Photo of Adrian Harpold, Extension

Adrian Harpold

Associate Professor


My interests are in quantifying catchment and basin scale water and solute budgets and the linkages between hydrology, hydrochemistry, geomorphology, and ecology in montane forested systems. Moutain ecosystems are the major water source and carbon sink in western North America and subject to ongoing changes in climate and disturbance.  Improved ecohydrological process understanding has the potential to improve local to global-scale water resource management in the 21st century.

My research program (Nevada Mountain Ecohydrology Lab) utilizes existing observation networks and new field observations to improve the ecohydrological process underpinnings of Earth systems models.  My diverse interests and background has led to investigations of runoff generation mechanisms via hydrological tracers and models, as well as the partitioning of water to its various stores and fluxes.  I am particularly interested in better linking the hydrological sub-disciplines of catchment and snow hydrology to improve our predictions of headwater catchment response to environmental change.


B.S. Virginia Polytechnic Institute, 2003
M.S. Virginia Polytechnic Institute, 2005
Ph.D. Cornell University, 2010


slide mountain from washoe lake

SNOWPACS: Synthesizing kNowledge to Optimize Water Policy for Agriculture under Changing Snowpack

SNOWPACS is a National Institute of Food and Agriculture (NIFA)-funded project on the impact of changes in mountain snowpack on agricultural production and water allocation institutions in the western United States.


NRES 295: Principles of Ecohydrology (Fall every year)

NRES 482/682: Small Watershed Hydrology (Spring every year)


Honors and Awards

  • CABNR Researcher of the Year, 2019
  • Haury Fellowship, University of Arizona, 2019
  • National Science Foundation EAR Postdoctoral Fellowship, 2012 - 2014
  • NSF Graduate Research Fellowship, 2005 - 2009
  • Virginia Conservationist of the Year, Soil and Water Conservation Society (SWCS), 2005
  • Summa cum laude, B.S., 2003


2012 - 2014         INSTAAR, University of Colorado and NCAR                Research Fellow

2010 - 2012         Hydrology and Water Resources Dept., U. of Arizona    Postdoctoral Researcher


  • UNR representative to Tahoe Science Advisory Council, 2019-present

News & Journal Articles, Fact Sheets, Reports...

