Building on the success of the Modern-Era Retrospective analysis for Research and Applications, MERRA, and its successor MERRA-2 (released in 2009 and 2015 respectively), the NASA Global Modeling and Assimilation Office (GMAO) continues its incremental effort towards a decadal goal of an Integrated Earth System retrospective analysis, MERRA-3 (~2025), coupling components of the atmosphere, ocean, chemistry, land, and ice. While aspects of the coupled Goddard Earth Observing System (GEOS) model and data assimilation are currently under active development, an intermediate reanalysis featuring recent advances in the GEOS atmospheric component is planned as a stepping-stone towards MERRA-3. The GEOS-5 Retrospective analysis for the 21st Century, GEOS-R21C, is a hybrid 4D-EnVar atmospheric reanalysis that will cover the period 2000-onwards and feature the NASA’s Earth Observing System EOS and post-EOS satellite observations. Analysis fields from GEOS-R21C are planned to drive two other retrospective products, an off-line chemistry reanalysis (GEOS-R21C-Chem) and a high-resolution downscaled product for the polar regions (PolarMERRA). Both are also expected to aid in the ongoing coupling effort in advance of MERRA-3.
This talk will present an overview of GMAO retrospective analysis products and focus on the strategy for the two upcoming reanalyses GEOS-R21C and MERRA-3. Configuration details and preliminary results from prototype-R21C will be presented along with an overall review of new and revised features from MERRA-2.
