Changes for reducing the influence of reflectivity observations in pr…

…ecipitation.

src/gsi/obsmod.F90

@@ -769,7 +769,8 @@ subroutine init_obsmod_dflts
     if_model_dbz=.false.
     if_model_fed=.false.
     innov_use_model_fed=.false.
-    inflate_obserr=.false.
+!   increase error for reflectivity observation when |O-F| exceeds gross error magnitude
+    inflate_obserr=.true.
     whichradar="KKKK"
 
     oneobradid="KKKK"

src/gsi/read_dbz_nc.f90

@@ -412,9 +412,15 @@ subroutine read_dbz_nc(nread,ndata,nodata,infile,lunout,obstype,sis,hgtl_full,no
 ! changed to hard-coded value for now; dbznoise used for two different purposes in this subroutine:
 !                   (1) threshold for lowest reflectivity value considered to be an observation and 
 !                   (2) ob error
-        thiserr = 5.0_r_kind
-
-
+
+!       Specify a larger error standard deviation for reflectivity observations in precipitation
+!       than for reflectivity observations that indicate a lack of preciptation.
+        if( dbzQC(i,j,k) < 5.0_r_kind ) then
+          thiserr = 5.0_r_kind
+        else
+          thiserr = 10.0_r_kind
+        end if
+
         nread = nread + 1
 
  !####################       Data thinning       ###################

src/gsi/setupdbz.f90

@@ -1260,7 +1260,10 @@ subroutine setupdbz(obsLL,odiagLL,lunin,mype,bwork,awork,nele,nobs,is,radardbz_d
          end if
 
      else
-        if (ratio > cgross(ikx) .or. ratio_errors < tiny_r_kind) then
+
+!       Apply gross error check only to reflectivity observations in precipitation (>= 5 dBZ).
+        if ( ( (data(idbzob,i) >= 5_r_kind) .and. (ratio > cgross(ikx)) ) .or. (ratio_errors < tiny_r_kind) ) then
+
            if ( inflate_obserr .and. (ratio-cgross(ikx)) <= cgross(ikx) .and. ratio_errors >= tiny_r_kind) then 
            ! Since radar reflectivity can be very different from the model background
            ! good observations may be rejected during this QC step.  However, if these observations