Changes in atmospheric pressure can indicate what the weather will be like. A decrease in pressure indicates an approaching low-pressure system, which is associated with cloudy and wetter conditions. An increase in pressure indicates an approaching high-pressure system, which is associated with clear and dry conditions. Over longer periods of time, weather maps show common patterns of high and low pressure. The names of these patterns often reflect the location of these patterns. In the Arctic, the common features are the Aleutian Low, Siberian High, Icelandic Low and Beaufort Sea High. Scientists look at the strength of these patterns to study changes in atmospheric circulation, and how these change are related to changes in temperature, precipitation and winds