GRACE satellite derived total water storage anomaly (TWSA) from April 2002 to December 2014

The Total Water Storage Anomaly (TWSA) data are derived from the Gravity Recovery and Climate Experiment satellite mission, with temporal and spatial resolutions of monthly and 1 degree respectively. The processed GRACE-derived TWSA data covered the period from April 2002 to December 2014. The GRACE TWSA data was pre-processed to remove the signal from atmosphere and ocean and was retrieved at monthly and 1° resolutions, with units of cm. To minimize the uncertainties associated with data processing, an ensemble average TWSA was calculated using GRACE data processed independently by three research centres, NASA Jet Propulsion Laboratory (JPL), University of Texas Center for Space Research (CSR) and the GeoForschungsZentrum (GFZ) Potsdam. As terrestrial gravity variations in space and time are mainly caused by changes in water storage, TWSA was obtained by subtracting the monthly GRACE data by a historical mean (2004–2009). We chose to use a file of scaling factors obtained from the NCAR's Community Land Model 4.0 (CLM4.0) to correct and restore the GRACE signal loss during low-pass filtering. The uncertainty range in TWSA time series was calculated at a 95% Confidence Interval (CI).