Dry Soils: The Highlands of the Antarctic Dry Valleys and the Defining Environmental Conditions

The cases explored are those of ice-cemented ground to the surface. We ask the question: under what environmental conditions does ice-cemented ground at the surface not melt? We find that in all cases, keeping the surface frozen requires that the air temperature does not exceed freezing. In addition, we find that the wind velocity plays an important role. The wind acts as a coupling between the atmosphere and the ground, thus with increasing wind velocity the ground temperature becomes increasingly similar to the air temperature. This also results in an increased sublimation rate from the ground, as vapour is quickly moved into the dry atmosphere. In cases where the wind velocity is very low, the ground surface can become very warm even with air temperatures which are significantly below freezing. Changes in the atmospheric relative humidity play a minor role, with lower humidities resulting in increased cooling of the ground by sublimation, and thus slightly lower ground temperatures.