Safeguard to prevent NaNs from CRTM affecting minimisation

src/gsi/qcmod.f90

@@ -194,7 +194,7 @@ module qcmod
   public :: npres_print,nlnqc_iter,varqc_iter,pbot,ptop,c_varqc,njqc,vqc,nvqc,hub_norm
   public :: use_poq7,noiqc,vadfile,dfact1,dfact,erradar_inflate,gps_jacqc
   public :: pboto3,ptopo3,pbotq,ptopq,newvad,tdrerr_inflate
-  public :: igood_qc,ifail_crtm_qc,ifail_satinfo_qc,ifail_interchan_qc,&
+  public :: igood_qc,ifail_crtm_qc,ifail_crtm_nan,ifail_satinfo_qc,ifail_interchan_qc,&
             ifail_gross_qc,ifail_cloud_qc,ifail_outside_range,&
             ifail_scanedge_qc, ifail_emiss_qc, ifail_cao_qc
   public :: ifail_iland_det, ifail_isnow_det, ifail_iice_det, ifail_iwater_det,&
@@ -268,6 +268,8 @@ module qcmod
   integer(i_kind),parameter:: ifail_outside_range=11
 !  Reject due to cold-air outbreak area check  in setuprad
   integer(i_kind),parameter:: ifail_cao_qc=12
+!  Reject due to NaN in the CRTM calculation
+  integer(i_kind),parameter:: ifail_crtm_nan=13
 !  Failures specific to qc routine start at 50 and the numbers overlap
 !  QC_SSMI failures 
 !  Reject due to krain type not equal to 0 in subroutine qc_ssmi

src/gsi/setuprad.f90

@@ -291,6 +291,7 @@ subroutine setuprad(obsLL,odiagLL,lunin,mype,aivals,stats,nchanl,nreal,nobs,&
   use crtm_interface, only: ilzen_ang2,iscan_ang2,iszen_ang2,isazi_ang2
   use clw_mod, only: calc_clw, ret_amsua, gmi_37pol_diff
   use qcmod, only: igood_qc,ifail_gross_qc,ifail_interchan_qc,ifail_crtm_qc,ifail_satinfo_qc,qc_noirjaco3,ifail_cloud_qc
+  use qcmod, only: ifail_crtm_nan  
   use qcmod, only: ifail_cao_qc,cao_check  
   use qcmod, only: ifail_iland_det, ifail_isnow_det, ifail_iice_det, ifail_iwater_det, ifail_imix_det, &
                    ifail_iomg_det, ifail_isst_det, ifail_itopo_det,ifail_iwndspeed_det
@@ -307,6 +308,8 @@ subroutine setuprad(obsLL,odiagLL,lunin,mype,aivals,stats,nchanl,nreal,nobs,&
   use radiance_mod, only: radiance_ex_obserr_gmi,radiance_ex_biascor_gmi
   use cads, only: cads_imager_calc
 
+  use, intrinsic :: ieee_arithmetic
+
   implicit none
 
 ! Declare passed variables
@@ -997,6 +1000,20 @@ subroutine setuprad(obsLL,odiagLL,lunin,mype,aivals,stats,nchanl,nreal,nobs,&
            varinv(1:nchanl) = zero
         endif
 
+! Include a separate check for NaNs in CRTM calculations.  These are not always caught by other tests
+
+        if (ANY(ieee_is_nan(tsim(1:nchanl)))) then
+           write(*,*) 'WARNING: NaN found in CRTM simulated radiance output'
+           do i = 1, nchanl
+              if (ieee_is_nan(tsim(i))) then
+                  write(*,*) 'NaN for ',trim(isis),' channel ', sc_index(i), ' at latitude = ', &
+                          cenlat,' longitude = ',cenlon
+              end if
+           end do
+           id_qc(1:nchanl) = ifail_crtm_nan
+           varinv(1:nchanl) = zero
+        endif
+
 !  For SST retrieval, use interpolated NCEP SST analysis
         if (retrieval) then
            if( avhrr_navy )then