A Statistical Analysis of the Frequency of United States and Eastern North Pacific Hurricanes Related to Solar Activity

摘要

In this chapter, we examine the statistical relationship between the frequency of United States and eastern North Pacific (ENP) hurricanes and the solar cycle. First, a relationship between the probability of a hurricane and sunspot num-bers is shown that is conditional on ocean temperature. For years of above normal ocean temperatures, the probability of three or more hurricanes in the United States decreases from 40% to 20% as sunspot numbers increase. Second, a solar index that tracks intraseasonal variability in sunspot numbers is constructed and correlated with hurricane activity. The index is inversely related to the total sunspot numbers (SSN) and is significantly correlated with the probability of hurricanes and major hurricanes affecting the United States. The chances of at least one U.S. hurricane in the lowest and highest SSN anomaly season are 25% and 64%, respectively. The solar index is then used as a predictor of major hurricane frequency over the ENP where it is found that the chance of at least six major ENP hurricanes increases from about 1% when the solar index lowest to 28% when the index is highest.