Downscaled GRACE-FO TWSA for Greece
Description
The dataset comprises GRACE-FO downscaled Total Water Storage Anomalies, at 0.1 degrees spatial resolution. Units are in mm with reference the 2004 - 2009 period. Abstract: A downscaling framework for coarse resolution Gravity Recovery and Climate Experiment (GRACE) Total Water Storage Anomaly (TWSA) data is described, exploiting the observations of precipitation from the Global Precipitation Measurement (GPM) mission, using the Integrated Multisatellite Retrievals for GPM (IMERG). Considering that the major driving force for changes in TWS is precipitation, we tested our hypothesis that coarse resolution, i.e., 1◦, GRACE TWSA can be effectively downscaled to 0.1◦ using GPM IMERG data. The algorithm for the downscaling process comprises the development of a regression equation at the coarse resolution between the GRACE and GPM IMERG data, which is then applied at the finer resolution with a subsequent residual correction procedure. An ensemble of GRACE data from three processing centers, i.e., GFZ, JPL and CSR, was used for the time period from June 2018 until March 2021. To verify our downscaling methodology, we applied it with GRACE data from 2005 to 2015, and we compared it against modeled TWSA from two independent datasets in the Thrace and Thessaly regions in Greece for the same period and found a high performance in all examined metrics. Our research indicates that the downscaled GRACE observations are comparable to the TWSA estimated with hydrological modeling, thus highlighting the potential of GRACE data to contribute to the improvement of hydrological model performance, especially in ungauged basins.
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Steps to reproduce
The methodology is described in detail in Gemitzi, A.; Koutsias, N.;Lakshmi, V. A Spatial Downscaling Methodology for GRACE TotalWater Storage Anomalies Using GPM IMERG Precipitation Estimates. Remote Sens. 2021, 13, 5149. https://doi.org/10.3390/rs13245149