Tropical cyclones in the North Indian Ocean will tend to occur later in the year, during the peak monsoon season, as the climate warms.

Credit: STRDEL/AFP/GETTY

Hiroyuki Murakami, now at the University of Hawaii at Manoa in Honolulu, and his colleagues used several versions of an atmospheric circulation model to project changes in cyclone activity in the North Indian Ocean in 2075–99 relative to 1979–2003. The researchers found that, in a simulated warmer future, fewer cyclones formed in the pre-monsoon season in spring, whereas a greater number of storms occurred in the peak-monsoon season in summer. Overall cyclone frequency in the region did not change significantly, however.

Increased sea surface temperature and a reduction in vertical wind shear — which pulls cyclones apart — could explain the projected increase in storm frequency during the summer monsoon season.

Clim. Dyn. http://dx.doi.org/10.1007/s00382-012-1407-z (2012)