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  2. Permafrost - Wikipedia

    en.wikipedia.org/wiki/Permafrost

    Permafrost temperature profile. Permafrost occupies the middle zone, with the active layer above it, while geothermal activity keeps the lowest layer above freezing. The vertical 0 °C or 32 °F line denotes the average annual temperature that is crucial for the upper and lower limit of the permafrost zone, while the red lines represent seasonal temperature changes and seasonal temperature ...

  3. Active layer - Wikipedia

    en.wikipedia.org/wiki/Active_layer

    The red dotted-to-solid line depicts the average temperature profile with depth of soil in a permafrost region. The trumpet-shaped lines at the top show seasonal maximum and minimum temperatures in the "active layer", which commences at the depth where the maximum annual temperature intersects 0 °C. The active layer is seasonally frozen.

  4. Frost line - Wikipedia

    en.wikipedia.org/wiki/Frost_line

    The maximum frost depth observed in the contiguous United States ranges from 0 to 8 feet (2.4 m). [1] Below that depth, the temperature varies, but is always above 0 °C (32 °F). Alternatively, in Arctic and Antarctic locations the freezing depth is so deep that it becomes year-round permafrost, and the term "thaw depth" is used

  5. Thaw depth - Wikipedia

    en.wikipedia.org/wiki/Thaw_depth

    In soil science, the thaw depth or thaw line is the instantaneous level down to which the soil has warmed to zero degrees Celsius. The active layer thickness is the maximum thaw depth over a period of two years. The layer of soil over the thaw depth is called the active layer, while the soil below is called permafrost.

  6. Permafrost carbon cycle - Wikipedia

    en.wikipedia.org/wiki/Permafrost_carbon_cycle

    The permafrost carbon cycle or Arctic carbon cycle is a sub-cycle of the larger global carbon cycle. Permafrost is defined as subsurface material that remains below 0 o C (32 o F) for at least two consecutive years. Because permafrost soils remain frozen for long periods of time, they store large amounts of carbon and other nutrients within ...

  7. Gelisol - Wikipedia

    en.wikipedia.org/wiki/Gelisol

    They have 80% or more organic materials from the soil surface to a depth of 50 cm (20 in) or to a glacic layer or densic, lithic, or paralithic contact, whichever is shallowest. These soils occur predominantly in subarctic and low arctic regions of continuous or widespread permafrost. Less than one-third of the active layer (the soil between ...

  8. Talik - Wikipedia

    en.wikipedia.org/wiki/Talik

    A talik is a layer of year-round unfrozen ground that lies in permafrost areas. In regions of continuous permafrost, taliks often occur underneath shallow thermokarst lakes and rivers, where the deep water does not freeze in winter and thus the soil underneath does not freeze either. Sometimes closed, open, and through taliks are distinguished.

  9. Canadian Arctic tundra - Wikipedia

    en.wikipedia.org/wiki/Canadian_Arctic_Tundra

    continuous permafrost (underlying 90 to 100% of the landscape) discontinuous permafrost (50 to 90%) sporadic permafrost (0 to 50%) In the discontinuous and sporadic zones permafrost distribution is complex and patchy, and permafrost-free terrain is common. The depth of permafrost varies from less than one meter to more than 1,500 m (4,900 ft). [23]