Linkage between the Atlantic Tropical Hurricane Frequency and the Antarctic Oscillation in the Western Hemisphere

• Main Author: Fan Ke
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: tropical hurricane frequency and the Antarctic Oscillation; Antarctic; Arctic; Soi; The Antarctic; Antarc*
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.499.6593; http://nzc.iap.ac.cn/uploadpdf/200905005-aosl.pdf

Abstract To examine the zonal asymmetry of the Ant-arctic oscillation (AAO), different portions of the AAO from June to October (JJASO) in the interannual variabil-ity of the Atlantic tropical hurricanes number (ATHN) are documented in this research. It follows that the AAO in the Western Hemisphere (AAOWH) is positively corre-lated with the ATHN, at 0.36 during the period of 1871−1998 and 0.42 during the period of 1949−98. After removing the linear regressions on the Southern Oscilla-tion Index (SOI) in all time series, the above correlation coefficients are 0.25 and 0.30, respectively. The underly-ing mechanisms are studied through analyses of the at-mospheric general circulation variability associated with the AAOWH. It turns out that the positive (negative) phase of JJASO AAOWH corresponds with several fac-tors: decreased (increased) vertical zonal wind shear magnitude, low-level anomalous convergence (diver-gence), 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.