Open-Earth-Monitor Global Workshop 2026

Satellite observations from the GRACE mission and its successor GRACE-FO have significantly advanced our ability to monitor terrestrial water storage (TWS) at regional to global scales. However, their limited spatial and temporal resolution hampers the reliable separation of individual hydrological fluxes, particularly precipitation. However, their coarse spatial and temporal resolution makes the individual separation of different hydrological fluxes from TWS a challenging problem. These limitations in current gravity mission concepts can be addressed by a joint collaboration between NASA and ESA initiated the Mass-change And Geosciences International Constellation (MAGIC), which can provide enhanced spatio-temporal observations of mass change and therefore enable improved monitoring of hydrological extremes and dynamics. The primary objective of this work to access how improving the spatial and temporal resolution of future gravity missions impacts precipitation estimation by developing a number of global synthetic experiments. The precipitation data used as forcing of ESM will be compared with the “true” precipitation for testing the reliability of the SM2RAIN approach (Brocca et al., 2014) using as input EWH data (in the past it was implemented by using surface soil moisture data). Simulated precipitation estimates derived from different gravity mission configurations (GRACE-C, NGGM, and MAGIC) were evaluated against reference precipitation to quantify performance improvements. The global correlation analysis shows median and mean correlation coefficients of 0.67 and 0.63, respectively, indicating satisfactory performance of the EWH based SM2RAIN framework across most terrestrial regions. Stronger correlations are observed over Northern Hemisphere mid-latitudes, including Europe, northern Asia, and North America, reflecting robust performance in temperate climates, while reduced performance is evident in several tropical regions such as central Africa, parts of the Amazon Basin, and Southeast Asia. Subsequently, synthetic experiments were developed using filter and unfiltered configurations of GRACE-C, NGGM, and MAGIC missions. The performance of NGGM and MAGIC filtered configurations indicates their capability to capture precipitation dynamics effectively as compared to unfiltered ones. The results of the study clearly highlight the added value of next generation gravity missions for global hydrological monitoring and develops new scalable EO based precipitation estimation systems that support emerging open and distributed EO infrastructures. The proposed framework enables improved assessment of water cycle dynamics as well as enhanced monitoring of hydrological extremes such as droughts and floods.

References

Brocca, L., Ciabatta, L., Massari, C., Moramarco, T., Hahn, S., Hasenauer, S., Kidd, R., Dorigo, W., Wagner, W., & Levizzani, V. (2014). Soil as a natural rain gauge: Estimating global rainfall from satellite soil moisture data. Journal of Geophysical Research: Atmospheres, 119(9), 5128–5141.