SUBROUTINE lpm_calc_liquid_water_content

!--------------------------------------------------------------------------------!
! 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 1997-2014 Leibniz Universitaet Hannover
!--------------------------------------------------------------------------------!
!
! Current revisions:
! ------------------
!
! Former revisions:
! -----------------
! $Id: lpm_calc_liquid_water_content.f90 1321 2014-03-20 09:40:40Z witha $
!
! 1320 2014-03-20 08:40:49Z raasch
! ONLY-attribute added to USE-statements,
! kind-parameters added to all INTEGER and REAL declaration statements,
! kinds are defined in new module kinds,
! comment fields (!:) to be used for variable explanations added to
! all variable declaration statements
!
! 1036 2012-10-22 13:43:42Z raasch
! code put under GPL (PALM 3.9)
!
! 849 2012-03-15 10:35:09Z raasch
! initial revision (former part of advec_particles)
!
!
! Description:
! ------------
! Calculate the liquid water content for each grid box.
!------------------------------------------------------------------------------!

    USE arrays_3d,                                                             &
        ONLY:  ql, ql_v, ql_vp

    USE cloud_parameters,                                                      &
        ONLY:  rho_l

    USE constants,                                                             &
        ONLY:  pi

    USE control_parameters,                                                    &
        ONLY:  dz, message_string, rho_surface

    USE cpulog,                                                                &
        ONLY:  cpu_log, log_point_s

    USE grid_variables,                                                        &
        ONLY:  dx, dy

    USE indices,                                                               &
        ONLY:  nxl, nxr, nyn, nys, nzb, nzt

    USE kinds

    USE particle_attributes,                                                   &
        ONLY:  particles, prt_count, prt_start_index

    IMPLICIT NONE

    INTEGER(iwp) ::  i   !:
    INTEGER(iwp) ::  j   !:
    INTEGER(iwp) ::  k   !:
    INTEGER(iwp) ::  n   !:
    INTEGER(iwp) ::  psi !:


    CALL cpu_log( log_point_s(45), 'lpm_calc_ql', 'start' )

!
!-- Set water content initially to zero
    ql = 0.0;  ql_v = 0.0;  ql_vp = 0.0

!
!-- Calculate for each grid box
    DO  i = nxl, nxr
       DO  j = nys, nyn
          DO  k = nzb, nzt+1

!
!--          Calculate the total volume in the boxes (ql_v, weighting factor
!--          has to beincluded)
             psi = prt_start_index(k,j,i)
             DO  n = psi, psi+prt_count(k,j,i)-1
                ql_v(k,j,i)  = ql_v(k,j,i)  + particles(n)%weight_factor *  &
                                              particles(n)%radius**3
             ENDDO

!
!--          Calculate the liquid water content
             IF ( ql_v(k,j,i) /= 0.0 )  THEN
                ql(k,j,i) = ql(k,j,i) + rho_l * 1.33333333 * pi *           &
                                        ql_v(k,j,i) /                       &
                                        ( rho_surface * dx * dy * dz )

                IF ( ql(k,j,i) < 0.0 ) THEN
                   WRITE( message_string, * )  'LWC out of range: ' , &
                                               ql(k,j,i)
                   CALL message( 'lpm_calc_liquid_water_content', '', 2, 2, &
                                 -1, 6, 1 )
                ENDIF

             ELSE

                ql(k,j,i) = 0.0

             ENDIF

          ENDDO
       ENDDO
    ENDDO

    CALL cpu_log( log_point_s(45), 'lpm_calc_ql', 'stop' )


 END SUBROUTINE lpm_calc_liquid_water_content