! $Id$

SUBROUTINE freinage(knon, uu, vv, &
        tt, veget, lai, height, ypaprs, ypplay, drag_pro, d_u, d_v)

  !ONLINE:
  USE dimphy, ONLY: klon, klev
  USE lmdz_clesphys
  USE lmdz_compbl, ONLY: iflag_pbl, iflag_pbl_split, iflag_order2_sollw, ifl_pbltree
  USE lmdz_dimpft, ONLY: nvm_lmdz
  !    USE control, ONLY: nvm
  !    USE indice_sol_mod, ONLY: nvm_orch
  USE lmdz_YOEGWD, ONLY: GFRCRIT, GKWAKE, GRCRIT, GVCRIT, GKDRAG, GKLIFT, GHMAX, GRAHILO, GSIGCR, NKTOPG, NSTRA, GSSEC, GTSEC, GVSEC, &
          GWD_RANDO_RUWMAX, gwd_rando_sat, GWD_FRONT_RUWMAX, gwd_front_sat
  USE lmdz_yomcst

  IMPLICIT NONE

  ! 0. DECLARATIONS:

  ! 0.1 INPUTS

  REAL, DIMENSION(klon, klev), INTENT(IN) :: ypplay
  REAL, DIMENSION(klon, klev + 1), INTENT(IN) :: ypaprs

  REAL, DIMENSION(klon, klev), INTENT(IN) :: uu
  REAL, DIMENSION(klon, klev), INTENT(IN) :: vv
  REAL, DIMENSION(klon, klev), INTENT(IN) :: tt
  REAL, DIMENSION(klon, nvm_lmdz), INTENT(IN) :: veget, lai
  REAL, DIMENSION(klon, nvm_lmdz), INTENT(IN) :: height

  REAL, DIMENSION(klon, klev) :: wind
  REAL, DIMENSION(klon, klev) :: yzlay
  INTEGER knon

  ! 0.2 OUTPUTS

  REAL, DIMENSION(klon, klev), INTENT(OUT) :: d_v        ! change in v
  REAL, DIMENSION(klon, klev), INTENT(OUT) :: d_u        ! change in v
  !knon nombre de points concernes
  REAL, DIMENSION(klon, klev) :: sumveg        ! change in v

  REAL, DIMENSION(klon, klev), INTENT(OUT) :: drag_pro
  ! (KLON, KLEV) tendencies on winds

  INTEGER k, jv, i


  !FCCCC    REAL Cd_frein

  ! 0.3.1 LOCAL VARIABLE


  !-----------------------------------------------------------------

  ! 1. INITIALISATIONS


  !    Cd_frein = 7.5E-2 ! (0.075) ! Drag from MASSON 2009
  !FC ESSAI
  !    Cd_frein = 1.5E-2 ! (0.075) ! Drag from MASSON 2009
  !    Cd_frein = 0.005 ! (0.075) ! Drag from MASSON 2009

  ! initialisation
  d_u(:, :) = 0.
  d_v(:, :) = 0.
  drag_pro(:, :) = 0.
  sumveg(:, :) = 0.
  !!        PRINT*, "Cd_frein" , Cd_frein

  wind(:, :) = sqrt(uu(:, :) * uu(:, :) + vv(:, :) * vv(:, :))

  yzlay(1:knon, 1) = &
          RD * tt(1:knon, 1) / (0.5 * (ypaprs(1:knon, 1) + ypplay(1:knon, 1))) &
                  * (ypaprs(1:knon, 1) - ypplay(1:knon, 1)) / RG
  DO k = 2, klev
    yzlay(1:knon, k) = &
            yzlay(1:knon, k - 1) + RD * 0.5 * (tt(1:knon, k - 1) + tt(1:knon, k)) &
                    / ypaprs(1:knon, k) * (ypplay(1:knon, k - 1) - ypplay(1:knon, k)) / RG
  END DO

  !    verifier les indexes .....
  !!       PRINT*, " calcul de drag_pro FC "

  do k = 1, klev

    do jv = 2, nvm_lmdz   !   (on peut faire 9 ?)

      do i = 1, knon

        sumveg(i, k) = sumveg(i, k) + veget(i, jv)

        !      if  ( (height(i,jv) .gt. yzlay(i,k)) .AND. (height(i,jv) .gt. 0.1) .AND. LAI(i,jv).gt.0. ) THEN
        IF  ((height(i, jv) > yzlay(i, k)) .AND. (height(i, jv) > 0.1)) THEN
          !FC attention veut on le test sur le LAI ?
          IF (ifl_pbltree==1) THEN
            drag_pro(i, k) = drag_pro(i, k) + &
                    veget(i, jv)
          elseif (ifl_pbltree==2) THEN
            drag_pro(i, k) = drag_pro(i, k) + &
                    6 * LAI(i, jv) * veget(i, jv) * (yzlay(i, k) * (height(i, jv) - yzlay(i, k)) / (height(i, jv) * height(i, jv) + 0.01))
          elseif (ifl_pbltree==3) THEN
            drag_pro(i, k) = drag_pro(i, k) + &
                    veget(i, jv) * (yzlay(i, k) * (height(i, jv) - yzlay(i, k)) / (height(i, jv) * height(i, jv) + 0.01))
          elseif (ifl_pbltree==0) THEN
            drag_pro(i, k) = 0.0
          endif
        else
          drag_pro(i, k) = drag_pro(i, k)
        endif

      enddo
    enddo
  enddo
  do k = 1, klev
    where (sumveg(1:knon, k) > 0.05)
      !        drag_pro(1:knon,k)=Cd_frein*drag_pro(1:knon,k)/sumveg(1:knon,k)
      drag_pro(1:knon, k) = Cd_frein * drag_pro(1:knon, k)
    elsewhere
      drag_pro(1:knon, k) = 0.0
    endwhere
    d_u(1:knon, k) = (-1) * drag_pro(1:knon, k) * uu(1:knon, k) * wind(1:knon, k)
    d_v(1:knon, k) = (-1) * drag_pro(1:knon, k) * vv(1:knon, k) * wind(1:knon, k)
  enddo

END SUBROUTINE freinage