A multiscalar Palmer drought severity index

The limitation of the fixed time scale in the Palmer drought severity index (PDSI) family has long been criticized in drought literatures. By modifying the algorithm of duration factors estimation of the self-calibrating PDSI (SC-PDSI), this paper proposed a new approach that could extend the time scale in a wide range. The properties of these newly derived SC-PDSI variants (denoted as SC-PDSIx) at short, medium, and long time scales, respectively, were evaluated through comparisons with the multiscalar standardized precipitation evapotranspiration index (SPEI) over 134 meteorological sites in China. Results show that new SC-PDSIx generally inherits the advantages of original SC-PDSI with a rather stable behavior in aspects of drought frequency and other statistical characteristics. Besides, the spatiotemporal pattern of the 2011 drought reflected by matched SC-PDSIx and SPEI is very similar, indicating that the multiscalar SC-PDSI could be a useful alternative to monitor droughts at different time scales.