add use_rh and calrh for grib2 humidity processing

sorc/chgres_cube.fd/grib2_util.F90

@@ -17,6 +17,11 @@ module grib2_util
 
 implicit none
 
+public :: rh2spfh_gfs
+public :: rh2spfh_nam
+public :: fpvsnew 
+
+
 contains 
 
 !> Convert relative humidity to specific humidity.
@@ -57,6 +62,174 @@ 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 w/NMC2X2  
+!! @date 30 dec 82
+
+!
+!-------------------------------------------------------------------------------------
+!
+      elemental function fpvsnew(t)
+!
+      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(esmf_kind_r8),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 +2459,7 @@ 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
 
  implicit none
 
@@ -2490,7 +2490,9 @@ subroutine read_input_atm_grib2_file(localpet)
  logical                               :: lret
  logical                               :: conv_omega=.false., &
                                           hasspfh=.true., &
-                                          isnative=.false.
+                                          isnative=.false., &
+                                          use_rh=.false. 
+
 
  real(esmf_kind_r8), allocatable       :: rlevs(:)
  real(esmf_kind_r4), allocatable       :: dummy2d(:,:)
@@ -2603,11 +2605,22 @@ subroutine read_input_atm_grib2_file(localpet)
      if (localpet==0) print*, "- LEVEL AFTER SORT = ",slevs(i)
    enddo
  endif
+
+! Is SPFH on full levels Jili Dong
+     do vlev = 1, lev_input
+      iret = grb2_inq(the_file,inv_file,':SPFH:',slevs(vlev))
+      if (iret <= 0) then
+        use_rh = .TRUE.
+        if (localpet == 0) print*,':SPFH:'//slevs(vlev)//' not existing. Use RH instead.'
+        exit
+      end if
+     end do
+
 
  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 +2795,13 @@ 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 (trim(external_model) .eq. 'GFS') then
+          print *,'CALRH GFS'
+          call rh2spfh_gfs(dummy2d,rlevs(vlev),dummy3d(:,:,vlev))
+        else 
+          print *,'CALRH non-GFS'
+          call rh2spfh(dummy2d,rlevs(vlev),dummy3d(:,:,vlev))
+        end if
       endif
 
        print*,'tracer ',vlev, maxval(dummy2d),minval(dummy2d)

tests/chgres_cube/CMakeLists.txt

@@ -83,6 +83,13 @@ target_link_libraries(ftst_dint2p
 
 add_test(NAME chgres_cube-ftst_dint2p COMMAND ftst_dint2p)
 
+add_executable(ftst_rh2spfh_gfs ftst_rh2spfh_gfs.F90)
+target_link_libraries(ftst_rh2spfh_gfs
+  chgres_cube_lib)
+
+add_test(NAME chgres_cube-ftst_rh2spfh_gfs COMMAND ftst_rh2spfh_gfs)
+
+
 add_executable(ftst_quicksort ftst_quicksort.F90)
 target_link_libraries(ftst_quicksort
   chgres_cube_lib)

tests/chgres_cube/ftst_rh2spfh_gfs.F90

@@ -0,0 +1,59 @@
+ program ftst_rh2spfh_gfs 
+
+ use grib2_util 
+
+ implicit none
+
+ real, parameter    :: eps=1E-4
+
+ real*4, dimension(3,2) :: rh_500hpa, rh_900hpa, rh_tmp                                                    
+ real*4, dimension(3,2) :: spfh_gfs_900hpa_expected, spfh_gfs_500hpa_expected                                            
+ real*4, dimension(3,2) :: spfh_nam_900hpa_expected, spfh_nam_500hpa_expected
+ real*8, dimension(3,2) :: temp_500hpa, temp_900hpa
+ real*8 :: pres
+
+data temp_900hpa /280.9, 282.6, 281.4, 289.9, 286.5, 288.7/
+data rh_900hpa /17.6, 75.2, 99.9, 95.4, 86.6, 89.1/
+
+data temp_500hpa /254.1, 259.7, 259.7, 267.2, 262.0, 269.5/
+data rh_500hpa /10.7, 9.1, 0.5, 10.1, 4.2, 0.9/
+
+data spfh_gfs_900hpa_expected /1.286259, 6.169457, 7.554718, 12.64650, 9.210890, 10.93505/                       
+data spfh_gfs_500hpa_expected /0.1519615, 0.2257435, 1.2403490E-02, 0.4856212, 0.1288972, 5.2061662E-02/                               
+
+data spfh_nam_900hpa_expected /1.281873, 6.145997, 7.528146, 12.56592, 9.164917, 10.87111/                                             
+data spfh_nam_500hpa_expected /0.1799187, 0.2447683, 1.3448806E-02, 0.4918184, 0.1360911, 5.2174598E-02/                                                                     
+
+i_input = 3
+j_input = 2
+
+! rh to spfh at 500 hPa with GFSv15/16 conversion
+rh_tmp=rh_500hpa
+pres=50000.0
+call rh2spfh_gfs(rh_tmp,pres,temp_500hpa)
+if (any((abs(rh_tmp*1000.0-spfh_gfs_500hpa_expected)) .gt. eps)) stop 500 
+
+! rh to spfh at 900 hPa with GFSv15/16 conversion
+rh_tmp=rh_900hpa
+pres=90000.0
+call rh2spfh_gfs(rh_tmp,pres,temp_900hpa)
+if (any((abs(rh_tmp*1000.0-spfh_gfs_900hpa_expected)) .gt. eps)) stop 900
+
+! rh to spfh at 500 hPa with GFSv17 conversion
+rh_tmp=rh_500hpa
+pres=50000.0
+call rh2spfh_nam(rh_tmp,pres,temp_500hpa)
+if (any((abs(rh_tmp*1000.0-spfh_nam_500hpa_expected)) .gt. eps)) stop 501
+
+! rh to spfh at 900 hPa with GFSv17 conversion
+rh_tmp=rh_900hpa
+pres=90000.0
+call rh2spfh_nam(rh_tmp,pres,temp_900hpa)
+if (any((abs(rh_tmp*1000.0-spfh_nam_900hpa_expected)) .gt. eps)) stop 901
+
+
+ print*, "OK"
+ print*, "SUCCESS!"
+
+ end program ftst_rh2spfh_gfs 
+