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;  Program Name: Combine_hgt.ncl                                              ;
;                                                                             ;
;  National Water Model (NWM) WRF-hydro forcing engine is developed by        ;
;  National Center for Atmospheric Research (NCAR), under the sponsorship     ;
;  of National Water Center (NWC).                                            ;
;                                                                             ;
;   Team Members:                                                             ;
;     NCAR Staff: Linlin Pan, Wei Yu, and David Gochis                        ;
;      NWC/OWP Staff: Brian Cosgrove, Zhengtao Cui, Cham Pham, and James Taft ;
;                                                                             ;
;  This is a ncl program to perform regridding for the long range forcing.    ;
;                                                                             ;
;  Input: hrrr, rap/gfs, outfile                                              ;
;                                                                             ;
;  Output: combined file                                                      ;
;                                                                             ;
; For non-fatal errors output is witten to $DATA/logs                         ;
;                                                                             ;
; Author(s)/Contact(s): Linlin Pan, lpan@ucar.edu                             ;
; Origination                                                  Sept., 2015    ;
;                                                                             ;
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;
begin
           hrrrFile = getenv("hrrrFile") ; HRRR data
           gfsFile = getenv("gfsFile") ; GFS data
           outFile = getenv("outFile") ; outFile data
           indexFlag = getenv("INDEX")
           
           if(indexFlag .eq. "true") then
              indexf = addfile("index.nc","r") 
              index = indexf->index
           end if
     
           f1 = addfile(hrrrFile,"r") 
           f2 = addfile(gfsFile,"r") 
           system("rm -f "+outFile)

           fout = addfile(outFile,"c")

           dd = dimsizes(f1->HGT)
            print("dd="+dd)
           dimlat = dd(0)
           dimlon = dd(1)



           v1d = ndtooned(f1->HGT)
           if(indexFlag .eq. "false") then
               findexOut = addfile("index_out.nc","c")
               index = ind(ismissing(v1d) )
               findexOut->index = index
               system("mv index_out.nc index.nc")
               exit 
           end if
           v1dgfs = ndtooned(f2->HGT)
           v1d(index) = v1dgfs(index)
           HGT = onedtond(v1d,(/dimlat,dimlon/))
           fout->HGT = HGT

end