Department of Physical Geography, University of Tehran, 14155-6465 Tehran, Iran.
MARUM-Center for Marine Environmental Sciences, University of Bremen, 28359 Bremen, Germany;
Proc Natl Acad Sci U S A. 2020 Aug 4;117(31):18272-18277. doi: 10.1073/pnas.2004071117. Epub 2020 Jul 20.
Rapid North Atlantic cooling events during the last deglaciation caused atmospheric reorganizations on global and regional scales. Their impact on Asian climate has been investigated for monsoonal domains, but remains largely unknown in westerly wind-dominated semiarid regions. Here we generate a dust record from southeastern Iran spanning the period 19 to 7 cal. ka B.P. We find a direct link between frequent occurrences of dust plumes originating from the Arabian Peninsula and North Africa and rapid southward shifts of the westerlies associated with changes of the winter stationary waves during Heinrich Stadial 1, the Younger Dryas, the Preboreal Oscillation, and the 8.2-ka event. Dust input rises and falls abruptly at the transitions into and out of these cooling events, which we attribute to changes in the ocean circulation strength that are modulated by the North Atlantic winter sea-ice cover. Our findings reveal that waxing and waning of North American ice sheets have a stronger influence than those of European ice sheets on the winter climate over West Asia.
末次冰消期北大西洋迅速降温事件导致了全球和区域尺度的大气重组。人们已经研究了这些事件对季风区亚洲气候的影响，但在西风主导的半干旱区，其影响仍知之甚少。本研究在伊朗东南部获得了一段 19 至 7 千年 cal. BP 的粉尘记录，发现源自阿拉伯半岛和北非的粉尘羽流频繁出现与西风迅速南移之间存在直接联系，这种西风的变化与 Heinrich 冷事件、新仙女木事件、北方涛动和 8.2ka 事件期间冬季定常波的变化有关。在进入和退出这些冷却事件的过程中，粉尘输入会突然增加或减少，我们将其归因于海洋环流强度的变化，这种变化受北大西洋冬季海冰覆盖的调制。我们的研究结果表明，北美冰盖的消长对西亚冬季气候的影响比欧洲冰盖的影响更大。
