Monitoring terrestrial water storage changes and drought in Jiangxi Province using GRACE and GRACE Follow-on data

Drought incidents often occur which have the non-negligible impact on human living and social economic development. In recent years, Jiangxi Province suffered from some drought disasters especially the Poyang Lake drought bottoming incident in year 2021. Thus, choosing the Jiangxi Province for studying area and April 2002 to December 2022 as studying period and using the Water Storage Deficit Index (WSDI) derived from the Gravity Recovery and Climate Experiment (GRACE) and GRACE Follow-on data to analyze and identify the drought incidents during the study period. Fourteen drought incidents occurred in the study period and the longest drought incident was in 2003-2004, which lasted eight months whose total water deficit is 100.68 km3. Especially, to deeply analyze the Poyang Lake bottoming drought event, the period from April 2022 to December 2022 is selected as the research interval. It demonstrates that the drought began in August 2022 from the northeastern region spread southwest and expanded to the entire area in October 2022 and November 2022, and then retreated to the northwestern region and drought severity of the Poyang Lake is in peak in November 2022 which led to the lake bottoming and severity of drought reaches the peak in whole province. To comprehensively verify accuracy of the WSDI, the self-calibrating palmer drought severity index (scPDSI) and Standardized Precipitation Evapotranspiration Index (SPEI) are adopted for comparison, the relation between precipitation and TWSA (Terrestrial Water Storage Anomaly) shows apparent periodicity and the correlation coefficient between them is 0.59, which indicates that precipitation is a vital factor affecting TWSA of the Jiangxi Province.