太平洋-印度洋贯穿流流量的观测研究

The Pacific-Indian Ocean Throughflow (PIOT) is one important part of the Great Ocean Conveyor Belt, and is also the significant channel of water and thermohaline exchange between the tropical Pacific and Indian Ocean. It plays an important role in the marine environments of the South China Sea and Indonesian Seas, regional and global climate system, and marine energy channel for our country. It is still lacking of direct observation for the ocean currents through the main straits of PIOT, and there is a significant imbalance between inflow and outflow of PIOT, which shows that it is unclear on the PIOT transport. Therefore, the PIOT transport and its distribution in different pathways, and their seasonal variations are still one important focus for the PIOT dynamics. Combied with support of other projects，this project plans to carry out long-term comprehensive observation in the main straits and passages of PIOT，deploying sub-surface moorings to measure current profile,temperature and salinity structure. Based on the in-situ, historical observation and satellite data, using the numerical simulation and objective analysis, the presnt study will analyse the basic characteristic of water exchange through main channels of PIOT, especially for water volume, heat and salt transports, and their seasonal variations. Based on numerical experiments and theoretical analysis, the dynamic mechenism of the water exchange of PIOT,and its distribution in the main straits and passages, and their seasonal variations will be studied.

太平洋-印度洋贯穿流是全球热盐环流的重要环节之一，也是热带太平洋与印度洋进行水体和热盐交换的重要通道，对南海和印尼海的海洋环境、区域和全球气候以及我国海上能源通道都有着重要影响。迄今贯穿流关键海峡的海流直接观测仍然缺乏，对其流量的估计存在出入流的显著不平衡，表明对贯穿流流量的认识仍不甚清楚，贯穿流流量在各海峡通道的分配及其季节变化仍是贯穿流动力学研究的焦点问题之一。在其他项目的共同支持下，本研究拟采用布放定点潜标观测系统测量海流剖面、温度和盐度结构，对贯穿流主要海峡通道进行全面长期观测，结合历史观测和卫星遥感资料，采用数值模拟和客观分析等手段，摸清太平洋-印度洋贯穿流入流和出流在各海峡的基本特征，特别是体积输运量、热盐输运量及其季节变化。基于观测结果，采用数值实验和理论分析手段，探讨太平洋-印度洋贯穿流流量在各海峡通道的分配及其季节变化的动力机制。

本项目按计划开展了太平洋-印度洋贯穿流流量的观测研究，收集整理了包括研究团队前期通过SITE国际合作项目在卡里马塔和巽他海峡的观测、INSTANT国际计划观测，以及卫星遥感、海洋再分析、历史水文等资料；依托SITE和TIMIT国际合作项目，完成了5个调查航次，在卡里马塔、巽他、龙目和望加锡海峡开展了海床基和潜标观测；针对太平洋-印度洋贯穿流的季节内、季节和年际变化的规律及机制，开展了研究工作；构建了覆盖太平洋-印度洋贯穿流海域的区域风-浪-流耦合模式，开展了贯穿流流量模拟、动力诊断等分析。取得了如下新认识：（1）揭示了卡里马塔海峡水体交换的季节和年际变化特征，其季节变化受季风驱动，年际变化受到ENSO影响；（2）巽他海峡冬季海水从印度洋输运到爪哇海，夏季相反，年平均流量从爪哇海流入印度洋；（3）巽他海峡海流存在显著地季节内变化，并能影响巽他海峡水体输运；（4）南海周边海域的位涡输入是南海环流维持的重要机制；（5）揭示了南太平洋水团进入ITF并非只有东部路径一种形式，而是包括直接和间接两种路径。以上研究成果共发表期刊论文13其中SCI收录12文核心收录1篇）。