Curriculum Materials
Exploring the Critical Zone with LiDAR. Harpold, A.A. and T.S. White. 2013, American Geosciences Institute handout for K-12 teachers.
Seeing the Disturbed Forest for the Trees: Remote Sensing Is Underutilized to Quantify Critical Zone Response to Unprecedented Disturbance Hwang, K., Harpold, A. A., Tague, C. L., Lowman, L., S. Boisramé, G. F., Lininger, K. B., Sullivan, P. L., Manning, A., Graup, L., Litvak, M., Lewis, G., Miller, K., Brooks, P. D., & Barnard, H. R. 2023, Earth's Future, 11(8), e2022EF003314
Leveraging Groundwater Dynamics to Improve Predictions of Summer Low-Flow Discharges Johnson, K., Harpold, A., H. Carroll, R. W., Barnard, H., Raleigh, M. S., Segura, C., Li, L., Williams, K. H., Dong, W., & Sullivan, P. L. 2023, Water Resources Research, 59(8), e2023WR035126
Antecedent Snowpack Cold Content Alters the Hydrologic Response to Extreme Rain-on-Snow Events Katz, L., G. Lewis, S. Krogh, S. Drake, E. Hanan, B. Hatchett, and A. Harpold 2023, J. Hydrometeor., 24, 1825–1846
The prediction of uneven snowpack response to forest thinning informs forest restoration in the central Sierra Nevada Lewis, G., Harpold, A., Krogh, S. A., Broxton, P., & Manley, P. N. 2023, Ecohydrology, 16(7), e2580
Machine-Learning Reveals Equifinality in Drivers of Stream DOC Concentration at Continental Scales Underwood, K. L., Rizzo, D. M., Hanley, J. P., Sterle, G., Harpold, A., Adler, T., Li, L., Wen, H., & Perdrial, J. N. 2023, Water Resources Research, 59(3), e2021WR030551
Spruce Beetle Outbreak Increases Streamflow From Snow-Dominated Basins in Southwest Colorado, USA A.L. Manning, A. Harpold, A. Csank 2022, Water Resources Research. 58 (2023) e2021WR029964
Subsurface Lateral Flows Buffer Riparian Water Stress Against Snow Drought L.J. Graup, C.L. Tague, A.A. Harpold, S.A. Krogh 2022, Journal of Geophysical Research: Biogeosciences. 127 (2023) e2022JG006980
Drivers of Dissolved Organic Carbon Mobilization From Forested Headwater Catchments: A Multi Scaled Approach. Adler, T., Underwood, K., Rizzo, D. Harpold, A., Sterle, G., Li, L., Wen, H., Stinson, L., Bristol, C., Shanley, J., Lini, A., Perdrial N., and Perdrial, J. 2021, Frontiers
Drivers and predictions of ice phenology in mountain lakes in the Western United States derived from remote sensing. Caldwell, T.J., S. Chandra, T.P. Albright, A.A. Harpold, T. Dilts, J.A. Greenberg, S. Sadro, and M.D. Dettinger. 2021, Limnology and Oceanography.
Estimating the Effects of Wildfire on Snow Water Resources Using Canopy Disturbance Patterns and Meteorological Conditions. Moeser, D., Broxton, P., Harpold, A., and Robertson, A. 2021, Water Resources Research
Performance Assessment of Optical Satellite-Based Operational Snow Cover Monitoring Algorithms in Forested Landscapes. Muhuri, A., Gascoin, S., Menzel, L., Kostadinov, T., Harpold, A.A., Sanmiguel-Valledo, A., and Lopez-Moreno, I. 2021, IEEE Selected Topics in Applied Earth Observations and Remote Sensing
Unraveling the Controls on Snow Disappearance in Montane Forests Using a Muli-Site Analysis of Lidar Observations Safa, H., Krogh, S., Greenberg, J., and Harpold, A. 2021, Water Resources Research
Streams as mirrors: reading subsurface water chemistry from stream chemistry Stewart, B., Hang Wen, James B. Shanley, James W. Kirchner, David Norris, Thomas Adler, Caitlin Bristol, Adrian Harpold, Julia N. Perdrial, Donna M. Rizzo, Gary Sterle, Kristen, L. Underwood, and Li Li. 2021, Water Resources Research
From hydrometeorology to water quality: can a deep learning model learn the dynamics of dissolved oxygen at the continental scale? Zhi, W., Feng, Dapeng, Tsai, Wen-ping; Sterle, Gary; Harpold, Adrian; Shen, Chaopeng; Li, Li 2021, Environmental Science and Technology
Patterns and drivers of atmospheric river hydrologic impact variability across the Western U.S. Albano, C., Dettinger, M., and Harpold, A.A. 2020, Journal of Hydrometeorology
