Triggering the Indian Ocean Dipole From the Southern Hemisphere
Triggering the Indian Ocean Dipole From the Southern Hemisphere
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DOI：
10.1029/2020gl088648
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发表时间：
2020-08
影响因子：
5.2
通讯作者：
Lianyi Zhang;Yan Du;W. Cai;Zesheng Chen;T. Tozuka;Jin‐Yi Yu
中科院分区：
文献类型：
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作者：
Lianyi Zhang;Yan Du;W. Cai;Zesheng Chen;T. Tozuka;Jin‐Yi Yu
这项研究确定了一个新的触发机制的印度洋偶极子（IOD）从南半球。这种机制独立于厄尔尼诺-南方涛动（ENSO），并倾向于在其典型的高峰季节之前诱导IOD。这一机制和ENSO的联合作用可以解释IOD的不同寿命和强度。在其正位相期间，在南印度洋开始发展海表温度冷异常，并伴随着异常的副热带高压系统和异常的东南风。这些异常的东移增强了5月至8月期间苏门答腊-爪哇的季风，导致IOD早期开始。副热带地区的气压变率与南方环状模态有关，表明高纬和中纬气候之间存在遥相关，并进一步影响热带地区。考虑副热带信号有助于IOD事件的预报。
This study identifies a new triggering mechanism of the Indian Ocean Dipole (IOD) from the Southern Hemisphere. This mechanism is independent from the El Niño‐Southern Oscillation (ENSO) and tends to induce the IOD before its canonical peak season. The joint effects of this mechanism and ENSO may explain different lifetimes and strengths of the IOD. During its positive phase, development of sea surface temperature cold anomalies commences in the southern Indian Ocean, accompanied by an anomalous subtropical high system and anomalous southeasterly winds. The eastward movement of these anomalies enhances the monsoon off Sumatra‐Java during May–August, leading to an early positive IOD onset. The pressure variability in the subtropical area is related with the Southern Annular Mode, suggesting a teleconnection between high‐latitude and midlatitude climate that can further affect the tropics. To include the subtropical signals may help model prediction of the IOD event.