Scientists discover that African dust may be hampering hurricane activity

The active Atlantic hurricane seasons in 2004 and 2005 and warming ocean temperatures led many researchers to look toward global warming to explain year-to-year changes in tropical storm activity. However, University of Wisconsin-Madison and NESDIS scientists have found a new cause for the year-to-year variability of these tropical storms: dust storms from Africa.

Published October 11, 2006, in Geophysical Research Letters (article abstract), these scientists reported that large dust clouds from the Saharan desert may suppress hurricane formation and growth in the Atlantic Ocean. Using a new dust detection algorithm for the data of the Advanced Very High Resolution Radiometer (AVHRR) instrument on the NOAA polar-orbiting satellites (a record that is 25 years long), these scientists discovered that few hurricanes formed in years with large amounts of Saharan dust over the Atlantic, while more tropical storms and stronger storms appeared in years with little dust activity.

In addition to explaining the long-term change in hurricane activity in the Atlantic Ocean, Saharan dust storms, which were numerous in the summer of 2006, may also explain why so few tropical storms formed in 2006, defying the predictions of many in NOAA for a very active season of storms. Furthermore, if it is possible to incorporate dust into weather forecast models, then the accuracy of seasonal predictions of hurricane activity would be boosted. The embarrassment of a "failed" hurricane season like the 2006 season might be averted. Research is still needed to understand why some years have few dust storms and others years have many.