Undisturbed measurement of the energy and mass balance of a deep alpine snowcover

The testing and development of energy balance snowmelt models requires the undisturbed measurement of various energy exchange components, snow mass balance, and snow and soil properties. A micrometeorological station providing such measurements has been established in cooperation with the U.S.F.S. at 2930 m on Mammoth Mtn. in the southern Sierra Nevada. This site has an average winter snow depth of around 3 m, and can be as deep as 8 m. Radiometers measure incoming and reflected solar radiation in two wavelength bands, and incoming and emmitted thermal radiation in one wavelength band. Surface fluxes of latent and sensible heat are determined with a very accurate dew point sensor utilizing the `condensation mirror approach', two anemometers, and the measurement of emitted thermal radiation. Snow-soil thermal interaction is estimated using thermistor arrays at fixed spacing. Snow water content and average density are obtained from a snow pillow and depth stake. Dynamic measurement of snow settlement, and temperature profiles is done using a sliding platter device similar to that described by Swanson (1968) which allow a depth location with temperature.