WPS Version 3.1
              Version 3.1 of the WRF Pre-Processing System (WPS)  was released on April 9, 2009. For V3.1.1 update of WPS, please click here. 
              Note: The V3 WRF model is NOT backward compatible with old input files. One must rerun WPS to generate data for real/wrf. 
              Also see 'Known 
                Problems' in this release. 
              New features and bug fixes 
               - Added support for MODIS-based land use categories as an alternative to USGS categories
               - Process static fields for the gravity wave drag schemes in both the ARW and the NMM
               - Generalized treatment of 3-d soil moisture and temperature arrays
              - Land use data sets with multiple water categories can now be handled
              - Added support for sigma-level GRIB1 data
              - Various fixes to interpolation schemes (thanks to Hyeyum Shin and Jeremy Krieger)
              - The calc_ecmwf_p utility now creates a 3-d geopotential height field to give a correct vertical interpolation in real.exe (thanks to Daniel van Dijke, Chiel van Heerwaarden, and Ravan Ahmadov)
              - The plotgrids utility can now handle NMM nests (thanks to John Halley-Gotway)
              - Fixed a problem with using 30' data and lat/lon grid.