Monitoring the 1996 Drought Using the Standardized Precipitation Index

TLDR

Droughts are difficult to detect and monitor, and while indices such as the Palmer Drought Severity Index have been used, they have limited success; the newly developed Standardized Precipitation Index offers simplicity and temporal flexibility that improve detection across all timescales. This article examines the 1996 drought in the southern plains and southwestern United States using the SPI. The authors use a series of maps to show how the SPI could detect the drought’s onset and track its progression, and present a detailed Texas case study. The SPI proved to be an effective operational tool for detecting and monitoring the 1996 drought, supporting its use in state‑level drought management.

Abstract

Abstract Droughts are difficult to detect and monitor. Drought indices, most commonly the Palmer Drought Severity Index (PDSI), have been used with limited success as operational drought monitoring tools and triggers for policy responses. Recently, a new index, the Standardized Precipitation Index (SPI), was developed to improve drought detection and monitoring capabilities. The SPI has several characteristics that are an improvement over previous indices, including its simplicity and temporal flexibility, that allow its application for water resources on all timescales. In this article, the 1996 drought in the southern plains and southwestern United States is examined using the SPI. A series of maps are used to illustrate how the SPI would have assisted in being able to detect the onset of the drought and monitor its progression. A case study investigating the drought in greater detail for Texas is also given. The SPI demonstrated that it is a tool that should be used operationally as part of a state, re...