Massive dust plumes over West Asia during North Atlantic cold events revealed by a dust record from southeastern Iran

سال انتشار: 1400
نوع سند: مقاله کنفرانسی
زبان: انگلیسی
مشاهده: 199

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شناسه ملی سند علمی:

IQA04_031

تاریخ نمایه سازی: 27 آبان 1400

چکیده مقاله:

cold events have been shown to cause large-scale atmosphericreorganizations over periods of glacial instabilities. However, due to a lack of high-resolution, well-datedpaleoclimate records from the westerly wind-dominated semi-arid regions in West Asia, the climateresponse of this region to North Atlantic cold events is poorly known. Nevertheless, the existence of largesubtropical deserts in and around West Asia, capable of releasing huge amounts of dust particles into theatmosphere during dry climate intervals, substantially increases the potential of West Asian sedimentarysequences to capture fingerprints of past changes in atmospheric circulation systems. Here, we present ahigh-resolution dust record based on a multiproxy approach including grain-size analysis, elemental andmineralogical compositions, and total organic matter content of a sediment core collected from KonarSandal peat bog, southeastern Iran, spanning the entire last deglaciation and the Early Holocene (۱۹ to ۷cal. ka B.P.). Our results reveal a link between recurring dust plumes originating from the ArabianPeninsula and North Africa associated with southward shifts of the Northern Hemisphere Westerliesduring Heinrich Stadial ۱, the Younger Dryas, the Preboreal Oscillation, and the ۸.۲ ka event. Dust inputrises and falls abruptly at the transitions into and out of these cooling events. We attribute the abruptnessof these dust plumes to sudden changes of stationary waves during winter in response to reduced oceancirculation strength that are modulated by the North Atlantic winter sea-ice cover. Changes in thestationary waves gave rise to the generation of a deep atmospheric trough over the EasternMediterranean/Red Sea, which in combination with upper jet streams entrained and transported massivedust particles from the largest dust sources of the globe—North Africa and the Arabian Peninsula—towards the east including West Asia. We also show that waxing and waning of the North American icesheets has a stronger impact compared to those of the European ice sheets on the winter climate over WestAsia. Moreover, we attribute this development to a faster slowdown of the Gulf Stream—a major part ofthe AMOC flowing along the east coast of North America—in response to freshwater and icebergdischarges from North America.

نویسندگان

R Safaierad

Department of Physical Geography, University of Tehran, ۱۴۱۵۵-۶۴۶۵ Tehran, Iran

M Mohtadi

MARUM-Center for Marine Environmental Sciences, University of Bremen, ۲۸۳۵۹ Bremen, Germany

B Zolitschka

Institute of Geography (GEOPOLAR), University of Bremen, ۲۸۳۵۹ Bremen, Germany

Y Yokoyama

Atmosphere and Ocean Research Institute, University of Tokyo, ۱۱۳-۰۰۳۳ Tokyo, Japan & Department of Earth and Planetary Sciences, University of Tokyo, ۱۱۳-۰۰۳۳ Tokyo, Japan

C Vogt

Faculty of Geosciences, University of Bremen, ۲۸۳۵۹ Bremen, Germany & MARUM-Center for Marine Environmental Sciences, University of Bremen, ۲۸۳۵۹ Bremen, Germany

E Schefub

MARUM-Center for Marine Environmental Sciences, University of Bremen, ۲۸۳۵۹ Bremen, Germany. North Atlantic