The Arctic
While the arctic is commonly thought to be anywhere that is fairly cold, The reality of the situation is that there are several specific attributes that compose the definition of Arctic and Sub-Arctic Regions.
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Arctic is derived from the Greek "Arctos" which is to indicate the land of the Big Bear, meaning the constellation Ursa Major, as well as Ursa Minor which points to the polar star. |
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One primary component in defining an Arctic region is that the underlying soil consists of continuous permafrost. |
(Note: Permafrost is soil that has remained below 32 degrees Fahrenheit for more than two years; not to be confused with soil that freezes and thaws each year which is properly known as seasonal frost.)
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Any region north of 67 degrees N Latitude is considered to be within the Arctic Circle, and therefore, The Arctic. |
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The Sub arctic is the region which while not technically within the boundaries of the Arctic Circle, have a similar climate and are located within several degrees of latitude of the Arctic Circle. This climate consists of brief summers and extremely cold winters. Sub arctic regions experience the coldest temperatures in the world with the exception of Antarctica. |
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Sub arctic regions have the largest annual temperature variance of any climate. Summer temperatures can rise above 25o C during a summer day, yet drop to 10o C during the evening. The summer or "freeze free" season is quite brief, lasting less than three months. |
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This treatise on windows is specifically relevant to Arctic and Sub arctic regions as attention is given to the large variation in temperatures that an Arctic~Grade window pane must withstand and properly interact with. |
From 11. Design Manual: Cold Regions Engineering
Note: The regions which are considered Arctic are those that are checkered as they are underlain by continuous permafrost.
Background Photo taken by Daniel C. Oliva