Global Assessment of Drought Recovery Time from Gridded Precipitation Datasets and GRACE/GRACE-FO Terrestrial Water Storage Anomalies

This study independently evaluated hydrological drought recovery time (DRT) using terrestrial water storage (TWS) and precipitation datasets. TWS data were sourced from the Global Gravity-based Ground Product (G3P) spherical harmonic solution and JPL mascon solution (RL06), the products of the Gravity Recovery and Climate Experiment (GRACE) and GRACE Follow-on (GRACE-FO). Precipitation data were obtained from the Global Precipitation Climatology Center (GPCC) Full Data Monthly Product (version 2022) and the Global Precipitation Climatology Project (GPCP) Monthly Analysis Product (version 3.2). GPCC provides a station-based dataset, while GPCP integrates station and satellite observations. Hydrological drought characteristics were assessed across Köppen-Geiger climate zones by using the two methods of storage deficit (SD) and required precipitation amount (RPA). The SD method estimated DRT using TWS anomalies (TWSA), while the RPA method incorporated TWSA and precipitation anomalies, leveraging their linear relationship. Results showed similar mean DRT estimates from GPCC and GPCP (~13 months), with 86.0% consistency. In contrast, mean DRT estimates from G3P were approximately three months shorter than those from JPL mascon. G3P exhibited 5.0% higher consistency in DRT estimates than JPL mascon. Among climate zones the equatorial zone demonstrated the shortest DRT (~10 months) and the highest consistency (~98%), while the polar zone had the longest DRT (~16 months) and the lowest consistency (~75%). Overall, strong agreement was found between GPCC and GPCP in mean DRT estimates and consistency. Furthermore, G3P demonstrated slightly better alignment with the precipitation products than JPL mascon. This study analyzes hydrological drought characteristics, offering valuable insights into meteorological and hydrological processes while evaluating the performance of precipitation and TWS products.