JP3.40
Possible climate impacts of Saharan dust on frequency and intensity of tropical cyclones
Kyu-Myong Kim, University of Maryland Baltimore County, Greenbelt, MD; and W. K. M. Lau
Using composite and correlation analysis based on long-term TOMS aerosol indices and Barbados dust record, we delineate the relative impacts of El Nino vs. Saharan dust on frequency of occurrence (FOC) and intensity of tropical cyclones (TC) in the North Atlantic. Results show that dust and Nino3 SST variations in July through November have insignificant correlations, indicating that they can be treated as independent forcing from North Africa, and from the Pacific SST, at least in the first order. The FOC of TC is inversely related to dust concentration over the Atlantic, i.e., more dust less TC, and that more TC occurs in La Nino compared to El Nino years. However, the most drastic reduction in TC days is found during years of El Nino with high dust condition. Conversely, strongly enhanced TC activity are fond in years of La Nina with low dust condition. In years of El Nino with low dust, and in years of La Nina with high dust, the impact of remote forcing from Pacific SST is greatly diminished. Correlation analysis suggest dust may have stronger impact on TC intensification over the Caribbean, but El Nino may have a stronger impact on TC genesis over the tropical eastern Atlantic. Dust is likely to impact TC formation and intensification via cooling of SST, while El Nino exerts impact through changes in large-scale wind shear.
Joint Poster Session 3, Tropical Cyclones and Climate Change Poster Session
Monday, 21 January 2008, 2:30 PM-4:00 PM, Exhibit Hall B
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