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GEOS2WRF and MERRA2WRF software

Created on: Jun 4, 2012 2:22 PM by Eric Kemp - Last Modified:  Jul 5, 2016 11:04 AM by Eric Kemp

This gzipped tar file contains updated (June 2016) source code for the GEOS2WRF and MERRA2WRF software, as well as a PDF copy of the NASA Open Source Software Agreement. These programs are responsible for preparing GEOS-5, MERRA, or MERRA2 data for use with the WRF (or NU-WRF) model. Please note the following:

  1. This software is provided as-is, without warranty or support. See the NASA Open Source Software Agreement for legal specifics.
  2. See Section 5.3 of the NU-WRF Version 8 User Guide for instructions on use.  Note that outside of NU-WRF, users must directly invoke a Makefile to compile or clean (the reference scripts are not included).
  3. Neither GEOS2WRF nor MERRA2WRF process soil conditions. The GEOS-5 Catchment LSM uses special bulk moisture variables that do not translate to unique profiles of soil moisture needed by WRF. Users will need a separate source of soil conditions, preferrably by running LIS in spin-up mode.
  4. Neither GEOS2WRF nor MERRA2WRF process chemistry or aerosol data. The programs were written as front-ends for the WRF preprocessors METGRID and REAL, and these in turn only support meteorological fields. 
  5. GEOS2WRF is broken up into multiple programs, with one program ('geos2wps') responsible for extracting user-specified variables from HDF4, HDFEOS2, or netCDF GEOS files, and additional utilities to derive new variables or interpolate isobaric fields underground. A collection of sample scripts are available to automate the GEOS2WRF programs, but users will ultimately need to customize these scripts to the files and variables in their possession. The GEOS2WRF software has been used to process MERRA and MERRA2 files, as well as the daily GEOS-5.7.2 files produced by the Global Modeling and Assimilation Office (GMAO) in May 2012. If the user's data are organized differently from these datasets, then new utilities may need to be written to handle their data.
  6. All input data must be on a equirectangular (lat/lon) grid. Any files on a "cubed sphere" grid will not be processed correctly.
  7. MERRA2WRF is customized to process HDF4, HDFEOS2, and netCDF files for MERRA or MERRA2 from the NASA GES DISC web site Users who wish to process MERRA or MERRA2 data are advised to use MERRA2WRF rather than the more generic GEOS2WRF programs. However, if the format of the data on GES DISC changes in the future, then MERRA2WRF may be retired in favor of GEOS2WRF.
  8. MERRA2WRF treats HDFEOS2 files differently from HDF4 (and netCDF).  The HDFEOS2 files from GES DISC have different variable names from the HDF4 and netCDF versions. Users with '.hdf' files should examine the variable names using the 'ncdump-hdf4' utility included with HDF4; if "EOSGRID" is used in the variable names, the file is HDFEOS2, and the appropriate format flag should be set in the namelist input file.
  9. Users do not need to generate the 2-meter temperature, 2-meter moisture, and 10-meter winds before running MERRA2WRF. Instead, 1-hourly time average values are available from the MERRA files and are processed instead. 
  10. Users are advised to process model-level data instead of isobaric data, for better vertical resolution and to avoid having to extrapolate data underground (e.g., to 850 mb in the Rockies).
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