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JT Reager

Photo of JT Reager


4800 Oak Grove Drive
M/S 300-323

Pasadena, CA 91109



Curriculum Vitae:

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Member of:

Water & Ecosystems



JT Reager is a Research Scientist in the Surface Hydrology group, in the Earth Sciences Section. He studies the Earth's water cycle with a particular focus on hydrologic extremes, sea level rise and water resources. He joined JPL in 2014.


  • Postdoctoral Researcher, UC Center for Hydrological Modeling (2014)
  • PhD in Earth System Science, University of California, Irvine, Irvine, CA (2012)
  • M.S. in Physical Ocean Science and Engineering, University of Delaware, College of Marine Studies, Newark, DE (2004)
  • B.S. in Aerospace Engineering, B.S. in Ocean Engineering, Virginia Polytechnic Institute and State University, Blacksburg, VA (2001)

Professional Experience

  • Jet Propulsion Laboratory, Pasadena, CA
    • Scientist (2014-present)
  • University of California, Los Angeles, CA
    • Visiting Researcher, JIFRESSE (2014-present)

Community Service

  • GRACE Deputy Project Applications Lead
  • Lead organizer and presenter, NASA Applied Sciences/CUAHSI workshop on 'Methods and tools in satellite hydrology'. CUAHSI HQ, Boston, April 2017.
  • Presenter, IPCC Conference of the Parties (COP-22), NASA Earth Sciences, Marrakech, Morrocco, November 2016.
  • Lead organizer: Workshop on hydrologic applications of GNSS-reflectometry, NASA Jet Propulsion Laboratory, June 2016.
  • Lead author, National Academies Decadal Survey, RFI2: Water beneath the land surface. Submitted May 15, 2016.
  • Lead organizer and presenter, CUAHSI workshop on 'Methods and tools in satellite hydrology'. Biosphere 2, Tuscon, March 2016.
  • Group leader, Hyper-resolution land surface modeling collaborative, Working Group I: Test case creation. [2014-present]
  • NASA DEVELOP Science Advisor

Research Interests

My research focuses on the study of Water in the Earth System, primarily using space-based observations. I am most interested in working on improving our understanding of hydrological processes, uncertainties and observational gaps across the interfaces of ocean/land water cycling, carbon/water interactions, and water/solid earth interactions. I also study human impacts on the Earth System and natural resource sustainability.

Selected Awards

  • JPL Voyager Award for advancements in the application of satellite data for the Hydrological Sciences and for student mentoring (2019)
  • PECASE: Presidential Early Career Award for Science and Engineering for studies of the Terrestrial Water Cycle using GRACE (2019)
  • NASA Early Career Achievement Medal for Contributions to understanding hydrologic extreme events (2017)
  • NOAA David Johnson Early Career Award for Innovative application of Earth observation satellite data for operational purposes (2016)
  • Newkirk Center for Science and Society Fellowship for Estimating long-range global flood potential using GRACE terrestrial water storage and CMIP precipitation (2011-2012)
  • ARCS Foundation Scholar Achievement Award for GRACE and the critical limits of the global water cycle (2010-2012)
  • NASA Earth and Space Science Fellowship for Applications of a frequency-domain terrestrial water balance using GRACE (2019-2012)

