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Sean Swenson

Associate Scientist
National Center for Atmospheric Research
P.O. Box 3000
Boulder, Colorado 80307
(303) 497-1761

franz marc painting

The Bewitched Mill
Franz Marc (1912)

  • My Blog
  • Honors

    • AGU Geodesy Section Award, 2011
    • National Center for Atmospheric Research Advanced Study Program Postdoctoral Fellowship, 2006 - 2008
    • 2005 Editors's Citation for Excellence in Refereeing for Geophysical Research Letters
    • NASA Earth Systems Science Fellowship, 2000 - 2002
    • Outstanding Student Paper Award, Geodesy Section, AGU Spring Meeting 1999

  • Recent Publications
  • Curriculum Vitae (pdf)
  • Recent Projects

    • Community Land Model (CLM) Soil moisture variability assessment (pdf)
    • Adding sub-grid scale snow covered area to CLM
    • Adding a surface water component to CLM (pdf)

  • Member, American Geophysical Union
  • Reviewer for:

    Geophysical Research Letters, Journal of Geophysical Research, Water Resources Research, Journal of Hydrometeorology, Geophysical Journal International, Journal of Geodesy, Global and Planetary Change, Earth and Planetary Science Letters, Remote Sensing of Environment

Research Focus

My research interests focus on the terrestrial water cycle, and especially human impacts on the water cycle, at spatial scales of river basins to regional and continental scales. On the observational side, I use multiple satellite remote sensing and in situ datasets to quantify the components of the water balance.

Of particular importance to my research has been data from the Gravity Recovery and Climate Experiment (GRACE). It can be argued that GRACE is the most interdisciplinary satellite mission launched to date. GRACE has been used to study surface processes involving hydrologic, oceanic, and cryospheric water mass redistribution. This website uses software that I developed to perform real-time data analysis of GRACE data. Data from this site has been downloaded by hundreds of users from around the globe.

At the monthly timescale, water redistribution is the primary source of temporal variations in the Earth's gravity field. Thus, GRACE is a valuable tool for studying the global water cycle. Most remote sensing instruments are based on some form of radiometric measurement, and therefore are confined to sampling the near-surface properties of their target. Because GRACE measures gravity, however, it provides a vertically integrated measurement that includes contributions from all hydrologic stores: soil moisture, groundwater, surface water, and snow.

Recently, I have been looking at areas where human activities are significantly disrupting the natural hydrologic cycle. During the period 2002-2006, Lake Victoria, the world's second largest freshwater lake, lost nearly 150 cubic km of water. Using GRACE and Jason-1 altimetric data, we confirmed that roughly half of this water loss was due to human management (for the generation of electicity). We have also shown that northern India, one of the world's most densely populated regions, is losing groundwater rapidly at a rate of roughly 50 cubic km per year, which is similar to the rate at which Alaskan glaciers are melting.