The Indo-Pacific Warm Pool (IPWP) is the largest source of atmospheric heating and moisture on Earth, energizing the global moisture and energy budgets and controlling global ocean-atmosphere circulation. However, the mechanisms driving orbital-scale changes in hydroclimate and proxy records of precipitation isotopic composition remain poorly known. Here, we use the isotope-enabled Transient Climate Evolution (iTRACE) experiment to investigate long-term hydroclimate and precipitation isotope changes in the IPWP during the last deglaciation, and their response to different climate forcings (sea level and ice sheet, greenhouse gases, orbital forcing, and meltwater flux). The simulations suggest land-sea configuration as the main factor driving long-term hydroclimate and precipitation isotope changes. The exposure of NW Australian shelf (before 14 ka) excited Bjerknes feedbacks across the equatorial Indian Ocean (IO), leading to a warm/wet western IO and cool/dry eastern IO dipole pattern, with overall drying and more enriched precipitation isotopic compositions over the Maritime Continent. However, the exposed Sunda Shelf and the main body of Sahul Shelf (before 12 ka) experienced locally dry conditions but more depleted precipitation isotopic compositions. Greenhouse gases and orbital forcing contribute to a weaker hydroclimate dipole pattern that opposes the effects of NW Australian shelf exposure. Different regions within the IPWP have different simulated sensitivities to these forcings. The heterogeneous responses of precipitation to different forcings across the Maritime Continent and location-dependent relationships between precipitation and its isotopic composition result from a variety of regional climatological processes and may explain the heterogeneity of isotopic records of hydroclimate around the IPWP.

印太暖池 (IPWP) 是地球上最大的大气加热和水分来源，为全球水分和能量收支提供能量并控制全球海洋-大气环流。然而，驱动水文气候轨道尺度变化的机制和降水同位素组成的替代记录仍然知之甚少。在这里，我们使用启用同位素的瞬态气候演化 (iTRACE) 实验来研究上次冰消期间 IPWP 中的长期水文气候和降水同位素变化，以及它们对不同气候强迫（海平面和冰盖、温室气体、轨道强迫和融水通量）。模拟表明，海陆配置是驱动长期水文气候和降水同位素变化的主要因素。澳大利亚西北大陆架的暴露（14 ka 之前）激发了横跨赤道印度洋 (IO) 的 Bjerknes 反馈，导致 IO 西部温暖/潮湿和 IO 东部凉爽/干燥偶极子模式，整体干燥和更丰富的降水同位素组成海洋大陆。然而，出露的巽他陆架和 Sahul 陆架主体（12 ka 之前）经历了局部干燥条件，但降水同位素组成更为枯竭。温室气体和轨道强迫导致较弱的水文气候偶极子模式与澳大利亚西北大陆架暴露的影响相反。IPWP 内的不同区域对这些强迫具有不同的模拟敏感性。