add use_rh and calrh for grib2 humidity processing

sorc/chgres_cube.fd/grib2_util.F90

@@ -57,6 +57,202 @@ subroutine rh2spfh(rh_sphum,p,t)
 
 end subroutine RH2SPFH
 
+
+
+!> Convert relative humidity to specific humidity (NAM formula)
+!!
+!! @param[inout] rh_sphum rel humidity on input. spec hum on output.
+!! @param[in] p pressure in Pa
+!! @param[in] t temperature
+!! @author Jili Dong NCEP/EMC 
+ subroutine rh2spfh_nam(rh_sphum,p,t)
+
+  implicit none
+
+ real, parameter :: PQ0=379.90516
+ real, parameter :: A2=17.2693882
+ real, parameter :: A3=273.16
+ real, parameter :: A4=35.86
+
+
+  real(esmf_kind_r4), intent(inout), dimension(i_input,j_input) ::rh_sphum
+  real(esmf_kind_r8), intent(in)                  :: p, t(i_input,j_input)
+
+  real, dimension(i_input,j_input)  :: QC, rh 
+
+  print*,"- CONVERT RH TO SPFH AT LEVEL ", p
+
+  rh = rh_sphum
+
+  QC = PQ0/P*EXP(A2*(T-A3)/(T-A4))
+
+  !print *, 'T = ', T, ' RH = ', RH, ' P = ', P
+  rh_sphum = rh*QC/100.0 
+  !print *, 'q = ', sphum
+
+end subroutine RH2SPFH_NAM
+
+!> Convert relative humidity to specific humidity (GFS formula)
+!!
+!! @param[inout] rh_sphum rel humidity on input. spec hum on output.
+!! @param[in] p pressure in Pa
+!! @param[in] t temperature
+!! @author Jili Dong NCEP/EMC 
+ subroutine rh2spfh_gfs(rh_sphum,p,t)
+
+  implicit none
+
+ integer kind_phys
+
+ parameter (kind_phys = selected_real_kind(13,60)) ! the '60' maps to 64-bit real
+
+
+ real(kind=kind_phys),parameter:: con_rd      =2.8705e+2 ! gas constant air    (J/kg/K)                         
+ real(kind=kind_phys),parameter:: con_rv      =4.6150e+2 ! gas constant H2O    (J/kg/K)
+
+ real(kind=kind_phys),parameter:: con_eps     =con_rd/con_rv
+ real(kind=kind_phys),parameter:: con_epsm1   =con_rd/con_rv-1.
+
+
+
+
+  real(esmf_kind_r4), intent(inout), dimension(i_input,j_input) ::rh_sphum
+  real(esmf_kind_r8), intent(in)                  :: p, t(i_input,j_input)
+
+  real, dimension(i_input,j_input)  :: QC, rh
+  real :: ES
+  integer :: i,j
+
+  print*,"- CONVERT RH TO SPFH AT LEVEL ", p
+
+  rh = rh_sphum
+
+do j=1,j_input
+  do i=1,i_input
+    ES = MIN(FPVSNEW(T(I,J)),P)
+    QC(i,j) = CON_EPS*ES/(P+CON_EPSM1*ES)
+    rh_sphum(i,j) = rh(i,j)*QC(i,j)/100.0
+  end do
+end do
+
+
+  !print *, 'T = ', T, ' RH = ', RH, ' P = ', P
+  !print *, 'q = ', sphum
+
+
+end subroutine RH2SPFH_GFS
+
+
+!> Compute saturation vapor pressure 
+!!
+!! @param[in] t temperature in Kelvin
+!! @return fpvsnew Saturation vapor pressure
+!! @author N Phillips  
+
+!
+!-------------------------------------------------------------------------------------
+!
+      elemental function fpvsnew(t)
+!$$$     Subprogram Documentation Block
+!
+! Subprogram: fpvsnew         Compute saturation vapor pressure
+!   Author: N Phillips            w/NMC2X2   Date: 30 dec 82
+!
+! Abstract: Compute saturation vapor pressure from the temperature.
+!   A linear interpolation is done between values in a lookup table
+!   computed in gpvs. See documentation for fpvsx for details.
+!   Input values outside table range are reset to table extrema.
+!   The interpolation accuracy is almost 6 decimal places.
+!   On the Cray, fpvs is about 4 times faster than exact calculation.
