Cryosphere glossary
a boundary sometimes identified in perennially frozen ground, representing the base of a relict active layer, as well as the corresponding earlier permafrost table.
the reduction in shear strength due to the decrease in effective stresses resulting from the generation and slow dissipation of excess pore pressures when frozen soils containing ice are thawing.
perennially frozen ground which, upon thawing, will experience significant thaw settlement and suffer loss of strength to a value significantly lower than that for similar material in an unfrozen condition.
perennially frozen ground which, upon thawing, will not experience either significant thaw settlement or loss of strength.
melting of the ice in frozen ground, usually as a result of a rise in temperature.
an optical instrument used to visually track a radiosonde balloon and determine its bearing and elevation while in flight.
the quantity of heat that will flow through a unit area of a substance in unit time under a unit temperature gradient.
the erosion of ice-bearing permafrost by the combined thermal and mechanical action of moving water.
the volume change per unit volume of a substance due to a one degree change in its temperature.
a foundation pile on which natural convection or forced circulation cooling systems or devices have been installed to remove heat from the ground.
the properties of the ground governing the flow of heat through it, and its freezing and thawing conditions.
a general term encompassing the temperature distribution and heat flows in the ground and their time-dependence.
a layer or body of unfrozen ground (in a permafrost area) in which the temperature is above 0 degrees Celsius due to the local thermal regime of the ground.