological features to improve regional and global climate studies.
• KAPP, P., PULLEN, A., PELLETIER, J. D., RUSSELL, J., & CAI, F. (2014). FROM DUST TO DUST: QUATERNARY WIND EROSION OF THE MU US DESERT AND LOESS PLATEAU, CHINA. 2014 GSA Annual Meeting in Vancouver, British Columbia.
• McGuire, L. A., Pelletier, J. D., & Roering, J. J. (2014). Development of topographic asymmetry: Insights from dated cinder cones in the western United States. Journal of Geophysical Research: Earth Surface, 119(8), 1725--1750.
• Niu, G., Pasetto, D., Scudeler, C., Paniconi, C., Putti, M., Troch, P. A., DeLong, S. B., Dontsova, K., Pangle, L., Breshears, D. D., Chorover, J., Huxman, T. E., Pelletier, J., Saleska, S. R., & Zeng, X. (2014). Incipient subsurface heterogeneity and its effect on overland flow generation – insight from a modeling study of the first experiment at the Biosphere 2 Landscape Evolution Observatory. Hydrology and Earth System Sciences.
• Niu, G., Pasetto, D., Scudeler, C., Paniconi, C., Putti, M., Troch, P., DeLong, S., Dontsova, K., Pangle, L., Breshears, D., & others, . (2014). Incipient subsurface heterogeneity and its effect on overland flow generation--insight from a modeling study of the first experiment at the Biosphere 2 Landscape Evolution Observatory. Hydrology and Earth System Sciences, 18(5), 1873--1883.
• Niu, G., Troch, P. A., Paniconi, C., Scott, R. L., Durcik, M., Zeng, X., Huxman, T., Goodrich, D., & Pelletier, J. (2014). An integrated modelling framework of catchment-scale ecohydrological processes: 2. The role of water subsidy by overland flow on vegetation dynamics in a semi-arid catchment. Ecohydrology, 7(2), 815--827.
• Pelletier, J. (2014). The linkages among hillslope-vegetation changes, elevation, and the timing of late-Quaternary fluvial-system aggradation in the Mojave Desert revisited. Earth Surface Dynamics, 2(2), 455--468.
• Pelletier, J. D., & Jerolmack, D. J. (2014). Multiscale bed form interactions and their implications for the abruptness and stability of the downwind dune field margin at White Sands, New Mexico, USA. Journal of Geophysical Research: Earth Surface, 119(11), 2396--2411.
• Pelletier, J. D., & Orem, C. A. (2014). How do sediment yields from post-wildfire debris-laden flows depend on terrain slope, soil burn severity class, and drainage basin area? Insights from airborne-LiDAR change detection. Earth Surface Processes and Landforms, 39(13), 1822--1832.
• Pelletier, J. D., Brad Murray, A., & Pierce, J. L. (2014). Assessing Ability to Forecast Geomorphic System Responses to Climate and Land-Use Changes. Eos, Transactions American Geophysical Union, 95(1), 3--3.
• Pelletier, J. D., Sweeney, K. E., Roering, J. J., & Finnegan, N. J. (2014). Controls on the geometry of potholes in bedrock channels. Geophysical Research Letters.
• Crouvi, O., Pelletier, J. D., & Rasmussen, C. (2013). Predicting the thickness and aeolian fraction of soils in upland watersheds of the Mojave Desert. Geoderma, 195, 94--110.
• Crouvi, O., Pelletier, J. D., & Rasmussen, C. (2013). Predicting the thickness and aeolian fraction of soils in upland watersheds of the Mojave Desert. Geoderma, 195-196, 94-110.
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  Abstract: Soil thickness and soil texture, and their spatial variability at hillslope scales, are important inputs for hydrologic models. Recent studies have demonstrated that mechanistic models can accurately predict the spatial distribution of soil thickness in areas where soil thickness varies gradually along hillslope profiles. To date, however, these models have not been tested in arid regions, where soils are often thin and highly variable at small scales (i.e., 1-10. m) and where the influence of aeolian accretion on soil thickness and soil texture may be significant. In addition, most of the data available for the fraction of the soil derived from aeolian deposition (which can serve as a proxy for soil texture) originate from soils developed on stable depositional landforms; data for aeolian fractions from upland soils are scarce. In this study, we developed and tested a numerical model for the prediction of thickness and aeolian fraction of soils in arid upland areas. The model assumes a long-term balance between the rates of soil production from bedrock, aeolian accretion, and soil erosion. Rates of soil production are quantified in the model using the exponential and humped soil production functions, and soil erosion rates are quantified using the nonlinear depth- and slope-dependent transport functions, assuming that only the upper soil horizons (A. +. B) are capable of transport. The rate of aeolian deposition is assumed to be spatially uniform. We calibrated the three free parameters of the model at a site in the Mojave Desert with a granite lithology using a combination of 1) field-measured data for soil thickness and 2) estimation of the aeolian fraction in the soil using laboratory analysis of immobile element concentrations. We validated the model results in three nearby sites using a combination of measured soil thickness in soil pits and the presence/absence of soil, and laboratory analysis of the aeolian fraction of soil. The study area is characterized by generally thin soils (
• Engelder, T. M., & Pelletier, J. D. (2013). Autogenic cycles of channelized fluvial and sheet flow and their potential role in driving long-runout gravel progradation in sedimentary basins. Lithosphere, 5(4), 343--354.
• Fenton, C. R., & Pelletier, J. D. (2013). Cosmogenic 3He age estimates of Plio-Pleistocene alluvial-fan surfaces in the Lower Colorado River Corridor, Arizona, USA. Quaternary Research, 79(1), 86--99.
• Fenton, C. R., & Pelletier, J. D. (2013). Cosmogenic ³He age estimates of Plio-Pleistocene alluvial-fan surfaces in the Lower Colorado River Corridor, Arizona, USA. Quaternary Research (United States), 79(1), 86-99.
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  Abstract: Plio-Pleistocene deposits of the Lower Colorado River (LCR) and tributary alluvial fans emanating from the Black Mountains near Golden Shores, Arizona record six cycles of Late Cenozoic aggradation and incision of the LCR and its adjacent alluvial fans. Cosmogenic 3He (3Hec) ages of basalt boulders on fan terraces yield age ranges of: 3.3-2.2Ma, 2.2-1.1Ma, 1.1Ma to 110ka,
• McGuire, L. A., & Pelletier, J. D. (2013). Relationships between debris fan morphology and flow rheology for wet and dry flows on Earth and Mars: A numerical modeling investigation. Geomorphology, 197, 145--155.
• McGuire, L. A., & Pelletier, J. D. (2013). Relationships between debris fan morphology and flow rheology for wet and dry flows on Earth and Mars: A numerical modeling investigation. Geomorphology, 197, 145-155.
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  Abstract: Liquid water may have flowed on the Martian surface in the recent geologic past. Arguments for and against liquid water flows have been made, in part, using interpretations of the morphology of Martian gullies and their associated debris fans. On Earth, sediment transport on steep, debris-flow-dominated hillslopes is often assumed to be a nonlinear function of hillslope gradient. In detail, however, sediment transport on such slopes must also depend on the rheology of the mass movements that drive the majority of transport, both in magnitude and frequency. In this study, we attempt to provide a firmer basis for (1) interpreting flow constituents and/or rheology from debris-fan morphology on Mars and (2) modeling debris-flow-dominated hillslopes on Earth by developing a mass-conservative numerical model that links the rheology of wet and dry granular flows on steep slopes to the morphology of debris fans deposited at their base. Individual flows are routed from initiation points on a slope to stopping points at the base of the hillslope. Model predictions for the shape and average slope of the fans depend on flow rheology. Model results indicate that debris fans associated with dry granular flows may develop average slopes below the kinetic angle of friction. In both the dry and wet cases, the model results suggest that fan morphology depends on the mean properties of the flows involved in fan formation as well as the amount of variation in flow behavior between individual mass movement events. These results provide an improved basis for interpreting the morphology of debris fans on both Earth and Mars. © 2013 Elsevier B.V.
• McGuire, L. A., Pelletier, J. D., G\'omez, J. A., & Nearing, M. A. (2013). Controls on the spacing and geometry of rill networks on hillslopes: Rain splash detachment, initial hillslope roughness, and the competition between fluvial and colluvial transport. Journal of Geophysical Research: Earth Surface, 118(1), 241--256.
• McGuire, L. A., Pelletier, J. D., Gómez, J. A., & Nearing, M. A. (2013). Controls on the spacing and geometry of rill networks on hillslopes: Rain splash detachment, initial hillslope roughness, and the competition between fluvial and colluvial transport. Journal of Geophysical Research F: Earth Surface, 118(1), 241-256.
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  Abstract: [1] Rill networks have been a focus of study for many decades, but we still lack a complete understanding of the variables that control the spacing of rills and the geometry of rill networks (e.g., parallel or dendritic) on hillslopes. In this paper, we investigate the controls on the spacing and geometry of rill networks using numerical modeling and comparison of the model results to terrestrial-laser-scanner-derived topographic data from rill networks formed in physical experiments. The landscape evolution model accounts for the transport of sediment due to rain splash and fluvial entrainment as well as the deposition of sediment being advected by the overland flow. In order to develop realistic rill networks in the model, we find that it is necessary to incorporate the effects of raindrop impact within the fluvial sediment transport process. Model results are only consistent with those of experiments when raindrop-aided fluvial sediment transport is accounted for. Dendritic networks are often predicted by the model in cases of high initial topographic roughness and high rates of advective (fluvial) sediment transport relative to diffusive (colluvial) transport. Parallel networks form within numerical experiments in low-roughness cases under a wide range of relative advective and diffusive transport rates as well as in high roughness cases in which diffusive sediment transport is high relative to advective transport. The transition from dendritic to parallel rill networks is shown to occur gradually rather than being associated with a particular threshold. Finally, based on a balance between diffusive and advective sediment transport processes, we predict that the mean spacing between parallel rills scales with the square root of the ratio of diffusivity to channel erodibility. © 2013. American Geophysical Union. All Rights Reserved.
• Pelletier, J. D. (2013). A robust, two-parameter method for the extraction of drainage networks from high-resolution digital elevation models (DEMs): Evaluation using synthetic and real-world DEMs. Water Resources Research, 49(1), 75--89.
• Pelletier, J. D. (2013). Deviations from self-similarity in barchan form and flux: The case of the Salton Sea dunes, California. Journal of Geophysical Research F: Earth Surface, 118(4), 2406-2420.
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  Abstract: Barchans are the type of aeolian dune associated with a relatively uniform wind direction, incomplete sand coverage of the substrate, and low vegetation cover. Here I present an analysis of the morphology and migration rates of 40 dunes in the Salton Sea dune field using historical aerial orthophotographs, airborne laser swath mapping, terrestrial laser scanning, and measurements of the aerodynamic roughness length derived from wind velocity profiles. The data demonstrate that the Salton Sea dunes deviate from self-similarity such that smaller dunes have a lower ratio of slip face height to crest height and a lower slope, on average, compared with larger dunes and that smaller dunes migrate more slowly than would be predicted based on an inverse relationship between migration rate and dune height. The lack of self-similarity in barchans has been attributed to the dependence of speed-up ratios on dune size and the presence of a finite saturation length in the physics of aeolian transport. Here I argue that deviations from self-similarity at this study site are more likely due to the systematic decrease in aerodynamic roughness length with increasing elevation on stoss slopes. The data set I developed should prove useful to the aeolian geomorphic community for the further testing of models for barchan evolution. Key Points Airborne and terrestrial lidar are used to monitor dune form and migration Barchans deviate from self-similarity as a function of dune size Such deviations may be a result of spatial variations in aerodynamic roughness ©2013. American Geophysical Union. All Rights Reserved.
