RPA Historical observational data (1979-2015) for the conterminous United States at the 1/24 degree grid scale based on MACA training data (METDATA): 2nd edition

This data publication contains a gridded historical (1979-2015) dataset for the conterminous United States that has been summarized to the monthly time scale. This monthly historical dataset was developed using the daily MACA observational data (METDATA), also called MACA Training Data (https://www.northwestknowledge.net/metdata/data/). The MACA training data were used to downscale global climate model projections to the 1/24 degree grid scale. This monthly data will be used in the modeling analyses for the 2020 RPA Assessment. Data include eight separate files containing mean daily mean potential evapotranspiration, total monthly precipitation, mean daily minimum and maximum relative humidity, mean daily downward shortwave radiation at surface, mean daily maximum air temperature, mean daily minimum air temperature, and mean daily mean wind speed at 10 meters high.
The USDA Forest Service (USFS) produces a periodic assessment of the conditions and trends of the Nation's renewable resources required by the Forest and Rangeland Renewable Resources Planning Act (RPA) of 1974. This RPA Assessment provides a snapshot of current U.S. forest and rangeland conditions and trends on all ownerships, identifies drivers of change, and projects 50 years into the future (https://www.fs.fed.us/research/rpa/, Resources Planning Act (RPA) Assessment). For the 2020 RPA Assessment, the implications of climate change are being analyzed across resource areas. These climate variables will support these analyses.
This data publication is a second edition of https://doi.org/10.2737/RDS-2017-0070. This newer edition addresses two issues found with two variables in the first edition. For mean daily maximum relative humidity and for mean daily mean wind speed at 10 meters high, the monthly calculations for February in leap years were not correct. For relative maximum humidity, the grid identifications were one longitude grid cell off from the correct grid identifications. New code was written to process the data, verified as correct. All variables were re-estimated and no additional errors were found. The data set for tmean is not included in the second edition because the computation for tmean was the midpoint of tmin and tmax, and this estimate may not represent the true mean given the variability of temperature through the 24 hour period. We recommend the use of this newer edition. These data were originally published on 02/18/2020. On 03/22/2021 the data were rescaled to match the metadata. Additional minor metadata updates were made on 02/27/2023. Metadata updated on 10/17/2023 to include reference to published document supporting the 2020 RPA Assessment.