Global CPC Unified Daily Precipitation: Drought Indices
National Weather Service Climate Prediction Center (CPC)
The National Weather Service's Climate Prediction Center (CPC) produces a Global Unified Daily Precipitation product from January 1, 1979-present. This product is the combination of all sources available to CPC with the goal of providing high quality and consistent precipitation data and offer a comprehensive view of precipitation patterns worldwide. The daily precipitation products are provided as aggregated 1, 2, 3, 6, 9, and 12-month accumulation periods with a 1-day latency.
SPI
The Standardized Precipitation Index, or SPI, is a drought index that captures how observed precipitation deviates from the climatological average over a given time period. This global SPI is derived from the CPC Daily Unified Precipitation dataset, using the Climate Engine tool, and includes timescales of 1, 2, 3, 6, 9, and 12 months. The SPI calculation uses a climatology period of 1991-2020 and non-parametric distribution type.
SPEI
The Standardized Precipitation Evapotranspiration Index (SPEI) is derived from the CPC Daily Unified Precipitation dataset, using the Climate Engine tool, and includes timescales of 1, 2, 3, 6, 9, and 12 months. The SPEI calculation uses a climatology period of 1991-2020 and non-parametric distribution type.
