| |
|---|---|
| System name (version) | Modern Era Retrospective-analysis for Research and Applications version 2 (MERRA-2) (using Goddard Earth Observing System version 5.12.4) |
| Date of implementation | 12 October, 2015 |
2. Configuration | |
|---|---|
Earth system components included in the analysis system (e.g., ocean, sea-ice, land, etc.) | Assimilated and Interactive Aerosols. Observation-based precipitation driving the land surface and aerosol wet deposition except in the high latitudes (Reichle et al. 2017a) |
Horizontal resolution of the model, with indication of grid spacing in km (for the different Earth system component included in the model) | The model is run on a cubed sphere grid. Data are provided at 0.625° longitude by 0.5° latitude (576 by 361 grid points, approximately 50km by 50km) |
Number of levels in the different Earth system components (for the different Earth system component included in the model) | 72 native model levels, also interpolated to 42 pressure levels |
| Frequency of the outputs | 2D variables at 1 hourly frequency, 3D variables at 3 hourly frequency, Analysis variables at 6-hourly frequency |
| Top of the atmospheric model | 0.01 hPa |
| Number of analysis cycle per day | 4 |
| Earliest start date | 00Z 01 January 1980 |
| Integration time step | 900 seconds |
| Length and frequency of the longest forecast | 6 hours, only for the analysis cycle |
| Dataset latency | Data is usually available monthly by the 15th of the following month |
Additional comments:
Documentation: https://gmao.gsfc.nasa.gov/reanalysis/MERRA-2/docs
| 3. Analysis system | |
| Data assimilation method | 3D variational analysis (3D-Var), with the first-guess at the appropriate time of the observations (FGAT) and variational bias correction. |
| Length of the analysis window | 6 hours |
| Number of ensemble members and their resolution | N/A |
Additional comments:
Uses Incremental Analysis Update (Bloom et al. 1996) and global mass constraint (Takacs et al. 2016)
| 4. Externally prescribed boundary conditions and their source | |
| Sea surface temperature | SST and Sea Ice are prescribed from observations; (Bosilovich et al. 2015) |
| Sea-ice | As with SST above, but sea ice albedo is discussed by Cullather et al. (2014) |
| Snow | Observation-based precipitation driving the land surface except in the high latitudes (Reichle et al. 2017a,b) |
| Vegetation | Seasonally-varying climatology of satellite leaf-area index; (Reichle et al. 2017b) |
| Land use (and its evolution in time) | Time invariant satellite land cover; (Reichle et al. 2017b) |
| Aerosols | Emissions (Section 2.2 of Randles et al. 2016); Aerosols are assimilated and interactive with the radiation |
| Green House Gases | Follows RCP 4.5 |
| Solar forcing | NOAA Climate Data Record (CDR) of Solar Spectral Irradiance (SSI), NRLSSI Version 2.1 (Coddington et al. 2017). There is lag in the release of latest data, so the near -real time analysis uses an extrapolation of the solar cycle. |
Additional comments:
| 5. Details of model | |
| Dynamical core (e.g., semi-Lagrangian) | Finite Volume (Putman and Lin, 2007) |
| Grid structure | Cubed sphere (Putman and Lin, 2007) |
| Hydrostatic or nonhydrostatic | Hydrostatic (Putman and Lin, 2007) |
| Radiations parameterization | Chou-Suarez (Molod et al. 2015) |
| Boundary layer parameterization | Molod et al. (2015) |
| Convection parameterization | Molod et al. (2015) |
| Cloud parameterization | Molod et al. (2015) |
| Land surface parameterization | Catchment land surface model (Koster et al. 2000; Reichle et al. 2017b) |
Other relevant details:
| 6. Further information | |
| Operational contact point | Michael Bosilovich, Michael.Bosilovich@nasa.gov |
| URL of the technical note/ reference paper | https://gmao.gsfc.nasa.gov/reanalysis/MERRA-2/docs/ |
| URL for list of products | Bosilovich et al (2016), MERRA-2 File Specification Document https://gmao.gsfc.nasa.gov/pubs/docs/Bosilovich785.pdf |
| DOI details | https://gmao.gsfc.nasa.gov/reanalysis/MERRA-2/citing_MERRA-2/ |
| 7. Observational data used | |
| URL with the list of observational data used in the reanalysis | McCarty et al. (2016), https://gmao.gsfc.nasa.gov/pubs/docs/McCarty885.pdf |
| DOI of data product if available |
Other sources for data access, if available
References
Bloom, S., L. Takacs, A. DaSilva, and D. Ledvina, 1996: Data assimilation using incremental analysis updates. Mon. Wea. Rev., 124, 1256–1271. doi:10.1175/1520-0493(1996)124,1256:DAUIAU.2.0.CO;2.
