GMI Simulations

GMI simulations with different chemical mechanisms (strat-trop, aerosol, tracers, etc.) are available via anonymous ftp to Most simulations since 2010 have been ‘Hindcasts’, that is, simulations of the recent past using reanalysis meteorology. The NASA Modeling Guru website is the primary source for detailed information on these simulations, where they are stored, what output was saved, etc. Below are links to guide you to detailed information on simulations, outputs, and readers.

To find out about recent chemistry and aerosol simulations, see the Summary of Hindcast Production Runs. This gives brief descriptions of our recent simulations, including the directories on dirac where they are stored. Greater detail on the simulations's inputs (e.g., emissions) is provided in the spreadsheet GMI Production Runs. The MERRA2 and MERRA pages also contain brief descriptions of the hindcasts.

To obtain recent tracer simulations, cd to /pub/gmidata2/users/steenrod on dirac. The tracer runs use the same met fields as the Hindcast simulations (MERRA and MERRA2). The tracer runs begin in either 1980 or 1990 and continue to the 2010s. Currently these simulations are not described in the summary of Hindcast runs but here is a list of tracers used in these simulations. Contact Steve Steenrod for more information.

To find out about older (pre-MERRA) simulations, see GMI Productions Runs. The Older Simulations page also contains brief descriptions.

To find out about variables saved and types of output files, see the GMI Production Output Guide. Eight constituent output file types are described in this guide. Outputs are saved at various frequencies including daily instantaneous, monthly average, daily column, and daily satellite overpass times. Other outputs, such as rates for thermal and photolytic reactions, fluxes, and tendencies, are also available; see this list. The linux command ncdump –h filename is useful for peeking inside the file to see all variable names and types.

To find the list of stations for which output is written, see GMI Stations. This list includes latitude, longitude, and altitude for most stations. Hourly output from the more than 300 stations saved is concatenated into single * file located in the ‘stations’ subdirectory, directly under each simulation’s main directory (see the Summary of Hindcast Production Runs for experiment directories).

To obtain IDL readers for reading in constituent output, use anonymous ftp to cd to /pub/atmos/Strahan/gmi2/reader and copy all the *.pro files. The main program is See comments inside this program for guidance on running this code. You will need to modify the default data directories specified in the code to match the location of your local GMI output files. Please contact Susan Strahan for help. The read* programs are useful for reading in multiple years of certain output types.

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MERRA2 Hindcasts

MERRA HIndcasts

Simulations prior to 2010 (pre-MERRA)