复杂地形作用下的印太跨海盆相互作用及其对印太淡水平衡的影响

The western Pacific Ocean has complex ocean-continent pattern and unique multi-island chain trench-arc-basin shape, shows strong inter-basin interaction with the Indian Ocean through the Indonesian Throughflow, and plays a very important role in the global ocean and climate system. The Indonesian Throughflow is the only passage connecting the tropical ocean basins in the global ocean and the key to the inter-basin transport from the western Pacific Ocean. Based on the simple assumption that the Indonesian Throughflow is controlled by the Indo-Pacific pressure gradient, numerous previous studies have been carried out, and variability of the Indonesian Throughflow is thought to be driven by wind forcing and salinity effect. However, the influence of complex topography in the Indonesian seas on the Indonesian Throughflow and its inter-basin transport have long been ignored, which is a key scientific problem that has yet to be solved. This project aims to study the following two aspects through theoretical derivation, data analysis and numerical sensitivity experiments: 1. The influence and physical mechanism of topography in the Indonesian Seas (size, type, roughness, etc.) on the Indonesian Throughflow, and explore the evolution of the Indonesian Throughflow with topography; 2. Complex topography-shaped inter-basin transport and its influence on the freshwater balance of the Indo-Pacific basin. The implementation of this project is conducive to breaking through the classical theory on the Indonesian Throughflow and making progress in fluid-solid coupling dynamics in the western Pacific, and hence is of great scientific significance.

西太平洋具有复杂的洋陆格局和独特的多岛链沟弧盆地形，通过印尼贯穿流与印度洋海盆产生强烈的跨海盆相互作用，在全球海洋与气候系统中扮演十分重要的角色。印尼贯穿流是全球海洋中连通不同热带大洋海盆的唯一通道，是西太平洋跨海盆输运的关键。前人基于“印尼贯穿流由印太压力梯度所控制”这一简单假设开展了大量研究，认为风场强迫和盐度效应是印尼贯穿流变化的主要驱动力。但是，印尼海域的复杂地形对印尼贯穿流及其跨海盆输运具体有怎样的影响却长期被忽视，是一个尚未回答的关键科学问题，亟待解决。本项目拟通过理论推导、资料分析和敏感性数值试验，研究以下两方面内容：1、印尼海域地形（海道尺寸、类型、粗糙度等）对印尼贯穿流的影响过程与物理机制，探讨印尼贯穿流随地形演变过程；2、复杂地形作用下的跨海盆输运对印太淡水平衡的影响。本项目的实施有助于突破印尼贯穿流经典理论，在西太平洋流固耦合动力学方面取得进展，具有重要科学意义。

西太平洋具有复杂的洋陆格局和独特的多岛链沟弧盆地形，通过印尼贯穿流与印度洋海盆产生强烈的跨海盆相互作用，在全球海洋与气候系统中扮演十分重要的角色。印尼贯穿流是全球海洋中连通不同热带大洋海盆的唯一通道，是西太平洋跨海盆输运的关键，但是，印尼海域的复杂地形对印尼贯穿流及其跨海盆输运具体有怎样的影响却不清楚，是一个长期未知的关键科学问题。围绕该科学问题，本项目系统研究了复杂地形作用下的印太跨海盆相互作用及其对印太淡水平衡的影响，结合数据分析、理论推导、数值模拟等多种技术手段，研究了地形对印尼贯穿流流量的影响，通过理论推导得到了三岛屿复杂地形下的绕岛环流理论，阐明了复杂地形作用下的印太跨海盆相互作用在印太盐度变化中的关键作用，揭示了印太跨海盆输运作用下的印度洋盐度年际-年代际变化特征，提出了热带太平洋温跃层盐度年际-年代际变化的三极模态，发现了气候变暖背景下全球平均海洋环流的加速趋势并揭示了印尼贯穿流在此背景下的变化趋势，取得了一系列研究成果。本项目的实施丰富和发展了印尼贯穿流经典理论，对理解西太平洋大尺度海洋环流动力学具有重要意义，因此或对理解西太平洋地球系统多圈层相互作用具有重要贡献。