Deglacial trends in Indo-Pacific warm pool hydroclimate in an isotope-enabled Earth system model and implications for isotope-based paleoclimate reconstructions
Deglacial trends in Indo-Pacific warm pool hydroclimate in an isotope-enabled Earth system model and implications for isotope-based paleoclimate reconstructions
复制标题
DOI：
10.1016/j.quascirev.2021.107188
复制
发表时间：
2021-09-20
影响因子：
4
通讯作者：
He, Chengfei
中科院分区：
文献类型：
--
作者：
Du, Xiaojing;Russell, James M.;He, Chengfei
印度-太平洋暖池（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动力，并控制着全球海洋-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。本文利用同位素支持的瞬态气候演化（iTRACE）实验研究了末次冰消期IPWP的长期水文气候和降水同位素变化及其对不同气候强迫（海平面和冰盖、温室气体、轨道强迫和融水通量）的响应。模拟结果表明，海陆结构是驱动长期水文气候和降水同位素变化的主要因素。西北澳大利亚陆架的暴露（14ka前）激发了横跨赤道印度洋（IO）的Bjerknes反馈，导致印度洋西部温暖/潮湿和东部凉爽/干燥的偶极子模式，海洋大陆整体干燥，降水同位素组成更丰富。而暴露的巽他陆架和萨胡尔陆架主体（12ka前）则经历了局地干旱，降水同位素组成更为枯竭的过程。温室气体和轨道强迫使水文气候偶极子模式变弱，与西北澳大利亚大陆架暴露的影响相反。IPWP内不同区域对这些强迫的模拟敏感性不同。海洋大陆降水对不同强迫的异质性响应以及降水与同位素组成的位置依赖关系源于多种区域气候过程，可以解释IPWP周围水文气候同位素记录的异质性。(C) 2021 Elsevier Ltd版权所有。
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. (C) 2021 Elsevier Ltd. All rights reserved.