An unexpected connection between solar cycles and hurricane frequency
The discussion on possible connections between global warming and increased in tropical cyclone activity has focused ocean surface temperatures. This study raises the issue of the influence of the natural cycle of sunspots on tropical storm and hurricane intensity and frequency. The authors investigated the relationship between the solar cycle and the intensity of tropical cyclones over the Caribbean and the Gulf of Mexico and found that during the height of the solar cycle, the lower stratosphere warms due to the absorption of more ultraviolet radiation in the production of ozone. This stratospheric warming could limit conditions for the development and intensification of tropical cyclones. In the case of hurricanes specifically, they identified a relationship with the solar activity that explains a significant portion of the interannual variability in hurricane frequency along the US coast after accounting for oceanic heat, shear, and steering. These results are certain to stimulate further research on understanding the natural variability of tropical storm and hurricane activity the potential consequences of global warming frequency and intensity.
Source: Elsner, J.B., and T.H. Jagger. 2008. United States and Caribbean tropical cyclone activity related to the solar cycle. GRL Vol.35, LI8705, doi:10,1029/2008GL034431.