Snow Melt
                                  ---- ----



The budget for the soil moisture is:

   dSW
   --- = rain - evap + sublim - runoff + snow_melt + relaxation_to_climo.
   dt

where
   SW = water in soil
   rain = liquid precipitation
   snow_melt = amount of snow that melted
   evap = evaporation from surface (including evaporation from snow)
   sublim = sublimation from the snow cover
   runoff
   relaxation_to_climo (see TEXT\DETAILS\RUNOF).

In snow-free regions, the soil-moisture budget can be computed given the
climatology needed for compute the last term.  However, the terms are
difficult to compute when snow is involved.


The budget for surface and soil moisture is:

   dW
   --- = precipitation - evaporation - runoff + relaxation_to_climo + snow_inc
   dt

where
   W = water in soil and snow layer
   snow_inc = changes in the snow pack from incorporating the externally 
       derived snow-cover analyses into the reanalysis.



For snow-free regions, it is possible to compute either budget.  For other 
regions, however, archived Reanalysis products make it easier to compute the 
budget for the soil and snow pack combined.