Cryosphere glossary
partially-bonded permafrost
ice-bearing permafrost in which some of the soil particles are not held together by ice.
passive construction methods in permafrost
special design and construction methods used for engineering works in permafrost areas where preservation of the frozen condition is feasible.
passive single-phase thermal pile
a foundation pile provided with a single-phase natural convection cooling system to remove heat from the ground.
passive two-phase thermal pile
a foundation pile provided with a two-phase natural convection cooling system to remove heat from the ground.
past weather
predominant characteristic of the weather which had existed at an observing station during a given period of time (during the preceding hour or six hours), specified in the international synop code.
patch
a collection of pack ice, less than 10 kilometers (6.2 miles) across, whose limits can be seen from the masthead.
patterned ground
a general term for any ground surface exhibiting a discernibly ordered, more or less symmetrical, morphological pattern of ground and, where present, vegetation.
Image
A photograph taken from the air reveals patterned ground surrounding thaw lakes in Alaskas Arctic National Wildlife Refuge.
U.S. Fish and Wildlife Service
peat
a deposit consisting of decayed or partially decayed humified plant remains.
peat hummock
a hummock consisting of peat.
peat plateau
a generally flat-topped expanse of peat, elevated above the general surface of a peatland, and containing segregated ice that may or may not extend downward into the underlying mineral soil.
peatland
peat-covered terrain.
penitents
the extreme relief of ablation hollows found most often at high altitudes in the tropics; the resulting spikes of snow resemble repentant souls.
pereletok
a layer of frozen ground which forms as part of the seasonally frozen ground (in areas free of permafrost or with a lowered permafrost table); remains frozen throughout one or several summers, and then thaws.
perennial snow
snow that persists on the ground year after year.
periglacial
the conditions, processes and landforms associated with cold, nonglacial environments.
periglacial phenomena
landforms and soil characteristics produced by periglacial processes.
periglacial processes
processes associated with frost action in cold, nonglacial environments.
permacrete
an artificial mixture of frozen soil materials cemented by pore ice, which forms a concrete-like construction material used in cold regions.
permafrost
layer of soil or rock, at some depth beneath the surface, in which the temperature has been continuously below 0°C for at least several years; it exists where summer heating fails to reach the base of the layer of frozen ground.
permafrost aggradation
a naturally or artificially caused increase in the thickness and/or areal extent of permafrost.