+!   This function should be expanded inline in the calling routine.
+!
+! Program History Log:
+!   91-05-07  Iredell             made into inlinable function
+!   94-12-30  Iredell             expand table
+! 1999-03-01  Iredell             f90 module
+! 2001-02-26  Iredell             ice phase
+!
+! Usage:   pvs=fpvsnew(t)
+!
+!   Input argument list:
+!     t          Real(krealfp) temperature in Kelvin
+!
+!   Output argument list:
+!     fpvsnew       Real(krealfp) saturation vapor pressure in Pascals
+!
+! Attributes:
+!   Language: Fortran 90.
+!$$$
+      implicit none
+      integer,parameter:: nxpvs=7501
+      real,parameter:: con_ttp     =2.7316e+2 ! temp at H2O 3pt
+      real,parameter:: con_psat    =6.1078e+2 ! pres at H2O 3pt
+      real,parameter:: con_cvap    =1.8460e+3 ! spec heat H2O gas   (J/kg/K)
+      real,parameter:: con_cliq    =4.1855e+3 ! spec heat H2O liq
+      real,parameter:: con_hvap    =2.5000e+6 ! lat heat H2O cond
+      real,parameter:: con_rv      =4.6150e+2 ! gas constant H2O
+      real,parameter:: con_csol    =2.1060e+3 ! spec heat H2O ice
+      real,parameter:: con_hfus    =3.3358e+5 ! lat heat H2O fusion
+      real,parameter:: tliq=con_ttp
+      real,parameter:: tice=con_ttp-20.0
+      real,parameter:: dldtl=con_cvap-con_cliq
+      real,parameter:: heatl=con_hvap
+      real,parameter:: xponal=-dldtl/con_rv
+      real,parameter:: xponbl=-dldtl/con_rv+heatl/(con_rv*con_ttp)
+      real,parameter:: dldti=con_cvap-con_csol
+      real,parameter:: heati=con_hvap+con_hfus
+      real,parameter:: xponai=-dldti/con_rv
+      real,parameter:: xponbi=-dldti/con_rv+heati/(con_rv*con_ttp)
+      real tr,w,pvl,pvi
+      real fpvsnew
+      real,intent(in):: t
+      integer jx
+      real  xj,x,tbpvs(nxpvs),xp1
+      real xmin,xmax,xinc,c2xpvs,c1xpvs
+! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
+      xmin=180.0
+      xmax=330.0
+      xinc=(xmax-xmin)/(nxpvs-1)
+!   c1xpvs=1.-xmin/xinc
+      c2xpvs=1./xinc
+      c1xpvs=1.-xmin*c2xpvs
+!    xj=min(max(c1xpvs+c2xpvs*t,1.0),real(nxpvs,krealfp))
+      xj=min(max(c1xpvs+c2xpvs*t,1.0),float(nxpvs))
+      jx=min(xj,float(nxpvs)-1.0)
+      x=xmin+(jx-1)*xinc
+
+      tr=con_ttp/x
+      if(x>=tliq) then
+        tbpvs(jx)=con_psat*(tr**xponal)*exp(xponbl*(1.-tr))
+      elseif(x<tice) then
+        tbpvs(jx)=con_psat*(tr**xponai)*exp(xponbi*(1.-tr))
+      else
+        w=(t-tice)/(tliq-tice)
+        pvl=con_psat*(tr**xponal)*exp(xponbl*(1.-tr))
+        pvi=con_psat*(tr**xponai)*exp(xponbi*(1.-tr))
+        tbpvs(jx)=w*pvl+(1.-w)*pvi
+      endif
+
+      xp1=xmin+(jx-1+1)*xinc
+
+      tr=con_ttp/xp1
+      if(xp1>=tliq) then
+        tbpvs(jx+1)=con_psat*(tr**xponal)*exp(xponbl*(1.-tr))
+      elseif(xp1<tice) then
+        tbpvs(jx+1)=con_psat*(tr**xponai)*exp(xponbi*(1.-tr))
+      else
+        w=(t-tice)/(tliq-tice)
+        pvl=con_psat*(tr**xponal)*exp(xponbl*(1.-tr))
+        pvi=con_psat*(tr**xponai)*exp(xponbi*(1.-tr))
+        tbpvs(jx+1)=w*pvl+(1.-w)*pvi
+      endif
+
+      fpvsnew=tbpvs(jx)+(xj-jx)*(tbpvs(jx+1)-tbpvs(jx))
+! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
+      end function fpvsnew
+
+
+
 !> Convert omega to vertical velocity.
 !!
 !! @param[inout] omega on input, vertical velocity on output