Snowmelt causes different limitations on transpiration in a Sierra Nevada conifer forest Cooper, A.E., Kirchner, J.W., Wolf, S., Lombardozzi, D.L., Sullivan, B., Tyler, S.W. and A.A. Harpold 2020, Agricultural and Forest Meteorology
Increasing the Efficacy of Forest Thinning for Snow Using High-Resolution Modeling: A Proof of Concept in the Lake Tahoe Basin, California, USA Harpold, A.A., Krogh, S., Kohler, M., Eckberg, D., Greenberg, J., Sterle, G., and Broxton, P.D. 2020, Ecohydrology
Using Process Based Snow Modelling and Lidar to Predict the Effects of Forest Thinning on the Northern Sierra Nevada Snowpack Krogh, S., Broxton, P., Manley, P., and Harpold, A.A. 2020, Frontiers
Temperature controls production but hydrology controls export of dissolved organic carbon at the catchment scale Wen, H., Perdrial, J., Bernal, S., Abbott, B. W., Dupas, R., Godsey, S. E., Harpold, A.A., Rizzo, D., Underwood, K., Adler, T., Hale, R., Sterle, G., and Li, L. 2020, Hydrology and Earth Systems Science
Twenty-three unsolved problems in hydrology (UPH) – a community perspective. Bloschl, G., and 229 co-authors including A.A. Harpold. 2019, Hydrological Sciences Journal
Partitioning snowmelt and rainfall in the critical zone: effects of climate type and soil properties Hammond, J.C., Harpold, A.A., Weiss, S., and Kampf, S.K. 2019, Hydrology and Earth Systems Sciences
Watershed-scale mapping of fractional snow cover under forest canopy using lidar Kostadinov, T.S. R. Schumer, M. Hausner, K. J. Bormann, R. Gaffney, K. McGwire, T. H. Painter, S. Tyler, and A.A. Harpold 2019, Remote Sensing of Environment
Bias correction of airborne thermal infrared observations over forests and melting snow. Pestana, S. Lundquist, J., Chickadel, C. Webster, C., Harpold, A.A., Pai, H., Kostadinov, T., and Tyler, S. 2019, Water Resources Research
Humidity Determines Snowpack Ablation Under a Warming Climate Harpold, A.A. and P.D. Brooks 2018, Proceedings of the National Academy of Sciences
Event-scale suspended sediment age influenced by hydrologic flux in a mixed-land use Mid-Atlantic Watershed Karwan, D.L., J.E. Pizzuto, R. Aalto, J. Marquard, A. Harpold, K. Skalak, A. Benthaem, D.F. Levia, C.M. Siegert, and A. Aufdenkampe. 2018, Water Resources Research
Watershed-scale mapping of fractional snow cover under conifer forest canopy using lidar Kostadinov, T.S. R. Schumer, M. Hausner, K. J. Bormann, R. Gaffney, K. McGwire, T. H. Painter, S. Tyler, and A.A. Harpold. 2018, Remote Sensing of Environment
A net ecosystem carbon budget for snow dominated forested headwater catchments: linking water and carbon fluxes to critical zone carbon storage Perdrial, J., P. Brooks, T. Swetnam, K.A. Lohse, C. Rasmussen, M. Litvak, A.A. Harpold, X. Zapata-Rios, P. Broxton, B. Mitra, T. Meixner, K. Condon, D. Huckle, C. Stielstra, A.Vazquez-O, , M. Holleran, C. Orem, J. Pelletier, and C. Chorover. 2018, Biogeochemistry
The sensitivity of snow ephemerality to warming climate across an arid to montane vegetation gradient Petersky R,, Shoemaker K.T., Weisberg P.J., Harpold A. 2018, Ecohydrology
Potential For Changing Extreme Snowmelt And Rainfall Events in the Mountains of the Western United States Harpold, A.A and M. Kohler 2017, Journal of Geophysical Research: Atmospheres
Defining Snow Drought and Why it Matters Harpold, A.A., M. Dettinger, and S. Rajagopal 2017, EOS, 8
Rain or Snow: Processes, Observations, Prediction, and Research Needs For Hydrologic Sciences. Harpold, A.A., M. Kaplan, Z. Klos, T. Link, J. McNamara, R. Schumer, C. Steele, and S. Rajagopal 2017, Hydrology and Earth System Sciences
Relative humidity has uneven effects on shifts from snow to rain over the western U.S. Harpold, A.A., S. Rajagopal, J. Crews, T. Winchell, and R. Schumer. 2017, Geophysical Research Letters
