85th AMS Annual Meeting

Tuesday, 11 January 2005
International stretched-grid model intercomparison project (SGMIP)
Michael S. Fox-Rabinovitz, University of Maryland, College Park, MD; and J. Cote, B. Dugas, M. Deque, J. McGregor, and P. Gleckler
The international Stretched-Grid Model Intercomparison Project (SGMIP) has been initiated in 2002 for studying the global variable-resolution/stretched-grid approach to regional climate modeling. The approach has been established over the last decade through the national and international group efforts. The phase-1 of the project, SGMIP-1, has been successfully completed in 2004. The variable-resolution stretched-grid (SG) GCMs participating in SGMIP-1 are the variable-resolution versions of the basic GCMs of the following four major meteorological centers/groups: the Meteo-France, ARPEGE model, the RPN/Canadian Meteorological Centre, GEM model, the Australian CSIRO C-CAM model, and the U.S. NASA/GSFC GEOS model. SGMIP-1 has been focused on addressing the following major scientific and computational issues: stretching strategies; approximations of model dynamics; treatment of model physics including its calculation on intermediate uniform resolution or directly on stretched grids; multi-model ensemble calculations; optimal performance on parallel supercomputers. The total number of global grid points for the SG-GCMs of SGMIP-1 is (or close to) that of the 1 x 1 uniform grid. The area of interest is (or close to) the major part of North America: 20 60 N and 130 60 W. The regional resolution is about 0.5. The surface boundary forcing (SST and sea ice) is used at 2 x 2.5 or 1 x 1 resolution. The 12-year period chosen for model simulations includes the recent ENSO cycles. SGMIP-1 data are stored in the AMIP format(s). The existing reanalysis data as well as independent data like high-resolution gauge precipitation and high-resolution satellite data are used for the SG-GCMs validation. The 12-year AMIP-type SG-GCM simulations for SGMIP-1 are analyzed in terms of studying: the impact of resolution on efficient/realistic downscaling to mesoscales; inter-annual variability, ENSO related and other anomalous regional climate events (floods, droughts, etc.) and major monsoonal circulations at mesoscale resolution; water and energy cycles. Analysis of SGMIP-1 multi-model ensemble integrations confirmed that a significant reduction of the uncertainty of regional climate simulations is achieved for the multi-model ensemble mean. The experience obtained allowed us to make a meaningful connection to AMIP-2 with a better understanding what could be contributed to regional climate studies at mesoscale resolution. The SGMIP-1 results are available on the web site (that is being updated): http://esic.umd.edu/~foxrab/sgmip.html SGMIP-1 laid a solid scientific foundation for conducting the new (already agreed upon) SGMIP-2 (phase-2 of SGMIP), with processing and analysis of data obtained with enhanced uniform and variable resolution SG-GCMs. SGMIP-2 will include multi-model ensemble simulation results for the extended period of over two decades or longer. The strong coordinated international SGMIP-2 effort, with the accompanying comparisons of enhanced uniform and variable resolution GCMs, will put us in a favorable position for a comprehensive investigation on the diversified impacts on climate simulations due to enhanced global and/or regional model resolution, including the multi-model ensemble results. We are establishing a connection with the AMIP group on introducing the SGMIP-1 data and their analysis as a regional project and the SGMIP-2 data and their analysis as an enhanced uniform and variable resolution project, both with the emphasis on the U.S. climate. Our joint SGMIP effort, focused on a better understanding of the SG-approach, is beneficial to all the participants as well as to a broader regional (and eventually global) climate modeling community.

Supplementary URL: