Cryosphere glossary
iciness
a qualitative term describing the quantity of ice in frozen ground.
icing
a sheetlike mass of layered ice formed on the ground surface, or on river or lake ice, by freezing of successive flows of water that may seep from the ground, flow from a spring or emerge from below river or lake ice through fractures.
icing blister
a seasonal frost mound consisting only of ice and formed at least in part through lifting of one or more layers of an icing by injected water.
icing glade
an area kept clear of trees and shrubs by the annual occurrence of icings.
icing mound
a seasonal frost mound consisting exclusively of thinly layered ice, formed by freezing of successive flows of water issuing from the ground or from below river ice.
inactive ice wedge
an ice wedge that is no longer growing.
inactive rock glacier
a mass of rock fragments and finer material, on a slope, that contains either an ice core or interstitial ice, and shows evidence of past, but not present, movement.
infrared radiation
electromagnetic radiation of wavelengths between approximately 0.75 and 1000 millimeters; see also atmospheric radiation, terrestrial radiation, longwave radiation.
inland ice sheet
an ice sheet of considerable thickness and an area of more than about 50,000 square kilometers (12.4 million acres), resting on rock; inland ice sheets near sea level may merge into ice shelves.
insolation
(1) exposure of an object to the sun (2) intensity of incoming solar radiation incident on a unit horizontal surface at a specific level.
instrument shelter
structure to protect certain instruments from insolation and weather while at the same time ensuring sufficient ventilation.
interfacial water
water that forms transition layers at mineral/water and mineral/water/ice interfaces in frozen ground.
intermediate discontinuous permafrost
(1) (North American usage) permafrost underlying 35 - 65% of the area of exposed land surface (2) (Russian usage) permafrost underlying 40 - 60% of the area of exposed land surface.
internal ice stress
a measure of the compactness, or strength of the ice; plays an important role in the deformation of the ice and formation of features such as ridges and leads.
interstitial ice
ice formed in narrow spaces between small rocks and sediment in soil.
intrapermafrost water
water occurring in unfrozen zones (taliks and cryopegs) within permafrost.
intrusive ice
ice formed from water injected into soils or rocks.
inversion
in meteorology, a departure from the usual (normal) decrease or increase with altitude of the value of an atmospheric property; also, the layer through which this departure occurs (the inversion layer); this term almost always refers to a temperature inversion.
isoband cryogenic fabric
a distinct soil micromorphology, resulting from the effects of freezing and thawing processes, in which soil particles form subhorizontal layers of similar thickness.
isobar
a line of equal or constant pressure; it most often refers to a line drawn through all points of equal atmospheric pressure.