;---------------------------------------------------------------------- ; ESMF_WRF_to_curv.ncl ; ; This is an NCL/ESMF template file for regridding from a WRF ; (curvilinear) grid to a different curvilinear grid. It uses ; ESMF_regrid to do the regridding. ; ; Both grids are assumed to be contained in separate NetCDF files. ; ; Search for lines with ";;---Change (likely)" or ";;---Change (maybe)". ; These are the lines you will likely or maybe have to change. ; ; Of course, you'll probably want to change other aspects of this ; code, like the options for plotting (titles, colors, etc). ; ; For more information on ESMF_regrid, see: ; ; http://www.ncl.ucar.edu/Document/Functions/ESMF/ESMF_regrid.shtml ;---------------------------------------------------------------------- ; This example uses the ESMF application "ESMF_RegridWeightGen" to ; generate the weights. ; ; For more information about ESMF: ; ; http://www.earthsystemmodeling.org/ ; ; This script uses built-in functions that are only available in ; NCL V6.1.0-beta and later. ;---------------------------------------------------------------------- load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/gsn_code.ncl" load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/gsn_csm.ncl" load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/contributed.ncl" load "$NCARG_ROOT/lib/ncarg/nclscripts/wrf/WRFUserARW.ncl" load "$NCARG_ROOT/lib/ncarg/nclscripts/esmf/ESMF_regridding.ncl" begin ;---WRF file containing source grid src_file = "wrfout_xxxxx.nc" ;;---Change (likely) sfile = addfile(src_file,"r") ;---Get variable to regrid var = wrf_user_getvar(sfile,"td2",0) ;;---Change (likely) src_lat = sfile->XLAT(0,:,:) ;;---Change (maybe) src_lon = sfile->XLONG(0,:,:) ;;---Change (maybe) ;---Data file containing destination grid dst_file = "YYYY.nc" ;;---Change (likely) dfile = addfile(dst_file,"r") dst_lat = dfile->TLAT ;;---Change (likely) dst_lon = dfile->TLON ;;---Change (likely) ;---Set up regridding options Opt = True ;---"bilinear" is the default. "patch" and "conserve" are other options. Opt@InterpMethod = "bilinear" ;;---Change (maybe) Opt@WgtFileName = "WRF_to_curv.nc" Opt@SrcGridLat = src_lat ; source grid Opt@SrcGridLon = src_lon Opt@SrcRegional = True ;;--Change (maybe) Opt@SrcInputFileName = src_file ; optional, but good idea Opt@DstGridLat = dst_lat ; destination grid Opt@DstGridLon = dst_lon Opt@DstRegional = True ;;--Change (maybe) Opt@DstMask2D = where(.not.ismissing(dst_lat).and.\ .not.ismissing(dst_lon),1,0) ; Necessary if lat/lon ; has missing values. Opt@ForceOverwrite = True Opt@PrintTimings = True Opt@Debug = True var_regrid = ESMF_regrid(var,Opt) ; Do the regridding printVarSummary(var_regrid) ;---------------------------------------------------------------------- ; Plotting section ; ; This section creates filled contour plots of both the original ; data and the regridded data, and panels them. ;---------------------------------------------------------------------- var@lat2d = src_lat ; Needed for plotting. "var_regrid" var@lon2d = src_lon ; already has these attrs attached. wks = gsn_open_wks("ps","WRF_to_curv") res = True res@gsnMaximize = True res@gsnDraw = False res@gsnFrame = False res@cnFillOn = True res@cnLinesOn = False res@cnLineLabelsOn = False res@cnFillMode = "RasterFill" res@lbLabelBarOn = False ; Turn on later in panel res@mpMinLatF = min(src_lat) res@mpMaxLatF = max(src_lat) res@mpMinLonF = min(src_lon) res@mpMaxLonF = max(src_lon) ;;--Change (maybe) mnmxint = nice_mnmxintvl( min(var), max(var), 18, False) res@cnLevelSelectionMode = "ManualLevels" res@cnMinLevelValF = mnmxint(0) res@cnMaxLevelValF = mnmxint(1) res@cnLevelSpacingF = mnmxint(2) ;---Resources for plotting regridded data res@gsnAddCyclic = False ;;---Change (maybe) res@tiMainString = "Curvilinear grid (" + Opt@InterpMethod + ")" plot_regrid = gsn_csm_contour_map(wks,var_regrid,res) ;---Resources for plotting original data res@gsnAddCyclic = False ;;---Change (maybe) res@tiMainString = "Original WRF grid" plot_orig = gsn_csm_contour_map(wks,var,res) ;---Compare the plots in a panel pres = True pres@gsnMaximize = True pres@gsnPanelLabelBar = True gsn_panel(wks,(/plot_orig,plot_regrid/),(/2,1/),pres) end