Instability of the Atlantic overturning circulation during Marine Isotope Stage 3
Instability of the Atlantic overturning circulation during Marine Isotope Stage 3
复制标题
DOI：
10.1002/2014gl060321
复制
发表时间：
2014-06
影响因子：
5.2
通讯作者：
X. Zhang;M. Prange;U. Merkel;M. Schulz
中科院分区：
文献类型：
--
作者：
X. Zhang;M. Prange;U. Merkel;M. Schulz
在海洋同位素阶段3 （MIS3）期间，大西洋经向翻转环流（AMOC）强度的变化与Dansgaard‐Oeschger （D‐O）事件的发生有关。利用MIS3边界条件下的综合气候模式研究了AMOC对北大西洋淡水扰动的稳定性。由一系列平衡淡水扰动实验构建的AMOC稳定性图揭示了AMOC强度对淡水强迫的高度非线性依赖。MIS3基线状态相对于微小的扰动是非常不稳定的。与AMOC强度变化相关的全球气候信号与从间日状态到平日状态的转变相一致，包括格陵兰中部年平均地表气温下降约8 K。我们认为，水文循环中较小的淡水扰动，例如与冰盖过程有关的扰动，有可能引发与大气-海洋系统阈值相关的D - O -型气候变化。
Variations in the strength of the Atlantic meridional overturning circulation (AMOC) were involved in the occurrences of Dansgaard‐Oeschger (D‐O) events during Marine Isotope Stage 3 (MIS3). The stability of the AMOC to North Atlantic freshwater perturbations is studied using a comprehensive climate model under MIS3 boundary conditions. An AMOC stability diagram constructed from a series of equilibrium freshwater perturbation experiments reveals a highly nonlinear dependence of AMOC strength on freshwater forcing. The MIS3 baseline state is remarkably unstable with respect to minor perturbations. The global climate signal associated with a change in AMOC strength is consistent with a transition from an interstadial to a stadial state including an annual mean surface air temperature drop of ~8 K in central Greenland. We suggest that minor freshwater perturbations in the hydrologic cycle, e.g., related to ice sheet processes, had the potential to trigger D‐O‐type climate shifts associated with a threshold in the atmosphere‐ocean system.