GRACE water-storage variation and drought tendency analysis in Wuhan area
XIE Ping1, ZHANG Shuangxi2,3*, JIN Taoyong2,3, WEI Yu2, CAI Jianfeng2, XU Chen4
1. Wuhan Central Meteorological Observatory, Wuhan, Hubei 430074, China; 2. School of Geodesy and Geomatics, Wuhan University, Wuhan, Hubei 430079, China; 3. Key Laboratory of Geospace, Environment and Geodesy, Ministry of Education, Wuhan University, Wuhan, Hubei 430079, China; 4. Bureau of Geophysical Prospecting Inc., China National Petroleum Co, Zhuozhou, Hebei 072750, China
Abstract：This study evaluated the water-storage variation of Wuhan city and drought tendency, based on GRACE time-varying gravity to revise the equivalent water height by comparing the rainfall recorded at Wuhan Station. The study found that there is a correlation between the change of equivalent water height and rainfall data, and cycle 1 a is consistent, only with phase lags. There is also a good consistency in the long-cycles of 2 a and 4 a, showing that the phase is advanced, and the short-term correlation is poor. The drought index GRACE-DSI extracted from GRACE data reflects the comprehensive changes of land water, such as soil water, interlayer water and surface water. On the other side,SPI mainly reflects rainfall and surface drought, and the combination of the two can further comprehensively reflect the degree of meteorological drought. According to the results, the correlation be-tween GRACE-DSI index and the SPI index during the period from August 2002 to April 2020 can be divided into three stages: low correlation, high correlation, and then low correlation stage. Especially, during the period of June 2013 to April 2020, the groundwater in Wuhan gradually saw an increase based on GRACE-DSI index, and the drought degree continued to easae. However the SPI indicator showed that during this period, there were many occurrences of low rainfall and severe surface drought.