Geochemical evolution of the Critical Zone across variable time scales informs concentration-discharge relationships: Jemez River Basin Critical Zone Observatory McIntosh, J. C, Schaumberg, C, Perdrial, J, Harpold, A., Vázquez-Ortega, A. and Rasmussen, C. Vinson, D, Zapata-Rios, X. and Brooks, P. D, Meixner, T., Pelletier, Jon, Derry, L., Chorover, J. 2017, Water Resources Research
Topographically-driven differences in energy and water constrain climatic control on forest carbon sequestration Swetnam, T., Brooks, P., Barnard, H., Harpold, A., Gallo, E. 2017, Ecosphere
Regional sensitivities of seasonal snowpack to elevation, aspect, and vegetation cover in western North America. Tennant, C. J., Harpold, A. A., Lohse, K. A., Godsey, S. E., Crosby, B. T., Larsen, L. G., Brooks, P. D., Van Kirk, R. W. and Glenn, N. F. 2017, Water Resources Research
Growing new generations of critical zone scientists Wymore, A. S., West, N. R., Maher, K., Sullivan, P. L., Harpold, A., Karwan, D., Marshall, J. A., Perdrial, J., Rempe, D. M., and Ma, L. 2017, Earth Surface Processes and Landforms
Snowmelt Rate Dictates Streamflow Barnhart, T. N.P. Molotch, B. Livneh, A.A. Harpold, J. Knowles and D. Schneider. 2016, Geophysical Research Letters. doi: 10.1002/2016GL069690
Riparian zones attenuate nitrogen loss following bark beetle-induced lodgepole pine mortality. Biederman, J. A., Meixner, T., Harpold, A. A., Reed, D. E., Gutmann, E. D., Gaun, J. A., & Brooks, P. D. 2016, Journal of Geophysical Research: Biogeosciences.
Diverging Sensitivity of Soil Water Stress To Changing Snowmelt Timing in the Western U.S. Harpold, A.A. 2016, Advances in Water Resources. 92: 116-129. Doi: 10.1016/j.advwatres.2016.03.017
Can Soil Moisture Information Improve Operational Streamflow Forecasts In Snow-Dominated Watersheds? Harpold, A.A., K. Sutcliffe, J. Clayton, A. Goodbody, and S. Vazquez 2016, Journal of American Water Resources Association
Testing and Improving Temperature Thresholds for Snow and Rain Prediction in the Western United States. Rajagopal, S. and A.A. Harpold 2016, Journal of the American Water Resources Association. DOI: 10.1111/1752-1688.12443
Recent tree die-off has little effect on streamflow in contrast to expected increases from historical studies Biederman, J.A., A. Somor, A.A. Harpold, E. Gutmann, D.D. Breshears, P.A. Troch, D.J. Gochis, R.L. Scott, A.J.H. Meddens, and P.D. Brooks. 2015, Water Resources Research
Quantifying the effects of vegetation structure on snow accumulation and ablation in mixed-conifer forests Broxton P. D., Harpold A. A., Biederman J. A., Troch P. A., Molotch N. P., and Brooks P. D. 2015, Ecohydrology
Laser vision: lidar as a transformative tool to advance critical zone science 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., Kirchner, P. B., Lam, N., Mankoff, K. D., McCreight, J. L., Molotch, N. P., Musselman, K. N., Pelletier, J., Russo, T., Sangireddy, H., Sjöberg, Y., Swetnam, T., and West, N. 2015, Hydrology and Earth Systems Science
Snowmelt infiltration in mixed-conifer subalpine forests Harpold, A.A, N.P. Molotch, P.D. Brooks, R. Bales, M. Litvak, K. Musselman. And P. Kirchner. 2015, Hydrological Processes
Use of LiDAR in Environmental Science Harpold, A.A. 2015, Oxford Bibliographies in Environmental Science
Sensitivity of soil water availability to changing snowmelt timing in the western U.S. Harpold, A.A. and N.P. Molotch 2015, Geophysical Research Letters
The relative contributions of alpine and subalpine ecosystems to the water balance of a mountainous, headwater catchment. Knowles, J.F., Harpold, A.A., Cowie, R., Zeliff, M., Barnard, H.R., Burns, S.P., Blanken, P.D., Morse, J.F., and Williams, M.W. 2015, Hydrological Processes
Rare Earth Elements as Reactive Tracers of Biogeochemical Weathering in Forested Rhyolitic Terrain. Vázquez-Ortega, A., Perdrial, J., Harpold, A., Zapata-Ríos, X., Rasmussen, C., McIntosh, J., ... & Chorover, J. 2015, Chemical Geology.
