Snow and Ice Overview
A tenth of Earth’s land surface is permanently occupied by ice sheets or glaciers, but the domain of the cryosphere – that part of the world where snow and ice can form – extends three times further still.
The cryosphere is an important regulator of global climate, its bright albedo reflecting sunlight back to space and its presence influencing regional weather and global ocean currents. Some 77% of the globes freshwater are bound up within the ice – but the cryosphere appears disproportionately sensitive to the effects of global warming.
Imaging radar systems like those of ERS and Envisat pierce through clouds or seasonal darkness to chart ice extent, possessing sensitivity to different ice types – from kilometers - thick ice sheets to new-born floating ‘pancake’ ice – supplemented by optical observations.
Radar altimeters gather data on changing ice height and mass: in 2009 ESA launched CryoSat-2 as the first altimetry mission specifically designed to accurately measure the thickness of sea ice and land ice margins.
Snow and Ice News
21 August 2015
Satellite images show that the fastest moving glacier in the world shed a chunk of ice measuring around 12.5 sq km this week - one of the most significant calving events on record.
20 July 2015
Measurements from ESA's CryoSat satellite show that the volume of Arctic sea ice increased by a third following the unusually cool summer of 2013. This new finding suggests that ice in the northern hemisphere is more sensitive to changes in summer melting than it is to winter cooling.
Specific Topics on Snow and Ice
The enormous permafrost areas of the world show seasonal change which has impact on not only vegetation and hydrological cycles, but also on the planning and safety of huge gas and oil pipelines which traverse these areas.
Sea ice is formed from ocean water that freezes, whether along coasts or to the sea floor (fast ice) or floating on the surface (drift ice) or packed together (pack ice). The most important areas of pack ice are the polar ice packs. Because of vast amounts of water added to or removed from the oceans and atmosphere, the behavior of polar ice packs have a significant impact of the global changes in climate.
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