• Pelletier, J. D., Barron-Gafford, G. A., Breshears, D. D., Brooks, P. D., Chorover, J., Durcik, M., Harman, C. J., Huxman, T. E., Lohse, K. A., Lybrand, R., & others, . (2013). Coevolution of nonlinear trends in vegetation, soils, and topography with elevation and slope aspect: A case study in the sky islands of southern Arizona. Journal of Geophysical Research: Earth Surface, 118(2), 741--758.
• Pelletier, J. D., Barron-Gafford, G. A., Breshears, D. D., Brooks, P. D., Chorover, J., Durcik, M., Harman, C. J., Huxman, T. E., Lohse, K. A., Lybrand, R., Meixner, T., Mcintosh, J. C., Papuga, S. A., Rasmussen, C., Schaap, M. G., Swetnam, T. W., & Troch, P. A. (2013). Coevolution of nonlinear trends in vegetation, soils, and topography with elevation and slope aspect: A case study in the sky islands of southern Arizona. J. Geophys. Res. - Earth Surf., 118, 741-758.
• Pelletier, J. D., Pelletier, J. D., Breshears, D. D., Breshears, D. D., Barron-Gafford, G. A., Barron-Gafford, G. A., Brooks, P. D., Brooks, P. D., Chorover, J. D., Chorover, J., Durick, M., Durick, M., Harman, C. J., Harman, C. J., Huxman, T. E., Huxman, T. E., Lohse, K. A., Lohse, K. A., Lybrand, R., , Lybrand, R., et al. (2013). Coevolution of nonlinear trends in vegetation, soils, and topography with elevation and slope aspect: A case study in the sky islands of southern Arizona. Journal of Geophysical Research - Earth Surface, 118(2), 1-18.
• Pelletier, J. D. (2012). A spatially distributed model for the long-term suspended sediment discharge and delivery ratio of drainage basins. Journal of Geophysical Research F: Earth Surface, 117(2).
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  Abstract: Understanding and quantifying the long-term suspended sediment discharge of drainage basins is a key goal of geomorphology, with important implications for the study of water quality, agricultural sustainability, and the evolution of landscapes and sedimentary basins over geologic timescales. Previous studies have highlighted the importance of relief/slope, precipitation, temperature, vegetation, and soil texture in controlling suspended sediment discharge in natural/undisturbed landscapes. However, globally applicable models currently used to predict suspended sediment discharges are limited because they are based on basin-averaged versions of these properties and do not incorporate all of the controlling variables into a single model. In this paper, I propose a spatially distributed, globally applicable model for the long-term suspended sediment discharge of drainage basins that includes all of the principal controls on suspended sediment discharge previously documented in the geomorphic literature. The model explicitly distinguishes the detachment of sediment on hillslopes and in low-order valleys from the transport of sediment in higher-order alluvial channels. The model uses slope, soil texture, mean monthly rainfall, and mean monthly leaf area index as controlling parameters for the detachment component. The transport component is modeled using a Rouse number-dependent transport criterion that explicitly includes the effects of slope and soil texture. The model is capable of reproducing the long-term sediment yield of 128 global rivers with a Pearson correlation coefficient (R value) of 0.79 using just two free parameters. The model also predicts sediment delivery ratios consistent with those measured in natural drainage basins. Copyright 2012 by the American Geophysical Union.
• Pelletier, J. D. (2012). A spatially distributed model for the long-term suspended sediment discharge and delivery ratio of drainage basins. Journal of Geophysical Research: Earth Surface, 117(F2).
• Pelletier, J. D. (2012). Fluvial and slope-wash erosion of soil-mantled landscapes: detachment-or transport-limited?. Earth Surface Processes and Landforms, 37(1), 37--51.
• Pelletier, J. D., & Perron, J. T. (2012). Analytic solution for the morphology of a soil-mantled valley undergoing steady headward growth: Validation using case studies in southeastern Arizona. Journal of Geophysical Research F: Earth Surface, 117(2).
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  Abstract: The geomorphic literature contains many analytic solutions for the topographic evolution of gently sloping soil-mantled hillslopes responding to base level changes. Most of these solutions are limited to vertical base level changes and/or to simplified geometries, however. In this paper we present an analytic solution for the morphology of a valley and its adjacent hillslopes undergoing steady headward growth. The mathematics of this problem were first solved by Ivantsov (1947) in the context of heat flow near a parabolic solidification boundary. Here we test whether the Ivantsov solution provides an accurate first-order prediction of the morphology of valley heads and their adjacent hillslopes by comparing the model predictions to survey data from two study sites in southeastern Arizona. The model predicts that elevation contours of valley heads are parabolas and that topographic transects normal to contour lines are error functions. High-resolution Digital Elevation Models (DEMs) were constructed for the two study sites using Real-Time Kinematic Global Positioning System (RTK-GPS) measurements and a Terrestrial Laser Scanner (TLS). Our analyses show that the model reproduces the first-order morphology of headward-growing valleys and their adjacent hillslopes. We also show that by analyzing hillslope profiles at different distances from the valley head, the model framework can be used to infer likely changes in the valley head migration rate through time. Copyright 2012 by the American Geophysical Union.
• Pelletier, J. D., & Perron, J. T. (2012). Analytic solution for the morphology of a soil-mantled valley undergoing steady headward growth: Validation using case studies in southeastern Arizona. Journal of Geophysical Research: Earth Surface, 117(F2).
• Pelletier, J. D., DeLong, S. B., Orem, C. A., Becerra, P., Compton, K., Gressett, K., Lyons-Baral, J., McGuire, L. A., Molaro, J. L., & Spinler, J. C. (2012). How do vegetation bands form in dry lands? Insights from numerical modeling and field studies in southern Nevada, USA. Journal of Geophysical Research: Earth Surface, 117(F4).
• Pelletier, J. D., Delong, S. B., Orem, C. A., Becerra, P., Compton, K., Gressett, K., Lyons-Baral, J., McGuire, L. A., Molaro, J. L., & Spinler, J. C. (2012). How do vegetation bands form in dry lands? Insights from numerical modeling and field studies in southern Nevada, USA. Journal of Geophysical Research F: Earth Surface, 117(4).
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  Abstract: Vegetation bands are periodic bands of vegetation, separated by interband spaces devoid of vegetation, oriented parallel to the topographic contour in some gently sloping arid to semiarid environments. Models of vegetation band formation attribute their formation to positive feedbacks among vegetation density, soil porosity/permeability, and infiltration rates. Here we present an alternative model based on field measurements at our study sites in southern Nevada. In this model, interband spaces between vegetation bands form because topographic mounds beneath vegetation bands detain water upslope from vegetation bands, leading to hydrologic and sedimentologic conditions that inhibit the survival of plants in interband spaces. We used terrestrial laser scanning (TLS) to create high-resolution (∼10 cm2/pixel) raster data sets of bare-earth topography and canopy height for four study sites. Analyses of the TLS data, in addition to measurements of soil shear strength and particle size, document the potential for detention in interband spaces and a near-inverse proportionality between band spacing and regional slope. We describe a cellular automaton model (herein called model 1) for vegetation band formation that includes just two user-defined parameters and that generates vegetation bands similar to those at our field sites, including the inverse proportionality between spacing and regional slope. A second model (model 2) accurately predicts the width of vegetation bands in terms of the number and spacing of plants and the geometry of individual plant mounds. We also present a GIS-based analysis that predicts where bands occur within a region based on topographic and hydroclimatic controls. © 2012. American Geophysical Union. All Rights Reserved.
• Chorover, J., Troch, P. A., Rasmussen, C., Brooks, P. D., Pelletier, J. D., Breshears, D. D., Huxman, T. E., Kurc, S. A., Lohse, K. A., McIntosh, J. C., & others, . (2011). How water, carbon, and energy drive critical zone evolution: The Jemez--Santa Catalina Critical Zone Observatory. Vadose Zone Journal, 10(3), 884--899.
• Chorover, J., Troch, P. A., Rasmussen, C., Brooks, P. D., Pelletier, J. D., Breshears, D. D., Huxman, T. E., Kurc, S. A., Lohse, K., Mcintosh, J. C., Meixner, T., Schaap, M. G., Litvak, M., Perdrial, J., Harpold, A., Durcik, M., Chorover, J., Troch, P. A., Rasmussen, C., , Brooks, P. D., et al. (2011). How water, carbon, and energy drive critical zone evolution: the Jemez-Santa Catalina Critical Zone Observatory. Vadose Zone Journal, 10, 884-899.
• DeLong, S. B., Pelletier, J. D., & Arnold, L. J. (2011). Late Holocene alluvial history of the Cuyama River, California, USA. Bulletin, 123(11-12), 2160--2176.
• DeLong, S. B., Pelletier, J. D., & Arnold, L. J. (2011). Late holocene alluvial history of the Cuyama River, California, USA. Bulletin of the Geological Society of America, 123(11-12), 2160-2176.
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  Abstract: Dryland river deposits are archives of past changes in fluvial-system form and process. Chronostratigraphic reconstruction of the late Holocene alluvial history of the Cuyama River in west-central California reveals past spatial and temporal variation in dryland channel form and process. The modern Cuyama River consists of a wide braided reach in the upper drainage basin, a narrower arroyo reach in the middle of the drainage basin, and a bedrock canyon reach in the lower drainage basin that drains to the Santa Maria coastal plain. Along the arroyo reach, late Holocene stratigraphy is well exposed and is the focus of this study. Between ca. 1700 and 350 yr B.P., two widespread deposits of tabular-bedded clay, silt, and fine sand were deposited, separated by a buried soil formed between 950 and 700 yr B.P. Channel incision occurred between 550 and 350 yr B.P. Next, deposition of massive to bedded sands occurred in a pattern alternating between poorly confined deposition on top of older deposits onto the broad valley floor, and channelized deposition along the valley axis inset into older deposits. The superposed deposits now underlie the main valley terrace, and the valley-axis deposits are preserved as inset fill terraces. Historical arroyo cutting then formed a 65-km-long arroyo ca. 150 yr B.P. Based on correlation to regional paleoclimate records, channel aggradation occurred during periods of relative aridity and low peak discharge events, while wet periods, possibly floods after drought, led to fluvial incision. These cycles are superimposed on a transition from a wide, silt- and fine-sand- dominated fluvial system to a modern, narrow, sand- and gravel-dominated arroyo channel. The relationship between times of fluvial process change and climate change in Cuyama Valley bears considerable similarity to other well-studied dryland rivers in the southwestern United States; however, the complex sedimentology and geometry of preserved fluvial deposits suggest that a wider range of fluvial modes occurred along the Cuyama River than has been reported in simpler cut-and-fill-dominated channels elsewhere. These spatial and sedimentological complexities underscore the need to link fluvial deposits and their bounding unconformities along a channel in order to fully understand the spatial and temporal evolution of ancient fluvial systems. © 2011 Geological Society of America.
• Kapp, P., Pelletier, J. D., Rohrmann, A., Heermance, R., Russell, J., Ding, L., & others, . (2011). Wind erosion in the Qaidam basin, central Asia: implications for tectonics, paleoclimate, and the source of the Loess Plateau. GsA Today, 21(4/5), 4--10.
