The Azimuth Project
Cryosphere

Contents

Idea

The cryosphere is all ice and snow present on Earth. Wikipedia defines it in more detail:

The cryosphere (from the Greek κρύος cryos “cold”, “frost” or “ice”) is the term which collectively describes the portions of the Earth’s surface where water is in solid form, including sea ice, lake ice, river ice, snow cover, glaciers, ice caps and ice sheets, and frozen ground (which includes permafrost).

Here is a map of the current distribution of the cryosphere:

map of cryosphere

Thus there is a wide overlap with the hydrosphere. The cryosphere is an integral part of the global climate system with important linkages and feedbacks generated through its influence on surface energy and moisture fluxes, clouds, precipitation, hydrology, atmospheric and oceanic circulation. Through these feedback processes, the cryosphere plays a significant role in global climate and in climate model response to global change.

Details

Here is a table from Ralf Greve showing the amount of ice present in the cryosphere:

amount of ice

An ice sheet is on land and larger than 50 000 km^2 and ice shelves floats in water but are connected to sheets. Ice caps are on land but less than 50 000 km^2. Glaciers are smaller typically limited to their surrounding geography. So due to the potentially huge impact of ice melting on Antarctica, there is a lot of research going on to get more knowledge on global warming impact and more fine grained models.

See our page on the sea level rise for more detailed facts and implications of the ice melting. Or see Greenland ice sheet, Arctic sea ice, West Antarctic Ice Sheet and Antarctic ice sheet.

Physics

What makes the ice flow?

Water is not sticky (non-viscous) and if one looks at and ice-block on the ground it will have velocity difference from the top of the ice block towards the part that is on the ground. This causes shearing and deformation inside the ice block and also enables the ice to start moving. As ice has honeycomb-like hexagonal crystals the gliding sheets form a “deck of card” model according to Ralf Greve. Deformation of the ice also forms a sticky and non-linear? form of the poly-crystalline ice, which is more than 10^12 times stickier than oil.

So that is one mechanism that may explain that four of the tipping points resides in the cryosphere; the melting of ice in Greenland and the Arctic, instabilities in the West Antarctic ice sheet and changes in the Antarctica bottom water formation.

References

Software

Currently, the largest homogeneous user group of Elmer is within Glaciology, which deals with all aspects of frozen water, commonly known as ice. Especially the dynamics of ice masses (ice-sheets and -shelves, glaciers) have been/are objects of investigations using Elmer as the numerical tool.

SICOPOLIS (SImulation COde for POLythermal Ice Sheets) is a 3-d dynamic/thermodynamic model which simulates the evolution of large ice sheets. It was originally created as a part of the doctoral thesis by Greve (1995) in a version for the Greenland Ice Sheet. Since then, SICOPOLIS has been developed continuously and applied to problems of past, present and future glaciation of Greenland, Antarctica, the entire northern hemisphere and also the polar ice caps of the planet Mars.

Books and reports

‘ Ralf Greve, Primer on the Cryosphere, course material.