Geography 2010A/B Study Guide - Quiz Guide: Silt, Periglaciation, Thermal Conductivity
29 Aug 2018
School
Department
Course
Professor
Document Summary
Principle factors: ground temperature, nature of ground cover, thermal properties of the ground, geothermal heat from the interior of the earth that must be transferred to the surface. The thermal characteristics of materials in and on the ground vary widely: thermal conductivity (w/m c) In practice, the factors that control the presence of permafrost reflect heat flow that is three-dimensional and transient (seasonal, longer term) In the case of the seasonal cycle, the ground near the surface warms significantly above freezing. The depth of the active layer will vary annually, depending on available melt energy. This provides substantial thermal buffering of the underlying permafrost due to the latent heat required to melt the ice in the transient layer. The depth of permafrost is determined by the propagation of temperature variations from the surface to depth. The variation in soil temperature declines sharply with depth, and by depths of 2-5 m, the variation in annual temperature is essentially zero.
