Temporal and spatial characteristics of positive and negative Indian Ocean dipole with and without ENSO
Temporal and spatial characteristics of positive and negative Indian Ocean dipole with and without ENSO
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DOI：
10.1029/2007jd009151
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发表时间：
2008-04-18
影响因子：
4.4
通讯作者：
Kanamitsu, Masao
中科院分区：
文献类型：
--
作者：
Hong, Chi-Cherng;Lu, Mong-Ming;Kanamitsu, Masao
利用1948 - 2002年的观测资料，研究了有和没有厄尔尼诺 - 南方涛动（ENSO）情况下，印度洋偶极子（IOD）正负事件在时间演变和空间特征上的差异。记录这些差异对于远东亚洲的气候预测尤为重要，因为在降水异常合成图中发现，不同类型的IOD在中国、韩国和日本上空的季风活动存在明显差异。IOD不同阶段的海表温度（SST）和风的合成图以及海洋混合层热收支表明，有和没有ENSO的IOD在时间演变及其触发机制上存在很大差异。在没有ENSO的正负IOD事件中，东印度洋的风异常似乎是海表温度异常形成的原因，而西印度洋的异常似乎是对东部异常的海洋动力响应。在ENSO年份，IOD演变不对称性的时空对比更小，海表温度异常是由与ENSO相关的异常大气环流引起的云量变化导致的入射辐射异常所驱动，而非由局地风异常驱动。
The differences in the temporal evolution and spatial characteristics of the Indian Ocean Dipole (IOD) between positive and negative events with and without ENSO have been investigated using observations for the period 1948 - 2002. To document such differences is particularly important for climate forecasts over far east Asia, since distinctly different monsoon activities over China, Korea, and Japan for different types of IOD are found in the composite maps of precipitation anomalies. The composite map of SST and wind during various stages of IOD and the ocean mixed layer heat budget showed that the IOD with and without ENSO has a large difference in its temporal evolutions and their triggering mechanisms. In both negative and positive IOD events without ENSO, the wind anomaly in the eastern Indian Ocean seems to be responsible for the formation of sea surface temperature anomalies, while the anomaly in the western Indian Ocean seems to be the oceanic dynamical response to the anomaly in the east. During the ENSO years, the temporal and spatial contrast of the asymmetry of the IOD evolution is smaller, and the SST anomaly is driven by the anomalies in incoming radiation due to changes in cloudiness caused by the ENSO associated anomalous atmospheric circulations and not by the local wind anomalies.