Gravity Recovery And Climate Experiment Drought Severity Index (GRACE-DSI)

“The GRACE-DSI is defined as the standardized anomalies of GRACE Total Water Storage (TWS) as follows:

Formula displayed

where i is year ranging from 2002 until now, j is month ranging from January to December,   and σj are the mean and standard deviation of TWS anomalies in month j, respectively. The GRACE-DSI is a dimensionless quantity that detects both drought and abnormally wet events. The values of GRACE-DSI are classified into 11 categories detailed in the table below.”

11 categories of Grace DSI values from exceptionally wet to exceptionally drought


Zhao, Meng, Geruo A, Isabella Velicogna, and John S. Kimball. 2017. “A Global Gridded Dataset of GRACE Drought Severity Index for 2002–14: Comparison with PDSI and SPEI and a Case Study of the Australia Millennium Drought.” Journal of Hydrometeorology 18, no. 8 (August): 2117–2129.


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