Hurricanes may be associated with sunspots

October 4, 2008

A recent study suggests that hurricane intensity may be linked to the number of  sunspots on the Sun. A decrease in the number of sunspots may be related to an increase in hurricane intensity. After examining the past 100 year hurricane records of the United States and  Caribbean, James Elsner and Thomas Jagger of  Florida State University in  Tallahassee conclude that their intensity may be linked to 10 to 12 year  solar magnetic activity cycles. Data from the National Hurricane Center,  Miami,  Florida was used in the study.

Sunspots are areas on the Sun with increased magnetic activity. The number of sunspots vary during the solar cycles. The number of sunspots is predicted by NOAA to currently be the lowest in an 11 year cycle.

Increased solar activity will allow more ultraviolet rays to reach Earth, resulting in warming of the relatively colder upper atmosphere. Decreased solar activity reverses this phenomenon. It is believed that the greater the temperature difference between upper and lower atmospheric regions, the higher the hurricane intensity.

Establishing a link between sunspots and hurricane intensity can provide a valuable tool for predicting storms. Other scientists however question the statistical basis of the study and the physical processes attributed to changes in hurricane activity. "This is something worth investigating, but they made too many assumptions for me to just accept their conclusion at this point," says Judy Curry of Georgia Institute of Technology,  Atlanta.