• Pelletier, J. D., & Baker, V. R. (2011). The role of weathering in the formation of bedrock valleys on Earth and Mars: A numerical modeling investigation. Journal of Geophysical Research: Planets, 116(E11).
• Pelletier, J. D., McGuire, L. A., Ash, J. L., Engelder, T. M., Hill, L. E., Leroy, K. W., Orem, C. A., Rosenthal, W. S., Trees, M. A., Rasmussen, C., & Chorover, J. (2011). Calibration and testing of upland hillslope evolution models in a dated landscape: Banco Bonito, New Mexico. Journal of Geophysical Research F: Earth Surface, 116(4).
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  Abstract: In this study we tested upland hillslope evolution models and constrained the rates of regolith production, colluvial transport, and eolian deposition over geologic time scales in a dated volcanic landscape in northern New Mexico using field measurements of regolith thickness; geochemical analyses of regolith, bedrock, and regional dust; numerical modeling of regolith production and transport; and quantitative analyses of airborne light detection and ranging (lidar) digital elevation models (DEMs). Within this volcanic landscape, many topographically closed basins exist as a result of compressional folding and explosion pitting during eruption. The landscape has evolved from an initial state of no regolith cover at 40 5 ka to its modern state, which has highly weathered regolith ranging from 0 to 3+ m, with local thickness values controlled primarily by topographic position. Our models constrain the maximum rate of regolith production in the study area to be in the range of 0.02 to 0.12 m kyr-1 and the rate of colluvial transport per unit slope gradient to be in the range of 0.2 to 2.7 m2 kyr-1, with higher values in areas with more aboveground biomass. We conclude that a depth-dependent colluvial transport model better predicts the observed spatial distribution of regolith thickness compared to a model that has no depth dependence. This study adds to the database of estimates for rates of regolith production and transport in the western United States and shows how dated landscapes can be used to improve our understanding of the coevolution of landscapes and regolith cover. Copyright 2011 by the American Geophysical Union.
• Pelletier, J. D., McGuire, L. A., Ash, J. L., Engelder, T. M., Hill, L. E., Leroy, K. W., Orem, C. A., Rosenthal, W. S., Trees, M. A., Rasmussen, C., & others, . (2011). Calibration and testing of upland hillslope evolution models in a dated landscape: Banco Bonito, New Mexico. Journal of Geophysical Research: Earth Surface, 116(F4).
• Pelletier, J. D., Quade, J., Goble, R. J., & Aldenderfer, M. S. (2011). Widespread hillslope gullying on the southeastern Tibetan Plateau: Human or climate-change induced?. Bulletin, 123(9-10), 1926--1938.
• Rasmussen, C., Troch, P. A., Chorover, J., Brooks, P., Pelletier, J., & Huxman, T. E. (2011). An open system framework for integrating critical zone structure and function. Biogeochemistry, 102(1), 15--29.
• Kolb, K. J., McEwen, A. S., & Pelletier, J. D. (2010). Investigating gully flow emplacement mechanisms using apex slopes. Icarus, 208(1), 132--142.
• Kolb, K. J., Pelletier, J. D., & McEwen, A. S. (2010). Modeling the formation of bright slope deposits associated with gullies in Hale Crater, Mars: Implications for recent liquid water. Icarus, 205(1), 113--137.
• Pelletier, J. D. (2010). How do pediments form?: A numerical modeling investigation with comparison to pediments in southern Arizona, USA. Bulletin of the Geological Society of America, 122(11-12), 1815-1829.
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  Abstract: Pediments are gently sloping, low-relief bedrock erosional surfaces at the bases of mountain ranges. Pediments tend to form more readily in arid climates and in weathering-resistant lithologies, but the processes responsible for pediment formation are still not widely understood after more than a century of debate. In this paper, I investigate the behavior of a coupled numerical model for the evolution of mountain ranges and their adjacent piedmonts that includes bedrock erosion in channels, soil production and erosion on hillslopes, and the flexural-isostatic response of the lithosphere to erosional unloading. For relatively small values of the flexural parameter, erosion of the mountain range leads to sufficient flexural-isostatic tilting of the adjacent piedmont that a suballuvial bedrock bench is exhumed to form an erosional surface on the piedmont. In addition, slope retreat at the mountain front and subsequent tilting of the abandoned surface can contribute to pediment formation by lengthening the pediment in the upslope direction. The rate of erosion on the piedmont must also be greater than or equal to the rate of soil production, thereby creating an erosional surface that has, at most, a thin veneer of soil or regolith. The rate of soil production depends primarily on climate and lithology, with lower soil production rates associated with more arid climates and more resistant lithologies. The model predictions are compared to morphometric analyses of pediments in the southwestern United States and to the detailed morphology of two classic pediments in southern Arizona. © 2010 Geological Society of America.
• Pelletier, J. D. (2010). How do pediments form?: A numerical modeling investigation with comparison to pediments in southern Arizona, USA. Bulletin, 122(11-12), 1815--1829.
• Pelletier, J. D. (2010). Minimizing the grid-resolution dependence of flow-routing algorithms for geomorphic applications. Geomorphology, 122(1-2), 91--98.
• Pelletier, J. D. (2010). Numerical modeling of the late Cenozoic geomorphic evolution of Grand Canyon, Arizona. Bulletin of the Geological Society of America, 122(3-4), 595-608.
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  Abstract: The late Cenozoic geomorphic evolution of Grand Canyon has been influenced by three primary tectonic and drainage adjustment events. First, 1 km of relief was produced along the Grand Wash-Wheeler Fault system beginning at 16.5 Ma. Second, the ancestral Colorado River became integrated with the lower Colorado River through Grand Canyon between 5.5 and 6 Ma. Third, the Colorado River was influenced by Plio-Quaternary normal faulting along the Hurricane and Toroweap Faults. Despite the relatively firm constraints available on the timing of these events, the geomorphic evolution of Grand Canyon is still not well constrained. For example, was there a deeply incised gorge in western Grand Canyon before Colorado River integration? How did incision rates vary through time and along the evolving river profile? What is the role of isostatic rebound and Plio-Quaternary faulting on the recent incision history of Grand Canyon? In this paper I describe the results of a process-based numerical modeling study designed to address these questions and to determine the plausibility of different proposed models for the erosional history of Grand Canyon. The numerical model I developed integrates the stream-power model for bedrock channel erosion with cliff retreat and the flexural-isostatic response to erosion. Two end-member paleodrainage and integration scenarios are considered. In the first model, I assume no incision in western Grand Canyon prior to 6 Ma. This model is equivalent to a lake-overtopping scenario for Colorado River integration. In this scenario, the model predicts that Colorado River integration at 6 Ma initiated the formation of a large (700 m) knickpoint that migrated headward at a rate of 100 km/Ma, resulting in rapid incision of western Grand Canyon down to the level of the Redwall Limestone from 6 to 4 Ma and incision of eastern Grand and Marble Canyons from 4 to 2 Ma. Widening of Grand Canyon by cliff retreat triggered flexural-isostatic rebound and renewed river incision of up to 350 m in Plio-Quaternary time according to this model. The model also indicates that Plio-Quaternary normal faulting significantly dampened incision rates in western Grand Canyon relative to eastern Grand Canyon. In the second paleodrainage scenario, I assume that a 13,000 km2 paleodrainage crossed the Grand Wash-Wheeler Fault system at 16.5 Ma. The results of this model scenario indicate that relief production along the Grand Wash-Wheeler Fault system could have initiated the formation of a large (700 m) knickpoint that migrated headward at a rate of 15 km/Ma prior to 6 Ma to form a 150-km-long gorge in western Grand Canyon. Following integration at 6 Ma, the results of this model scenario are broadly similar to those of the first model, i.e., rapid incision through Grand and Marble Canyons from 6 to 2 Ma followed by cliff retreat, isostatic rebound, and fault-controlled incision. The results of the second model scenario illus trate that headward erosion of a proto-Grand Canyon could have been sufficient to capture the ancestral Colorado River east of the Shivwitz Plateau. © 2010 Geological Society of America.
• Pelletier, J. D. (2010). Numerical modeling of the late Cenozoic geomorphic evolution of Grand Canyon, Arizona. Bulletin, 122(3-4), 595--608.
• Pelletier, J. D., Comeau, D., & Kargel, J. (2010). Controls of glacial valley spacing on earth and mars. Geomorphology, 116(1-2), 189-201.
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  Abstract: Low-order alpine glacial valleys on Earth commonly have a characteristic spacing of 1-3 km. Here we develop analytic and numerical solutions of a coupled numerical model for alpine glacial flow and subglacial bedrock erosion to quantitatively determine the controls on glacial valley spacing assuming an initially-undissected landscape, an initially-fluvially-dissected landscape, and an initially-cratered landscape. The characteristic spacing of glacial valleys produced by the model is controlled by a competition between the thickening of ice in incipient glacial valleys, which acts to enhance flow and valley deepening, and viscous/sidewall drag, which acts to limit flow and deepening. The glacial valley spacing that represents the best compromise between these two competing effects is found to be a function of valley slope, the threshold basal shear stress for ice motion, the effective ice viscosity, a bed-friction parameter, and gravity. This model framework provides the preliminary basis for understanding the relative spacing of glacial valleys on Earth and Mars. On Mars, montane glacial valleys have widths and spacings that are approximately 10-20 times larger than those on Earth. Model results suggest that this difference is predominantly a consequence of lower bed slopes and larger temperature-controlled ice viscosities of glacial ice on Mars compared to Earth. © 2009 Elsevier B.V. All rights reserved.
• Pelletier, J. D., Comeau, D., & Kargel, J. (2010). Erratum to "Controls of glacial valley spacing on Earth and Mars" (Geomorphology 116 (2010) 189-201) (DOI:10.1016/j.geomorph.2009.10.018). Geomorphology, 117(1-2), 206-.
• Pelletier, J. D., DeCelles, P. G., & Zandt, G. (2010). Relationships among climate, erosion, topography, and delamination in the Andes: A numerical modeling investigation. Geology, 38(3), 259--262.
• Banks, M. E., Lang, N. P., Kargel, J. S., McEwen, A. S., Baker, V. R., Grant, J. A., Pelletier, J. D., & Strom, R. G. (2009). An analysis of sinuous ridges in the southern Argyre Planitia, Mars using HiRISE and CTX images and MOLA data. Journal of Geophysical Research: Planets, 114(E9).
• Evans, J. P., Pelletier, J. D., & Russo, R. M. (2009). Welcome to Lithosphere. Lithosphere, 1(1), 3-.
• Huxman, T., Troch, P., Chorover, J., Breshears, D. D., Saleska, S., Pelletier, J., & Zeng, X. (2009). The hills are alive: Earth science in a controlled environment. Eos, Transactions American Geophysical Union, 90(14), 120--120.
• Murray, A. B., Lazarus, E., Ashton, A., Baas, A., Coco, G., Coulthard, T., Fonstad, M., Haff, P., McNamara, D., Paola, C., & others, . (2009). Geomorphology, complexity, and the emerging science of the Earth's surface. Geomorphology, 103(3), 496--505.
• Murray, A. B., Lazarus, E., Ashton, A., Baas, A., Coco, G., Coulthard, T., Fonstad, M., Haff, P., McNamara, D., Paola, C., Pelletier, J., & Reinhardt, L. (2009). Geomorphology, complexity, and the emerging science of the Earth's surface. Geomorphology, 103(3), 496-505.
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  Abstract: The following is a white paper (adapted here for print) for the U.S. National Research Council's committee on Challenges and Opportunities in Earth Surface Processes, drafted at a National Science Foundation sponsored workshop associated with the 38th Binghamton Geomorphology Symposium, "Complexity in Geomorphology," held at Duke University in October 2007. © 2008 Elsevier B.V. All rights reserved.
