Polar High

A polar high is a persistent area of high atmospheric pressure centered on the North or South Pole, formed as cold polar air sinks in a process called subsidence, the opposite of the rising warm air that produces low pressure at the equator; together these form the polar cell of the general atmospheric circulation. The Antarctic high is markedly stronger than its Arctic counterpart because land exchanges heat with the atmosphere more efficiently than ocean, and the Arctic holds far more open water than Antarctica. Regions beneath the polar highs experience some of the coldest surface temperatures on Earth, with no month averaging above freezing, and receive so little precipitation that they are classified as polar deserts.