Bosilovich, Michael G., Santha Akella, Lawrence Coy, Richard Cullather, Clara Draper, Ronald Gelaro, Robin Kovach, Qing Liu, Andrea Molod, Peter Norris, Krzysztof Wargan, Winston Chao, Rolf Reichle, Lawrence Takacs, Yury Vikhliaev, Steve Bloom, Allison Collow, Stacey Firth, Gordon Labow, Gary Partyka, Steven Pawson, Oreste Reale, Siegfried D. Schubert, and Max Suárez, 2015: MERRA-2: Initial Evaluation of the Climate. NASA/TM–2015–104606, Vol. 43, 139 pp. Link
Bosilovich, M. G., R. Lucchesi, and M. Suárez, 2016: MERRA-2: File Specification. GMAO Office Note No. 9 (Version 1.1), 73 pp. Link
Coddington O., J. L. Lean, D. Lindholm, P. Pilewskie, M. Snow, and NOAA CDR Program (2017): NOAA Climate Data Record (CDR) of Solar Spectral Irradiance (SSI), NRLSSI Version 2.1. NOAA National Centers for Environmental Information. https://doi.org/10.7289/V53776SW
Cullather, R.I., S.M.J. Nowicki, B. Zhao, and M. J. Suárez, 2014: Evaluation of the surface representation of the Greenland Ice Sheet in a general circulation model. J. Climate, 27, 4835–4856, doi: 10.1175/JCLI-D-13-00635.1.
Gelaro, R., and Coauthors, 2017: The Modern-Era Retrospective Analysis for Research and Applications, Version 2 (MERRA-2). J. Climate, 30, 5419–5454, https://doi.org/10.1175/JCLI-D-16-0758.1
Koster, R. D., M. J. Suarez, A. Ducharne, M. Stieglitz, and P. Kumar, 2000: A catchment-based approach to modeling land surface processes in a general circulation model: 1. Model structure. J. Geophys. Res., 105, 24 809–24 822, doi:10.1029/2000JD900327.
McCarty, Will, Lawrence Coy, Ronald Gelaro, Albert Huang, Dagmar Merkova, Edmond B. Smith, Meta Seinkiewicz, and Krzysztof Wargan, 2016: MERRA-2 Input Observations: Summary and Assessment. NASA Technical Report Series on Global Modeling and Data Assimilation, NASA/TM-2016-104606, Vol. 46, 61 pp https://gmao.gsfc.nasa.gov/pubs/docs/McCarty885.pdf
Molod, A., Takacs, L., Suárez, M., and Bacmeister, J., 2015: Development of the GEOS-5 atmospheric general circulation model: evolution from MERRA to MERRA2, Geosci. Model Dev., 8, 1339–1356, https://doi.org/10.5194/gmd-8-1339-2015.
Putman, W.M. and Lin, S.J., 2007. Finite-volume transport on various cubed-sphere grids. Journal of Computational Physics, 227(1), pp.55-78. 10.1016/j.jcp.2007.07.022
Randles, C. A., A. M. da Silva, V. Buchard, A. Darmenov, P. R. Colarco, V. Aquila, H. Bian, E. P. Nowottnick, X. Pan, A. Smirnov, H. Yu, and R. Govindaraju, 2016: The MERRA-2 Aerosol Assimilation. NASA Technical Report Series on Global Modeling and Data Assimilation, NASA/TM-2016-104606, Vol. 45, 143 pp. https://gmao.gsfc.nasa.gov/pubs/docs/Randles887.pdf
Reichle, R. H., Q. Liu, R. D. Koster, C. S. Draper, S. P. P. Mahanama, and G. S. Partyka, 2017a: Land surface precipitation in MERRA-2, Journal of Climate, 30, 1643-1664, doi:10.1175/JCLI-D-16-0570.1.
Reichle, R. H., C. S. Draper, Q. Liu, M. Girotto, S. P. P. Mahanama, R. D. Koster, and G. J. M. De Lannoy, 2017b: Assessment of MERRA-2 land surface hydrology estimates, Journal of Climate, 30, 2937-2960, doi:10.1175/JCLI-D-16-0720.1.
Takacs, L.L., Suárez, M.J. and Todling, R., 2016: Maintaining atmospheric mass and waterbalance in reanalyses. Q.J.R. Meteorol. Soc., 142: 1565- 1573.https://doi.org/10.1002/qj.2763