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.

拟议的项目将测试这样的假设：大西洋经向翻转环流（AMOC）——一个对地球气候产生主要控制作用的地表和深海洋流系统，在从最后一个冰河时代过渡到目前温暖的间冰期（约20,000-10,000年前）期间，导致北大西洋气候突然变化。格陵兰冰芯记录显示明确的证据表明，这一时期的特点是不到十年的时间里发生了重大的气候突变，这归因于AMOC制度的变化，与高纬度北大西洋向北表面热传输及其向南回流的减少有关。至关重要的是，过去几十年来，由于北极变化而导致北极融水和冰出口通量增加，导致 AMOC 异常减弱，这引发了一个问题：当前 AMOC 的下降是否预示着类似于冰芯和海洋沉积物中记录的突变的新阶段，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多少？ 因此，量化海洋-大气耦合系统内的异步变化对于提高我们对气候过程的理论理解和气候模型的预测能力以及确定气候突变发生的条件至关重要。 ASYNC 是由剑桥大学领导的一个国际合作项目，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来生成一套精确年代和数十年解析的海洋环流和气候变化代理记录。 ASYNC 代表了第一个有针对性的工作，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。海洋记录将与格陵兰冰芯年代学同步，通过使用来自海底沉积物和公布的冰芯的数十年解析的宇宙成因 10Be 记录，独立且连续地重建传入宇宙射线通量的全球同步变化。拟议项目将产生新的宇宙成因 10Be、海冰、融水排放以及底层和地表水通风 三个北大西洋海洋沉积物岩心的重建。古海洋重建，特别是反映 AMOC 向南深部部分的底层水通风记录，将直接与格陵兰岛冰芯气候重建记录的事件进行比较。总之，ASYNC 将产生第一个大气、海洋和海冰变化连续同步记录网络，该网络将解决北大西洋扰动对气候系统在上一次冰消期（约 20,000-10,000 年前）期间的主要气候转变期间的时间和空间传播问题。 ASYNC 的结果将促进目前对以下方面的理解：i) 气候档案中气候突变的性质和时间；ii) AMOC 和气候对格陵兰冰盖和北极海冰融水逐渐强迫的非线性响应；以及 iii) 北大西洋地区气候快速变化的海洋前兆。

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