Identification of drought events in the major basins of Central Asia based on a combined climatological deviation index from GRACE measurements.

Under climate change, droughts are causing increasingly larger damages around the world, attracting the attention of governments and researchers. In this study, the terrestrial water storage anomalies (TWSA) obtained from a Gravity Recovery and Climate Experiment (GRACE) were coupled with precipitation, creating a Combined Climatological Deviation Index (CCDI). This index was used to analyze the drought events that occurred in the major basins of Central Asia between April 2002–June 2017. The main conclusions are as follows: (1) the certain but not significant (i.e., p >.05) impacts of precipitation were detected on the total water storage anomalies (TWSA) of three basins (i.e., Irtysh River Basin (IRB), Syr Darya Basin (SDB), and Amu Darya Basin (ADB)) that originate from the Tienshan Mountains based on the correlation coefficient between precipitation and terrestrial water storage (TWS); (2) the Drought Severity Index (DSI), the Palmer Drought Severity Index (PDSI), and the Standardized Precipitation Index over a 12-month scale (SPI12) were related to the CCDI in the major basins of Central Asia, suggesting that the CCDI can be applied effectively to assess the drought characteristics of these basins; (3) the most severe drought events detected by the CCDI in the IRB, SDB, and ADB occurred in 2012, 2014, and 2014, respectively. A humidification trend was observed for the IRB, while a drought trend was observed in the SDB and ADB. Therefore, it appears that the CCDI can be effectively applied to determine the severity of droughts, increase water-saving awareness, and avoid the effects of droughts. • Precipitation has little effect on TWS in Central Asia. • CCDI can character the drought events in Central Asia well. • The drought severity from CCDI was more severe than that from other traditional drought indices. • All the drought indices were discovered the obvious drought events in Central Asia during 2008–2009. [ABSTRACT FROM AUTHOR]