SnowAge

INTERFACE:

   subroutine SnowAge (lbc, ubc)

DESCRIPTION:

   Updates snow age Based on BATS code.

USES:

     use shr_kind_mod, only: r8 => shr_kind_r8
     use clmtype
     use clm_varcon, only : tfrz
     use time_manager, only : get_step_size

ARGUMENTS:

     implicit none
     integer , intent(in) :: lbc, ubc ! column bounds

CALLED FROM:

REVISION HISTORY:

   Original Code:  Robert Dickinson
   15 September 1999: Yongjiu Dai; Integration of code into CLM
   15 December 1999:  Paul Houser and Jon Radakovich; F90 Revision
   3/4/02, Peter Thornton: Migrated to new data structures.
   8/20/03, Mariana Vertenstein: Vectorized routine

LOCAL VARIABLES:

   local pointers to implicit in arguments
     real(r8), pointer :: t_grnd(:)     ! ground temperature (Kelvin)
     real(r8), pointer :: h2osno(:)     ! snow water (mm H2O)
     real(r8), pointer :: h2osno_old(:) ! snow mass for previous time step (kg
   local pointers to implicit inout arguments
     real(r8), pointer :: snow_age(:)   ! non dimensional snow age [-]