Precipitation: Evapotranspiration: S i o l il M o t s ure: Groundwater: Streamflow: Vegetation:

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1 Satellite and Ground-based Approaches for Monitoring Impacts of Agriculture on Ground Resources Bridget R. Scanlon, Laurent Longuevergne, Guillaume Favreau*, Claudia Faunt** Center for Sustainable Water Resources, CR Bureau of Economic Geology, Jackson School of Geosciences, University of Texas at Austin *Universite de Montpelier, France **US Geological Survey, San Diego, California Water Balance Components Precipitation: SSM/I, TRMM Evapotranspiration: MODIS, AVHRR, LandSat Soil Moisture: SSM/I, AMSR, SMOS Ground: GRACE Streamflow: Laser/Radar Altimeter Vegetation: AVHRR, TM, MODIS P ET R off = SS Can we close the budget using satellite data? Outline Back on GRACE data Applications Ganges Niger US High Plains US California Central Valley Global surface basin product (Google Earth) Methods Gravity Recovery and Climate Expt. Methods GRACE Launched March 22 Total storage change GRACE (Change in Total Water Storage, TWS) Total Water Storage Change (TWSC) : surface ; SM GW, : surface ; SM GW, GW = TWS SM

2 Total Water Storage Change (TWSC) Total Water Storage Change (TWSC) : surface ; SM GW, : surface ; SM GW, GW = TWS SM GW = TWS SM GW = TWS SM GW = TWS SM SM: estimated from GLDAS: Global Land Data Assimilation System Four land surface models:vic, CLM, NOAH, and MOSAIC GRACE Analysis centers: CSR, GFZ, JPL, GRGS, DEOS Time scale: 7 d - monthly Spatial scale: 4, km 2 Data processing: remove atmospheric, oceanic, and tidal effects (centers), destripe the data, filter the data Correct for bias and leakages Error analysis: measurement errors, processing errors, model errors Work with a geodesist Use of GRACE Data in Water Resources Ground WL Rising Recharge Discharge = GW = GRACE SM Use of GRACE Data in Water Resources Use of GRACE Data in Water Resources WL Rising Ground Ground Recharge Discharge = GW = GRACE SM Increase in recharge from climate or land use change Recharge Discharge = GW = GRACE SM GW from GRACE ~ irrigation pumpage

3 Outline Ground Depletion in Ganges Basin Back on GRACE data Applications Ganges Niger US High Plains US California Central Valley Global surface basin product (Google Earth) Rodell et al., 29 Ground Depletion based on GRACE Drilling in Rajasthan Trend in storage: 12.5 mm/yr (basin area 1 million km 2 ) ~ 1 mm/yr in irrigated area (15, km 2 ) Jaipur site Recharge rates under rainfed agriculture: 6 9 mm/yr Recharge under irrigated agriculture: 5 12 mm/yr 8 19% of mean annual precipitation (6 mm/yr) Irrigation of 2 4% of cultivated land with 3 mm/yr should be sustainable. Scanlon et al., 21 (2) Example of Ground Storage Increase Ground Level Rises 1 3. Niger WL Grou und level change (m m) Studied since 199s International ti AMMA project Favreau et al., 29 Favreau et al., 22, GW

4 ) Ground Level Rises, No Link to Climate WL Mean 563 mm ( ) Grou und level change (m m) (mm/yr) recipitation ( Pr Favreau et al., 22, GW Ground Level Rises Caused by Cultivation (land use changes) and area (%) La Natural Plateau Cultivated Fallow WL Mean 563 mm ( ) ange (m) Gro ound level change (m m) ter level cha Groundwa (mm/yr) recipitation ( Pr Favreau et al., 22, GW Ground results GRACE results Area: 1 km² Area: 15 km² Trend: +23 mm/yr Trend: +18 mm/yr GRACE GLDAS ( SM) = GW Increase in GW = 18 mm/yr GRACE can be used to regionalize trends (3) US High-Plains Aquifer 45, km 2 area High Plains Aquifer, US Water available: 4, km 3 Water depleted: 33 km 3 (8%) Recharge: 1 86 mm/yr Grassland 56% Shrubland 3% Other Irrigated 1% 12% Rainfed 28% SHP: Recharge increase from 1 to 3 mm/yr after cultivation Could support irrigation of 1% of cultivated land with 3 mm/yr McGuire et al., 29

5 Ground Depletion under Irrigated Agriculture GRACE Data for High Plains to (m m) Depth Comparison of GRACE Data with Measured SM + GW r 2 =.87 (4) California Central Valley r 2 =84.84 Area: 52, km 2 Total stored: 1 km 3 Water depletion: 6 km 3 r 2 =.88 Faunt et al., 29 Change in Storage with Time GRACE data (CSR, GRGS) GRACE data (CSR, GRGS) NOAH (SM + Snow) Faunt et al., 29

6 GRACE data (CSR, GRGS) NOAH (SM + SNOW) GRACE data (CSR, GRGS) NOAH (SM + SNOW) Surface storage 26 reservoirs Surface storage 26 reservoirs GRACE SM Snow Ground hydrograph Outline Google Earth Product for Surface Water 218 basins, TRIP database Back on GRACE data Applications Ganges Niger US High Plains US California Global surface basin product (Google Earth) Longuevergne, 21 Google Earth Basins Product Download links Basin explorer Longuevergne et al., 21

7 GRACE Total Water Storage Change (GRGS) (mm) Annual Signal (mean: 23 29) GRACE Total Water Storage Change (GRGS) (mm/yr) Trend (23 29) Amplitude of annual signal ranges from 25 mm (median 46 mm) Median error 1 mm Trend: -3 to 3 mm/yr; median 2. mm/yr precipitation (climate), permafrost ice loss, drought, irrigation GRGS GRACE Summary NOAH LSM Soil Moisture Useful tool for estimating seasonal, interannual, and secular variations in total storage changes down to 4, km 2 spatial resolution and ~ 7dtemporal resolution Seasonal signal dominant: median 46 mm in 218 basins Error: ±1 mm Disaggregation of TWS to, SM, and GW depends on GLDAS models Need to improve modeling to include surface and, irrigation Calculation of trends depends on time period and interannual variability