• Pelletier, J. D. (2009). Controls on the height and spacing of eolian ripples and transverse dunes: A numerical modeling investigation. Geomorphology, 105(3-4), 322--333.
• Pelletier, J. D. (2009). The impact of snowmelt on the late Cenozoic landscape of the southern Rocky Mountains, USA. GSA Today, 19(7), 4-11.
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  Abstract: The intramontane basins of the southern Rocky Mountains, USA, have undergone up to 1.5 km of erosion from the middle Miocene to the present. Here I explore the hypothesis that this erosion could have been caused primarily by an increase in the intensity of snowmelt flooding. In the middle Miocene, snow-melt runoff was limited to the highest elevations (>3 km) and hence impacted only a small fraction of the regional landscape. As the global climate system cooled during the late Miocene and Plio-Quaternary periods, the fraction of total river discharge derived from snowmelt increased significantly in areas between 1.5 and 3 km elevation, thereby increasing the magnitude of flooding during periods of snowmelt and the resulting bedload sediment flux and erosion of rivers in that elevation range. In this paper, the fraction of modern discharge derived from snowmelt is used, together with an assumed lapse rate, to map the change in snowmelt discharge and sediment flux through time from the middle Miocene to the Quaternary in the southern Rocky Mountain region. These data are then used as input to a landscape evolution model that maps the spatial distribution of late Cenozoic snowmelt-driven erosion in the region. The model predicts a spatial distribution of erosion that broadly matches the actual distribution determined from geographic information system (GIS) analyses and dated basin-fill remnants. In the model, a factor-of-four increase in sediment flux within the 1.5-3 km elevation range, well within reasonable estimates, is capable of producing the observed magnitude of late Cenozoic erosion in the region. The longitudinal profiles of major rivers sourced from the southern Rocky Mountains are also modeled through time in order to better understand the downstream response to intramontane basin erosion. Model results indicate that erosion would have triggered widespread deposition downstream from those basins, which is broadly consistent with the magnitude, timing, and spatial distribution of the Ogallala Formation. The results of this study suggest that snowmelt-driven erosion may be an important component of late Cenozoic landscape evolution in mid- to high-elevation regions worldwide.
• Pelletier, J. D. (2009). The impact of snowmelt on the late Cenozoic landscape of the southern Rocky Mountains, USA. GSA today, 19(7), 4--11.
• Pelletier, J. D., & Rasmussen, C. (2009). Geomorphically based predictive mapping of soil thickness in upland watersheds. Water Resources Research, 45(9).
• Pelletier, J. D., & Rasmussen, C. (2009). Quantifying the climatic and tectonic controls on hillslope steepness and erosion rate. Lithosphere, 1(2), 73--80.
• Pelletier, J. D., & Rasmussen, C. (2009). Quantifying the climatic and tectonic controls on hillslope steepness and erosion rate. Lithosphere, 1(2), 73-80.
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  Abstract: Hillslopes in humid regions are typically convex to concave in profile and have a relatively thick, continuous regolith cover. Conversely, hillslopes in arid regions are typically cliff-dominated and have a relatively thin, discontinuous regolith cover. The difference between these two end-member slope forms is classically attributed to climate, but climate, tectonics, and lithology all play a role. In this paper, we describe a mathematical model for hillslope gradient and regolith thickness using basic climatic and tectonic input data for a given rock type. The model first solves for the regolith thickness on a planar slope segment in topographic steady state using the soil production function and a prescribed uplift/incision rate. The climatic and lithologic controls on soil production rates are quantified using an empirical energy-based model for the physical weathering of bedrock. The slope gradient is then computed by balancing uplift/incision rates with sediment fluxes calculated using a nonlinear depth- and slope-dependent sediment transport model. The model quantifies the ways in which, as aridity and uplift/incision rates increase, regolith thicknesses decrease and hillslope gradients increase nonlinearly until a threshold condition is reached, beyond which bare, cliff-dominated slopes form. The model can also be used to estimate long-term erosion rates and soil residence times using basic input data for climate and regolith thickness. Model predictions for erosion rates closely match cosmogenically derived erosion rates in granitic landscapes. This approach provides a better quantitative understanding of the climatic and tectonic controls on slope form, and it provides a simple, widely applicable method for estimating long-term erosion rates and the thickness of regolith cover on hillslopes. © 2009 Geological Society of America.
• Pelletier, J. D., Engelder, T., Comeau, D., Hudson, A., Leclerc, M., Youberg, A., & Diniega, S. (2009). Tectonic and structural control of fluvial channel morphology in metamorphic core complexes: The example of the Catalina-Rincon core complex, Arizona. Geosphere, 5(4), 363--384.
• Pelletier, J. D., Leier, A. L., & Steidtmann, J. R. (2009). Wind-driven reorganization of coarse clasts on the surface of Mars. Geology, 37(1), 55-58.
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  Abstract: Coarse (pebble to cobble sized) clasts on the intercrater plains of the Mars Exploration Rover Spirit landing site exhibit a nonrandom (i.e., uniformly spaced) distribution. This pattern has been attributed to the entrainment and redistribution of coarse clasts during extreme wind events. Here we propose an alternative mechanism readily observable in wind tunnels and numerical models at modest wind speeds. In this process, coarse clasts modify the air flow around them, causing erosion of the underlying substrate on the windward side and deposition on the leeward side until a threshold bed-slope condition is reached, after which the clast rolls into the windward trough. Clasts can migrate across an erodible substrate in repeated cycles of trough formation and clast rolling, "attracting" or "repelling" one another through feedbacks between the local clast density, substrate erosion and/or deposition rate, and substrate elevation. The substrate beneath areas of locally high clast densities aggrades, building up a topographic high that can cause clasts to repel one another to form a more uniform distribution of clasts through time. This self-organized process likely plays a significant role in the evolution of mixed grain size eolian surfaces on Earth and Mars. © 2009 The Geological Society of America.
• Pelletier, J. D., Mitasova, H., Harmon, R. S., & Overton, M. (2009). The effects of interdune vegetation changes on eolian dune field evolution: a numerical-modeling case study at Jockey's Ridge, North Carolina, USA. Earth Surface Processes and Landforms, 34(9), 1245--1254.
• Banks, M. E., & Pelletier, J. D. (2008). Forward modeling of ice topography on Mars to infer basal shear stress conditions. Journal of Geophysical Research E: Planets, 113(1).
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  Abstract: Understanding the history of ice caps on Mars could reveal important information about Martian geologic and climatic history. To do this, an ice reconstruction model is needed that operates over complex topography and can be constrained with a limited number of free parameters. In this study we developed a threshold-sliding model for ice cap morphology based on the classic model of Nye later incorporated into the models of Reeh and colleagues. We have updated the Nye-Reeh model with a new numerical algorithm. Although the model was originally developed to model perfectly plastic deformation, it is applicable to any ice body that deforms when a threshold basal shear stress is exceeded. The model requires three inputs: a digital elevation model of bed topography, a "mask" grid that defines the position of the ice terminus, and a function defining the threshold basal shear stress. To test the robustness of the model, the morphology of the Greenland ice sheet is reconstructed using an empirical equation between threshold basal shear stress and ice surface slope. The model is then used to reconstruct the morphology of ice draping impact craters on the margins of the south polar layered deposits using an inferred constant basal shear stress of ∼0.6 bar for the majority of the examples. This inferred basal shear stress value is almost 1/3 of the average basal shear stress calculated for the Greenland ice sheet. What causes this lower basal shear stress value on Mars is unclear but could involve the strain-weakening behavior of ice. Copyright 2008 by the American Geophysical Union.
• Banks, M. E., & Pelletier, J. D. (2008). Forward modeling of ice topography on Mars to infer basal shear stress conditions. Journal of Geophysical Research: Planets, 113(E1).
• Banks, M. E., McEwen, A. S., Kargel, J. S., Baker, V. R., Strom, R. G., Mellon, M. T., Gulick, V. C., Keszthelyi, L., Herkenhoff, K. E., Pelletier, J. D., & others, . (2008). High Resolution Imaging Science Experiment (HiRISE) observations of glacial and periglacial morphologies in the circum-Argyre Planitia highlands, Mars. Journal of Geophysical Research: Planets, 113(E12).
• Blainey, J. B., & Pelletier, J. D. (2008). Infiltration on alluvial fans in arid environments: Influence of fan morphology. Journal of Geophysical Research: Earth Surface, 113(F3).
• Blainey, J. B., & Pelletier, J. D. (2008). Infiltration on alluvial fans in arid environments: Influences of fan morphology. Journal of Geophysical Research F: Earth Surface, 113(3).
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  Abstract: Mountain-front recharge through highly permeable alluvial fans can be an important source of groundwater recharge in arid climates. To better understand the geomorphic factors (e.g., fan slope, fan area, active channel proportion of fan area, sediment permeability, and entrenchment of the active channel) that control flow and infiltration on alluvial fans, we developed a coupled numerical model of steady surface water flow and Green-Ampt-type infiltration. The model was applied to synthetic alluvial fans using random walkers to create connected distributary networks. The purpose of this approach is to predict where and how recharge occurs on fans as a function of fan morphology. Using the numerical model, we examined how the fan shape and the sequence of fan surfaces influenced where infiltration occurred on the fan. We also investigated how fan morphology influenced the partitioning of infiltration between the fan and the valley floor. Finally, we examined how infiltration influenced the spatial distribution of flooding. The greatest amount of infiltration occurred on low gradient fans where water spread laterally with shallower ponded water depths, although the large inundation area often included less permeable sediments outside of the active channel. The ratio of the incision depth to the input flow depth was an important predictor of the amount of infiltration. The greatest amount of infiltration occurred on fans with incision depths slightly smaller than the input flow depth. These results have implications for groundwater resource assessment and for development of monitoring networks on fans in arid environments. Copyright 2008 by the American Geophysical Union.
• DeLong, S. B., Pelletier, J. D., & Arnold, L. J. (2008). Climate change triggered sedimentation and progressive tectonic uplift in a coupled piedmont--axial system: Cuyama Valley, California, USA. Earth Surface Processes and Landforms: The Journal of the British Geomorphological Research Group, 33(7), 1033--1046.
• DeLong, S. B., Pelletier, J. D., & Arnold, L. J. (2008). Climate change triggered sedimentation and progressive tectonic uplift in a coupled piedmont-axial system: Cuyama Valley, California, USA. Earth Surface Processes and Landforms, 33(7), 1033-1046.
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  Abstract: Channels on the north-facing piedmont of the Sierra Madre range in Cuyama Valley, California have alternated between three process regimes during the late Quaternary: (1) vertical incision into piedmont alluvium and older sedimentary deposits; (2) lateral erosion; and (3) sediment accumulation. The state of the piedmont system at a given time has been controlled by upstream sediment flux, regional tectonic uplift and incision of the axial Cuyama River. To better understand the timing and to attempt to interpret causes of past geomorphological processes on the Sierra Madre piedmont, we mapped the surficial geology and dated alluvial deposits using radiocarbon, cosmogenic and optical dating methods. Four primary episodes of sedimentation have occurred since ca. 100 ka, culminating in the most recent period of extensive piedmont sedimentation between 30 and 20 ka. Fill terraces in Cuyama Valley formed by piedmont sediment accumulation followed by vertical incision and lateral erosion are fairly planar and often mantle strath bedrock surfaces. Their vertical spatial arrangement is a record of progressive regional tectonic uplift and concomitant axial Cuyama River channel incision migrating up tributary piedmont channels. Subparallel longitudinal terrace profiles which have a linear age-elevation relationship indicate that multiple episodes of climatically controlled sedimentation overprints ∼1 m kyr-1 of regional uplift affecting the Cuyama River and its tributaries. Sedimentation was probably a result of increased precipitation that caused saturation landsliding in steep catchments. It is possible that increased precipitation during the Last Glacial Maximum was caused by both continental-scale circulation pattern reorganization and increased Pacific storm frequency and intensity caused by 'early warming' of nearby Pacific Ocean surface waters. Older episodes of piedmont sedimentation are difficult to correlate with specific climate regimes, but may correlate with previous periods of increased precipitation. Copyright © 2007 John Wiley & Sons, Ltd.