Changes in water partitioning and runoff at the hillslope to catchment scale following insect-induced tree mortality in lodgepole pine forests. Biederman, J.A., A.A. Harpold, D. Reed, D. Gochis, B. Ewers, E. Gutmann, and P.D. Brooks. 2014, Water Resources Research
Changes in winter season snowpack accumulation and ablation following the Las Conchas Forest Fire. Harpold, A.A., J. Biederman, K. Condon, M. Merino, Y. Korganokar, T. Nan, L.L. Sloat, M. Ross, and P.D. Brooks. 2014, Ecohydrology. 7: 440-452. doi: 10.1002/eco.1363.
A LiDAR derived snowpack dataset from mixed conifer forests in the Western U.S. Harpold, A.A., Q. Guo, N. Molotch, P. Brooks, R. Bales, J.C. Fernandez-Diaz, K.N. Musselman, T. Swetnam, P. Kirchner, M. Meadows, J. Flannagan, and R. Lucas 2014, Water Resources Research
Stream water carbon controls in seasonally snow-covered mountain catchments: impact of interannual variability of water fluxes, catchment aspect and seasonal processes. Perdrial, J. McIntosh, A.A. Harpold, P.D. Brooks, X. Zapata-Rios, J. Ray, T. Meixner, T. Kanduc, M. Litvak, P. Troch, and J. Chorover. 2014, Biogeochemistry. doi:10.1007/s10533-013-9929-y
Explaining the spatial variability of aquatic biota using watershed features in the Neversink River watershed, New York, USA Harpold, A.A., D.A. Burns, M.T. Walter, and T. Steenhuis 2013, Ecological Applications. 23: 791-800. doi: 10.1890/12-0603.
Explaining the spatial variability of aquatic biota using watershed features in the Neversink River watershed, New York, USA. Harpold, A.A., D.A. Burns, M.T. Walter, and T. Steenhuis 2013, Ecological Applications
Aeresol and Precipitation Chemistry in the Southwestern United States: Spatiotemporal Trends and Interrelationships. Sorooshian, A.S., T.S. Shingler, A.A. Harpold, C.W. Feagles, T.M. Meixner, and P.D. Brooks. 2013, Atmospheric Chemistry and Physics. 13: 7361-7379. doi:10.5194/acp-13-7361-2013
Multi-scale Observations of Snow Accumulation and Peak Snowpack Following Widespread, Insect-induced Lodgepole Pine Mortality Biederman, J., P.D. Brooks, A.A. Harpold, D. Gochis, E. Gutman, D. Reed, E. Pendall, and B. Ewers. 2012, Ecohydrology
Changes in snowpack volume and snowmelt timing in the Intermountain West. Harpold, A.A., P.D. Brooks, S. Rajogopalan, I. Heidebuchel, A. Jardine, and C. Stielstra 2012, Water Resources Research. 48:11. doi: 10.1029/2012WR011949
Probing dissolved organic matter in the critical zone: a comparison between in situ passive capillary wick samplers (PCaps) to aqueous soil extracts Perdrial, J., N. Perdrial, A.A. Harpold, X. Gao, K. LaSharr, J. Chorover 2012, Soil Science Society of America Journal. 76(6): 2019-2030. doi:10.2136/sssaj2012.0061
Probing how water, carbon, and energy driven landscape evolution and surface water dynamics: Jemez River Basin – Santa Catalina Mountains Critical Zone Observatory. Chorover, J., P.A. Troch, C. Rasmussen, P.D. Brooks, J.D. Pelletier, D.D. Breshears, T.E. Huxman, S.A. Kurc, K.A. Lohse, J.C. McIntosh, T. Meixner, M.G. Schaap, M.E. Litvak, J. Perdrial, A.A. Harpold, M. Durcik. 2011, Vadose Zone Journal. 10(3): 884-899. doi:10.2136/vzj2010.0132
Relating hydrogeomorphologic properties to stream buffering chemistry in the Neversink River watershed, New York, USA Harpold, A.A., S.B. Shaw, D.A. Burns, M.T. Walter, and T. Steenhuis. 2010, Hydrological Processes. 24(26): 3759-3771. doi:10.1002/hyp.7802
The hydrological effects of lateral preferential flow paths in a glaciated watershed in the Northeastern U.S. Harpold, A.A., S.W. Lyon, P.A. Troch, and T.S. Steenhuis. 2009, Vadose Zone Journal. 9(2): 397-414. doi:10.2136/vzj2009.0107.
Investigating a high-resolution, stream chloride time series from Biscuit Brook catchment, Catskills, NY. Shaw, S. A.A. Harpold, J.A. Taylor, and M.T. Walter. 2007, Journal of Hydrology. 348(3-4): 245-256. doi:10.1016/j.hydrol.2007.10.009
Global Warming Harpold, A. , Chandra, S. and Houston, D. 2016, Lawyers, Guns & Money -