For going from a coarse grid to a finer one, you need to interpolate; however, doing so will cause you to lose resolution in your input data: you won’t “see” geographic features smaller than twice the resolution of the coarser grid. Be aware, however, that emissions data does not use MKS units but instead has an additional implicit “per grid cell” for its units. You could use a combination of M3Tools programs m3cple for the interpolation and m3combo (with a trivial one-variable combination) for the re-scaling.
D in the numbers for the GRIDDESC file indicates that the value is double precision and separates the mantissa from the exponent (so that D3 indicates that the fraction should be multiplied by 10^3=1000 and so can easily be read in kilometers instead of standard MKS meters). Normal “good practice” also has a decimal point in the fraction also.
Please be aware that this is a very sloppy GRIDDESC, where many of the parts that in fact should be double precision are not represented that way, and furthermore does not have the required “end-of-grids” marker. Far better would have been:
! coords --line: name; type, P-alpha, P-beta, P-gamma, xcent, ycent
2, 33.0D0, 45.0D0, -97.0D0, -97.0D0, 40.0D0
’ ’ ! end coords. grids: name; xorig,yorig,xcell,ycell,ncols,nrows,nthik
‘LAM_40N97W’, 1128.0D3, -672.0D3, 12.0D3, 12.D3, 66, 52, 1
‘LAM_40N97W’, -2952.0D3, -2772.0D3, 12.0D3, 12.0D3, 516, 444, 1
' ' ! end grids