MERRA2

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

 

MERRA2 at NCI

We are hosting a copy of some of the MERRA-2 products on gadi in the rr7 project. The data is available in /g/data/rr7/MERRA2/raw/<MERRA-product>/<year>/<files> Filenames are <runid>.<collection>.<timestamp>.nc4

Since the rr7 project is going to be removed and the datasets relocated elsehwere, from 2020 we started downloading newly requested products to the ua8 project:

/g/data/ua8/MERRA2/<frequency>/<product>/

Hosted in rr7

tavg1_2d_rad_Nx

  • MERRA 2D,1-hourly,time-averaged,single-level,assimilation,radiation diagnostics
  • rr7/MERRA2/raw/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

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  • ​​​​​​​MERRA2 2D 1-hourly,time-averaged,single-level,assimilation,surface flux diagnostics
  • ​​​​​​​rr7/MERRA2/raw/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

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  • ​​​​​​​​​​​​​​MERRA 2D ,1-hourly,time-averaged,single-level,assimilation,vertically integrated diagnostics
  • rr7/MERRA2/raw//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
  • rr7/MERRA2/raw/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

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tavg1_2d_slv_Nx

  •  
  • MERRA 2D,1-hourly,Time-Averaged,Single-Level,Assimilation,Single-Level Diagnostics
  • rr7/MERRA2/raw//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
  • ​​​​​​​/rr7/raw/MERRA2/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

Hosted in ua8

​​​​​​​inst1_2d_asm_Nx

  •  
  • ​​​​​​​MERRA-2 inst1_2d_asm_Nx: 2d,1-Hourly,Instantaneous,Single-Level,Assimilation,Single-Level Diagnostics V5.12.4
  • ua8/MERRA2/1hr/M2I1NXASM.5.12.4/<yyyy>/<mm>/MERRA2_100.inst1_2d_asm_Nx.<yyyymmdd>.nc4
  • ​​​​​​​resolution: lat/lon - 0.5 /0.625 degrees Timestep: 1 hourly 
  • ​​​​​​​doi: 10.5067/3Z173KIE2TPD
  • ​​​​​​​file size: 198 MB
  • ​​​​​​​citation: Global Modeling and Assimilation Office (GMAO) (2015), MERRA-2 inst1_2d_asm_Nx: 2d,1-Hourly,Instantaneous,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]10.5067/3Z173KIE2TPD 

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inst3_2d_gas_Nx

  •  
  • ​​​​​​​MERRA-2 inst3_2d_gas_Nx: 2d,3-Hourly,Instantaneous,Single-Level,Assimilation,Aerosol Optical Depth Analysis V5.12.4
  • ua8/MERRA2/3hr/M2I3NXGAS.5.12.4/<yyyy>/<mm>/MERRA2_100.inst3_2d_gas_Nx.<yyyymmdd>.nc4
  • ​​​​​​​doi: 10.5067/HNGA0EWW0R09
  • ​​​​​​​resolution: lat/lon - 0.5 /0.625 degrees Timestep: 3 hourly
  • ​​​​​​​file size: 9.2 MB
  • ​​​​​​​citation: Global Modeling and Assimilation Office (GMAO) (2015), MERRA-2 inst3_2d_gas_Nx: 2d,3-Hourly,Instantaneous,Single-Level,Assimilation,Aerosol Optical Depth Analysis V5.12.4, Greenbelt, MD, USA, Goddard Earth Sciences Data and Information Services Center (GES DISC), Accessed: [Data Access Date]10.5067/HNGA0EWW0R09

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instM_2d_gas_Nx​​​​​​​

  •  
  • MERRA-2 instM_2d_gas_Nx: 2d,Monthly mean,Instantaneous,Single-Level,Assimilation,Aerosol Optical Depth Analysis V5.12.4​​​​​​​
  • ​​​​​​​ua8/MERRA2/monthly/M2IMNXGAS.5.12.4/<yyyy>/MERRA2_100.instM_2d_gas_Nx.<yyyymm>.nc4
  • doi: 10.5067/XOGNBQEPLUC5
  • resolution: lat/lon - 0.5 /0.625 degrees Timestep: monthly
  • file size: 9.2 MB
  • citation: Global Modeling and Assimilation Office (GMAO) (2015), MERRA-2 instM_2d_gas_Nx: 2d,Monthly mean,Instantaneous,Single-Level,Assimilation,Aerosol Optical Depth Analysis V5.12.4, Greenbelt, MD, USA, Goddard Earth Sciences Data and Information Services Center (GES DISC), Accessed: [Data Access Date]10.5067/XOGNBQEPLUC5

 

tavgM_2d_aer_Nx

  •  
  • ​​​​​​​MERRA-2 tavgM_2d_aer_Nx: 2d,Monthly mean,Time-averaged,Single-Level,Assimilation,Aerosol Diagnostics V5.12.4
  • ua8/MERRA2/monthly/M2TMNXAER.5.12.4/<yyyy>/MERRA2_100.tavgM_2d_aer_Nx.<yyyymm>.nc4
  • doi: 10.5067/FH9A0MLJPC7N
  • resolution: lat/lon - 0.5 /0.625 degrees Timestep: monthly
  • file size: 481 MB
  • citation: Global Modeling and Assimilation Office (GMAO) (2015), MERRA-2 tavgM_2d_aer_Nx: 2d,Monthly mean,Time-averaged,Single-Level,Assimilation,Aerosol Diagnostics V5.12.4, Greenbelt, MD, USA, Goddard Earth Sciences Data and Information Services Center (GES DISC), Accessed: [Data Access Date]10.5067/FH9A0MLJPC7N

 

List of variables available for each product