Snow Energy Exchanges
Latent Heat (condensation or sublimation)
- Vapor Pressure Gradients over Snow
Saturation vapor pressure of a melting
snow cover at 0oC is about 6 mb.
Most of the time the atmosphere is not
saturated, and air samples would plot
to the right side of the curve (e.g. “A”).
If we hold the temperature at point A constant and increase the water vapor by amount “y”, the air will saturate (vapor pressure deficit: “drying power relative to saturated surface”).
If we hold the water vapor at point A constant and decrease the temperature by amount “x”, the air will saturate (dew point).
Vapor Pressure at the snow surface is generally at or very near the saturation level.