New publication in Nature Water by Gou and Soja (2024)

The Gravity Recovery and Climate Experiment (GRACE) and its follow-on (GRACE-FO) satellite missions can monitor the monthly variations in total water storage (TWS) from space by measuring Earth's gravity variations. GRACE(-FO) missions have tremendous value since they are the only available techniques that can measure the global TWS by definition. However, the coarse spatial resolution (around 300 km) of the measurements is among the key factors limiting the applications in related fields, such as understanding water storage changes in small catchments.

In the recent paper published in Nature Water, we developed a self-supervised learning model to downscale GRACE(-FO) measurements and provide a global product with an effective spatial resolution of about 50 km. The specifically designed loss function allows the model to be optimized in the absence of high-resolution ground truth. The quality of the downscaled product has been proven by investigating different aspects, including closing the water balance equation in basins smaller the effective resolution of GRACE(-FO) missions and validating against altimetry-measured water levels. We also discuss the potential downstream applications, including monitoring environmental extremes at the local scale. The downscaled product should be beneficial for the geoscience community and society, especially in the fields of hydrology, climate science, sustainable water management and hazard prediction.

The product is available at external page https://doi.org/10.3929/ethz-b-000648738.
The full paper is available at external page https://doi.org/10.1038/s44221-024-00194-w.
An associated commentary written by Dr. Alexander Sun from Bureau of Economic Geology, The University of Texas at Austin, is available at the News & Views section of Nature Water: external page https://doi.org/10.1038/s44221-024-00199-5.