末次间冰期东地中海地区与降温及大气环流变化相关的大西洋经向翻转环流减弱。

Weakened AMOC related to cooling and atmospheric circulation shifts in the last interglacial Eastern Mediterranean.

作者信息

Levy Elan J, Vonhof Hubert B, Bar-Matthews Miryam, Martínez-García Alfredo, Ayalon Avner, Matthews Alan, Silverman Vered, Raveh-Rubin Shira, Zilberman Tami, Yasur Gal, Schmitt Mareike, Haug Gerald H

机构信息

Department of Climate Geochemistry, Max-Planck Institute for Chemistry, Mainz, Germany.

The Geological Survey of Israel, Jerusalem, Israel.

出版信息

Nat Commun. 2023 Aug 25;14(1):5180. doi: 10.1038/s41467-023-40880-z.

DOI:10.1038/s41467-023-40880-z

PMID:37620353

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC10449873/

Abstract

There is limited understanding of temperature and atmospheric circulation changes that accompany an Atlantic Meridional Overturning Circulation (AMOC) slowdown beyond the North Atlantic realm. A Peqi'in Cave (Israel) speleothem dated to the last interglacial period (LIG), 129-116 thousand years ago (ka), together with a large modern rainfall monitoring dataset, serve as the base for investigating past AMOC slowdown effects on the Eastern Mediterranean. Here, we reconstruct LIG temperatures and rainfall source using organic proxies (TEX) and fluid inclusion water d-excess. The TEX data show a stepwise cooling from 19.8 ± 0.2° (ca. 128-126 ka) to 16.5 ± 0.6 °C (ca. 124-123 ka), while d-excess values decrease abruptly (ca. 126 ka). The d-excess shift suggests that rainfall was derived from more zonal Mediterranean air flow during the weakened AMOC interval. Decreasing rainfall d-excess trends over the last 25 years raise the question whether similar atmospheric circulation changes are also occurring today.

摘要

对于伴随大西洋经向翻转环流（AMOC）减缓而出现的温度和大气环流变化，在北大西洋区域以外的地方人们了解有限。佩基因洞穴（以色列）的一个洞穴沉积物可追溯到末次间冰期（LIG），即12.9 - 11.6万年前（ka），再加上一个大型现代降雨监测数据集，构成了研究过去AMOC减缓对东地中海影响的基础。在这里，我们使用有机指标（TEX）和流体包裹体水氘过量来重建LIG时期的温度和降雨来源。TEX数据显示温度从19.8±0.2°C（约12.8 - 12.6 ka）逐步降至16.5±0.6°C（约12.4 - 12.3 ka），而氘过量值在约12.6 ka时突然下降。氘过量的变化表明，在AMOC减弱的时期，降雨源自更具纬向性的地中海气流。过去25年中降雨氘过量趋势的下降引发了一个问题，即类似的大气环流变化如今是否也在发生。