CombineSnowLayers

INTERFACE:

   subroutine CombineSnowLayers (c)

DESCRIPTION:

   Combine snow layers that are less than a minimum thickness or mass
   If the snow element thickness or mass is less than a prescribed minimum,
   then it is combined with a neighboring element.  The subroutine 
   clm_combo.f90 then executes the combination of mass and energy.

USES:

     use clmtype
     use clm_varcon, only : istsoil

ARGUMENTS:

     implicit none
     type (column_type),target,intent(inout):: c		!column derived type

CALLED FROM:

   subroutine Hydrology2 in module Hydrology2Mod

REVISION HISTORY:

   15 September 1999: Yongjiu Dai; Initial code
   15 December 1999:  Paul Houser and Jon Radakovich; F90 Revision 
   2/28/02, Peter Thornton: Migrated to new data structures.

LOCAL VARIABLES:

   local pointers to implicit in scalars
     integer,pointer:: itypwat  !water type
   local pointers to implicit inout scalars
     integer ,pointer:: snl     !number of snow layers
     real(r8),pointer:: h2osno  !snow water (mm H2O)
     real(r8),pointer:: snowdp  !snow height (m)
   local pointers to implicit inout arrays
     real(r8),dimension(:),pointer:: dz           !layer depth (m)
     real(r8),dimension(:),pointer:: zi           !interface level below a "z" level (m)
     real(r8),dimension(:),pointer:: t_soisno     !soil temperature (Kelvin)
     real(r8),dimension(:),pointer:: h2osoi_ice   !ice lens (kg/m2)
     real(r8),dimension(:),pointer:: h2osoi_liq   !liquid water (kg/m2)
   local pointers to implicit out arrays
     real(r8),dimension(:),pointer:: z            !layer thickness (m)