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Drought Indices

There are a wide variety of drought indices and variables used to describe various forms of drought. This data is best accessed via VSI and STAC to enable climate data summarization at the desired temporal and spatial resolution.

To accelerate your access to basic drought data, the ESIIL team has made annual averages of SPEI and PDSI for the Southern Rockies available on the Cyverse data store at the below directory:


SPEI, or the Standardised Precipitation-Evapotranspiration Index, is a multiscalar drought index based on climatic data. It can be used for determining the onset, duration and magnitude of drought conditions with respect to normal conditions in a variety of natural and managed systems such as crops, ecosystems, rivers, water resources, etc. An overview of SPEI is available here. The pre-compiled datasets are at the 30 day, 1 year, and 5 year time scales and are from the TerraClimate dataset.

PDSI, or the Palmer Drought Severity Index, uses readily available temperature and precipitation data to estimate relative dryness. However, it is not multiscalar. An overview of PDSI from NCAR is here. The pre-compiled dataset is from the TerraClimate dataset.

Last update: 2024-05-09