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

基本信息

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

项目摘要

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.

拟议的项目将检验以下假设：大西洋子午倾覆循环（AMOC）的逐渐变化 - 表面和深洋流的系统，该系统对地球气候产生了主要控制，导致北大西洋气候的突然转变在过渡期间突然变化。最后一个冰河时代进入目前的温暖冰河（约20,000-10，000年前）。格陵兰冰核记录显示了明确的证据表明，这一时期的特征是不到十年的重大气候变化，这归因于与北大西洋高纬度及其其北面北面热传输相关的AMOC政权的变化。深度向南回流。至关重要的是，在过去的几十年中，AMOC的异常削弱是由于北极的融化和冰的增加而引起的北极变化导出的北极变化，这引起了一个问题：AMOC的当前降低是否在突然的突然变化阶段相似，类似于记录的新阶段。在冰芯和海洋沉积物中，北大西洋对高纬度表面和深海循环变化的响应时间是多少？解决和量化耦合的海洋 - 大气系统内的异步变化是什么，因此，对于提高我们对我们对我们对我们对我们对理论理解的理论理解至关重要气候过程和气候模型的预测能力，并确定在哪些情况下突然发生气候变化。 Async是由剑桥大学领导的国际合作项目，将解决这个基本问题。该项目将利用独特的北大西洋沉积物记录，以产生一套精确的日期和多年降级的海洋循环和气候变化代理记录。异步代表了第一个针对性的努力，该努力是通过以连续的方式精确整合基础时间尺度来比较北大西洋代理记录的高分辨率。海洋记录将通过使用多年座位上分辨的宇宙宇宙学10BE记录从海底沉积物和发表的冰核中导致新的cosmogent 10be记录，通过独立和连续重建全球同步变化，将海洋记录与格陵兰冰核年代同步。从三个北大西洋海洋沉积物核心的宇宙基因10BE，海冰，融合水排放以及底部和地表水通风重建。形成了反映AMOC的南部深层组成部分的古生物学重建，尤其是底水通风记录，将直接与格陵兰冰镇气候重建中记录的事件进行比较。共同将异步将导致第一个连续同步的大气，海洋和海冰变化记录网络，这将解决北大西洋北大西洋对气候系统跨境的时间和空间传播，这些气候系统跨越了最后的气候过渡（〜 20,000-10，000年前）。异步的结果将提高对i）跨气候档案中突然气候变化的性质和时机，ii）ii）AMOC和气候对渐进的格陵兰冰板和北极海冰融化的反应，以及iiii iii）海洋前体。北大西洋地区的气候变化。