County-Level Monthly Aggregates of gridMET Drought Indices and Meteorological Variables

This dataset provides county-level monthly aggregates of drought indices and meteorological variables for the contiguous United States from 2000 to 2020, derived from gridMET. The drought indices in this dataset include the monthly Standardized Precipitation Evapotranspiration Index (SPEI), Evaporative Demand Drought Index (EDDI), and Standardized Precipitation Index (SPI) at 30-, 90-, 180-day, and 1-year accumulation windows, and monthly Palmer Drought Severity Index (PDSI). In the original gridMET drought products, values are provided at 5-day intervals. For each EOM date, the EOM value was computed by linear interpolation between the two adjacent pentad values and was used as a proxy for the month’s accumulated exposure. The meteorological variables include tmmx and tmmn (daily maximum and minimum 2-m air temperature), rmax and rmin (daily maximum and minimum relative humidity), pr (precipitation), srad (surface downward shortwave radiation), th (wind direction at 10 m), and vs (wind speed at 10 m). Monthly values are the means of the daily series. All variables were aggregated from the ~4-km × 4-km grid to county means using area-weighted spatial averaging. The county polygon boundaries used for spatial aggregation originate from the U.S. Census Bureau’s TIGER/Line shapefiles. For 2000-2009 data, the 2000 county boundary shapefile was used for the spatial aggregation; for 2010-2020 data, the corresponding year county boundary shapefiles were used. This dataset was created to support population-level climate-health research by providing spatially and temporally harmonized climate metrics at the county level and linking these exposures to health and socio-demographic data aggregated at the county level.