Extended Abstract (388K)JP3.37
An evaluation of long-term variability of tropical storm and hurricane activity in the Atlantic
Jose Maliekal, SUNY, Brockport, NY
Several studies have posited that recent increases in the tropical storm and hurricane activity in the Atlantic are attributable to anthropogenic climate change. As evidence, many of these studies point to the simultaneous increases in sea surface temperature and tropical storm activity, though simultaneity is not a sufficient reason to attribute causation. In this study, a multi-pronged approach is used to describe the long-term variability of tropical storm activity in the Atlantic and to associate this variability with sea surface temperature of the area of the Atlantic where most tropical storms form, the Atlantic Multidecadal Oscillation and rainfall from the Western Sahel region. First, stochastic trends of the time series of yearly tropical storm, hurricane and major hurricane counts as well as that of the time series of yearly accumulated cyclone energy are estimated with the help of nonparametric regression. These estimates are used to describe how tropical storm activity in the Atlantic has varied between 1851 and 2006. Treating each of the aforementioned aspect of the Atlantic tropical storm activity as a dependent variable, a series of ordinary, partial and semi-partial correlation coefficients are estimated between the dependent variable and the two explanatory variables, namely sea surface temperature of the main storm development region and the Western Sahel rainfall. Preliminary results show that: (i) the correlation between dependent and explanatory variables appear to change with time, (ii) the Western Sahel precipitation is at least as important as the sea surface temperature of the main storm development region in explaining the long-term variability of the Atlantic tropical storm activity and (iii) the influence that the sea surface temperature of the main development region exerts on the Atlantic tropical storm activity is mediated by the Atlantic Multidecadal Oscillation.
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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