Collaboratively Enabling Reanalysis Intercomparison Using the Earth System Grid Federation (ESGF): A Case Study.

Wednesday, 17 December 2014
Gerald L Potter, NASA Goddard Space Flight Center, Greenbelt, MD, United States, Michael G Bosilovich, Earth Sciences Division, Greenbelt, MD, United States, Laura Carriere, NCCS, NASA Goddard, Greenbelt, MD, United States, Mark McInerney, NASA Goddard, Greenbelt, MD, United States, Denis Nadeau, Climate Model Data Service, NASA Goddard Space Flight Center, Greenbelt, MD, United States and Yingshuo Shen, NASA GSFC, Greenbelt, MD, United States
The NASA Climate Model Data Service (CDS) and the NASA Center for Climate Simulation (NCCS) are collaborating to provide an end-to-end system for the comparative study of the major reanalysis projects: ECMWF ERA-Interim, NASA/GMAO MERRA, NOAA/NCEP CFSR, NOAA/ESRL 20CR, JMA JRA25, and JRA55. These reanalyses have been repackaged to adhere to the CMIP5 standards and published on the ESGF. Reanalysis centers provide interfaces to the various reanalyses, but each data set requires some effort to either compare with other reanalyses or with atmospheric model output. The repackaging for ESGF required reformatting, restructuring and modifications to the metadata to facilitate the ESGF search capabilities. Once this was done, the data structure is the same as used by the very successful CMIP3 and CMIP5 making comparison among reanalyses and climate models a relatively easy exercise. The data can now be accessed using WGET, OPENDAP, or HTTPServer at .

An example using this interface will be shown including comparison of the reanalyses portrayal of the surface heat balance during the 2010 Russian heat wave. We have found that although the difference reanalyses produce very similar atmospheric features of the heat wave, the surface energy balance terms such as latent and sensible heat show considerable differences. This comparison helps point out systematic differences in the reanalyses surface moisture and may lead to a better understanding of the differences.