• Keating, G. N., Pelletier, J. D., Valentine, G. A., & Statham, W. (2008). Evaluating suitability of a tephra dispersal model as part of a risk assessment framework. Journal of Volcanology and Geothermal Research, 177(2), 397-404.
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  Abstract: In volcanic risk assessment it is necessary to determine the appropriate level of sophistication for a given predictive model within the contexts of multiple sources of uncertainty and coupling between models. A component of volcanic risk assessment for the proposed radioactive waste repository at Yucca Mountain (Nevada, USA) involves prediction of dispersal of contaminated tephra during violent Strombolian eruptions and the subsequent transport of that tephra toward a hypothetical individual via surface processes. We test the suitability of a simplified model for volcanic plume transport and fallout tephra deposition (ASHPLUME) coupled to a surface sediment-transport model (FAR) that calculates the redistribution of tephra, and in light of inherent uncertainties in the system. The study focuses on two simplifying assumptions in the ASHPLUME model: 1) constant eruptive column height and 2) constant wind speed and direction during an eruption. Variations in tephra dispersal resulting from unsteady column height and wind conditions produced variations up to a factor of two in the concentration of tephra in sediment transported to the control population. However, the effects of watershed geometry and terrain, which control local remobilization of tephra, overprint sensitivities to eruption parameters. Because the combination of models used here shows limited sensitivity to the actual details of ash fall, a simple fall model suffices to estimate tephra mass delivered to the hypothetical individual.
• Keating, G. N., Pelletier, J. D., Valentine, G. A., & Statham, W. (2008). Evaluating suitability of a tephra dispersal model as part of a risk assessment framework. Journal of volcanology and geothermal research, 177(2), 397--404.
• Moores, J. E., Pelletier, J. D., & Smith, P. H. (2008). Crack propagation by differential insolation on desert surface clasts. Geomorphology, 102(3-4), 472--481.
• Pelletier, J. D. (2008). Glacial erosion and mountain building. Geology, 36(7), 591--592.
• Pelletier, J. D. (2008). Quantitative modeling of earth surface processes. Quantitative Modeling of Earth Surface Processes.
• Pelletier, J. D., DeLong, S. B., Cline, M. L., Harrington, C. D., & Keating, G. N. (2008). Dispersion of channel-sediment contaminants in distributary fluvial systems: Application to fluvial tephra and radionuclide redistribution following a potential volcanic eruption at Yucca Mountain. Geomorphology, 94(1-2), 226--246.
• Pelletier, J. D., Kolb, K. J., McEwen, A. S., & Kirk, R. L. (2008). Recent bright gully deposits on Mars: Wet or dry flow?. Geology, 36(3), 211--214.
• Cook, J. P., & Pelletier, J. D. (2007). Relief threshold for eolian sand transport on alluvial fans. Journal of Geophysical Research F: Earth Surface, 112(2).
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  Abstract: Many arid alluvial-fan terraces downwind from eolian sand sources exhibit an abrupt increase in eolian epipedon thickness and sand content below a critical elevation which varies from fan to fan. Above this elevation, sand accumulates locally and is not transported across the fan. Below this elevation eolian sand from nearby playa and channel sources is readily transported across the distal fan. Here we test the hypothesis that these distal-fan eolian "corridors" are controlled by a threshold fan-surface relief. We propose that when along-strike relief falls below a critical threshold value, an eolian surface of transportation or "corridor" develops. To test this hypothesis, we measured multiple along-strike topographic profiles and eolian epipedon textures on two piedmonts in the Ivanpah Valley and adjacent Hidden Valley in Clark County, Nevada. Both piedmonts are located near sand-dominated playas and exhibit clear evidence of eolian transport across their distal fan regions. The near-surface boundary layer flow above each topographic profile was quantified using the multispectral finite difference (MSFD) numerical model. This model predicts the surface shear stress above complex terrain for any wind condition assuming neutrally stable flow. The minimum shear stress calculated by MSFD for each profile during extreme wind conditions was compared to the shear-velocity threshold necessary to initiate saltation. Model results showed that in proximal fan areas, along-strike relief was large enough to prevent eolian transport of all but fine sand particles. In distal fan profiles within the eolian corridor, model results predict shear stresses everywhere above threshold for both fine and coarse sand. Copyright 2007 by the American Geophysical Union.
• Cook, J. P., & Pelletier, J. D. (2007). Relief threshold for eolian sand transport on alluvial fans. Journal of Geophysical Research: Earth Surface, 112(F2).
• DeLong, S. B., Pelletier, J. D., & Arnold, L. (2007). Bedrock landscape development modeling: Calibration using field study, geochronology, and digital elevation model analysis. Bulletin of the Geological Society of America, 119(1-2), 157-173.
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  Abstract: Stream power-based models of bedrock landscape development are effective at producing synthetic topography with realistic fluvial-network topology and three-dimensional topography, but they are difficult to calibrate. This paper examines ways in which field observations, geochronology, and digital elevation model (DEM) data can be used to calibrate a bedrock landscape development model for a specific study site. We first show how uplift rate, bedrock erodibility, and landslide threshold slope are related to steady-state relief, hypsometry, and drainage density for a wide range of synthetic topographies produced by a stream power-based planform landscape development model. Our results indicate that low uplift rates and high erodibility result in low-relief, high drainage density, fluvially dominated topography, and high uplift rates and low erodibility leads to high-refief, low drainage density, mass wasting-dominated topography. Topography made up of a combination of fluvial channels and threshold slopes occurs for only a relatively narrow range of model parameters. Using measured values for hypsometric integral, drainage density, and relief, quantitative values of bedrock erodibility can be further constrained, particularly if uplift rates are independently known. We applied these techniques to three sedimentary rock units in the western Transverse Ranges in California that have experienced similar climate, uplift, and incision histories. The 10Be surface exposure dating and optically stimulated luminescence (OSL) burial dating data indicated that incision of initially low-relief topography there occurred during the last ∼60 k.y. We estimated the relative dependence of drainage area and channel slope on erosion rate in the stream power law from slope-area data, and inferred values for bedrock erodibility ranging from 0.09 to 0.3 m (0.2-0.4) k.y.-1 for the rock types in this study area. © 2006 Geological Society of America.
• DeLong, S. B., Pelletier, J. D., & Arnold, L. (2007). Bedrock landscape development modeling: Calibration using field study, geochronology, and digital elevation model analysis. GSA Bulletin, 119(1-2), 157--173.
• Pelletier, J. D. (2007). Cantor set model of eolian dust deposits on desert alluvial fan terraces. Geology, 35(5), 439--442.
• Pelletier, J. D. (2007). Erosion-rate determination from foreland basin geometry. Geology, 35(1), 5--8.
• Pelletier, J. D. (2007). Erosion-rate determination from foreland basin geometry. Geology, 35(1), 5-8.
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  Abstract: The geometry of foreland basins is controlled by a dynamic balance between thrust-belt migration, flexural subsidence, and fluvial deposition. To improve our ability to quantify the relationships between tectonics, climate, and foreland basin geometry, I developed analytic solutions for basin topography and stratigraphy using a classic two-dimensional mathematical model of foreland basin evolution. Model predictions for basin topography are successfully tested against observed profiles along a humid-to-arid climatic gradient in the central Andes. Using published estimates for the thrust-belt migration rate, flexural parameter, and thrust-front basin depth in this region, I show that basin topographic proffies can be used to estimate the upstream erosion rate at any point along a foreland basin. Basin-averaged erosion rates estimated in this way vary from 0.025 to 0.045 mm/yr in the central Andes, increasing from semiarid to humid climates. © 2007 Geological Society of America.
• Pelletier, J. D. (2007). Fractal behavior in space and time in a simplified model of fluvial landform evolution. Geomorphology, 91(3-4), 291--301.
• Pelletier, J. D. (2007). Numerical modeling of the Cenozoic geomorphic evolution of the southern Sierra Nevada, California. Earth and Planetary Science Letters, 259(1-2), 85--96.
• Pelletier, J. D., & Cline, M. L. (2007). Nonlinear slope-dependent sediment transport in cinder cone evolution. Geology, 35(12), 1067--1070.
• Pelletier, J. D., Cline, M., & DeLong, S. B. (2007). Desert pavement dynamics: Numerical modeling and field-based calibration. Earth Surface Processes and Landforms, 32(13), 1913-1927.
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  Abstract: Desert pavements are widely used as a relative surface-dating tool because they are progressively better developed on surfaces ranging from thousands to hundreds of thousands of years in age. Recent work, however, has highlighted the dynamic nature of pavements and undermined their use as surface-age indicators. Quade (2001) proposed that latest Pleistocene vegetation advances destroyed all Mojave Desert pavements above 400 m elevation, making all such pavements Holocene in age. In an effort to reconcile young-pavement evidence with their widespread use as Pleistocene surface-age indicators, we developed a numerical model based on the classic conceptual model in which pavements co-evolve with their underlying eolian epipedons over millennial timescales. In this co-evolutionary process, fine-grained eolian deposition and Av-horizon development within the eolian epipedon promotes surface clast motion and pavement development, enhancing the eolian-sediment-trapping ability of the pavement in a positive feedback. Model results illustrate the multi-scale nature of pavement dynamics: pavements may require tens of thousands of years to fully develop from a newly abandoned alluvial surface, but may heal over timescales of decades to centuries if a mature eolian epipedon is present. As such, there is no inconsistency between rapid pavement healing and a Pleistocene age for the underlying alluvial surface. To calibrate the model, we conducted surficial geologic mapping and pavement-sedimentological analysis on two desert piedmonts. Our study areas include both proximal and distal fan environments, illustrating the role of parent-material texture in controlling the mode of pavement formation. Using available geochronology, our work provides a rigorous calibration of pavement formation rates in our study areas and provides evidence supporting the use of pavements as local relative surface-age indicators over Holocene to late Pleistocene timescales. Copyright © 2007 John Wiley & Sons, Ltd.
• Pelletier, J. D., Cline, M., & DeLong, S. B. (2007). Desert pavement dynamics: numerical modeling and field-based calibration. Earth Surface Processes and Landforms: The Journal of the British Geomorphological Research Group, 32(13), 1913--1927.
• Barnes, J. B., & Pelletier, J. D. (2006). Latitudinal variation of denudation in the evolution of the Bolivian Andes. American Journal of Science, 306(1), 1--31.
• Barnes, J. B., Ehlers, T. A., McQuarrie, N., O'Sullivan, P. B., & Pelletier, J. D. (2006). Eocene to recent variations in erosion across the central Andean fold-thrust belt, northern Bolivia: Implications for plateau evolution. Earth and Planetary Science Letters, 248(1-2), 118--133.
