The Indonesian Throughflow (ITF), as the sole low-latitude conduit connecting the Pacific and Indian Oceans, regulates the thermohaline balance between these oceans. Thus, investigating the variability in the ITF and its relationship with the precessional forcing is crucial for understanding the drivers of tropical climate change. Here, we reconstruct the history of the ITF over the past ∼120 kyr based on high-resolution (∼400 years) δ¹⁸O and Mg/Ca records of Globigerinoides ruber and Pulleniatina obliquiloculata from core SO217-18540 retrieved from the Flores Sea upwelling region within the main pathway of the ITF. A comparison of these new records with published paleo-oceanographic and climatological data from the western tropical Pacific Ocean suggests that annual mean conditions in the Flores Sea were controlled by ITF variability rather than by monsoonal upwelling. Our results further indicate that precessional insolation was a major forcing for the hydrological evolution of the ITF during the past 120 kyr. We suggest that the precessional insolation forcing paced ITF variability by modulating the mean state of El Niño-Southern Oscillation-like conditions and latitudinal shifts and/or expansion/contraction of the Intertropical Convergence Zone.

中文翻译：

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过去 120 kyr 对进动引起的热带气候过程的响应的印度尼西亚通流上部水文变化

印度尼西亚通流 (ITF) 作为连接太平洋和印度洋的唯一低纬度管道，调节这些海洋之间的温盐平衡。因此，研究 ITF 的变异性及其与岁差强迫的关系对于了解热带气候变化的驱动因素至关重要。在这里，我们基于Globigerinoides ruber和Pulleniatinaobliquiloculata的高分辨率（~400 年）δ ¹⁸ O 和 Mg/Ca 记录重建了过去~120 kyr 的 ITF 历史来自 ITF 主要通道内弗洛雷斯海上升流区域的核心 SO217-18540。将这些新记录与来自西热带太平洋的已发表古海洋学和气候学数据进行比较表明，弗洛雷斯海的年平均条件受 ITF 变率而不是季风上升流控制。我们的结果进一步表明，岁差日照是过去 120 kyr 期间 ITF 水文演变的主要推动力。我们建议岁差日照强迫通过调节厄尔尼诺-南方涛动条件的平均状态和热带辐合带的纬度偏移和/或扩张/收缩来调节 ITF 的变化。