Solar cycle and the Pacific ‘centers of action'



The sun's integrated irradiance varies by about 0.1% during its 11 year cycle, a change that is apparently too small to directly alter the mean climate of the earth. Yet, large correlations between the sunspot cycle and local climate variables have been noted. In this study the variations of the semi-permanent pressure systems the Aleutian Low and the Hawaiian High are investigated. It is found that extremes in solar variability as measured by the mean annual sunspot numbers, correlate highly with the locations of these centers of action. The Aleutian Low migrates eastward during minimum solar activity and the Hawaiian High migrates southward. Effects on the intensity of the Centers of Action were also significant and were in general agreement with recent theoretical results. Because shifts in the Centers of Action change storm trajectories, large anomalies in regional climatic conditions can be generated in the extreme phases of the solar cycle.