The Modern Era Retrospective-Analysis for Research and Applications (MERRA) is a NASA reanalysis integrating satellite observations using a major new version of the Goddard Earth Observing System Data Assimilation System Version 5 (GEOS-5).
MERRA focuses on historical analyses of the hydrological cycle on a broad range of weather and climate time scales covering the modern satellite era from 1979 to present.
The state-of-the-art GEOS-5 data assimilation system includes many modern observing systems (such as EOS) in a climate framework Specifically, the GEOS-DAS Version 5 implements Incremental Analysis Updates (IAU) to slowly adjust the model states toward the observed state.

MERRA-2 is produced with the GMAO/GEOS-5 Data Assimilation System Version 5.12.4 and its native resolution is 0.5° x 0.625° x 72 hybrid sigma/pressure levels. Hourly data intervals are used for two-dimensional products, while 3-hourly intervals are used for three-dimensional products. These may be on the model’s native 72-layer vertical grid or at 42 pressure surfaces extending to 0.1 hPa.
MERRA-2 spans from 1979 to present (with about 5 months lag).

The 42 pressure levels are: 1000, 975, 950, 925, 900, 875, 850, 825, 800, 775, 750, 725, 700, 650, 600, 550, 500, 450, 400, 350, 300, 250, 200, 150,100, 70, 50, 40, 30, 20,10, 7, 5, 4, 3, 2, 1,0.7, 0.5, 0.4, 0.3, 0.1 hPa
The 72 native grid levels are:

Information retrieved from NCAR climate re-analysis guide and
GEOS-CHEM MERRA-2 wiki. The data was downloaded from the GES DISC data store where
information on all the MERRA-2 products is available.

License and Acknowledgements

Access to GES DISC data requires all users to be registered with the Earthdata Login system, even if we downloaded the data for you you should register. It is important for the data providers to have an estimate of users to justify the work that goes with providing the data services.
Complete terms of use and information on how to sign up are available on the GEOS-DISC data policy webpage .
Example of citation including the DOI, each product has its own (see below).
Global Modeling and Assimilation Office (GMAO)(2015), MERRA-2 inst6_3d_ana_Np: 3d,6-Hourly,Instantaneous,Pressure-Level,Analysis,Analyzed Meteorological Fields V5.12.4, Greenbelt, MD, USA, Goddard Earth Sciences Data and Information Services Center (GES DISC), Accessed [Data Access Date] 10.5067/A7S6XP56VZWS

MERRA-2 on raijin


We are hosting a copy of some of the MERRA-2 products on raijin in new "Global Observations and Re-analysis Datasets" group rr7, in collaboration with CAWCR.
The data is available in /g/data1/rr7/MERRA2/raw/<MERRA-product>/<year>/<files>
Filenames are <runid>.<collection>.<timestamp>.nc4

Last update on 24th of October 2016: updated to September 2016 included.

