Abstract: The Modern-Era Retrospective Analysis for Research and Applications (MERRA) is a state-of-the-art reanalysis data product that provides, in addition to atmospheric fields, global estimates of soil moisture, latent heat flux, snow, and runoff for 1979-present. A supplemental and improved set of land surface hydrological fields (MERRA-Land) was generated by re-running a revised version of the land ... component of the MERRA system (Reichle et al., 2012). Specifically, the MERRA-Land estimates benefit from corrections to the precipitation forcing with the global gauge-based NOAA Climate Prediction Center Unified (CPCU) precipitation product and from revised parameter values in the rainfall interception model, changes that effectively correct for known limitations in the MERRA surface meteorological forcings. With a few exceptions, the MERRA-Land data appear more accurate than the original MERRA estimates and are thus recommended for those interested in using MERRA output for land surface hydrological studies.
The MERRA-Land product, MSTMNXMLD or tavgM_2d_mld_Nx, is a simulated 2-Dimensional monthly mean at the native resolution. All collections from this group are at reduced horizontal resolution.
The data are on the GEOS-5 native 540 x 361 grid with 2/3° longitude x 1/2° latitude resolution. Data are archived in the HDF-EOS (Grid) format, based on HDF4.
The Simple Subset Wizard (SSW) is designed to provide a simple, unified user interface for submitting subset requests for data. The SSW uses an agent-based architecture to interface with the diversity of subsetters across EOSDIS.
*Reichle, R. H., R. D. Koster, G. J. M. De Lannoy, B. A. Forman, Q. Liu, S. P. P. Mahanama, and A. Toure, 2011: Assessment and enhancement of MERRA land surface hydrology estimates, Journal of Climate, 24, 6322-6338, doi:10.1175/JCLI-D-10-05033.1.
* Bloom, S., L. Takacs, A. DaSilva, and D. Ledvina, 1996: Data assimilation using incremental analysis updates. Mon. Wea. Rev., 124, 1256-1271.
* Bloom, S., A. da Silva, D. Dee, M. Bosilovich, J.-D. Chern, S. Pawson, S. Schubert, M. Sienkiewicz, I. Stajner, W.-W. Tan, M.-L. Wu, 2005: Documentation and Validation of the Goddard Earth Observing System (GEOS) Data Assimilation System - Version 4. Technical Report Series on Global Modeling and Data Assimilation 104606, v26.
* Collins, N., G. Theurich, C. DeLuca, M. Suarez, A. Trayanov, V. Balaji, P. Li, W. Yang, C. Hill, and A. da Silva, 2005: Design and implementation of components in the Earth System Modeling Framework. Int. J. High Perf. Comput. Appl., 19, 341-350, DOI: 10.1177/1094342005056120.