National Aeronautics and Space Administration

The MERRA-2 AMIP dataset consists of a 10-member ensemble of free-running simulations with the GEOS atmospheric model. The model version, along with imposed boundary conditions, is configured identically to the GEOS model used in the MERRA-2 reanalysis dataset. The simulations were performed using a c180L72 configuration of the cubed-sphere grid and output fields are interpolated to a 0.5° latitude by 0.625° longitude grid, on either the native layers or on a selected set of pressure levels, as with the MERRA-2 dataset.

As such, the M2-AMIP dataset supplements the MERRA-2 reanalysis, providing a suite of model simulations that are identical to the analyses, with the exception that they do not ingest the observations. The 10-member ensemble provides information on the natural variations inherent in any free-running model simulation.

The M2-AMIP model ensemble and some aspects of its performance are documented in a GMAO Technical Memorandum: Collow et al. (2017) GMAO Tech Memo #47

The file specifications are available at: Collow et al. (2018) GMAO Office Note #15

Monthly mean data from each of the 10 ensemble members and daily data from one member are available via a data portal at the NCCS: https://portal.nccs.nasa.gov/datashare/gmao_m2amip/