Selected Publications

  1. Pascolini‐Campbell, M. A., Reager, J. T., & Fisher, J. B. (2020). GRACE‐based mass conservation as a validation target for basin‐scale evapotranspiration in the contiguous United States. Water Resources Research, 56.
  2. Sadeghi, M., Lun Gao, Ardeshir Ebtehaj, Jean-Pierre Wigneron, Wade T Crow, John T Reager, Arthur W Warrick (2020) Retrieving Global Surface Soil Moisture from GRACE Satellite Gravity Data. Journal of Hydrology.
  3. Massoud, E., Turmon, M., Reager, J., Hobbs, J., Liu, Z., & David, C. H. (2020). Cascading Dynamics of the Hydrologic Cycle in California Explored through Observations and Model Simulations. Geosciences, 10(2), 71.
  4. Chandanpurkar, H. A., Fasullo, J. T., Reager, J. T., Nerem, R. S., & Famiglietti, J. S. (2019). Asymmetric Response of Land Storage to ENSO Phase and Duration. Water, 11(11), 2249.
  5. Morris, M., Chew, C., Reager, J. T., Shah, R., & Zuffada, C. (2019). A novel approach to monitoring wetland dynamics using CYGNSS: Everglades case study. Remote Sensing of Environment, 233, 111417.
  6. Ehalt Macedo, H., Beighley, R. E., David, C. H., & Reager, J. T. (2019). Using GRACE in a streamflow recession to determine drainable water storage in the Mississippi River basin. Hydrology and Earth System Sciences, 23(8), 3269-3277.
  7. Fournier, S., Reager, J. T., Dzwonkowski, B., & Vazquez‐Cuervo, J. (2019). Statistical Mapping of Freshwater Origin and Fate Signatures as Land/Ocean "Regions of Influence" in the Gulf of Mexico. Journal of Geophysical Research: Oceans, 124(7), 4954-4973.
  8. Stampoulis, D., Reager, J. T., David, C. H., Andreadis, K. M., Famiglietti, J. S., Farr, T. G., ... & Lundgren, P. R. (2019). Model-data fusion of hydrologic simulations and GRACE terrestrial water storage observations to estimate changes in water table depth. Advances in Water Resources, 128, 13-27.
  9. Hamlington, B. D., Reager, J. T., Chandanpurkar, H., & Kim, K. Y. (2019). Amplitude Modulation of Seasonal Variability in Terrestrial Water Storage. Geophysical Research Letters, 46(8), 4404-4412.
  10. Tapley, B. D., Watkins, M. M., Flechtner, F., Reigber, C., Bettadpur, S., Rodell, M., ... & Reager, J. T. (2019). Contributions of GRACE to understanding climate change. Nature Climate Change, 1.
  11. Oaida, C.M., J.T. Reager, K.M. Andreadis, C.H. David, S.R. Levoe, T.H. Painter, K.J. Bormann, A.R. Trangsrud, M. Girotto, and J.S. Famiglietti (2019): A high-resolution data assimilation framework for snow water equivalent estimation across the Western United States and validation with the Airborne Snow Observatory. J. Hydrometeor., 0.
  12. Wang, J., Song, C., Reager, J. T., Yao, F., Famiglietti, J. S., Sheng, Y., ... & Wada, Y. (2018). Recent global decline in endorheic basin water storages. Nature geoscience, 11(12), 926.
  13. Behrangi, A., Gardner, A., Reager, J. T., Fisher, J. B., Yang, D., Huffman, G. J., & Adler, R. F. (2018). Using GRACE to Estitmate Snowfall Accumulation and Assess Gauge Undercatch Corrections in High Latitudes. Journal of Climate, 31(21), 8689-8704.
  14. Chew, C., Reager, J. T., & Small, E. (2018). CYGNSS data map flood inundation during the 2017 Atlantic hurricane season. Scientific Reports (Nature Publisher Group), 8, 1-8.
  15. Rodell, M., Famiglietti, J. S., Wiese, D. N., Reager, J. T., Beaudoing, H. K., Landerer, F. W., & Lo, M. H. (2018). Emerging trends in global freshwater availability. NATURE, 1.
  16. Tourian, M. J., Reager, J. T., & Sneeuw, N. (2018). The Total Drainable Water Storage of the Amazon River Basin: A First Estimate Using GRACE. Water Resources Research, 54(5), 3290-3312.
  17. Fournier, S., J.T. Reager, T. Lee, C.H. David, J. Vazquez and M. Gierach (2016) A Texas flood from land to ocean observed by SMAP, Geophysical Research Letters.