sorc/chgres_cube.fd/input_data.F90

@@ -2459,7 +2459,8 @@ subroutine read_input_atm_grib2_file(localpet)
 
  use wgrib2api
 
- use grib2_util, only                   : rh2spfh, convert_omega
+ use grib2_util, only                   : rh2spfh, rh2spfh_gfs, convert_omega
+ use program_setup, only         : use_rh, calrh 
 
  implicit none
 
@@ -2607,7 +2608,7 @@ subroutine read_input_atm_grib2_file(localpet)
  if (localpet == 0) print*,"- FIND SPFH OR RH IN FILE"
  iret = grb2_inq(the_file,inv_file,trim(trac_names_grib_1(1)),trac_names_grib_2(1),lvl_str_space)
 
- if (iret <= 0) then
+ if (iret <= 0 .or. use_rh) then
    iret = grb2_inq(the_file,inv_file, ':var0_2','_1_1:',lvl_str_space)
    if (iret <= 0) call error_handler("READING ATMOSPHERIC WATER VAPOR VARIABLE.", iret)
    hasspfh = .false.
@@ -2782,7 +2783,13 @@ subroutine read_input_atm_grib2_file(localpet)
       endif !iret<=0
 
       if (n==1 .and. .not. hasspfh) then 
-        call rh2spfh(dummy2d,rlevs(vlev),dummy3d(:,:,vlev))
+        if (calrh .eq. 0) then
+          call rh2spfh(dummy2d,rlevs(vlev),dummy3d(:,:,vlev))
+        else if (calrh .eq. 1) then
+          call rh2spfh_gfs(dummy2d,rlevs(vlev),dummy3d(:,:,vlev))
+        else
+          call error_handler("calrh option not supported",1)
+        end if
       endif
 
        print*,'tracer ',vlev, maxval(dummy2d),minval(dummy2d)

sorc/chgres_cube.fd/program_setup.F90

@@ -88,13 +88,15 @@ module program_setup
  integer, public                 :: cycle_hour = -999 !< Cycle hour.
  integer, public                 :: regional = 0 !<  For regional target grids.  When '1' remove boundary halo region from atmospheric/surface data and
                                                  !! output atmospheric boundary file. When '2' output boundary file only. Default is '0' (global grids).
+ integer, public                 :: calrh = 0 !< rh to spfh calculation. 0:original; 1: GFSv15/16                                         
  integer, public                 :: halo_bndy = 0 !< Number of row/cols of lateral halo, where pure lateral bndy conditions are applied (regional target grids).
  integer, public                 :: halo_blend = 0 !< Number of row/cols of blending halo, where model tendencies and lateral boundary tendencies are applied. Regional target grids only.
  integer, public                 :: nsoill_out = 4 !<  Number of soil levels desired in the output data. chgres_cube can interpolate from 9 input to 4 output levels. DEFAULT: 4.
 
  logical, public                 :: convert_atm = .false. !< Convert atmospheric data when true.
  logical, public                 :: convert_nst = .false. !< Convert nst data when true.
  logical, public                 :: convert_sfc = .false. !< Convert sfc data when true.
+ logical, public                 :: use_rh = .false. !< for grib2, use rh (if true) or spfh (if false)                 
  logical, public                 :: wam_cold_start = .false. !< When true, cold start for whole atmosphere model.
 
  ! Options for replacing vegetation/soil type, veg fraction, and lai with data from the grib2 file
@@ -181,6 +183,7 @@ subroutine read_setup_namelist(filename)
                    cycle_year, cycle_mon, cycle_day,    &
                    cycle_hour, convert_atm, &
                    convert_nst, convert_sfc, &
+                   use_rh, calrh,      &
                    wam_cold_start, &
                    vgtyp_from_climo, &
                    sotyp_from_climo, &