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通过分析深海潜标系统的实际观测海流数据对2013年赤道印度洋上层Wyrtki急流(WJ)的变异进行了研究,发现WJ在2013年呈现明显异常变化,主要表现为春季WJ强度略强于同年秋季WJ。再分析资料的分析结果也同样验证此结论,而这与气候态WJ的演化特征相反。在气候平均态下,印度洋春季WJ强度远弱于秋季WJ强度。进一步数据分析与数值模式结果表明,2013年春季WJ异常加强与赤道印度洋海表风场变化密切相关,而春季海表风场的变化主要归因于2013年春季异常增强的季节内振荡(ISO)事件,发生在2013-05的ISO对流位相是导致春季印度洋海表西风异常的直接原因。本研究揭示了中小时间尺度海气相互作用可以影响更长时间尺度海洋环流系统的年际变化。
Based on the analysis of actual observed ocean current data from deep-sea subscanitary system, the variation of the upper Wyrtki jet stream (WJ) over the equatorial Indian Ocean in 2013 was studied. It was found that the WJ showed an obvious anomalous change in 2013, mainly showing that the spring WJ intensity was slightly stronger than that of the autumn WJ . The results of the reanalysis also validate this conclusion, which is contrary to the evolutionary characteristics of WJ in climate. In the climate averages, the spring WJ intensity of the Indian Ocean is much weaker than the autumn WJ intensity. Further data analysis and numerical results show that the WJ anomaly intensification in spring 2013 is closely related to the changes of the sea surface wind in the equatorial Indian Ocean. However, the variation of the spring sea surface wind field is mainly attributed to the abnormally enhanced intraseasonal oscillation (ISO) in spring 2013, The event, the ISO convection phase occurring in 2013-05, is the direct cause of the anomalous Westerly winds in the Indian Ocean during the spring. This study reveals that small-scale time-scale air-sea interactions can affect the interannual variation of the ocean circulation system over longer time scales.