  18. Behrangi, A., Gardner, A. S., Reager, J. T., & Fisher, J. B. (2017). Using GRACE to constrain precipitation amount over cold mountainous basins. Geophysical Research Letters, 44(1), 219-227.
  19. Jensen, D., Reager, J. T., Zajic, B., Rousseau, N., Rodell, M., & Hinkley, E. (2018). The sensitivity of US wildfire occurrence to pre-season soil moisture conditions across ecosystems. Environmental research letters, 13(1), 014021.
  20. Taeb, A., J.T. Reager, V. Chandrasekaran and M. Turmon (2017) California reservoir drought sensitivity and exhaustion risk using statistical graphical models, Water Resources Research.
  21. Chandanpurkar, H.A., J.T. Reager, J.S. Famiglietti and TH. Syed (2017) Satellite- and reanalysis-based mass balance estimates of global continental discharge (1993-2015), Journal of Climate.
  22. Solander, K. C., Reager, J. T., Wada, Y., Famiglietti, J. S., & Middleton, R. S. (2017). GRACE satellite observations reveal the severity of recent water over-consumption in the United States. Nature Scientific Reports, 7.
  23. Wada, Y., M.-H. Lo, J.T. Reager et al. (2016) Fate of water pumped from underground and contributions to sea level rise, Nature Climate Change.
  24. Castle, S. S., Reager, J. T., Thomas, B. F., Purdy, A. J., Lo, M. H., Famiglietti, J. S., & Tang, Q. (2016). Remote detection of water management impacts on evapotranspiration in the Colorado River Basin. Geophysical Research Letters, 43(10), 5089-5097.
  25. Richey, A.S., B.F. Thomas, M.-H. Lo, J.S. Famiglietti, J.T. Reager, K.S. Voss, S.C. Swenson and M. Rodell (2015) Uncertainty in Global Groundwater Storage Estimates in a Total Groundwater Stress Framework. Water Resources Research.
  26. Singh, R.S., J.T. Reager and N.L. Miller, J.S. Famiglietti (2015) Towards hyper-resolution land surface modeling: The effects of fine-scale model grid resolution on CLM4.0 simulations in the Southwestern US. Water Resources Research 50.
  27. Bierkens, M.F.P., V.A. Bell, P. Burek, N. Chaney, L. Condon, C.H.
David, A. de Roo, P. Döll, N. Drost, J.S. Famiglietti, M. Flörke, D.J. Gochis, P. Houser, R. Hut, J. Keune, S. Kollet, R. Maxwell, J.T. Reager, L. 
Samaniego, E. Sudicky, E.H. Sutanudjaja, N. van de Giesen, H. Winsemius and E.F. Wood (2015) Hyper-resolution global hydrological modeling: what's next? Hydrological Processes, 29 (2), 310-320.
  28. Reager, J.T., A.C. Thomas, E.A. Sproles, M. Rodell, H.K. Beaudoing, B.-L. Li, J.S. Famiglietti (2015) Assimilation of GRACE terrestrial wáter storage observations into a land surface model for the assesment of regional flood potential. <,em>Remote Sensing 7 (11), 14663-14679.
  29. Castle, S.S., B.F. Thomas, J.T. Reager, M. Rodell, S.C. Swenson and J.S. Famiglietti (2014) Groundwater Depletion During Drought Threatens Future Water Security of the Colorado River Basin. Geophysical Research Letters, 41, 5904-5911.
  30. ^Highlighted in Science, Editors' choice, "Looking beneath the drying surface", August 2014.
  31. Thomas, A.C., J.T. Reager, J.S. Famiglietti and M. Rodell (2014) GRACE-observed water storage deficits for hydrological drought characterization. Geophysical Research Letters, 41, 1537-1545.
  32. Reager, J.T., B.F. Thomas and J.S. Famiglietti (2014) River basin flood potential inferred using GRACE gravity observations at several months lead-time. Nature Geoscience, 7, 588-592.
  33. ^Highlighted in Science, "Gravity measurements can predict river flooding", July, 2014.
  34. Reager, J.T. and J.S. Famiglietti (2013), Characteristic mega-basin water storage behavior from GRACE. Water Resources Research, 49, 3314-3329.
  35. Reager, J.T. and J.S. Famiglietti (2009), Global terrestrial water storage capacity and flood potential using GRACE. Geophysical Research Letters, 36, L23402.