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| Linkage between the Atlantic Tropical Hurricane Frequency and the Antarctic Oscillation in the Western Hemisphere |
| FAN Ke |
| Nansen-Zhu International Research Center, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China |
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Abstract To examine the zonal asymmetry of the Antarctic oscillation (AAO), different portions of the AAO from June to October (JJASO) in the interannual variability of the Atlantic tropical hurricanes number (ATHN) are documented in this research. It follows that the AAO in the Western Hemisphere (AAOWH) is positively correlated with the ATHN, at 0.36 during the period of 18711998 and 0.42 during the period of 194998. After removing the linear regressions on the Southern Oscillation Index (SOI) in all time series, the above correlation coefficients are 0.25 and 0.30, respectively. The underlying mechanisms are studied through analyses of the atmospheric general circulation variability associated with the AAOWH. It turns out that the positive (negative) phase of JJASO AAOWH corresponds with several factors: decreased (increased) vertical zonal wind shear magnitude, low-level anomalous convergence (divergence), high-level anomalous divergence (convergence), and warmed (cooled) sea surface temperature in the tropical Atlantic. Therefore, the positive (negative) phase of JJASO AAOWH is favorable (unfavorable) to the tropical hurricane genesis.
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Received: 11 April 2009
Revised: 08 May 2009
Accepted: 08 May 2009
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