SUBROUTINE user_init_plant_canopy

!--------------------------------------------------------------------------------!
! This file is part of PALM.
!
! PALM is free software: you can redistribute it and/or modify it under the terms
! of the GNU General Public License as published by the Free Software Foundation,
! either version 3 of the License, or (at your option) any later version.
!
! PALM is distributed in the hope that it will be useful, but WITHOUT ANY
! WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
! A PARTICULAR PURPOSE.  See the GNU General Public License for more details.
!
! You should have received a copy of the GNU General Public License along with
! PALM. If not, see <http://www.gnu.org/licenses/>.
!
! Copyright 1997-2012  Leibniz University Hannover
!--------------------------------------------------------------------------------!
!
! Current revisions:
! -----------------
!
! Former revisions:
! -----------------
! $Id: user_init_plant_canopy.f90 1037 2012-10-22 14:10:22Z witha $
!
! 1036 2012-10-22 13:43:42Z raasch
! code put under GPL (PALM 3.9)
!
! 667 2010-12-23 12:06:00Z suehring/gryschka
! nxl-1, nxr+1, nys-1, nyn+1 replaced by nxlg, nxrg, nysg, nyng
!
! 274 2009-03-26 15:11:21Z heinze
! Output of messages replaced by message handling routine.
!
! 211 2008-11-11 04:46:24Z raasch
! Former file user_interface.f90 split into one file per subroutine
!
! Description:
! ------------
! Initialisation of the leaf area density array (for scalar grid points) and 
! the array of the canopy drag coefficient, if the user has not chosen any 
! of the default cases 
!------------------------------------------------------------------------------!

    USE arrays_3d
    USE control_parameters
    USE indices
    USE user

    IMPLICIT NONE

    INTEGER :: i, j 

!
!-- Here the user-defined grid initializing actions follow:

!
!-- Set the 3D-arrays lad_s and cdc for user defined canopies
    SELECT CASE ( TRIM( canopy_mode ) )

       CASE ( 'block' )
!
!--       Not allowed here since this is the standard case used in init_3d_model.

       CASE ( 'user_defined_canopy_1' )
!
!--       Here the user can define his own topography. 
!--       The following lines contain an example in that the 
!--       plant canopy extends only over the second half of the 
!--       model domain along x
!          DO  i = nxlg, nxrg
!             IF ( i >= INT(nx+1/2) ) THEN
!                DO  j = nysg, nyng
!                   lad_s(:,j,i) = lad(:)
!                   cdc(:,j,i)   = drag_coefficient
!                ENDDO
!             ELSE
!                lad_s(:,:,i) = 0.0
!                cdc(:,:,i)   = 0.0
!             ENDIF
!          ENDDO 
!--       After definition, please
!--       remove the following three lines!
          message_string = 'canopy_mode "' // canopy_mode // &
                           '" not available yet'
          CALL message( 'user_init_plant_canopy', 'UI0007', 0, 1, 0, 6, 0 )
          
       CASE DEFAULT
!
!--       The DEFAULT case is reached if the parameter canopy_mode contains a
!--       wrong character string that is neither recognized in init_3d_model nor
!--       here in user_init_plant_canopy.
          message_string = 'unknown canopy_mode "' // canopy_mode // '"'
          CALL message( 'user_init_plant_canopy', 'UI0008', 1, 2, 0, 6, 0 )

    END SELECT


 END SUBROUTINE user_init_plant_canopy