DOI: 10.5066/p9phpk4f
title: CONUS404: Four-kilometer long-term regional hydroclimate reanalysis over the conterminous United States (ver. 2.0, December 2023)

description: CONUS404 is a unique, high-resolution hydro-climate dataset appropriate for forcing hydrological models and conducting meteorological analysis over the contiguous United States.  CONUS404, so named because it covers the CONtiguous United States for 40 years at 4-km resolution, was produced by the Weather Research and Forecasting (WRF) Model simulations run by National Center for Atmospheric Research (NCAR) as part of a collaboration with the U.S. Geological Survey (USGS) Water Mission Area.  In fact, CONUS404 includes 41 years of data (water years 1980-2020) and 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. 

The CONUS404 dataset, produced using WRF version 3.9.1.1, is the successor to the CONUS1 dataset (Liu and others, 2017) with improved representation of weather and climate conditions in the central United States due to the addition of a shallow groundwater module and several other improvements in the Noah-Multiparameterization (Noah-MP) Land Surface Model land surface model.  It also uses a more up-to-date and higher-resolution reanalysis dataset (ERA5; Hersbach and others, 2020) as input and covers a longer period than CONUS1.

Access to Original Dataset
The full CONUS404 simulation output files are being archived on the USGS&amp;amp;amp;amp;amp;rsquo;s Black Pearl tape drive system. In order to provide access to the entire output dataset, we have created a Globus access portal for the raw output files, which can be found here: https://app.globus.org/file-manager?origin_id=39161d64-419d-4cc4-853f-f6e737644eb4&amp;amp;amp;amp;amp;amp;origin_path=%2F. In order to access the files, you will need to log in with an existing Globus account or create one and then perform a file transfer. If you are transferring the files to your local computer, you will also want to install and set up Globus Connect Personal to turn your local machine into an available Globus endpoint. There is no cost for a Globus account. 

Once Globus is set up, you are ready to access the raw output files. At the highest level, the data files are organized into folders by water year (for example, WY2020). Inside each water year folder, you will find three sets of files, which were produced at different temporal resolutions.  

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 are attached to this data release. 

NOTE: The entire set of CONUS404 outputs files are not yet available, as the data transfer to the Globus endpoint will be ongoing through early May 2023. As of February 13, 2023, data files for water years 1980-1989 have already been transferred and are currently available. The remainder of the files are being populated in order of water year. 

Access to Additional Versions of the Content
The data provided through the Globus endpoint is raw model output, and the format may not be optimal for many users. The Globus endpoint also does not provide the ability to subset the data along some of its dimensions before download (for example, a spatial subset could not be pulled directly from the GLOBUS endpoint). Consequently, we have two additional pathways that are likely to provide more convenient access to a subset of the data. The format of the data available through each of these access points will be different than what is seen at the Globus endpoint, and there can be differences in the data (detailed with description for each access point, below). However, the data values are scientifically equivalent at every access point described below. 

NCAR Research Data Archive 
The first alternate access point is NCAR&amp;amp;amp;amp;amp;rsquo;s Research Data Archive (RDA). The values in this dataset are the same as those in the raw files, with an exception for some variables having a slight reduction in numerical precision, but no loss of scientific information. In addition, duplicate and empty data variables have been removed. In addition, 14 additional variables derived from the raw output have been added to this version of the CONUS404 dataset (details are provided in the data dictionary found on the &amp;amp;amp;amp;amp;ldquo;Documentation&amp;amp;amp;amp;amp;rdquo; tab on the RDA page for this dataset). RDA data access can be found here: https://rda.ucar.edu/datasets/ds559.0/. There is no cost associated with data download. The transfer of data files to the RDA is also an ongoing process, and the data files at this access point will continue to be populated over the next several months. 

AWS Cloud (requester pays) 
The second alternate access point is provided through object storage within an Amazon Web Services (AWS) Simple Storage Service (S3) bucket. This data access point links to zarr-formatted data files which contain a subset of the CONUS404 variables. This chunked data format is optimized for workflows utilizing distributed computing. This data is free to access for workflows that are running in the AWS us-west-2 region. If you would like to pull the data out of the cloud or into another AWS region, you will need an AWS account. The bucket storing the data is &amp;amp;amp;amp;amp;ldquo;requester pays,&amp;amp;amp;amp;amp;rdquo; meaning that the user will incur AWS fees (as described on the &amp;amp;amp;amp;amp;ldquo;Requests and Data Retrievals&amp;amp;amp;amp;amp;rdquo; tab). Access to these data files can be found in the CONUS404 intake catalog. You can find a demonstration of how to use intake catalogs in python here, or you can manually parse the information in the yaml file if you are using it in another programming language. We strongly recommend pulling the access url from the intake catalog each time you run a workflow as the storage location may change, but we will always keep the link in the intake catalog up-to-date. 

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