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;  Program Name: rh_correction_narr_double.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 height adjustment.                        ;
;                                                                             ;
;  Input: height file1, height file2, variable file, output file              ;
;                                                                             ;
;  Output: height adjusted file                                               ;
;                                                                             ;
; For non-fatal errors output is witten to $DATA/logs                         ;
;                                                                             ;
; Author(s)/Contact(s): Linlin Pan, lpan@ucar.edu                             ;
; Origination                                                   June, 2015    ;
;                                                                             ;
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;----------------------------------------------------------------------

begin
           inputFile1 = getenv("inputFile1") ; height data
           inputFile2 = getenv("inputFile2") ; height data
           inputFile3 = getenv("inputFile3") ; GFS data
           outFile = getenv("outFile") ; outFile data
           
; input files 
           f1 = addfile(inputFile1,"r") 
           f2 = addfile(inputFile2,"r") 
           f3 = addfile(inputFile3,"r") 
; out files
           fout = addfile(outFile,"w")
; input variables
           HGT1 = f1->HGT
           HGT2 = f2->HGT_M(0,:,:)
           T2D  = f3->T2D
           Q2D  = f3->Q2D
	   PSFC = f3->PSFC
; calculation 
	   W2D  = Q2D/(1-Q2D)
	   RH = relhum(T2D,W2D,PSFC)
	   RH = RH < 100
	   DHGT  = HGT1-HGT2
           delete(HGT1)
           delete(HGT2)
	   T2D=T2D+DHGT*6.49/1000.
	   PSFC = PSFC+DHGT*PSFC/287.05/T2D*9.8
	   Q2D = mixhum_ptrh (PSFC/100., T2D, RH, 2) 
; output
           fout->T2D  = T2D
           fout->Q2D  = Q2D
           fout->PSFC = PSFC 
	   delete(T2D)
;

end