BalanceCheck

INTERFACE:

   subroutine BalanceCheck (c)

DESCRIPTION:

   Water and energy balance check  
   This subroutine accumulates the numerical truncation errors of the water
   and energy balance calculation. It is helpful to see the performance of 
   the process of integration.
   The error for energy balance: 
   error = abs(Net radiation - the change of internal energy - Sensible heat
               - Latent heat) 
   The error should be less than 0.02 W/m2 in each time integration interval;
   The error for water balance:
   error = abs(precipitation - change of water storage - evaporation - runoff)
   The error should be less than 0.001 mm in  each time integration interval.

USES:

     use clmtype
     use globals, only: dtime, nstep

ARGUMENTS:

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

CALLED FROM:

   subroutine driver

REVISION HISTORY:

   15 September 1999: Yongjiu Dai; Initial code
   15 December 1999:  Paul Houser and Jon Radakovich; F90 Revision 
   10 November 2000: Mariana Vertenstein
   Migrated to new data structures by Mariana Vertenstein and 
   Peter Thornton

LOCAL VARIABLES:

   local pointers to original implicit in scalars
     real(r8), pointer :: forc_rain     !rain rate [mm/s]
     real(r8), pointer :: forc_snow     !snow rate [mm/s]
     real(r8), pointer :: forc_lwrad    !downward infrared (longwave) radiation (W/m**2)
     real(r8), pointer :: endwb         !water mass end of the time step
     real(r8), pointer :: begwb         !water mass begining of the time step
     real(r8), pointer :: fsa           !solar radiation absorbed (total) (W/m**2)
     real(r8), pointer :: fsr           !solar radiation reflected (W/m**2)
     real(r8), pointer :: eflx_lwrad_out!emitted infrared (longwave) radiation (W/m**2)
     real(r8), pointer :: eflx_lwrad_net!net infrared (longwave) rad (W/m**2) [+ = to atm]
     real(r8), pointer :: sabv          !solar radiation absorbed by vegetation (W/m**2)
     real(r8), pointer :: sabg          !solar radiation absorbed by ground (W/m**2)
     real(r8), pointer :: eflx_sh_tot   !total sensible heat flux (W/m**2) [+ to atm]
     real(r8), pointer :: eflx_lh_tot   !total latent heat flux (W/m8*2)  [+ to atm]
     real(r8), pointer :: eflx_soil_grnd!soil heat flux (W/m**2) [+ = into soil]
     real(r8), pointer :: qflx_evap_tot !qflx_evap_soi + qflx_evap_veg + qflx_tran_veg
     real(r8), pointer :: qflx_surf     !surface runoff (mm H2O /s)
     real(r8), pointer :: qflx_qrgwl    !qflx_surf at glaciers, wetlands, lakes
     real(r8), pointer :: qflx_drain    !sub-surface runoff (mm H2O /s)
   local pointers to original implicit inout scalars
     real(r8), pointer :: acc_errh2o    !accumulation of water balance error
     real(r8), pointer :: acc_errseb    !accumulation of surface energy balance error
   local pointers to original implicit out scalars
     real(r8), pointer :: errh2o        !water conservation error (mm H2O)
     real(r8), pointer :: errsol        !solar radiation conservation error (W/m**2)
     real(r8), pointer :: errlon        !longwave radiation conservation error (W/m**2)
     real(r8), pointer :: errseb        !surface energy conservation error (W/m**2)
   local pointers to original implicit in arrays
     real(r8),dimension(:), pointer :: forc_solad   !direct beam radiation (vis=forc_sols , nir=forc_soll )
     real(r8),dimension(:), pointer :: forc_solai   !diffuse radiation     (vis=forc_solsd, nir=forc_solld)