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JT Reager

Photo of JT Reager

Address:

4800 Oak Grove Drive
M/S 300-323

Pasadena, CA 91109

Phone:

818.354.0552

Curriculum Vitae:

Click here

Member of:

Water & Ecosystems

Scientist

Biography

J.T. Reager is an Earth scientist in the Water and Ecosystems Group at NASA’s Jet Propulsion Laboratory, where he studies global freshwater dynamics and hydrologic extremes using space-based observations. His research spans the interactions between the terrestrial water cycle and broader Earth system processes, including land-ocean exchanges, climate variability, groundwater sustainability, and human impacts on water resources.

He currently serves as Deputy Project Scientist for the GRACE Follow-On mission, and as a Discipline Program Manager for the Water and Energy Cycle at JPL. He also leads Decadal Survey planning for the freshwater science community and provides science advising to philanthropic and governmental stakeholders, including the California Department of Water Resources.

Dr. Reager has authored over 100 peer-reviewed publications, received the Presidential Early Career Award for Scientists and Engineers (PECASE), and regularly represents NASA Earth Science at public events, science workshops, and international forums. He is passionate about conceptualizing future Earth missions, advancing the societal relevance of satellite observations, and helping shape the next generation of water science strategy.

Education

  • 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

  • Scientist, Jet Propulsion Laboratory, California Institute of Technology (2014–Present)
    • Member of the Water and Ecosystems Group in the Earth Sciences Section. Conducts research on global freshwater dynamics, hydrologic extremes, and terrestrial water storage using satellite observations. Contributed over 100 peer-reviewed publications and received multiple national honors for scientific leadership and innovation.
  • Deputy Project Scientist – GRACE-FO Mission, JPL (2024–Present)
    • Supports science direction and stakeholder engagement for NASA’s gravity satellite mission monitoring mass change across the Earth system.
  • Deputy Discipline Program Manager – Water & Energy Cycle, JPL (2024–Present)
    • Helps guide JPL’s institutional strategy in Earth science, supporting water and energy cycle research and alignment with NASA priorities.

Community Service

  • Lead Author, NASA Mass Change Designated Observable Community Assessment Report (2022)
  • Organizer and Convener, annual GRACE/GRACE-FO AGU sessions (2018–present)
  • Co-Lead, Water Focus Area for NASA Decadal Survey Preparatory Activities at JPL (2024–present)
  • Science Advisor, Caltech Data to Discovery Summer Program (2022)
  • Organizer, Workshops on satellite hydrology with CUAHSI, UNESCO, and NASA DEVELOP (2015–2020)
  • Science Advisor, California Department of Water Resources – Satellite-Based Groundwater Updates (2021–present)

Research Interests

  • Global freshwater monitoring and mass change
  • Hydrologic extremes and drought/flood risk
  • Strategic Earth mission formulation
  • Integration of NASA observations into decision-making
  • Groundwater sustainability and human-Earth interactions

Selected Awards

  • JPL Voyager Award (2020) for leadership in the Surface Deformation and Change D.O. Study Hydrology Science and Applications Traceability Team.
  • JPL Voyager Award (2019) for advancements in the application of satellite data for the Hydrological Sciences and for student mentoring.
  • PECASE: Presidential Early Career Award for Science and Engineering (2019) for studies of the Terrestrial Water Cycle using GRACE.
  • NASA Early Career Achievement Medal (2017) for Contributions to understanding hydrologic extreme events.
  • NOAA David Johnson Early Career Award (2016) for Innovative application of Earth observation satellite data for operational purposes.
  • Newkirk Center for Science and Society Fellowship (2100-2012) for Estimating long-range global flood potential using GRACE terrestrial water storage and CMIP precipitation.
  • ARCS Foundation Scholar Achievement Award (2010-2012) for GRACE and the critical limits of the global water cycle.
  • NASA Earth and Space Science Fellowship (2009-2012) for Applications of a frequency-domain terrestrial water balance using GRACE.

Selected Publications

100+ publications; Citations: 10,829; H-index: 45; i10-index: 86 (as of 05/2025)

*See CV for full list

  1. Boser, A., Caylor, K., Larsen, A., Pascolini-Campbell, M., Reager, J. T., & Carleton, T. (2024). Field-scale crop water consumption estimates reveal potential water savings in California agriculture. Nature Communications, 15(1), 2366. https://doi.org/10.1038/s41467-024-42050-3
  2. Rodell, M., & Reager, J. T. (2023). Water cycle science enabled by the GRACE and GRACE-FO satellite missions. Nature Water, 1(1), 47-59.
  3. Liu, P. W., Famiglietti, J. S., Purdy, A. J., Adams, K. H., McEvoy, A. L., Reager, J. T., ... & Rodell, M. (2022). Groundwater depletion in California’s Central Valley accelerates during megadrought. Nature Communications, 13(1), 7825.
  4. Adams, K. H., Reager, J. T., Rosen, P., Wiese, D. N., Farr, T. G., Rao, S., ... & Rodell, M. (2022). Remote sensing of groundwater: current capabilities and future directions. Water Resources Research, 58(10), e2022WR032219.
  5. Wiese, D. N., Bienstock, B., Blackwood, C., Chrone, J., Loomis, B. D., … Reager, J. T., Sauber, J. & Zlotnicki, V. (2022). The mass change designated observable study: overview and results. Earth and Space Science, 9(8), e2022EA002311.
  6. Farahmand, A., Reager, J. T., & Madani, N. (2021). Drought Cascade in the Terrestrial Water Cycle: Evidence from Remote Sensing. Geophysical Research Letters, e2021GL093482.
  7. Chandanpurkar, H. A., Reager, J. T., Famiglietti, J. S., Nerem, R. S., Chambers, D. P., Lo, M. H., ... & Syed, T. H. (2021). The seasonality of global land and ocean mass and the changing water cycle. Geophysical Research Letters, 48(7), e2020GL091248.
  8. Pascolini‐Campbell, M., Fisher, J. B., & Reager, J. T. (2021). GRACE‐FO and ECOSTRESS Synergies Constrain Fine‐Scale Impacts on the Water Balance. Geophysical Research Letters, 48(15).
  9. 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.
  10. 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.
  11. 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.
  12. 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.
  13. 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.
  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.

Projects

GRACE Follow-On
NASA Sea Level Change Team
SMAP - Soil Moisture Active Passive