• Barnes, J. B., Ehlers, T. A., McQuarrie, N., O'Sullivan, P., & Pelletier, J. D. (2006). Eocene to recent variations in erosion across the central Andean fold-thrust belt, northern Bolivia: Implications for plateau evolution. Earth and Planetary Science Letters, 248(1-2), 103-118.
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  Abstract: Quantifying the erosional and kinematic evolution of orogenic plateaus has been limited by insufficient age constraints on their deformation and erosion histories. Palinspastic restorations suggest the central Andean fold-thrust belt and plateau evolved concurrently in Bolivia. We present an analysis that synthesizes 19 new and 32 previous apatite and zircon fission-track and (U-Th)/He mineral cooling ages along a 200 km traverse across the plateau margin and entire thrust belt in northern Bolivia. The new apatite fission-track data are interpreted using a grain-age deconvolution algorithm with inverse thermal modeling of track lengths, grain ages and mineral composition proxy data. Results suggest: (1) Eo-Oligocene (∼ 40-25 Ma) initial rapid erosion of the plateau margin, (2) accelerated, distributed erosion across the entire thrust belt since the early to mid-Miocene (∼ 15 Ma), and (3) the magnitude of erosion decreases eastward from ∼ 10 to 4 km. We compare these results with two end-member models of the central Andes that contrast in duration and magnitude of deformation. The rapid Eo-Oligocene (∼ 40-25 Ma) erosion is only consistent with the end-member that emphasizes the long duration and large magnitude deformation controlled by the sequential stacking of basement thrust sheets. However, the distributed Miocene (∼ 15 Ma) to recent erosion is consistent with both end-members because the recorded cooling could have resulted from active deformation, protracted erosion or both. If the long duration model is correct, the time between the two phases of accelerated cooling brackets the cessation of the first basement thrust sheet and implies the early development of the Andean plateau analogous to its modern width, but unknown elevation by the early Miocene (∼ 20 Ma). © 2006 Elsevier B.V. All rights reserved.
• Pelletier, J. D. (2006). Reply to comment by Kenneth Hinkel on "Formation of oriented thaw lakes by thaw slumping". Journal of Geophysical Research F: Earth Surface, 111(1).
• Pelletier, J. D. (2006). Sensitivity of playa windblown-dust emissions to climatic and anthropogenic change. Journal of Arid Environments, 66(1), 62--75.
• Pelletier, J. D., DeLong, S. B., Al-Suwaidi, A. H., Cline, M., Lewis, Y., Psillas, J. L., & Yanites, B. (2006). Evolution of the Bonneville shoreline scarp in west-central Utah: Comparison of scarp-analysis methods and implications for the diffusion model of hillslope evolution. Geomorphology, 74(1-4), 257--270.
• Kohfeld, K. E., Reynolds, R. L., Pelletier, J. D., & Nickling, B. (2005). Linking the scales of observation, process, and modeling of dust emissions. Eos, 86(11), 113-.
• Leier, A. L., DeCelles, P. G., & Pelletier, J. D. (2005). Mountains, monsoons, and megafans. Geology, 33(4), 289--292.
• Pelletier, J. D. (2005). Formation of oriented thaw lakes by thaw slumping. Journal of Geophysical Research F: Earth Surface, 110(2).
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  Abstract: In the classic model for oriented thaw lakes, sublittoral shelves form by wind-driven circulation near shorelines oriented perpendicular to the wind, protecting the adjacent banks from thaw and wave cut erosion. Here I propose an alternative model based on thaw slumping and test the model predictions against observations in northern Alaska. Thermal modeling illustrates that bank height controls the rate of thaw slumping because summertime thaw penetrates only decimeters into a tall bank but as much as tens of meters into a short bank. This effect also leads to oriented lakes because of a nonlinear relationship between bank height and bank retreat rate. Bank material texture also controls the rate of thaw slumping because fine-grained sediments drain slowly and maintain higher pore pressures than coarse-grained sediments, resulting in lower critical angles for slumping. To test the thaw slumping model quantitatively, I constructed a process-based numerical model that includes thaw slumping, lacustrine sediment dispersal, and thawdriven lake floor subsidence. The model predicts that lake orientations and aspect ratios are controlled by topographic aspect and slope, not by wind direction and intensity. The thaw slumping model further predicts inverse correlations between lake area and bank height and between lake area and bank material texture. An analysis of oriented thaw lakes in northern Alaska shows that systematically smaller, deeper lakes form in coarse-grained eolian sediments compared with those formed in fine-grained fluvial marine sediments. This pattern strongly supports the thaw slumping model. Copyright 2005 by the American Geophysical Union.
• Pelletier, J. D. (2005). Formation of oriented thaw lakes by thaw slumping. Journal of Geophysical Research: Earth Surface, 110(F2).
• Pelletier, J. D., & Cook, J. P. (2005). Deposition of playa windblown dust over geologic time scales. Geology, 33(11), 909--912.
• Pelletier, J. D., Harrington, C. D., Whitney, J. W., Cline, M., DeLong, S. B., Keating, G., & Ebert, K. T. (2005). Geomorphic control of radionuclide diffusion in desert soils. Geophysical research letters, 32(23).
• Pelletier, J. D., Harrington, C. D., Whitney, J. W., Cline, M., DeLong, S. B., Keating, G., & Ebert, T. K. (2005). Geomorphic control of radionuclide diffusion in desert soils. Geophysical Research Letters, 32(23), 1-4.
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  Abstract: Diffusion is a standard model for the vertical migration of radionuclides in soil profiles. Here we show that diffusivity values inferred from fallout 137CS profiles in soils on the Fortymile Wash alluvial fan, Nye County, Nevada, have a strong inverse correlation with the age of the geomorphic surface. This result suggests that radionuclide-bound particles are predominantly transported by infiltration rather than by bulk-mixing processes such as wetting/ drying, freeze/thaw, and bioturbation. Our results provide a preliminary basis for using soil-geomorphic mapping, point-based calibration data, and the diffusion model to predict radionuclide trans desert soils within a pedotransfer-function approach. Copyright 2005 by the American Geophysical Union.
• Pelletier, J. D., Mayer, L., Pearthree, P. A., House, P. K., Demsey, K. A., Klawon, J. E., & Vincent, K. R. (2005). An integrated approach to flood hazard assessment on alluvial fans using numerical modeling, field mapping, and remote sensing. Geological Society of America Bulletin, 117(9-10), 1167--1180.
• Pelletier, J. D., Mayer, L., Pearthree, P. A., House, P. K., Demsey, K. A., Klawon, J. E., Vincent, K. R., Pelletier, J. D., Mayer, L., Pearthree, P. A., House, P. K., Demsey, K. A., Klawon, J. K., & Vincent, K. R. (2005). An integrated approach to flood hazard assessment on alluvial fans using numerical modeling, field mapping, and remote sensing. Bulletin of the Geological Society of America, 117(9-10), 1167-1180.
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  Abstract: Millions of people in the western United States live near the dynamic, distributary channel networks of alluvial fans where flood behavior is complex and poorly constrained. Here we test a new comprehensive approach to alluvial-fan flood hazard assessment that uses four complementary methods: twodimensional raster-based hydraulic modeling, satellite-image change detection, fieldbased mapping of recent flood inundation, and surficial geologic mapping. Each of these methods provides spatial detail lacking in the standard method and each provides critical information for a comprehensive assessment. Our numerical model simultaneously solves the continuity equation and Manning's equation (Chow, 1959) using an implicit numerical method. It provides a robust numerical tool for predicting flood flows using the large, high-resolution Digital Elevation Models (DEMs) necessary to resolve the numerous small channels on the typical alluvial fan. Inundation extents and flow depths of historic floods can be reconstructed with the numerical model and validated against field- and satellite-based flood maps. A probabilistic flood hazard map can also be constructed by modeling multiple flood events with a range of specified discharges. This map can be used in conjunction with a surficial geologic map to further refine floodplain delineation on fans. To test the accuracy of the numerical model, we compared model predictions of flood inundation and flow depths against field- and satellite-based flood maps for two recent extreme events on the southern Tortolita and Harquahala piedmonts in Arizona. Model predictions match the field- and satellite-based maps closely. Probabilistic flood hazard maps based on the 10 yr, 100 yr, and maximum floods were also constructed for the study areas using stream gage records and paleoflood deposits. The resulting maps predict spatially complex flood hazards that strongly reflect small-scale topography and are consistent with surficial geology. In contrast, FEMA Flood Insurance Rate Maps (FIRMs) based on the FAN model predict uniformly high flood risk across the study areas without regard for small-scale topography and surficial geology. © 2005 Geological Society of America.
• Hsu, L., & Pelletier, J. D. (2004). Correlation and dating of Quaternary alluvial-fan surfaces using scarp diffusion. Geomorphology, 60(3-4), 319-335.
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  Abstract: Great interest has recently been focused on dating and interpreting alluvial-fan surfaces. As a complement to the radiometric methods often used for surface-exposure dating, this paper illustrates a rapid method for correlating and dating fan surfaces using the cross-sectional shape of gullies incised into fan surfaces. The method applies a linear hillslope-diffusion model to invert for the diffusivity age, κt (m2), using an elevation profile or gradient (slope) profile. Gullies near the distal end of fan surfaces are assumed to form quickly following fan entrenchment. Scarps adjacent to these gullies provide a measure of age. The method is illustrated on fan surfaces with ages of approximately 10 ka to 1.2 Ma in the arid southwestern United States. Two areas of focus are Death Valley, California, and the Ajo Mountains piedmont, Arizona. Gully-profile morphology is measured in two ways: by photometrically derived gradient (slope) profiles and by ground-surveyed elevation profiles. The κt values determined using ground-surveyed profiles are more consistent than those determined using photo-derived κt values. However, the mean κt values of both methods are comparable. The photometric method provides an efficient way to quantitatively and objectively correlate and relatively-date alluvial-fan surfaces. The κt values for each surface are determined to approximately 30-50% accuracy. © 2003 Elsevier B.V. All rights reserved.
• Pelletier, J. D. (2004). Estimate of three-dimensional flexural-isostatic response to unloading: Rock uplift due to late Cenozoic glacial erosion in the western United States. Geology, 32(2), 161--164.
• Pelletier, J. D. (2004). How do spiral troughs form on Mars?. Geology, 32(4), 365--367.
• Pelletier, J. D. (2004). Persistent drainage migration in a numerical landscape evolution model. Geophysical Research Letters, 31(20), L20501 1-4.
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  Abstract: Numerical landscape evolution models driven by uniform vertical uplift often develop a static drainage network and a precise balance between uplift and erosion. Small-scale physical models of uplifting drainage basins, however, continually reorganize by ridge migration and do not reach an ideal steady state. Here I show that the presence or absence of persistent drainage migration in a bedrock numerical landform evolution model depends on the flow-routing algorithm used to determine upstream contributing area. The model version that uses steepest-descent routing achieves an ideal steady state, while the model version that uses bifurcation routing results in continually-evolving drainage basins, even under conditions of uniform vertical uplift, bedrock erodibility, precipitation, and landsliding threshold. This result suggests that persistent drainage migration can occur by erosional processes alone. This result has important implications for numerical-modeling methodology, our understanding of the natural variability of landform evolution, and the interpretation of thermochronological data. Copyright 2004 by the American Geophysical Union.
• Pelletier, J. D. (2004). Persistent drainage migration in a numerical landscape evolution model. Geophysical Research Letters, 31(20).
