Search results
Results from the WOW.Com Content Network
Less than one-third of the active layer (the soil between the ground surface and a permafrost table) or an ice layer which is at least 30 cm (12 in) thick has been cryoturbated. Turbels : soils that show marked influence of cryoturbation (more than one-third of the depth of the active layer) such as irregular, broken, or distorted horizon ...
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 ...
The middle zone is permanently frozen as "permafrost". And the bottom layer is where the geothermal temperature is above freezing. Note the importance of the vertical 0 °C line: It denotes the bottom of the active layer in the seasonally variable temperature zone and the bottom limit of permafrost as the temperature increases with depth.
Overview of the cryosphere and its larger components [1]. The cryosphere is an umbrella term for those portions of Earth's surface where water is in solid form. This includes sea ice, ice on lakes or rivers, snow, glaciers, ice caps, ice sheets, and frozen ground (which includes permafrost).
Visualization of the ice and snow covering Earth's northern and southern polar regions Northern Hemisphere permafrost (permanently frozen ground) in purple. The polar regions, also called the frigid zones or polar zones, of Earth are Earth's polar ice caps, the regions of the planet that surround its geographical poles (the North and South Poles), lying within the polar circles.
Example of a periglacial landscape with both pingos and polygon wedge ice near Tuktoyaktuk, Northwest Territories, Canada. Periglaciation (adjective: "periglacial", referring to places at the edges of glacial areas) describes geomorphic processes that result from seasonal thawing and freezing, very often in areas of permafrost.
Examples of tipping points include thawing permafrost, which will release methane, a powerful greenhouse gas, or melting ice sheets and glaciers reducing Earth's albedo, which would warm the planet faster. Thawing permafrost is a threat multiplier because it holds roughly twice as much carbon as the amount currently circulating in the ...
According to the definition of the Multi-Language Glossary of Permafrost and Related Ground-Ice Terms compiled by the International Permafrost Association (IPA)'s Terminology Working Group, "retrogressive thaw slumps consist of a steep headwall that retreats in a retrogressive fashion due to thawing, and a debris flow formed by the mixture of ...