Energy & Snow

               
             The energy properties of snow are vast and remarkable.  I will focus on one effect snow has globally and one application of snow locally. 

             The albedo and radiative properties of snow have the greatest global impacts.  Albedo is the ratio of light reflected and received by an object.  Snow doesn’t have the same impact as clouds when regulating radiation and temperature of the planet, but it still has a great impact.  Snow’s albedo is responsible for a portion of the reflected global incoming solar radiation. 

Albedo is dependent on snow type, spectral distribution of the incoming radiation, and vegetation and surface roughness.¹²  Fresh snow will produce the highest albedo.  As snow melts, it is likely the albedo will decrease from the increase of impurities in older snow.  This increases the absorption and increases the rate of melt in snow.  This is not always certain, however, older snow does not always contain more impurities.  Spectral distribution can decrease snow albedo.  This is contingent on the clarity of the atmosphere such as clouds.  “Clear-sky diffuse radiation is focused in the visible part where clean snow always shows a high reflectance.”¹³  Vegetation and surface roughness also have effects.  Canopy cover, such as forests, can lower the albedo along with mountainous regions and large surface areas.  This decrease in albedo is primarily contributed to the patchiness of the snow surface.

            Snow becomes increasingly interesting when looking at its emissivity in the thermal spectrum.  “It absorbs all the long-wave radiation emitted by the atmosphere or by the surrounding obstacles and emits the maximum thermal radiation allowed by its surface temperature.”¹⁴ The albedo and emissivity are the cause for the rapid cooling of continental regions in winter. 

The outstanding properties of snow allow accumulation to be practically applied to life (other than for consumption and crop sustenance).  Probably the most recognized is an igloo, a snow shelter native to northern North America.  An igloo is a small structure made from snow pack.  It is a hemisphere with a small entrance protruding from the front.  The snow operates as insulation between the occupant and the outside elements.  The porous properties of snow and the shape of the igloo allow for a warmer climate with proper circulation.  The climate is not the same as a heated, modern western home.  It is to protect from severe elements such as temperatures at -50˚F and blowing wind and snow.

There are many more properties of snow relating to energy.  The albedo and radiative properties are examples.  The igloo is one example of the applications of snow.  Other major applications are for drinking water and crops.  Runoff from the Colorado Rockies supplies water for a large number of people and farms.  The properties, applications and contributions of snow are seemingly endless.  

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