Snow areal extent

The snowpack forms an interface between the atmosphere and the ground or sea ice that affects the energy balance of the Earth s surfaceand the exchange of chemical species between the surface and the atmosphere. Studies of snow areal extent (e.g. ref. 4) show that during the boreal winter snow covers about 14% of the Earth s surface, therefore affecting the surface energy balance at near-planetary scales, while its overall effect on tropospheric chemistry still needs to be assessed. 

Comets are surviving members of a formerly vast distribution of solid bodies that formed in the cold regions of the solar nebula. Cometary bodies escaped incorporation into planets and ejection from the solar system and they have been stored in two distant reservoirs, the Oort cloud and the Kuiper Belt, for most of the age of the solar system. Observed comets appear to have formed between 5 AU and 55 AU. From a cosmochemical viewpoint, comets are particularly interesting bodies because they are preserved samples of the solar nebula s cold ice-bearing regions that occupied 99% of the areal extent of the solar nebula disk. All comets formed beyond the snow line of the nebula, where the conditions were... 

The reflectivity of ice and snow-covered surfaces. The albedo of freshly fallen snow may be as much as 90%, while older snow may have values of 75% or less. The larger the areal extent of snow and ice cover, the higher the albedo value. 

Interactions that can be described as a theoretical concept of a feedback mechanism in which the interacting elements are the areal extent of polar ice and snow cover, the albedo of the polar region (dependent on areal extent of ice and snow), absorption of solar radiation (dependent on the albedo), temperature (dependent on the absorption of solar radiation) and the area of ice and snow cover (dependent on temperature). Less snowfall would mean more absorption of solar radiation, therefore a surface warming would occur. Climate modeling studies indicate an amplification effect (i.e., positive feedback) of the ice and snow-albedo feedback on increased surface air temperatures caused by increases in the atmospheric concentration of carbon dioxide, ice cover... 

For weather prediction in the polar areas, it is important to take into account the effects of sea ice. Approximately 2% of the total water on the earth is stored in the form of ice in polar areas and glaciers. Sea ice accounts for nearly two-thirds of the earth s ice cover in areal extent. Sea ice plays the major role of controlling the exchange of heat, water vapor, and momentum between sea and air in the polar regions. Ice cuts off heat and water vapor transport from the ocean to the atmosphere and increases the albedo. Thus, similar to snow cover over land, sea ice contributes to cooling over the ice surface, which, in turn, tends to thicken the ice— a positive climatic feedback. 

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