• Pelletier, J. D. (2004). The influence of piedmont deposition on the time scale of mountain-belt denudation. Geophysical Research Letters, 31(15), L15502 1-4.
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  Abstract: The linear correlation between modem sediment yields and mean drainage-basin elevation suggests that mountain-belt topography is denuded exponentially with a time scale of approximately 50 Myr following the cessation of active uplift. Some Paleozoic orogens, however, still exist as high-elevation terrain. Here I explore this paradox within the broader question of what variables control the denudational time scales of mountain belts. Using a two-dimensional model that couples the stream-power law for bedrock channel erosion with the diffusion equation for alluvial piedmonts, I determined the time scale of mountain-belt denudation using numerical and analytic techniques. The piedmont plays an important role in mountain-belt denudation because it sets the base level for bedrock erosion, substantially reducing bedrock relief in mountain belts with broad or steep piedmonts. The persistence of the Appalachian and Ural Mountains may be understood within the model framework as largely the result of resistant bedrock and a broad piedmont, respectively. Copyright 2004 by the American Geophysical Union.
• Pelletier, J. D. (2004). The influence of piedmont deposition on the time scale of mountain-belt denudation. Geophysical research letters, 31(15).
• Pelletier, J. D., & DeLong, S. (2004). Oscillations in arid alluvial-channel geometry. Geology, 32(8), 713--716.
• Pelletier, J. D. (2003). Coherence resonance and ice ages. Journal of Geophysical Research: Atmospheres, 108(D20).
• Pelletier, J. D. (2003). Drainage basin evolution in the Rainfall Erosion Facility: dependence on initial conditions. Geomorphology, 53(1-2), 183--196.
• Pelletier, J. D. (2002). Natural variability of atmospheric temperatures and geomagnetic intensity over a wide range of time scales. Proceedings of the National Academy of Sciences of the United States of America, 99(SUPPL. 1), 2546-2553.
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  PMID: 11875208;PMCID: PMC128574;Abstract: The majority of numerical models in climatology and geomagnetism rely on deterministic finite-difference techniques and attempt to include as many empirical constraints on the many processes and boundary conditions applicable to their very complex systems. Despite their sophistication, many of these models are unable to reproduce basic aspects of climatic or geomagnetic dynamics. We show that a simple stochastic model, which treats the flux of heat energy in the atmosphere by convective instabilities with random advection and diffusive mixing, does a remarkable job at matching the observed power spectrum of historical and proxy records for atmospheric temperatures from time scales of one day to one million years (Myr). With this approach distinct changes in the power-spectral form can be associated with characteristic time scales of ocean mixing and radiative damping. Similarly, a simple model of the diffusion of magnetic intensity in Earth's core coupled with amplification and destruction of the local intensity can reproduce the observed 1/f noise behavior of Earth's geomagnetic intensity from time scales of 1 (Myr) to 100 yr. In addition, the statistics of the fluctuations in the polarity reversal rate from time scales of 1 Myr to 100 Myr are consistent with the hypothesis that reversals are the result of variations in 1/f noise geomagnetic intensity above a certain threshold, suggesting that reversals may be associated with internal fluctuations rather than changes in mantle thermal or magnetic boundary conditions.
• Pelletier, J. D. (2002). Natural variability of atmospheric temperatures and geomagnetic intensity over a wide range of time scales. Proceedings of the National Academy of Sciences, 99(suppl 1), 2546--2553.
• Pelletier, J., & Pelletier, J. D. (2002). Natural variability of atmospheric temperatures and geomagnetic intensity over a wide range of time scales. Proceedings of the National Academy of Sciences of the United States of America, 99 Suppl 1.
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  The majority of numerical models in climatology and geomagnetism rely on deterministic finite-difference techniques and attempt to include as many empirical constraints on the many processes and boundary conditions applicable to their very complex systems. Despite their sophistication, many of these models are unable to reproduce basic aspects of climatic or geomagnetic dynamics. We show that a simple stochastic model, which treats the flux of heat energy in the atmosphere by convective instabilities with random advection and diffusive mixing, does a remarkable job at matching the observed power spectrum of historical and proxy records for atmospheric temperatures from time scales of one day to one million years (Myr). With this approach distinct changes in the power-spectral form can be associated with characteristic time scales of ocean mixing and radiative damping. Similarly, a simple model of the diffusion of magnetic intensity in Earth's core coupled with amplification and destruction of the local intensity can reproduce the observed 1/f noise behavior of Earth's geomagnetic intensity from time scales of 1 (Myr) to 100 yr. In addition, the statistics of the fluctuations in the polarity reversal rate from time scales of 1 Myr to 100 Myr are consistent with the hypothesis that reversals are the result of variations in 1/f noise geomagnetic intensity above a certain threshold, suggesting that reversals may be associated with internal fluctuations rather than changes in mantle thermal or magnetic boundary conditions.
• PELLETIER, J. D. (2000). Model assessments of the optimal design of nature reserves for maximizing species longevity. Journal of Theoretical Biology, 202(1), 25--32.
• Pelletier, J. D. (2000). Are large complex ecosystems more unstable? A theoretical reassessment with predator switching. Mathematical Biosciences, 163(1), 91--96.
• Pelletier, J. D. (2000). Model assessments of the optimal design of nature reserves for maximizing species longevity. Journal of Theoretical Biology, 202(1), 25-32.
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  PMID: 10623496;Abstract: Using a computational model for the population growth and dispersal of a model species in a fluctuating environment, we test three nature reserve geometries (one large, many small, and a self-similar distribution of reserve sizes) to determine which geometry maximizes species longevity. The self-similar distribution is a close approximation to the distribution of managed areas in the conterminous United States. We consider models with and without migration from or between reserve fragments and both short- and long-range dispersal mechanisms. The optimal geometry depends on the type of dispersal and on the relative probability of survival in protected and non-protected areas. When no migration is allowed from or between reserve fragments of the three geometries, many small equally sized reserves are the optimal geometry. When migration is allowed, the optimal geometry is a single large reserve when the survivability in non-protected areas is low and a self-similar distribution when the survivability is high. (C) 2000 Academic Press.
• Pelletier, J. D. (2000). Spring-block models of seismicity: Review and analysis of a structurally heterogeneous model coupled to a viscous asthenosphere. GEOPHYSICAL MONOGRAPH-AMERICAN GEOPHYSICAL UNION, 120, 27--42.
• Pelletier, J. D., & Turcotte, D. L. (2000). Shapes of river networks and leaves: Are they statistically similar?. Philosophical Transactions of the Royal Society B: Biological Sciences, 355(1394), 307-311.
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  PMID: 10724463;PMCID: PMC1692726;Abstract: The structure of river networks is compared with the vein structure of leaves. The two structures are visually similar at the smaller scales. The statistics of branching and side branching are nearly identical. The branching structure of diffusion-limited aggregation clusters is also similar and can provide an explanation for the structure of river networks. The origin of the self-similar branching and side branching of the vein structure in leaves is not clear but it appears to be an optimal network in terms of transporting nutrients to all parts of the leaf with the least total resistance.
• Pelletier, J. D., & Turcotte, D. L. (2000). Shapes of river networks and leaves: are they statistically similar?. Philosophical Transactions of the Royal Society of London. Series B: Biological Sciences, 355(1394), 307--311.
• Pelletier, J., & Pelletier, J. D. (2000). Are large complex ecosystems more unstable? A theoretical reassessment with predator switching. Mathematical biosciences, 163(1).
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  Multi-species Lotka-Volterra models exhibit greater instability with an increase in diversity and/or connectance. These model systems, however, lack the likely behavior that a predator will prey more heavily on some species if other prey species decline in relative abundance. We find that stability does not depend on diversity and/or connectance in multi-species Lotka-Volterra models with this 'predator switching'. This conclusion is more consistent with several empirical observations than the classic conclusion, suggesting that large complex ecosystems in nature may be more stable than previously supposed.
• Pelletier, J., & Pelletier, J. D. (2000). Model assessments of the optimal design of nature reserves for maximizing species longevity. Journal of theoretical biology, 202(1).
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  Using a computational model for the population growth and dispersal of a model species in a fluctuating environment, we test three nature reserve geometries (one large, many small, and a self-similar distribution of reserve sizes) to determine which geometry maximizes species longevity. The self-similar distribution is a close approximation to the distribution of managed areas in the conterminous United States. We consider models with and without migration from or between reserve fragments and both short- and long-range dispersal mechanisms. The optimal geometry depends on the type of dispersal and on the relative probability of survival in protected and non-protected areas. When no migration is allowed from or between reserve fragments of the three geometries, many small equally sized reserves are the optimal geometry. When migration is allowed, the optimal geometry is a single large reserve when the survivability in non-protected areas is low and a self-similar distribution when the survivability is high.
• Pelletier, J. D. (1999). Paleointensity variations of Earth's magnetic field and their relationship with polarity reversals. Physics of the Earth and Planetary Interiors, 110(1-2), 115-128.
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  Abstract: Power-spectral analyses of the intensity of Earth's magnetic field inferred from ocean sediment cores and archeomagnetic data from time scales of 100 yr to 10 Myr have been carried out. The power spectrum is proportional to 1/f where f is the frequency. These analyses compliment previous work which has established a 1/f2 spectrum for variations at time scales less than 100 yr. We test the hypothesis that reversals are the result of variations in field intensity with a 1/f spectrum which occasionally are large enough to cross the zero intensity value. Synthetic binormal time series with a 1/f power spectrum representing variations in Earth's dipole moment are constructed. Synthetic reversals from these time series exhibit statistics in good agreement with the reversal record, suggesting that polarity reversals may be the end result of autocyclic intensity variations with a 1/f power spectrum.
• Pelletier, J. D. (1999). Paleointensity variations of Earth's magnetic field and their relationship with polarity reversals. Physics of the earth and planetary interiors, 110(1-2), 115--128.
• Pelletier, J. D. (1999). Self-organization and scaling relationships of evolving river networks. Journal of Geophysical Research: Solid Earth, 104(B4), 7359--7375.
• Pelletier, J. D. (1999). Species-Area Relation and Self-Similarity in a Biogeographical Model of Speciation and Extinction. Physical Review Letters, 82(9), 1983-1986.
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  Abstract: We introduce a generic model for the population growth and dispersal of individuals in species with heterogeneous, fluctuating environments. New species originate with a probability inversely proportional to the abundance of the parent species. The model generates an average number of species which depends on the domain area in agreement with the species-area relation for islands. The model also generates self-similar radiations characterized by a power-law distribution for the number of subtaxa with the same parent taxon and a 1/f power spectrum for the time series of extinctions and originations.
• Pelletier, J. D. (1999). Species-area relation and self-similarity in a biogeographical model of speciation and extinction. Physical Review Letters, 82(9), 1983.
• Pelletier, J. D. (1999). Statistical self-similarity of magmatism and volcanism. Journal of Geophysical Research: Solid Earth, 104(B7), 15425--15438.
• Pelletier, J. D., & Turcotte, D. L. (1999). Application of a Stochastic Deposition and Erosion Model to Reservoir Heterogeneity and Stratigraphic Data.
• Pelletier, J. D., & Turcotte, D. L. (1999). Self-Affine Time Series: II. Applications and Models. Advances in Geophysics, 40(C), 91-166.
• Turcotte, D. L., Pelletier, J. D., & Malamud, B. D. (1999). Preface. Advances in Geophysics, 40(C), ix-xi.
• Pelletier, J. D. (1998). The power spectral density of atmospheric temperature from time scales of 10- 2 to 106 yr. Earth and planetary science letters, 158(3-4), 157--164.
