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!

      subroutine lpreobs 2,3
#if defined (DOC)
*
***s/r lpreobs  - Build increments of derived fields assimilated. TLM of preobs.
*
*
*Author  : L. Fillion *ARMA/AES  7 oct 98
*
*Revision: L. Fillion *ARMA/AES  25 nov 98
*        - Option ES or LQ humidity analysis
*Revision: C. Charette *ARMA/AES  09 dec 98
*        - GOMQ copied to GOMES when humidity analysis variable is T-Td
*Revision: L. Fillion *ARMA/EC  5 Apr 2006
*        - Validate Shallow-Water LAM 4dvar.
*Revision: L. Fillion *ARMA/EC  14 Aug 2007 - Update to v_10_0_3.
*Revision: L. Fillion *ARMA/EC  10 Feb 2010 - Conditionally calls ltt2phi
*
*          Bin He   - ARMA/MRB   - Oct. 2011,
*                   - 4Dvar optimization.

*     -------------------
**    Purpose: Used in evaluation of Jo and Grad Jo
*
*Arguments
#endif
      USE modfgat,only : istepobs,nobs,notag
      IMPLICIT NONE
*implicits
#include "comct0.cdk"
#include "comdim.cdk"
#include "comcva.cdk"
#include "comdimo.cdk"
#include "commvo.cdk"
#include "comstate.cdk"
*modules
*
**
      INTEGER JLEV,JOBS,iobs 

       if(nobs(istepobs)==0)return
C
C*1   Geopotential increments from Temperature increments
C     ---------------------------------------------------
C

 100  CONTINUE
      if((.not.lsw).and.(NMVOEXIST(NOGZ).eq.1)) call ltt2phi
C
C*2   Analysis increments of humidity variable
C     ----------------------------------------------------------------
C
 200  CONTINUE
C
C     Analysis increments of ln(specific humidity) to increments of (T-Td)
C     when analysis variable is lnq
C
      if((.not.lsw).and.chum.eq.'LQ') then
        call lmhu2es
      endif
C
C     Analysis increments of T-Td when analysis variable is T-Td
C
      IF(CHUM .EQ. 'ES') THEN
         DO IOBS=1,nobs(istepobs) 
             jobs=notag(iobs,istepobs)
             GOMES(1:NFLEV,JOBS) = GOMQ(1:NFLEV,JOBS)
         ENDDO
      ENDIF
C
      RETURN
      END