reprojecting Lambert Conformal WRF data

From: Bryan K Woods <bryan.woods_at_nyahnyahspammersnyahnyah>
Date: Wed Dec 28 2011 - 13:06:05 MST

Hi all,

My challenge of the day is reconciling NARR and WRF data that are given on different Lambert grids. I found a nice piece of Fortran code that allows me to transform NARR grib data to a Mercator grid by computing the i,j indices of a given lat/lon point. This code works perfectly.

http://www.nco.ncep.noaa.gov/pmb/docs/libs/w3lib/w3fb11.html

However, the required inputs for this function do not match up nicely to those provided in WRF NetCDF files. Note that only one tangent latitude is expected in the Fortran code, yet two are provided by WRF netCDF files. The NCL documentation hints at this problem:
http://www.ncl.ucar.edu/Applications/lcnative.shtml
" The problem with Lambert grids is they are are sometimes described by a meridian, parallel and a delta X and delta Y in meters at the intersection of the meridian and top parallel. It can be VERY difficult to come up with corner points when this method is used. "

Can anyone pass along a tip or some code that might illuminate this issue? Would it be wrong to arbitrarily select one of the two tangent latitudes and pick the corner point from XLAT, XLONG?

Thanks,
Bryan

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Received on Wed Dec 28 13:04:24 2011

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