A dipole mode in the tropical Indian Ocean
A dipole mode in the tropical Indian Ocean
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DOI：
10.1038/43854
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发表时间：
1999-09-23
期刊：
影响因子：
64.8
通讯作者：
Yamagata, T
中科院分区：
文献类型：
--
作者：
Saji, NH;Goswami, BN;Yamagata, T
对于热带太平洋和大西洋，导致气候振荡的内部变率模式已被确认（1,2），但在印度洋区域，尚未发现导致年际气候变化的类似海 - 气相互作用（3）。在此，我们报告一项对过去40年观测数据的分析，该分析显示印度洋存在一种偶极子模式：一种内部变率模式，苏门答腊岛附近海面温度异常偏低，而西印度洋海面温度偏高，同时伴有风和降水异常。海面温度与风之间的时空联系揭示了通过降水场和海洋动力学产生的强耦合。这种海 - 气相互作用过程在印度洋是独特且固有的，并且表明与厄尔尼诺/南方涛动无关。这种偶极子模式的发现解释了印度洋海面温度变率的约12%，并且在其活跃年份，还会导致东非暴雨和印度尼西亚干旱，这为受影响国家的降雨异常长期预报带来了希望。
For the tropical Pacific and Atlantic oceans, internal modes of variability that lead to climatic oscillations have been recognized(1,2), but in the Indian Ocean region a similar ocean-atmosphere interaction causing interannual climate variability has not yet been found(3). Here we report an analysis of observational data over the past 40 years, showing a dipole mode in the Indian Ocean: a pattern of internal variability with anomalously low sea surface temperatures off Sumatra and high sea surface temperatures in the western Indian Ocean, with accompanying wind and precipitation anomalies. The spatio-temporal links between sea surface temperatures and winds reveal a strong coupling through the precipitation field and ocean dynamics. This air-sea interaction process is unique and inherent in the Indian Ocean, and is shown to be independent of the El Nino/Southern Oscillation. The discovery of this dipole mode that accounts for about 12% of the sea surface temperature variability in the Indian Ocean-and, in its active years, also causes severe rainfall in eastern Africa and droughts in Indonesia-brightens the prospects for a long-term forecast of rainfall anomalies in the affected countries.