Cryosphere glossary

A B C D E F G H I J K L M N O P R S T U V W Y Z

tabular berg

a flat-topped iceberg that shows horizontal banding; typically form by breaking from an ice shelf.

taiga

the open northern part of the boreal forest; consists of open woodland of coniferous trees growing in a rich floor of lichen (mainly reindeer moss or caribou moss), and is generally cold and swampy; lies immediately south of the tundra; in spring, it is often flooded by water from northward flowing rivers, the lower reaches of which are still frozen.

talik

a layer or body of unfrozen ground occurring in a permafrost area due to a local anomaly in thermal, hydrological, hydrogeological, or hydrochemical conditions.

tarn

a small mountain lake or pool.

telescoped ice

deformed sea ice in which one piece has overridden another; also called rafted ice.

temperature

a physical quantity characterizing the mean random motion of molecules in a physical body; in other words, it is a measure of the degree of hotness or coldness of a substance.

temperature profile

the graphic or analytical expression of the variation in ground temperature with depth.

temperature-gradient metamorphism

snow metamorphism that occurs when there are strong differences in temperature between the bottom and top of a snow layer.

terminus

the lowest end of a glacier, also called the glacier toe or glacier snout.

terrestrial radiation

longwave radiation emitted by the earth, including its atmosphere.

thaw basin

a depression of the permafrost table created by naturally induced thawing.

thaw bulb

a zone of thawed ground below or surrounding a man-made structure placed on or in permafrost and maintained at temperatures above 0 degrees Celsius.

thaw consolidation

time-dependent compression resulting from thawing of frozen ground and subsequent draining of excess water.

thaw consolidation ratio

a dimensionless ratio describing the relationship between the rate of thaw and the rate of consolidation of a thawing soil, which is considered to be a measure of the relative rates of generation and expulsion of excess water during thaw.

thaw hole

vertical hole in floating ice formed when a puddle melts through to the underlying water.

thaw penetration

the downward movement of the thawing front during thawing of frozen ground.

thaw settlement

compression of the ground due to thaw consolidation.

thaw sink

a closed thaw basin with subterranean drainage.

thaw slumping

a slope failure mechanism characterized by the melting of ground ice, and downslope sliding and flowing of the resulting debris.

thaw strain

the amount that frozen ground compresses upon thawing.