University of California, Merced and the Desert Research Institute
The Multi-Indicator Drought Index (MIDI) looks at current drought conditions across the U.S. by integrating several key drought monitoring indices into a single objective, computer-generated map. This experimental drought map is based on the methodology developed at the NOAA National Weather Service's Climate Prediction Center.
The short-term MIDI combines the Palmer Drought Severity Index (PDSI), Z-Index, 1-month Standardized Precipitation Index (SPI), and 3-month SPI to approximate drought impacts from changes in precipitation and moisture over a short-term timeframe.
The long-term MIDI combines PDSI, Z-Index, and 6-month, 1-year, 2-year, and 5-year SPI to to approximate drought impacts from changes in precipitation and moisture over a long-term timeframe.
The short- and long-term MIDI products are created using the Climate Engine tool, and apply the Climate Prediction Center's weighting ratios to the high-resolution gridMET gridded dataset (with a reference period of 1979–present). The data are updated every 5 days, with a delay of 4 to 5 days to allow for data collection and quality control.
The Multi-Indicator Drought Index is the result of NIDIS-funded research.