A Self-Calibrating Palmer Drought Severity Index

Authors

Nathan Wells, University of Nebraska—Lincoln
Steve Goddard, University of Nebraska—LincolnFollow
Michael Hayes, University of Nebraska - LincolnFollow

Date of this Version

2004

Citation

2004 American Meteorological Society

Comments

Journal of Climate Volume 17 2335-2351

Abstract

The Palmer Drought Severity Index (PDSI) has been used for more than 30 years to quantify the long-term drought conditions for a given location and time. However, a common critique of the PDSI is that the behavior of the index at various locations is inconsistent, making spatial comparisons of PDSI values difficult, if not meaningless.

A self-calibrating Palmer Drought Severity Index (SC-PDSI) is presented and evaluated. The SC-PDSI automatically calibrates the behavior of the index at any location by replacing empirical constants in the index computation with dynamically calculated values. An evaluation of the SC-PDSI at 761 sites within Nebraska, Kansas, Colorado, Wyoming, Montana, North Dakota, and South Dakota, as well as at all 344 climate divisions shows that it is more spatially comparable than the PDSI, and reports extreme wet and dry conditions with frequencies that would be expected for rare conditions.