SUBROUTINE oda_qcv
      use modmask, only : lmask,lmaskgo,lmaskro
      IMPLICIT NONE
*
*Purpose : 1) Modify Jo [ROBDATA8(NCMOMI,*)] according to
*             Andersson and Jarvinen 1999, Variational quality control,
*             Q.J.R., 125, pp. 697-722.
*          2) Save the values of (1-Wqc) in ROBDATA8(NCMOMN,*)
*             for gradient factorization and postalt flag criterion.
*
*Author  : S. Pellerin, ARMA, January 2009
*          Generalisation of QCVAR originally embeded in observation
*          operators from P. Koclas, J. Halle and J. St-James
*
*Revisions :
*
#include "comdimo.cdk"
#include "comdim.cdk"
#include "comoabdy.cdk"
#include "comoahdr.cdk"
#include "comoba.cdk"
#include "comnumbr.cdk"
#include "comstate.cdk"
*
      integer :: jdata,istyp,jj,jo,ityp,idata
      real*8 :: zgami,zjon,zqcarg,zppost,zlev,zslev
      logical :: lluv,llmask(ndata)
C
      llmask = lmask .neqv. lmaskgo  ! Exclusion of GOES QCVAR
      llmask = llmask .neqv. lmaskro ! Exclusion of GPSRO QCVAR
      DO JDATA=1,ndata
        IF (llmask(jdata)) THEN
          jo = MOBDATA(NCMOBS,jdata)
          idata = MOBHDR(NCMRLN,JO)
          ZLEV = ROBDATA8(NCMPPP,JDATA)
          zgami = robdata(ncmpob,jdata)
          ITYP = MOBDATA(NCMVNM,JDATA)
          LLUV = ((ITYP .EQ. NVNUMB(1) .OR. ITYP .EQ. NEUS) .AND.
     &         NMVOEXIST(NOUU) .EQ. 1) .OR. ((ITYP .EQ. NVNUMB(2) .OR.
     &         ITYP .EQ. NEVS).AND. NMVOEXIST(NOVV) .EQ. 1)
          IF (LLUV) THEN
            IF (ITYP .EQ. NVNUMB(1) .OR. ITYP .EQ. NEUS)THEN
C
C  In order to calculate the contribution to Jo from a wind, the o-a
C  must be available for both u and v components. Hence, loop over only
C  data for which o-a has already been calculated
C
              DO JJ=IDATA, JDATA
                ISTYP = MOBDATA(NCMVNM,JJ)
                ZSLEV = ROBDATA8(NCMPPP,JJ)
                IF ((ISTYP .EQ. NVNUMB(2)
     1               .OR. ISTYP .EQ. NEVS) .AND.
     2               ZSLEV .EQ. ZLEV) THEN
                  ZJON=ROBDATA8(NCMOMI,JDATA)+
     &                 ROBDATA8(NCMOMI,JJ)
                  ZQCARG = ZGAMI + EXP(-1.0*ZJON)
                  ZPPOST = ZGAMI/ZQCARG
C
C     Store the value of o-a multiplied by one minus the posterior
C     probability of gross error (needed for the adjoint calculations)
C
                  ROBDATA8(NCMOMN,JDATA) = ZPPOST
                  ROBDATA8(NCMOMN,JJ) = ZPPOST

                  ROBDATA8(NCMOMI,JDATA)=-LOG(ZQCARG/(ZGAMI+1.))
     &                 /2.
                  ROBDATA8(NCMOMI,JJ) = -LOG(ZQCARG/(ZGAMI+1.))
     &                 /2.
C
C     Contribution of both u and v added to the cost function at the
C     same time (see tech. note by Andersson and Jarvinen)
C
                ENDIF
              ENDDO
            ELSE
              DO JJ=IDATA, JDATA
                ISTYP = MOBDATA(NCMVNM,JJ)
                ZSLEV = ROBDATA8(NCMPPP,JJ)
                IF ((ISTYP .EQ. NVNUMB(1) .OR.
     1               ISTYP .EQ. NEUS) .AND.
     2               ZSLEV .EQ. ZLEV) THEN
                  ZJON=ROBDATA8(NCMOMI,JDATA)+
     &                 ROBDATA8(NCMOMI,JJ)
                  ZQCARG = ZGAMI + EXP(-1.0*ZJON)
                  ZPPOST = ZGAMI/ZQCARG
                  ROBDATA8(NCMOMN,JDATA) = ZPPOST
                  ROBDATA8(NCMOMN,JJ) = ZPPOST
                  ROBDATA8(NCMOMI,JDATA)=-LOG(ZQCARG/(ZGAMI+1.))
     &                 /2.
                  ROBDATA8(NCMOMI,JJ) = -LOG(ZQCARG/(ZGAMI+1.))
     &                 /2.
                ENDIF
              enddo
            endif
          else
            zjon = robdata8(ncmomi,jdata)
            zqcarg = zgami + exp(-1.0*zjon)
            zppost = zgami/zqcarg
            robdata8(ncmomn,jdata) = zppost
            ROBDATA8(NCMOMI,JDATA)= - log(zqcarg/(zgami+1.))
          endif
        endif
      enddo

      RETURN
      END