Possible influence of the Antarctic Oscillation on tropical cyclone activity in the western North Pacific
Possible influence of the Antarctic Oscillation on tropical cyclone activity in the western North Pacific
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DOI：
10.1029/2005jd005766
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发表时间：
2005-10
影响因子：
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通讯作者：
Chang‐Hoi Ho;Joo‐Hong Kim;Hyeong‐Seog Kim;C. Sui;D. Gong
中科院分区：
文献类型：
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作者：
Chang‐Hoi Ho;Joo‐Hong Kim;Hyeong‐Seog Kim;C. Sui;D. Gong
[1]本研究探讨如何在南半球（SH）的大尺度大气环流调制热带气旋（TC）活动在西北太平洋（WNP）在台风季节（7月，8月和9月;北方夏季）。感兴趣的SH环流的变化是南极涛动（AAO）。在AAO的正位相和负位相之间，两个异常高压分别在西太平洋上发展：澳大利亚东南部的一个巨大的反气旋和东海的一个相对较弱的反气旋。这些遥相关模式进行检查，并与以前的分析进行比较。与AAO的变化相关，在WNP上发现TC活动的统计上显著的变化。在AAO最高和最低的8个年之间，东海（120° ~ 140 ° E，20° ~ 40 ° N）上空的平均TC通过次数相差2次，相当于从气候学角度看增加了50-100%。这种变化主要是由于菲律宾海东部形成了更多的TC。另一方面，南海的TC通过次数略有减少。TC活动的这些变化在8月占主导地位，并与副热带西北太平洋低层涡度的变化相一致。SH环流变率对大尺度环境和热带对流在副热带北半球的影响表明，AAO变化的长期预测的TC活动在WNP的可能用途。
[1] The present study investigates how large-scale atmospheric circulation in the Southern Hemisphere (SH) modulates tropical cyclone (TC) activity in the western North Pacific (WNP) during a typhoon season (July, August, and September; boreal summer). The variation of the SH circulation of interest is the Antarctic Oscillation (AAO). In the positive phase of AAO relative to its negative phase, two anomalous highs develop over the western Pacific in both hemispheres: a huge anticyclone in southeastern Australia and a relatively weak anticyclone in the East China Sea. These teleconnection patterns are examined and compared with previous analyses. Related to the AAO variations, a statistically significant alteration of TC activities is found over the WNP. The difference in the mean TC passage numbers over the East China Sea (120°–140°E, 20°–40°N) between the eight highest-AAO years and the eight lowest-AAO years is as large as 2, equivalent to a 50–100% increase from the climatology. This change is primarily a result of more TCs forming over the eastern Philippine Sea. On the other hand, TC passage numbers slightly decrease over the South China Sea. These changes in TC activity are predominant in August and are consistent with changes in low-level vorticity over the subtropical WNP. The influence of SH circulation variability on large-scale environments and tropical convection in the subtropical NH suggest a possible usage of AAO variation for long-range forecasting of TC activity over the WNP.