Glacial-Interglacial Indian Summer Monsoon Dynamics

• Published in: Science (American Association for the Advancement of Science) Vol. 333; no. 6043; pp. 719 - 723
• Main Authors: Zhisheng, An, Clemens, Steven C., Shen, Ji, Qiang, Xiaoke, Jin, Zhangdong, Sun, Youbin, Prell, Warren L., Luo, Jingjia, Wang, Sumin, Xu, Hai, Cai, Yanjun, Zhou, Weijian, Liu, Xiaodong, Liu, Weiguo, Shi, Zhengguo, Yan, Libin, Xiao, Xiayun, Chang, Hong, Wu, Feng, Ai, Li, Lu, Fengyan
• Format: Journal Article
• Language: English
• Published: Washington, DC American Association for the Advancement of Science 05-08-2011; The American Association for the Advancement of Science
• Subjects: Atmospheric circulation; Atmospheric sciences; Climate; Earth sciences; Earth, ocean, space; Exact sciences and technology; Glaciers; Ice; In kind support and maintenance; Marine and continental quaternary; Mathematical maxima; Mathematical minima; Monsoons; Musical intervals; Oceans; Proxy reporting; Proxy statements; Summer; Surficial geology; Wind; Southwest China; Far East; Asia; China; India; China, People's Rep; Teleconnection; Historical reconstruction; Southern Hemisphere; Quaternary; paleoclimatology; Interhemispheric connection; Summer monsoon; drill cores; Atmospheric dynamics; Proxy; Northern Hemisphere; Forcing; Cenozoic; Phanerozoic; sediments
• ISSN: 0036-8075; 1095-9203
• DOI: 10.1126/science.1203752

The modern Indian summer monsoon (ISM) is characterized by exceptionally strong interhemispheric transport, indicating the importance of both Northern and Southern Hemisphere processes driving monsoon variability. Here, we present a high-resolution continental record from southwestern China that demonstrates the importance of interhemispheric forcing in driving ISM variability at the glacial-interglacial time scale as well. Interglacial ISM maxima are dominated by an enhanced Indian low associated with global ice volume minima. In contrast, the glacial ISM reaches a minimum, and actually begins to increase, before global ice volume reaches a maximum. We attribute this early strengthening to an increased cross-equatorial pressure gradient derived from Southern Hemisphere high-latitude cooling. This mechanism explains much of the nonorbital scale variance in the Pleistocene ISM record.