Physical Scientist, National Climatic Data Center, 151 Patton Avenue, Asheville, North Carolina 28801–5001 (e-m: firstname.lastname@example.org).
COMPARING THE PALMER DROUGHT INDEX AND THE STANDARDIZED PRECIPITATION INDEX1
Version of Record online: 8 JUN 2007
JAWRA Journal of the American Water Resources Association
Volume 34, Issue 1, pages 113–121, February 1998
How to Cite
Guttman, N. B. (1998), COMPARING THE PALMER DROUGHT INDEX AND THE STANDARDIZED PRECIPITATION INDEX. JAWRA Journal of the American Water Resources Association, 34: 113–121. doi: 10.1111/j.1752-1688.1998.tb05964.x
Paper No. 97028 of the Journal of the American Water Resources Association. Discussions are open until October 1, 1998.
- Issue online: 8 JUN 2007
- Version of Record online: 8 JUN 2007
- drought index;
- time series analysis
ABSTRACT: The Palmer Drought Index (PDI) is used as an indicator of drought severity, and a particular index value is often the signal to begin or discontinue elements of a drought contingency plan. The Standardized Precipitation Index (SPI) was recently developed to quantify a precipitation deficit for different time scales. It was designed to be an indicator of drought that recognizes the importance of time scales in the analysis of water availability and water use.
This study compares historical time series of the PDI with time series of the corresponding SPI through spectral analysis. Results show that the spectral characteristics of the PDI vary from site to site throughout the U.S., while those of the SPI do not vary from site to site. They also show that the PDI has a complex structure with an exceptionally long memory, while the SPI is an easily interpreted, simple moving average process.