220.127.116.11. Variations in Atmospheric Circulation
The atmospheric circulation is the main control behind regional changes in wind, temperature, precipitation, moisture and other climatic variables. Variations in many of these are quite strongly related through large-scale features of the atmospheric circulation. Changes in a number of circulation features, including El Niño Southern Oscillation (ENSO) events in the south-east Pacific, mid-latitude Northern Hemisphere westerlies and the location and intensity of the Aleutian low pressure system in the North Pacific, may all be related to the more general global warming of the twentieth century (Folland et al., 1990).