石笋δ^(18)O揭示的亚洲夏季风变化及机制综述  

Variations and mechanisms of the Asian summer monsoon revealed by stalagmiteδ^(18)O records

作　　者：杨会会 周祐民 仲义 刘青松 YANG Huihui;ZHOU Youmin;ZHONG Yi;LIU Qingsong(School of Environment,Harbin Institute of Technology,Harbin 150006,China;Department of Ocean Science and Engineering,Southern University of Science and Technology,Shenzhen 518055,China;Southern Marine Science and Engineering Guangdong Laboratory(Guangzhou),Guangzhou 511458,China)

机构地区：[1]哈尔滨工业大学环境学院,哈尔滨150006 [2]南方科技大学海洋科学与工程系,深圳518055 [3]南方海洋科学与工程广东省实验室(广州),广州511458

出　　处：《海洋地质与第四纪地质》2024年第1期143-155,共13页Marine Geology & Quaternary Geology

基　　金：国家自然科学基金面上项目“末次间冰期以来地磁漂移事件的高分辨率石笋古地磁记录研究”(42074071),“轨道尺度上北太平洋中层水的演化特征及其对全球气候变化响应机制”(42274094);深圳市科技创新委员会项目(20200925154739001);上海佘山地球物理国家野外科学观测研究站项目(SSKP202101,SSKP202102)。

摘　　要：亚洲夏季风(ASM,Asian Summer Monsoon)是全球气候系统的重要组成部分,也是目前地球系统科学的热点问题。亚洲石笋δ^(18)O揭示的亚洲古季风变化,加深了我们对其时空演化机制的理解。然而,目前东亚夏季风区和印度夏季风区石笋δ^(18)O记录在不同时间尺度上的相互关系和主控因素仍存在一些争议。针对这一问题,本文综述了东亚夏季风(EASM,East Asian Summer Monsoon)区和印度夏季风(ISM,Indian Summer Monsoon)区的高分辨率石笋δ^(18)O记录,发现两者在轨道尺度上都受控于岁差驱动的北半球夏季日照量的变化,其机制涉及海陆热力差异强度、辐合强度和上升气流强度以及夏季时长的变化。这些机制共同导致了在北半球夏季日照高值期EASM和ISM区夏季降雨量增加以及降雨和石笋的δ^(18)O值负偏。在千年尺度上,EASM区和ISM区的石笋δ^(18)O记录则响应于北大西洋区的气候变化,具体响应机制主要有热带辐合带南移导致的印度洋水汽分馏减弱(主要影响ISM区和EASM区),以及西风带调节的水汽来源和降雨季节性变化(主要影响EASM区)。在百年及以下尺度,EASM区和ISM区石笋δ^(18)O记录都受到与厄尔尼诺-南方涛动有关的大尺度大气环流影响。未来在关键区域构建更多高分辨率的石笋δ^(18)O记录及相关的降雨指标,将有助于理解大气环流变化与东亚夏季风区降雨的关系。The Asian summer monsoon is an important part of the global climate system and a hot issue of the earth system science.The variation of the Asian paleo-monsoon revealed byδ^(18)O data from the Asian stalagmites deepens our understanding of the mechanisms of its spatiotemporal evolution.However,the main controlling factors of the stalagmiteδ^(18)O records in the East Asian and Indian summer monsoon regions in different time scales remain controversial.Aiming at this problem,we reviewed the high-resolution stalagmiteδ^(18)O records in the East Asian summer monsoon(EASM)and Indian summer monsoon(ISM)regions and revealed that they are in response to the variation in the Northern Hemisphere summer insolation driven by the precession on orbital scale.The specific mechanism involves the variation of zonal sealand thermal contrast,seasonal humidity changes and cycles in low-level convergence,and the variation of summer length.These mechanisms jointly lead to increased summer rainfall with depletedδ^(18)O in the EASM and ISM regions during high Northern Hemisphere summer insolation.On millennial scale,the stalagmiteδ^(18)O records in EASM and ISM regions are in response to the abrupt North Atlantic climate changes consistently,by mainly the weakening of water vapor fractionation in the Indian Ocean due to southward migration of the intertropical convergence zone(mainly influenced the ISM and EASM regions)and seasonal variation of water vapor sources and rainfall amount regulated by the westerly(mainly influenced the EASM region).Finally,at the centennial or shorter scale,the stalagmiteδ^(18)O records in both EASM and ISM regions are influenced by large-scale atmospheric circulation associated with EI Niño-Southern Oscillation.In the future,the development of more high-resolution stalagmiteδ^(18)O and other rainfall indicators records in key areas would facilitate our understanding of the relationship between atmospheric circulation and rainfall changes in the Asian summer monsoon region.

关 键 词：石笋氧同位素 东亚夏季风 印度夏季风 北半球日照 HEINRICH事件 

分 类 号：P532[天文地球—古生物学与地层学]