Spatiotemporal Characteristics of Drought Occurrence in Kansas Using Multiple Indices.

Kansas periodically experiences drought of varying durations and severities that constrain the state’s agricultural and hydrological resources. Climatological data from 1900 to 2014 was collected from long-term stations in Kansas and adjacent states to develop a complete, accessible drought datasets for the Palmer Drought Severity Index (PDSI), Standardized Precipitation Index (SPI), and the Standardized Precipitation-Evapotranspiration Index (SPEI). Statistical analysis was performed for each station, and results were summarized by eastern, central, and western zone classifications to facilitate comparisons. The results showed that the relative frequency of mild drought is highest in the southeast and western regions of the state. Moderate to extreme drought occurs more often in central and western Kansas. The mean interrival time between mild droughts is 1-2 years and 2-8 years for severe drought. During the last century, the most severe droughts peaked in the midcentury (1930s and 1950s) for all regions of the state with the average number of drought events per decade between 3 and 9. Less than 7% of short-term agricultural droughts last longer than one year. Mean PDSI, SPI, and SPEI durations are not statically different at the 12 and 18-month time steps for central and western Kansas. PDSI drought severities were computed corresponding to 5, 10, 20, and 50-year return periods. The severity of the 2011 to 2014 drought had return periods between 25-98 years in southwestern Kansas and between 5 and 40 years in central and eastern Kansas.