Atlantic Ocean circulation changes preceded millennial tropical South America rainfall events during the last glacial

作者：Burckel Pierre^*; Waelbroeck Claire; Gherardi Jeanne Marie; Pichat Sylvain; Arz Helge; Lippold Joerg; Dokken Trond; Thil Francois

来源：Geophysical Research Letters, 2015, 42(2): 411-418.

DOI：10.1002/2014GL062512

• Heinrich stadials
• Dansgaard-Oeschger stadials
• AMOC
• ITCZ
• Pa
• Th

During the last glacial period, Greenland's climate shifted between cold (stadial) and warm (interstadial) phases that were accompanied by ocean circulation changes characterized by reduced Atlantic Meridional Overturning Circulation (AMOC) during stadials. Here we present new data from the western tropical Atlantic demonstrating that AMOC slowdowns preceded some of the large South American rainfall events that took place during stadials. Based on Pa-231/Th-230 and Ti/Ca measurements in the same sediment core, we determine that the AMOC started to slowdown 1420250 and 690180 (1 sigma) years before the onset of two large precipitation events associated with Heinrich stadials. Our results bring unprecedented evidence that AMOC changes could be at the origin of the large precipitation events observed in tropical South America during Heinrich stadials. In addition, we propose a mechanism explaining the differences in the extent and timing of AMOC slowdowns associated with shorter and longer stadials.

• 出版日期2015-1-28
• 单位中国地震局