Palmer Drought Severity Index as a Measure of Hydrologic Drought

The Palmer Drought Severity Index (PDSI) for climatic divisions in New Jersey is compared to the occurrence within each climatic division of streamflows in their lower quartile for the month (streamflow index) and ground-water levels in their lower quartile for the month (ground-water index). These indices are found to have distinct properties. The PDSI values and groundwater index indicate more persistent subnormal conditions than the streamflow index for truncation levels yielding the same total duration of drought over a period. Overall, the three indices of drought can provide three very different characterizations of drought. Refs.