We started with the following products, that will be regularly updated:
  • tavg1_2d_rad_Nx
    • MERRA 2D,1-hourly,time-averaged,single-level,assimilation,radiation diagnostics
    • /M2T1NXRAD.5.12.4/yyyy/mm/MERRA2_100.tavg1_2d_rad_Nx.yyyymmdd.nc4
    • resolution: lat/lon - 0.5 /0.625 degrees Timestep: 1 hourly
    • doi: 10.5067/Q9QMY5PBNV1T
    • file size: 209 Mb
    • citation: Global Modeling and Assimilation Office (GMAO)(2015), MERRA-2 tavg1_2d_rad_Nx: 2d,1-Hourly,Time-Averaged,Single-Level,Assimilation,Radiation Diagnostics V5.12.4, Greenbelt, MD, USA, Goddard Earth Sciences Data and Information Services Center (GES DISC), Accessed [Data Access Date] 10.5067/Q9QMY5PBNV1T
  • tavg1_2d_flx_Nx
    • MERRA2 2D 1-hourly,time-averaged,single-level,assimilation,surface flux diagnostics
    • /M2T1NXFLX.5.12.4/yyyy/mm/MERRA2_100.tavg1_2d_flx_Nx.yyyymmdd.nc4
    • resolution: lat/lon - 0.5 /0.625 degrees Timestep: 1 hourly
    • doi: 10.5067/7MCPBJ41Y0K6
    • file size: 380 Mb
    • citation: Global Modeling and Assimilation Office (GMAO)(2015), MERRA-2 tavg1_2d_flx_Nx: 2d,1-Hourly,Time-Averaged,Single-Level,Assimilation,Surface Flux Diagnostics V5.12.4, Greenbelt, MD, USA, Goddard Earth Sciences Data and Information Services Center (GES DISC), Accessed [Data Access Date] 10.5067/7MCPBJ41Y0K6
  • tavg1_2d_int_Nx
    • MERRA 2D ,1-hourly,time-averaged,single-level,assimilation,vertically integrated diagnostics
    • /M2T1NXINT.5.12.4/yyyy/mm/MERRA2_100.tavg1_2d_int_Nx.yyyymmdd.nc4
    • resolution: lat/lon - 0.5 /0.625 degrees Timestep: 1 hourly
    • doi: 10.5067/Q5GVUVUIVGO7
    • file size: 1.3 Gb
    • citation: Global Modeling and Assimilation Office (GMAO)(2015), MERRA-2 tavg1_2d_int_Nx: 2d,1-Hourly,Time-Averaged,Single-Level,Assimilation,Vertically Integrated Diagnostics V5.12.4, Greenbelt, MD, USA, Goddard Earth Sciences Data and Information Services Center (GES DISC), Accessed [Data Access Date] 10.5067/Q5GVUVUIVGO7
  • inst6d_3d_ana_Np
    • MERRA 3D,6-hourly,instantaneous,pressure-level,analysis,analyzed meteorological fields
    • /M2I1NPANA.5.12.4/yyyy/mm/MERRA2_100.inst6_3d_ana_Np.yyyymmdd.nc4
    • resolution: lat/lon - 0.5 /0.625 degrees Timestep: 6 hourly Levels: 42
    • doi: 10.5067/A7S6XP56VZWS
    • file size: 511 Mb
    • citation: Global Modeling and Assimilation Office (GMAO)(2015), MERRA-2 inst6_3d_ana_Np: 3d,6-Hourly,Instantaneous,Pressure-Level,Analysis,Analyzed Meteorological Fields V5.12.4, Greenbelt, MD, USA, Goddard Earth Sciences Data and Information Services Center (GES DISC), Accessed [Data Access Date] 10.5067/A7S6XP56VZWS
  • tavg1_2d_slv_Nx
    • MERRA 2D,1-hourly,Time-Averaged,Single-Level,Assimilation,Single-Level Diagnostics
    • /M2T1NXSLV.5.12.4/yyyy/mm/MERRA2_100.tavg1_2d_slv_Nx.yyyymmdd.nc4
    • resolution: lat/lon - 0.5 /0.625 degrees Timestep: 1 hourly
    • doi: 10.5067/VJAFPLI1CSIV
    • file size: 400 Mb
    • citation: Global Modeling and Assimilation Office (GMAO)(2015), MERRA-2 tavg1_2d_slv_Nx: 2d,1-Hourly,Time-Averaged,Single-Level,Assimilation,Single-Level Diagnostics V5.12.4, Greenbelt, MD, USA, Goddard Earth Sciences Data and Information Services Center (GES DISC), Accessed [Data Access Date] 10.5067/VJAFPLI1CSIV
  • inst3d_3d_asm_Np
    • MERRA 3D,3-hourly,Instantaneous,Pressure-Level,Assimilation,Assimilated Meteorological Fields
    • /M2I3NPASM.5.12.4/yyyy/mm/MERRA2_100.inst3_3d_asm_Np.yyyymmdd.nc4
    • resolution: lat/lon - 0.5 /0.625 degrees Timestep: 3 hourly Levels: 42
    • doi: 10.5067/QBZ6MG944HW0
    • file size: 1.2 Gb
    • citation: Global Modeling and Assimilation Office (GMAO)(2015), MERRA-2 inst3_3d_asm_Np: 3d,3-Hourly,Instantaneous,Pressure-Level,Assimilation,Assimilated Meteorological Fields V5.12.4, Greenbelt, MD, USA, Goddard Earth Sciences Data and Information Services Center (GES DISC), Accessed [Data Access Date] 10.5067/QBZ6MG944HW0

  • List of variables available for each product