CONUS404 PGW: Four-kilometer long-term regional hydroclimate reanalysis perturbed with pseudo-global warming (PGW) conditions over the conterminous United States (ver 2.0, June 2026)

The CONUS404 pseudo-global warming (PGW) dataset is a future-perturbed hydro-climate dataset, created as a follow on to the CONUS404 dataset (https://doi.org/10.5066/P9PHPK4F). This metadata record serves as documentation for the authoritative version of the CONUS404 PGW atmospheric forcing dataset. The CONUS404 PGW dataset represents the weather from 1980 to 2024 under a warmer and wetter climate environment and provides an opportunity to explore the event-based climate change impacts when used with the CONUS404 historical data. It covers a future-perturbed 45-year period (water years 1980-2024, October 1, 1979 - September 30, 2024) and has sufficient temporal and spatial detail to resolve probable mesoscale atmospheric states and processes in a future warmer climate, making it appropriate for forcing hydrological models and conducting meteorological analyses to study one possible scenario of climate changes and resultant hydrologic impacts over the conterminous United States (CONUS).

The CONUS404 PGW simulation was run by National Center for Atmospheric Research (NCAR) as part of a collaboration with the U.S. Geological Survey (USGS) Water Mission Area. The dataset is the output of the Weather Research and Forecasting (WRF) v 3.9.1.1 model (Skamarock and others, 2008), forced with European Centre for Medium-Range Weather Forecasts (ECMWF) fifth generation atmospheric reanalysis (ERA5) data (Hersbach and others, 2020) plus Community Earth System Model 2 (CESM2) Large Ensemble Community Project (LENS2) projected climate perturbations (Rodgers and others, 2021). It consists of time series of nearly 200 2-dimensional variables and a wide range of 3-dimensional variables. The spatial domain extends beyond the CONUS into Canada and Mexico, thereby capturing transboundary river basins and covering all contributing areas for the CONUS surface waters.
Access to Original Dataset
The full CONUS404 PGW simulation output files are approximately one petabyte (1 PB) in volume and are being archived on the U.S. Geological Survey's Black Pearl* tape drive system. This is raw model output in a format that does not support efficient subsetting, so it is not optimal for many users. We have an additional pathway that is likely to provide more convenient access to a subset of the data, described below. The data available through this access point will be in a different format than the original model output archived on Black Pearl; however, the data values are scientifically equivalent. Please reach out to the data release contact if you think you need access to the original model outputs archived on Black Pearl.

The metadata in this data release was organized to align with the structure of the original model outputs, but it can be used as a reference for data at the access point. The original model outputs include three sets of files, each of which has a different time step.

wrfout files are hourly files with all model outputs. These are stored as 1 netCDF4 file per hour.
auxhist24 files are 15-minute files for precipitation and 2-meter temperature. These are stored as 1 netCDF4 file per day (96 time steps in each); these daily files have been bundled into monthly tar files.
wrfxtrm files are daily minimum, maximum, and mean values of a selection of surface variables. These are stored as 1 netCDF4 file per day; these daily files have been bundled into monthly tar files.
The data dictionaries documenting the variables available in each of the sets of files listed above are attached as csv files in this data release.

NOTE: One file from this simulation is missing from the archived raw outputs (wrfout for 2/1/2017). This raw output file cannot be recovered; however, data for this timestamp is still available in the derivative data products: the Analysis-Ready Zarr Store.

Analysis-Ready Zarr Store
Access to a subset of the CONUS404 PGW data is provided in zarr format, which is a chunked data format (https://www.unidata.ucar.edu/blogs/developer/entry/chunking_data_why_it…) that is optimized for workflows that only require a subset of the dataset or workflows that utilize distributed computing. This data includes a subset of the variables available in the wrfout and wrfxtrm files from the original model output. Access to these data files is described here: https://hytest-org.github.io/hytest/dataset_access/CONUS404_ACCESS.html. Please note that these sample workflows were built around the CONUS404 zarr dataset (https://doi.org/10.5066/P9PHPK4F), but the methods are equally applicable to the CONUS404 PGW zarr dataset.

Please refer to the Supplemental Information element of this metadata record for further information on CONUS404 PGW.

*Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government.