Dipolar redistribution of summertime tropical cyclone genesis between the Philippine Sea and the northern South China Sea and its possible mechanisms
Dipolar redistribution of summertime tropical cyclone genesis between the Philippine Sea and the northern South China Sea and its possible mechanisms
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DOI：
10.1029/2009jd012196
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发表时间：
2010-03
影响因子：
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通讯作者：
Joo‐Hong Kim;Chang‐Hoi Ho;P. Chu
中科院分区：
文献类型：
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作者：
Joo‐Hong Kim;Chang‐Hoi Ho;P. Chu
[1]近年来的观测资料表明，菲律宾海（PS）和南海北方（nSCS）之间的偶极子振荡是北太平洋西部（WNP）夏季热带气旋（TC）生成的主要经验正交函数。这种PS-nSCS振荡的特点是除了年际变化的一个杰出的年代际变化。同时，在第二模态中发现了典型的与厄尔尼诺-南方涛动（ENSO）相关的模态，该模态主要是年际模态。就PS-nSCS振荡而言，其年际分量似乎与前一次冬季ENSO事件有关，但这种联系并不十分明显，约有一半的重要事件与ENSO事件有关，而其年代际分量则与赤道核心位于Nino-4区附近的中太平洋海表温度异常（SSTA）耦合。其两侧沿着纬向带有相反的海温异常。有趣的是，这种海温异常模式类似于ENSO Modoki，相当于ENSO的过渡阶段。ENSO Modoki在区域上表现为赤道西太平洋和赤道中太平洋之间的纬向海温梯度异常，这种纬向海温梯度异常的年代际调制可以看作是形成和调制年代际PS-nSCS振荡的实际强迫。此外，还从太平洋海温异常的格局和相关的异常大尺度环境两个方面，对PS-nSCS年代际振荡与海盆TC成因的年代际变化进行了比较。
[1] Recent observational records show that the dipole oscillation between the Philippine Sea (PS) and the northern South China Sea (nSCS) is a leading empirical orthogonal function (EOF) of summertime tropical cyclone (TC) genesis in the western North Pacific (WNP). This PS-nSCS oscillation is characterized by a distinguished decadal variability in addition to an interannual variability. Meanwhile, the typical El Nino–Southern Oscillation (ENSO)-related mode is found in the second EOF mode, which is predominantly interannual. With regard to the PS-nSCS oscillation, its interannual component appears to be linked with the previous wintertime ENSO event, but the linkage is not so robust in the sense that about half of its significant events are classified as the ENSO-related case, whereas its decadal component is coupled to a sea surface temperature anomaly (SSTA) in the central Pacific with its equatorial core near the Nino-4 region, which is flanked by an opposite SSTA on both sides along the latitudinal belt. Interestingly, this SSTA pattern resembles that related to the ENSO Modoki, and equivalently, the transitional phase of ENSO. The ENSO Modoki is regionally manifested by the anomalous zonal SST gradient between the equatorial western and central Pacific; thus the decadal modulation of this anomalous zonal SST gradient can be regarded as an actual forcing that forms and modulates the decadal PS-nSCS oscillation. In addition, the decadal PS-nSCS oscillation is compared with the decadal basin-wide TC genesis variation in terms of the Pacific SSTA pattern and the associated anomalous large-scale environments.