snowLiqFlx.f90

! SUMMA - Structure for Unifying Multiple Modeling Alternatives
! Copyright (C) 2014-2020 NCAR/RAL; University of Saskatchewan; University of Washington
!
! This file is part of SUMMA
!
! For more information see: http://www.ral.ucar.edu/projects/summa
!
! This program 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.
!
! This program 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 this program.  If not, see <http://www.gnu.org/licenses/>.

module snowLiqFlx_module

! access modules
USE nrtype                                    ! numerical recipes data types
USE multiconst,only:iden_ice,iden_water       ! intrinsic density of ice and water (kg m-3)

! access missing values
USE globalData,only:integerMissing  ! missing integer
USE globalData,only:realMissing     ! missing real number

! named variables
USE var_lookup,only:iLookINDEX      ! named variables for structure elements
USE var_lookup,only:iLookPARAM      ! named variables for structure elements
USE var_lookup,only:iLookPROG       ! named variables for structure elements
USE var_lookup,only:iLookDIAG       ! named variables for structure elements

! data types
USE data_types,only:var_d           ! x%var(:)       (dp)
USE data_types,only:var_dlength     ! x%var(:)%dat   (dp)
USE data_types,only:var_ilength     ! x%var(:)%dat   (i4b)

! privacy
implicit none
private
public::snowLiqFlx
contains


 ! ************************************************************************************************
 ! public subroutine snowLiqFlx: compute liquid water flux through the snowpack
 ! ************************************************************************************************
 subroutine snowLiqFlx(&
                       ! input: model control
                       nSnow,                   & ! intent(in):    number of snow layers
                       firstFluxCall,           & ! intent(in):    the first flux call
                       scalarSolution,          & ! intent(in):    flag to indicate the scalar solution
                       ! input: forcing for the snow domain
                       scalarThroughfallRain,   & ! intent(in):    rain that reaches the snow surface without ever touching vegetation (kg m-2 s-1)
                       scalarCanopyLiqDrainage, & ! intent(in):    liquid drainage from the vegetation canopy (kg m-2 s-1)
                       ! input: model state vector
                       mLayerVolFracLiqTrial,   & ! intent(in):    trial value of volumetric fraction of liquid water at the current iteration (-)
                       ! input-output: data structures
                       indx_data,               & ! intent(in):    model indices
                       mpar_data,               & ! intent(in):    model parameters
                       prog_data,               & ! intent(in):    model prognostic variables for a local HRU
                       diag_data,               & ! intent(inout): model diagnostic variables for a local HRU
                       ! output: fluxes and derivatives
                       iLayerLiqFluxSnow,       & ! intent(inout): vertical liquid water flux at layer interfaces (m s-1)
                       iLayerLiqFluxSnowDeriv,  & ! intent(inout): derivative in vertical liquid water flux at layer interfaces (m s-1)
                       ! output: error control