SUBROUTINE global_mean(field,airephy,laire,mfield)

! I.Musat: 05.2011
! calcul moyenne globale d'un champ pondere par l'aire de la maille
! (laire=.TRUE.) ou somme globale du champ (laire=.FALSE.)

  USE dimphy
  USE lmdz_phys_para, ONLY: is_sequential
  USE lmdz_phys_transfert_para, ONLY: reduce_sum
  USE lmdz_phys_mpi_data, ONLY: is_mpi_root
  USE ioipsl
  IMPLICIT NONE

  REAL,DIMENSION(klon),INTENT(IN) :: field
  REAL,DIMENSION(klon),INTENT(IN) :: airephy
  LOGICAL, INTENT(IN) :: laire
  REAL, INTENT(OUT) :: mfield
  REAL :: airetot     ! Total area the earth
  REAL :: sumtmp
  INTEGER :: i

  IF (is_sequential) THEN
   airetot = 0.
   sumtmp = 0.
   DO i=1, klon
    airetot = airetot + airephy(i)
    sumtmp = sumtmp + field(i)
   END DO
   IF (laire) THEN
    IF(airetot/=0.) THEN
     mfield=sumtmp/airetot
    endif
   else
    mfield=sumtmp
   endif

  else

   CALL reduce_sum(SUM(airephy),airetot)
   CALL reduce_sum(SUM(field),sumtmp)

!$OMP MASTER
  IF (is_mpi_root) THEN
  IF (laire) THEN
!  PRINT*,'gmean airetot=',airetot
   IF(airetot/=0.) THEN
    mfield=sumtmp/airetot
!  else
!   mfield=sumtmp
   endif
  else
   mfield=sumtmp
  ENDIF

! PRINT*,'gmean sumtmp mfield=',sumtmp,mfield

  ENDIF !(is_mpi_root) THEN
!$OMP END MASTER

  ENDIF

  END SUBROUTINE  global_mean