Areal depletion curve

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The percent of the area that is covered by snow must be computed to determine the portion of the area over which energy exchange is taking place and, in the case of rain-on-snow, to determine how much rain falls on bare ground.

The areal depletion of snow has been shown in several studies to be predominantly a function of how much of the original snow cover remains.
The distribution of the snow cover during the accumulation season is influenced by topography, vegetation cover, storm type, and wind conditions.
Because these factors are stationary or similar from year to year, the snow cover accumulation patterns are also similar.
Snowmelt patterns are influenced by topography, vegetation cover, and weather conditions and are also similar from year to year.
Because of these similarities in snow accumulation and melt patterns, each area should have a reasonably unique areal depletion curve.
An areal depletion curve, as used in the model, is a plot of the areal extent of the snow cover versus a ratio which indicates how much of the original snow cover remains.