At the Intertropical Convergence Zone (ITCZ), the northern and southern Tradewinds converge, and this region is characterized by low atmospheric pressure and high precipitation. The climate in the Timor Sea is characterized by seasonal precipitation changes driven by meridional migrations of the ITCZ and the monsoonal front. The ITCZ shifts in response to changes in the thermal balance between the northern and southern hemispheres. Thus, reconstruction of paleo-precipitation in the Timor Sea is expected to reveal past changes in both regional and global climate, the latter through inference of the ITCZ position. To reconstruct paleo-precipitation in the Timor Sea, we performed extensive radiocarbon analysis on both planktonic foraminifera and total organic carbon (TOC), which is derived from terrestrial and marine sources. Increased precipitation enhances the fraction of relatively old, terrestrial carbon to the core site, which in turn increases the difference between the ages of TOC and planktonic foraminifera. Variations in radiocarbon ages reveal that during northern hemisphere cooling intervals such as Heinrich Stadial 1 and the Younger Dryas, the ITCZ was in a southern position, thus increasing precipitation in the Timor Sea. However, the Timor Sea was dryer during the Bølling–Allerød warming as the ITCZ shifted northward.

中文翻译：

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通过广泛的放射性碳测年发现帝汶海末次冰消期间热带辐合带的经向迁移

在热带辐合区（ITCZ），南北信风交汇，该地区的特点是低气压和高降水。帝汶海气候的特点是由 ITCZ 和季风锋的经向迁移驱动的季节性降水变化。ITCZ 会随着北半球和南半球之间热平衡的变化而发生变化。因此，帝汶海古降水的重建预计将揭示区域和全球气候的过去变化，后者是通过 ITCZ 位置的推断来揭示的。为了重建帝汶海的古降水，我们对浮游有孔虫和来自陆地和海洋的总有机碳 (TOC) 进行了广泛的放射性碳分析。降水量的增加增加了相对古老的陆地碳在核心位点的比例，这反过来又增加了 TOC 和浮游有孔虫年龄之间的差异。放射性碳年龄的变化表明，在北半球冷却期，如海因里希·斯塔迪尔 1 期和新仙女木期，ITCZ 位于南部位置，从而增加了帝汶海的降水量。然而，在 Bølling-Allerød 变暖期间，随着 ITCZ 向北移动，帝汶海变得干燥。