Physical Sciences and Mathematics Commons^™

A Modified Standardized Precipitation Index For Drought Monitoring, Brent Mcroberts, John Nielsen-Gammon

2011 Symposium on Data-Driven Approaches to Droughts

The SPI Blend is a modified Standardized Precipitation Index (SPI) created for use in a newly developed, high-resolution drought monitoring tool, assessing drought using precipitation data on multiple time scales. Unlike the traditional SPI, the SPI Blend uses a linear weighting system that places a higher importance on recent precipitation within a time period. At each time scale, the MPE precipitation data are divided into several periods and the precipitation total from the most recent period is given the highest weight, with a linear decrease in the weights for succeeding periods. The high-resolution (4 km) precipitation data are obtained daily …