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[NOAA bullet] Where can I find information about the atmospheric model grid and land model grid used in CM2.0?  

The atmospheric model component's horizontal grid dimensions are 144 by 90. The horizontal grid arrangement used in the model is the staggered Arakawa B-grid with a resolution of 2.5 degrees longitude by 2.0 degrees latitude. In preparing the model output files, momentum variables have been interpolated from "V" points to "T" points. The model output netCDF files provide specific information about the grid point locations and the grid cell bounds. The land model grid follows the atmospheric model's grid exactly, with the center of the land cells being located at the "T" points of the B-grid. Coastal land points can be partially land and partially ocean (see land_area_fraction "sftlf" file).

The CM2.0 atmospheric model component has 24 vertical levels. The model uses a hybrid coordinate grid; sigma surfaces near the ground continuously transform to pressure surfaces above 250 hP. In the model itself, the lowest model level is about 30 meters above the surface. Data contained in model output files of near-surface reference levels have been interpolated to levels closer to the surface. For analysis purposes, most 3D atmospheric model output files contain values that have been interpolated from the model's own 24 vertical levels to 17 standard pressure levels.

More atmospheric and land model grid information can be found in a paper titled "The new GFDL global atmosphere and land model AM2/LM2: Evaluation with prescribed SST simulations", which will appear in the Journal of Climate. A copy of the manuscript [4 MB pdf] is available.

Questions related to the GFDL CM2.x models may be directed to…

[email GFDL.Climate.Model.Info at noaa dot gov] 
last modified: June 24 2019.