印尼穿越流调节着西太平洋和印度洋的热量和淡水平衡，对东亚季风和厄尔尼诺－南方涛动（ENSO）等气候现象具有反馈作用。我国受东亚夏季风影响强烈，并在厄尔尼诺次年容易发生洪涝。对印尼穿越流研究，理解东亚季风和ENSO的变化规律，不仅具有全球意义，对我国洪涝灾害的预防也具有参考价值。现代海洋观测和古海洋学记录均表明，印尼穿越流在传输中的变化主要发生在次表层。古海洋学记录揭示，末次冰期至末次冰消期印尼穿越流逐渐恢复并增强之后，次表层流经历了两个阶段的强化。我们推测其背后的影响机制可能迥异，即“相似记录、不同影响机制”的猜想。项目以望加锡海峡内5个站位为主，以西太平洋边缘2个站位为辅，分析钻孔中浮游有孔虫次表层种壳体稳定同位素和Mg/Ca比值，结合帝汶海已有数据，恢复末次冰期以来印尼穿越流从“入口”到“中途”再到“出口”次表层流海水性质以及上部水体结构的时空变迁，检验上述猜想。

Indonesian Throughflow (ITF) modulates heat and freshwater budgets between the western Pacific and Indian Ocean, with potential feedbacks to East Asian monsoon and El Nino-Southern Oscillation (ENSO) phenomena. The territory of China is under significant influence of East Asian summer monsoon and devastating floods used to happen in the years next to El Nino years. Thus, understanding of East Asian monsoon and ENSO activities, through study on variability of the ITF in the past, is of global significance and is as well as of valuable reference for defense against devastating floods probably happened in our country. It is revealed by modern oceanic observations and as well as paleoceanographic records that significant change of the ITF en route mainly took place in its subsurface waters. It is further indicated by paleoceanographic records that subsurface flow of the ITF experienced two stages of strengthening after gradual recovery and increase of the ITF during the last glacial to the last deglaciation. We speculated that the two stages of strengthening of the ITF subsurface flow may be respectively caused by very different mechanisms, which we hypothesized as 'similar records due to different influencing mechanisms'. The objective of this proposal is to testify the above hypothesis. We will focus on five cores retrieved from the Makassar Strait and two cores from the margin of the western Pacific. Oxygen isotopes and Mg/Ca ratios in shells of planktonic foraminiferal subsurface dwellers from these cores will be analyzed, in combination with published data sets from the Timor Sea, to reconstruct tempo-spatial changes in ITF subsurface waters and upper ocean thermal structure en route from the entrance to the exit since the last glacial.