ASYNC - Resolving asynchronous responses of North Atlantic climate to deglacial changes in ocean circulation

ASYNC - 解决北大西洋气候对海洋环流冰消变化的异步响应

• 批准号: NE/W006243/1
• 负责人: Francesco Muschitiello
• 金额: $ 69.22万
• 依托单位: University of Cambridge
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2022
• 资助国家: 英国
• 起止时间: 2022 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FW006243%2F1
• 关键词: ASYNC; Resolving; asynchronous; responses; North

The proposed project will test the hypothesis that gradual changes in Atlantic Meridional Overturning Circulation (AMOC) -a system of surface and deep ocean currents that exerts a primary control on Earth's climate, led to abrupt shifts in North Atlantic climate during the transition out of the last ice age and into the present warm interglacial (~20,000-10,000 years ago). Greenlandic ice-core records show clear evidence that this period was characterised by major abrupt climate shifts in less than a decade, which have been attributed to changes in the AMOC regime associated with reduced northward surface heat transport in the high-latitude North Atlantic and its deep southward return flow. Critically, the anomalous weakening of the AMOC in the last decades caused by enhanced fluxes of meltwater and ice export from the Arctic in response to Arctic change prompts the question: Is the current decline in AMOC heralding a new phase of abrupt change similar to those recorded in ice cores and ocean sediments, and what is the response time of North Atlantic climate to changes in high-latitude surface and deep ocean circulation?Resolving and quantifying asynchronous changes within the coupled ocean-atmosphere system is hence essential to improve our theoretical understanding of climate processes and predictive capacity of climate models, as well as identifying under which conditions abrupt climate change occurs. ASYNC is an international collaborative project led by the University of Cambridge that will tackle this fundamental problem. The project will avail of unique North Atlantic Ocean sediment records to generate a suite of precisely dated and multidecadally-resolved proxy records of ocean circulation and climate change. ASYNC represents the first targeted effort to compare high resolution North Atlantic proxy records by precisely integrating the underlying timescales in a continuous fashion. The marine records will be synchronised to the Greenland ice-core chronology via independent and continuous reconstructions of globally synchronous variations in the incoming cosmic ray flux using multidecadally-resolved cosmogenic 10Be records from seafloor sediments and published ice cores.The proposed project will result in new cosmogenic 10Be, sea ice, meltwater discharge, and bottom- and surface-water ventilation reconstructions from three North Atlantic marine sediment cores. The palaeoceanographic reconstructions, and in particular the bottom-water ventilation records, which reflect the southward deep component of AMOC, will be directly compared to events recorded in ice-core climate reconstructions from Greenland. Together, ASYNC will result in the first network of continuously synchronised records of atmospheric, oceanic and sea ice change that will resolve the temporal and spatial propagation of North Atlantic ocean perturbations on the climate system across the major climatic transitions that punctuated the last deglaciation (~20,000-10,000 years ago). Results from ASYNC will advance the current understanding of i) the nature and timing of abrupt climate shifts across climate archives, ii) nonlinear responses of AMOC and climate to gradual Greenland Ice Sheet and Arctic sea ice meltwater forcing, and iii) ocean precursors of rapid climate change in the North Atlantic region.

该计划将检验大西洋经向翻转环流（AMOC）的逐渐变化（AMOC是一个表层和深层洋流系统，对地球气候起着主要的控制作用）导致北大西洋气候在从最后一个冰河期过渡到目前温暖的间冰期（约2万至1万年前）期间的突然转变的假设。格陵兰冰芯记录清楚地表明，这一时期的特点是在不到十年的时间里发生了重大的气候突变，这被归因于与高纬度北大西洋向北的地表热输送减少及其向南的深回流有关的AMOC状态的变化。至关重要的是，在过去几十年里，由于北极融化水和冰输出通量的增加而导致的AMOC的异常减弱引发了以下问题：当前AMOC的下降是否预示着与冰芯和海洋沉积物中记录的突变相似的新阶段，以及北大西洋气候对高纬度表层和深海环流变化的响应时间是什么？因此，解决和量化耦合海洋-大气系统内的非同步变化对于提高我们对气候过程的理论认识和气候模式的预测能力，以及识别在何种条件下发生气候突变至关重要。ASYNC是一个由剑桥大学领导的国际合作项目，旨在解决这一基本问题。该项目将利用独特的北大西洋沉积物记录，生成一套精确确定年代的、以几十年为单位的海洋环流和气候变化代用记录。ASYNC代表了第一个通过以连续的方式精确整合底层时间尺度来比较高分辨率北大西洋代理记录的目标。海洋记录将与格陵兰冰芯年代学进行同步，方法是利用海底沉积物和公布的冰芯的多年分辨宇宙成因10Be记录，对入射宇宙射线通量的全球同步变化进行独立和连续的重建。拟议的项目将产生新的宇宙成因10Be，海冰，融水排放，以及三个北大西洋海洋沉积物岩心的底部和地表水通风重建。古海洋学重建，特别是反映AMOC南向深层成分的底水通风记录，将与格陵兰冰芯气候重建记录的事件进行直接比较。总之，ASYNC将产生第一个连续同步记录大气、海洋和海冰变化的网络，这将解决北大西洋扰动对气候系统的时空传播，这些扰动跨越了最后一次冰川消融（~20,000-10,000年前）的主要气候转变。ASYNC的结果将促进当前对以下方面的认识：1)气候突变的性质和时间，2)AMOC和气候对格陵兰冰盖和北极海冰融化强迫的非线性响应，以及3)北大西洋地区快速气候变化的海洋前兆。

项目成果

Publisher Correction: Sea ice-ocean coupling during Heinrich Stadials in the Atlantic-Arctic gateway.

出版商更正：大西洋-北极门户海因里希体育场期间的海冰-海洋耦合。

• DOI: 10.1038/s41598-024-54224-4
• 发表时间: 2024
• 期刊: Scientific reports
• 影响因子: 4.6
• 作者: Altuna NEB

Coastal permafrost was massively eroded during the Bølling-Allerød warm period

伯林-阿勒德暖期期间，沿海永久冻土层遭到大规模侵蚀

• DOI: 10.1038/s43247-023-01013-y
• 发表时间: 2023
• 期刊: Communications Earth & Environment
• 影响因子: 7.9
• 作者: Nogarotto A

The Temporal Phasing of Rapid Dansgaard-Oeschger Warming Events Cannot Be Reliably Determined

丹斯加德-厄施格快速变暖事件的时间阶段无法可靠确定

• DOI: 10.5194/egusphere-2023-2496
• 发表时间: 2023
• 作者: Slattery J