How to create a map file between different grids?

[hines_91@osu_edu]

Hi, we have created a new regional grid. The idea is to first run some active atmosphere + data others, or active CLM + data others, or active atmosphere + CLM plus data others, until eventually running a fully coupled system on the regional grid. Anyway, my question is how to create a map file similar to "map_gx3v7_to_T62_aave_da_090911.nc" (though not for those specific grids). This should allow us to run the "data" models from existing global grids. We have the map coordinates (latitude, longitudes of grid centers and grid corners) of the new grid and can pick off the values for the other grid from an existing map netcdf file. That is, the yc_*, xc_*, yv_*, and xv_* grid values are accounted for. I presume the int mask_a, and int mask_b values are just a land/sea mask - and those are easily obtained. We also can obtain the grid areas in square radians, and just assign 0 or 1 for the (land/sea?) fractions. OK, so all those are easily handled.

The big question is the "S" (and S2) variables. Is that some sort of weighting? Is there a program we can run to obtain that? There seem to be 2 choices "Bilinear remapping" or "Conservative remapping" - whatever those are.

Thanks for any advice