Matt Rodell NASA GSFC
GRACE and Human Impacts on the Water Cycle
Matt Rodell, Ph.D.
Chief, Hydrological Sciences Laboratory NASA Goddard Space Flight Center
Greenbelt, MD
Matt Rodell NASA GSFC
Soil Moisture Snow, Ice, Rainfall Snow
Vegetation Radiation
Gravity Recovery and Climate Experiment (GRACE)
Aqua: MODIS, AMSR-E, etc.
GRACE
GRACE is unique in its ability to monitor water at all levels, down to the deepest aquifer
Conventional radiation-based remote sensing technologies cannot sense water below the first few centimeters of the snow-canopy-soil column
Matt Rodell NASA GSFC
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Wat
er S
tora
ge, m
mSnow Water Equivalent
Top 2m Soil Moisture
Deep SM and Groundwater
Terrestrial Water Storage Variations
TWS variations are dominated by:!Soil moisture in temperate regions;!Snow in polar and alpine regions;!Surface water in the wet tropics.!
Top: 23 year time series of snow, soil moisture, and groundwater storage in Illinois, USA (right)
Updated from Rodell and Famiglietti, WRR, 2001
Matt Rodell NASA GSFC
Emerging Trends in Terrestrial Water Storage from GRACE
• “Trends” in GRACE derived terrestrial water storage, 2002-2015. • Best fit linear rate of change of TWS (cm/yr). • Based on JPL/Tellus GRACE mascon land hydrology product. • Which apparent trends are real and likely to continue?
cm/yr
Matt Rodell NASA GSFC
Terrestrial Water Storage “Trends” from GRACE
Exploitation of Water Resources
Percentage of Irrigated Area
Source: FAO and University of Frankfurt
Groundwater Depletion Rate (ca. 2000)
Equivalent height of water (mm/yr)
Wada et al. (2010)
Equivalent height of water (mm/yr)
Döll et al. (2011)
Net Consumptive Use of Ground and Surface Waters, 1998-2002
Equivalent height of water (cm/yr)
Matt Rodell NASA GSFC
• “Trends” in GRACE derived terrestrial water storage, 2002-2015. • Best fit linear rate of change of TWS (cm/yr). • Based on JPL/Tellus GRACE mascon land hydrology product. • Which apparent trends are real and likely to continue?
Matt Rodell NASA GSFC
Maupin, M.A., Kenny, J.F., Hutson, S.S., Lovelace, J.K., Barber, N.L. and Linsey, K.S., 2014. Estimated use of water in the United States in 2010 (No. 1405). US Geological Survey.
Total U.S. Water Withdrawals, 2010
Matt Rodell NASA GSFC
Maupin, M.A., Kenny, J.F., Hutson, S.S., Lovelace, J.K., Barber, N.L. and Linsey, K.S., 2014. Estimated use of water in the United States in 2010 (No. 1405). US Geological Survey.
Irrigation Water Withdrawals, 2010
Matt Rodell NASA GSFC
Annual irrigation water use ca. 2000 reported by the USGS at the county level in cubic kilometers, from Ozdogan et al., J. Hydrometeor., 2010.
Irrigation Water Withdrawals, ca. 2000
Matt Rodell NASA GSFC
Increase in evapotranspiration due to irrigation, from Ozdogan et al., J. Hydrometeor., 2010. The increase in ET due to irrigation, averaged over the entire contiguous U.S., was 4% during the growing season, which is a huge impact on the water budget that also affects temperature and the energy budget.
Irrigation Impacts on Evapotranspiration