• Pelletier, J. D. (1998). The power spectral density of atmospheric temperature from time scales of 10^-2 to 10⁶ yr. Earth and Planetary Science Letters, 158(3-4), 157-164.
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  Abstract: After removing annual variability, power spectral analyses of local atmospheric temperature from hundreds of stations and ice core records have been carried out from time scales of 10-2 to 106 yr. A clear sequence of power-law behaviors is found as follows: 1) from 40 ka to 1 Ma a flat spectrum is observed; 2) from 2 ka to 40 ka the spectrum is proportional to f-2 where f is the frequency; and 3) below time scales of 2 ka the power spectrum is proportional to f-1/2. At time scales less than 1 month we observe that the power spectra of continental stations become proportional to f-3/2 while maritime stations continue to have power spectra proportional to f-1/2 down to time scales of 1 day. To explain these observations, we model the vertical transport of heat in the atmosphere as a stochastic diffusion process. The power spectrum of temperature fluctuations at the earth's surface expected from this model equation in a two-layer geometry with thermal and eddy diffusion properties appropriate to the atmosphere and the ocean and a radiation condition at the top of the atmosphere agrees with the observed spectrum. The difference in power spectra between continental and marine stations can be understood with this approach as a consequence of the air mass above a maritime station exchanging heat with both the atmosphere above and the ocean below while a continental station exchanges heat mostly with the atmosphere above.
• Turcotte, D. L., Pelletier, J. D., & Newman, W. I. (1998). Networks with side branching in biology. Journal of Theoretical Biology, 193(4), 577--592.
• Pelletier, J. D. (1997). Analysis and modeling of the natural variability of climate. Journal of Climate, 10(6), 1331--1342.
• Pelletier, J. D. (1997). Fractal models in Geology. Ph. D. Thesis, 4109.
• Pelletier, J. D. (1997). Kardar-Parisi-Zhang scaling of the height of the convective boundary layer and fractal structure of cumulus cloud fields. Physical review letters, 78(13), 2672.
• Pelletier, J. D. (1997). Kardar-parisi-zhang scaling of the height of the convective boundary layer and fractal structure of cumulus cloud fields. Physical Review Letters, 78(13), 2672-2675.
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  Abstract: We present the cumulative frequency-area distribution of tropical cumulus clouds as observed from satellite and space shuttle images from scales of 0.1 to 1000 km. The distribution is a power-law function of area with exponent -0.8. We show that this result and the fractal dimension of cloud perimeters implies that the top of the convective boundary layer (CBL) is a self-affine interface with roughness exponent or Hausdorff measure H ≈ 0.4, the same value as that of the Kardar-Parisi-Zhang equation in 2 + 1 dimensions. In addition, we identify dynamic scaling in a time series of the local altitude of the top of the CBL as measured with FM/CW radar backscatter intensity. A possible growth model is discussed.
• Pelletier, J. D., & Turcotte, D. L. (1997). Long-range persistence in climatological and hydrological time series: analysis, modeling and application to drought hazard assessment. Journal of hydrology, 203(1-4), 198--208.
• Pelletier, J. D., & Turcotte, D. L. (1997). Synthetic stratigraphy with a stochastic diffusion model of fluvial sedimentation. Journal of Sedimentary Research, Section B: Stratigraphy and Global Studies, 67(6), 1060-1067.
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  Abstract: Models of stratigraphic completeness and bed formation in fluvial depositional environments have most often assumed that successive depositional and erosional events deposit or erode amounts of sediment independently. This results in a random-walk model for the total amount of deposited sediment locally as a function of time. We consider an extension of the random-walk model of sedimentation in an alluvial plain in which deposition or erosion is concentrated in randomly avulsing channels and sediment transport is modeled by the diffusion equation (Culling's model). In contrast to the random-walk model, this model results in an anticorrelated sequence locally as a function of time, i.e., after an area has aggraded it has a higher elevation and a lower rate of future aggradation. In a previous paper we analyzed the topography generated by the model and argued that porosity variations could be associated with topographic variations. The power spectrum S (the square of the coefficients in a Fourier series) of one-dimensional transects of topography and porosity horizontally and vertically in this model have a power-law dependence on wave number k: S(k) ∝ k-β, with values of β close to those observed. In this paper we show that the model deposits sediment with a rate depending on time interval as a power law with exponent -3/4, more consistent with observations than the random-walk model. The model produces an exponential bed-thickness distribution with a skew dependent on the sedimentation rate of the basin in accordance with observations. We also examine the persistence in the series of bed thicknesses as a function of depth. For the stochastic diffusion model of sedimentation no persistence is observed. If the model fully characterizes the autocyclic dynamics in fluvial sedimentary basins, the lack of persistence in the synthetic bed sequences suggests that observed persistence and cyclicity in real bed-thickness sequences must be the result of allocyclic processes. Copyright © 1997, SEPM (Society for Sedimentary Geology).
• Pelletier, J. D., & Turcotte, D. L. (1997). Synthetic stratigraphy with a stochastic diffusion model of fluvial sedimentation. Journal of Sedimentary Research, 67(6), 1060--1067.
• Pelletier, J. D., Malamud, B. D., Blodgett, T., & Turcotte, D. L. (1997). Scale-invariance of soil moisture variability and its implications for the frequency-size distribution of landslides. Engineering Geology, 48(3-4), 255--268.
• Pelletier, J. D. (1996). Variations in solar luminosity from timescales of minutes to months. Astrophysical Journal Letters, 463(1 PART II), L41-L45.
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  Abstract: We present the power spectrum of solar irradiance during 1985 and 1987, obtained from the active cavity radiometer irradiance monitor project from timescales of minutes to months. At low frequency, the spectra are Lorentzian [proportional to 1/(f2 + f02)]. At higher frequencies, they are proportional to f-1/2. A linear, stochastic model of the turbulent heat transfer between the granulation layer (modeled as a homogeneous thin layer with a radiative boundary condition) and the rest of the convection zone (modeled as a homogeneous thick layer with thermal and diffusion constants appropriate the lower convection zone) explains the observed spectrum. © 1996. The American Astronomical Society. All rights reserved.
• Pelletier, J. D. (1996). Variations in solar luminosity from timescales of minutes to months. The Astrophysical Journal Letters, 463(1), L41.
• Pelletier, J. D., & Turcotte, D. L. (1996). Scale-invariant topography and porosity variations in fluvial sedimentary basins. Journal of Geophysical Research B: Solid Earth, 101(12), 28165-28175.
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  Abstract: We consider a model of a floodplain evolving with channel avulsion, deposition, and erosion. Avulsion is modeled as a random process in space and time. Sediment transport is modeled by the diffusion equation (Culling's model). The power spectrum of variations in the topographic profiles predicted by the model S(k) is proportional to k-2 (where k is the wavenumber). This is the Brown noise often observed in topography. The power spectrum of variations in fhe local elevation in time is proportional to f-3/2 (where f is the frequency). The model prediction of Brown noise floodplain topography is roughly consistent with spectal analyses of microtopography measured with laser altimetry. We inferred Brown noise paleotopography by comparing the pair correlation function of showing wells in the Denver and Powder River basins with a synthetic oil field based on a caprock with Brown noise topography. Topographic control of variations in the grain size of deposited sediment suggests that porosity variations may exhibit the scale invariance predicted for the topographic profile. To illustrate vertical scale invariance in porosity variations, we computed the power spectrum of vertical porosity well logs in 15 offshore wells in the Gulf of Mexico. At spatial scales above 3 m we find an average power spectral exponent of -1.4, close to our model prediction of -1.5.
• Pelletier, J. D., & Turcotte, D. L. (1996). Scale-invariant topography and porosity variations in fluvial sedimentary basins. Journal of Geophysical Research: Solid Earth, 101(B12), 28165--28175.
• Pelletier, J. D., Shapiro, M. H., & Tombrello, T. A. (1992). Molecular dynamics simulations of low-energy cluster deposition on metallic targets. Nuclear Inst. and Methods in Physics Research, B, 67(1-4), 296-300.
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  Abstract: A modified version of the multiple interaction code SPUT2 was used to simulate impacts of 63-atom Al and Au clusters on 7-layer Au targets. For 1, 5, and 10 eV/atom Al and Au clusters, 50 impacts each were calculated up to a cutoff time of 2 ps. For each case studied, we found that the final shape and penetration depth of the incoming cluster was almost independent of the initial cluster position relative to the target. The 1 and 5 eV/atom Al clusters were flattened to less than 40% of their initial thickness and exhibited registration with the substrate at 2 ps. The 10 eV/atom Al clusters formed a poorly registered monolayer on the Au surface. In these higher-energy collisions a significant number of Al atoms were reflected from the Au surface. The 1 eV/atom Au clusters were flattened to approximately 60% of their initial thickness and also exhibited clear registration with the substrate at 2 ps. Higher-energy Au clusters penetrated deeply into the targets, causing substantial damage and crater formation. © 1992.
• Pelletier, J. D., Shapiro, M. H., & Tombrello, T. A. (1992). Molecular dynamics simulations of low-energy cluster deposition on metallic targets. Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 67(1-4), 296--300.

Presentations

• Bryan, M., Alyssa, W., Ben, P., Andres, S., Dawson, F., Mcintosh, J. C., Pelletier, J. D., Gallery, R. E., Rasmussen, C., & Chorover, J. D. (2016, Winter). Coring the deep Critical Zone in the Jemez River Basin Critical Zone. 2016 American Geophysical Union Annual Meeting. San Francisco CA: American Geophysical Union.
• Chorover, J. D., Pelletier, J. D., Breshears, D. D., Mcintosh, J. C., Rasmussen, C., Brooks, P. D., Barron-Gafford, G. A., Gallery, R. E., Ferre, P. A., Meixner, T., Niu, Y., Papuga, S. A., Schaap, M. G., Troch, P. A., Chorover, J. D., Pelletier, J. D., Breshears, D. D., Mcintosh, J. C., Rasmussen, C., , Brooks, P. D., et al. (2014, September). The Catalina-Jemez CZO: Transformative Behavior of Energy, Water and Carbon in the Critical Zone II. Interactions between Long and Short Term Processes that Control Delivery of Critical Zone Services.. National Critical Zone Observatory All-Hands Meeting.

Poster Presentations

• Bryan, M., Alyssa, W., Ben, P., Andres, S., Dawson, F., Mcintosh, J. C., Pelletier, J. D., Gallery, R. E., Rasmussen, C., & Chorover, J. D. (2016, Winter). Coring the deep Critical Zone in the Jemez River Basin Critical Zone. 2016 American Geophysical Union Annual Meeting. San Francisco CA: American Geophysical Union.
• Breshears, D. D., Breshears, D. D., Field, J. P., Field, J. P., Law, D. J., Law, D. J., Brooks, P. D., Brooks, P. D., Chorover, J. D., Chorover, J., Pelletier, J. D., Pelletier, J. D., Troch, P. A., Troch, P. A., Lopez Hoffman, L. -., Lopez Hoffman, L., Rasmussen, C. -., Rasmussen, C., Papuga, S. A., , Papuga, S. A., et al. (2013, October 2013). Bridging from soil to ecosystem goods and services provided by the Critical Zone. AGU Chapman Conference: Soil-mediated drivers of coupled biogeochemical and hydrological processes across scales. Tucson.

Others

• Kohfeld, K. E., Reynolds, R. L., Pelletier, J. D., & Nickling, B. (2005). Linking the scales of observation, process, and modeling of dust emissions.