权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

Decadal Variation of the Indian Ocean Dipole

印度洋偶极子的年代际变化

基本信息

批准号：
17204040
负责人：
YAMAGATA Toshio
金额：
$ 26.79万
依托单位：
The University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (A)
财政年份：
2005
资助国家：
日本
起止时间：
2005 至 2007
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-17204040/
关键词：
Indian Ocean Dipole Decadal Variation E1 Nino Southern Oscillation Indonesian Throughflow Mascarene High Agulhas Current Coupled GCM Tropical Indian Ocean

项目摘要

The processes that affect the decadal variation of the Indian Ocean Dipole (IOD) are investigated.1) Using outputs from a high-resolution coupled general circulation model (CGCM), decadal modulations of El Nino/Southern Oscillation (ENSO) is examined. Changes in the phase-locking nature of the ENSO to the seasonal cycle are shown to play an important role in the decadal modulation of the ENSO. This, in turn, modulates the heat transport by the Indonesian Throughflow, and thus the occurrence of the IOD.2) Heat budget analysis using the above model outputs has revealed that the occurrence of IOD events is governed by variations in the southward Ekman heat transport across 15°S, which is strongly linked with the Mascarene high activities.3) To understand the variability of the Agulhas Current, which influences the heat budget of the Indian Ocean, the interannual variation in the west coast of Africa is studied. It is found that the Angola Dome located in the above region undergoes significant interannual variations associated with the Atlantic Nino, which is a major climate mode in the tropical Atlantic.4) Since understanding of the past IOD is useful in understanding the current and future variability of the IOD, atmospheric general circulation model (AGCM) experiments with the permanent IOD and E1 Nino condition seen in Pliocene are conducted. The heat absorption from the atmosphere to the ocean in the tropics and the heat release from the ocean to the atmosphere in the mid-latitude are significantly reduced under this condition.

本文研究了印度洋偶极子（IOD）年代际变化的过程。1）利用高分辨率耦合大气环流模式（CGCM）的输出，研究了厄尔尼诺/南方涛动（ENSO）的年代际调制。ENSO与季节周期的锁相性质的变化在ENSO的年代际调制中起着重要的作用。这反过来又调节了印度尼西亚洋流的热量输送，从而调节了IOD的发生。2）使用上述模式输出的热量收支分析表明，IOD事件的发生受15°S范围内向南Ekman热量输送的变化所控制，这与Mascarene高活动密切相关。3）为了了解Agulhas海流的变化，影响印度洋热量收支的主要因素，研究了非洲西海岸的年际变化。研究发现，位于上述地区的安哥拉穹与大西洋Nino（大西洋Nino）有显著的年际变化，而大西洋Nino是热带南极洲的一种主要气候模态。4）由于对过去IOD的了解有助于了解IOD的当前和未来变化，因此利用大气环流模式（AGCM）对上新世的永久IOD和E1 Nino条件进行了试验。在这种条件下，热带地区从大气到海洋的热量吸收和中纬度地区从海洋到大气的热量释放都显著减少。