The MAIMCPASM or instM_3d_asm_Cp data product is the MERRA Data Assimilation System 3-Dimensional assimilated state on pressure, at a reduced resolution. It is a history file that is produced from the GCM during the corrector segment of the IAU cycle. All collections from this group are at reduced horizontal resolution. MERRA, or the Modern Era Retrospective-analysis for Research and Application, ... is a NASA reanalysis for the satellite era (30 years 1979-current) using the Goddard Earth Observing System Data Assimilation System Version 5 (GEOS-5 DAS).
This data product contains 2-dimensional and 3-dimensional fields that do not vary during the reanalysis.
The data are on the GEOS-5 native 288 x 144 grid with 1.25° longitude x 1.25° latitude resolution. The pressure-level data will be output in 42 pressure levels. The files contain the data processed as monthly means. Data are archived in the HDF-EOS (Grid) format, based on HDF4.