Web site navigation : home > Antarctica > Land and Climate of Antarctica > Climate and Weather in Antarctica

Search this website ::

Land and Climate of Antarctica

Climate and Weather in Antarctica

Antarctica has several climates, all cold but differing considerably in severity. East Antarctica’s high plateau region yields the lowest year-round temperatures due to its relatively high elevation. The world’s lowest yearly air temperatures, typically –88°C (–126°F), are recorded in late August at Russia’s Vostok station. In coastal regions latitude is more significant than elevation. The higher the latitude (that is, the closer to the pole) the lower the average temperatures. The west coast of the Antarctic Peninsula and the neighboring islands have the mildest climates, with average January temperatures above freezing. Some of the fastest warming on Earth has occurred around the Antarctic Peninsula, with a rise of almost 3°C (5°F) over the past 50 years. Elsewhere in Antarctica, however, temperatures and precipitation have remained relatively steady over the same time period.

The entire region south of the Antarctic Circle, which is the parallel of latitude at 66°30’ south, experiences at least one day of continuous daylight during the Southern Hemisphere’s summer (around December 21) and one day of continuous darkness during the winter (around June 21). The interior of Antarctica has almost continuous daylight during the summer and darkness during the winter. In coastal areas farther north, there are fewer days of continuous daylight and darkness, and sunrises and sunsets occur more frequently.

Precipitation falls mainly as snow or ice, with occasional rain in coastal areas. Very little precipitation falls on the high plateau. Average annual accumulations of 50 mm (2 in) there make it one of the world’s driest deserts. Successive low-pressure systems around the coasts and islands bring heavier snow, which is packed down by wind and its own weight to form ice. Winds are light and variable on the plateaus, rarely reaching more than 30 km/h (20 mph), but are strong and persistent closer to the coasts. Katabatic, or downslope, winds blow cold, dense air down the steep slopes from the interior highlands onto the lower ice slopes.

Chemical reactions that occur at high altitudes in the atmosphere have affected the ozone layer over the Antarctic region, creating an ozone hole. During the cold polar night, naturally forming clouds of nitrogen-containing compounds and water vapor in the stratosphere over Antarctica react with synthetic chemicals such as chlorofluorocarbons and bromine halocarbons. When the mix of chemicals is exposed to sunlight in spring, additional chemical reactions with chlorine or bromine remove ozone from the stratosphere. Preventing the release or reducing the levels of the chlorine and bromine-containing chemicals would allow the ozone layer to recover.

Search this website ::