Modelling North Atlantic's Heinrich events and associated impacts on the Earth System

模拟北大西洋海因里希事件及其对地球系统的相关影响

• 批准号: NE/G006989/1
• 负责人: Paul Valdes
• 金额: $ 46.24万
• 依托单位: University of Bristol
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2009
• 资助国家: 英国
• 起止时间: 2009 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FG006989%2F1
• 关键词: Modelling; North; Atlantic; Heinrich; events

Future climate change involves complex interactions between physical processes on land, in the ocean, in the cryosphere, and in the atmosphere. Moreover, by all natural standards the changes predicted over the next century are likely to be 'rapid'. To have confidence in the predictions of models for the future behaviour of the ice-ocean-atmosphere-biosphere system, it is valuable for models to be tested and evaluated against past rapid Earth System changes. Although there are no direct analogues for future change, past rapid events allow us to investigate the ability of models to simulate the processes, feedbacks and time scales of response. Past climate behaviour is recorded within ice cores, marine sediment cores, cave and lake deposits and in geomorphological land forms. From these data there are clear climate cycles both on long time scales (glacial to interglacial, 100 kyr) and more rapid variations on millennial time scales (1.5 kyr - 16 kyr periods). One type of rapid variation is the massive release of icebergs from the ice sheets surrounding the North Atlantic, as indicated by freshening of the water column and increased deposition of Ice Rafted Debris (IRD) within marine sediment cores (Heinrich events). The Earth system response to these rapid changes are nearly instantaneous, with near synchronous changes in air temperature identified from ice cores in Greenland, emphasizing the sensitivity of the climate to freshwater forcing in the North Atlantic. Further feedbacks are observed through changes in vegetation, indicating changes in not only temperature but also in precipitation. Advances of glaciers across the globe at these times support a global cooling signal. While enhanced upwelling along the West coast of Africa points towards an increase in the strength of the South Atlantic trade winds. While these data tell us the timing and spatial pattern of Earth system changes associated with Heinrich events, numerical models are required to quantify the important processes related to these short term climate oscillations. Numerical modelling has already been used to reveal the importance of freshening of the North Atlantic to global climate, however, a number of aspects of these Heinrich events remain largely unexplained. Firstly, the mechanism for the trigger of ice sheet surging that produces the large number of icebergs. Secondly, the mode within which sediment is transported by the icebergs over the large distances observed within the marine records. Thirdly, the feedbacks and teleconnections which exist within the climate system that produces the wealth of evidence of both synchronous and asynchronous global signals associated with these events. This project aims to address these issues by using a newly developed fully coupled GCM which includes a detailed fully dynamic atmosphere-ocean model, combined with an ice sheet model, a vegetation model and a carbon cycle model. The model includes isotopic representation and can be coupled offline to dust and methane emission models. The model will be used to investigate the mechanisms and timings associated with the Heinrich events and associated Earth system changes. Understanding these processes and feedbacks within the Earth system and being able to compare the modelled results to the data of these past climatic events will give us confidence in using these models to predict future responses of the Earth system.

未来的气候变化涉及陆地，海洋，冰冻圈和大气中的物理过程之间的复杂相互作用。此外，按照自然标准，下一世纪预测的变化可能会“迅速”。为了对模型的预测有信心，对冰山 - 大气 - 双性恋系统的未来行为有信心，对于过去快速地球系统变化进行测试和评估模型是有价值的。尽管没有直接变化的直接类似物，但过去的快速事件使我们能够研究模型模拟响应的过程，反馈和时间范围的能力。过去的气候行为记录在冰芯，海洋沉积物核心，洞穴和湖泊沉积物以及地貌土地形式中。从这些数据中，长时间尺度（冰川冰期，100 kyr）都有清晰的气候周期，并且在千禧一代时尺度（1.5 kyr -16 kyr时期）上有更快的变化。一种快速变化的一种类型是从北大西洋周围的冰层中大量释放冰山，如水柱的清新，并增加了海洋沉积物岩心内冰筏碎屑（IRD）的沉积（海因里希事件）。地球系统对这些快速变化的响应几乎是瞬时的，从格陵兰岛的冰芯鉴定出空气温度几乎同步变化，强调了气候对北大西洋淡水强迫的敏感性。通过植被的变化观察到进一步的反馈，这不仅表明温度的变化，而且表明降水的变化。在这些时代，全球冰川的进步支持全球冷却信号。在非洲西海岸的增强范围时，向南大西洋贸易风的实力提高了。尽管这些数据告诉我们与海因里希事件相关的地球系统变化的时机和空间模式，但需要数值模型来量化与这些短期气候振荡相关的重要过程。数值建模已被用来揭示北大西洋对全球气候的新鲜研究的重要性，但是，这些海因里希事件的许多方面在很大程度上无法解释。首先，产生大量冰山的冰盖触发机制。其次，在海洋记录中观察到的大距离内，冰山被沉积物传输的模式。第三，在气候系统中存在的反馈和远程连接产生了与这些事件相关的同步和异步全球信号的大量证据。该项目旨在通过使用新开发的完全耦合的GCM来解决这些问题，该GCM包括详细的完全动态的大气 - 海洋模型，并结合了冰盖模型，植被模型和碳循环模型。该模型包括同位素表示，可以离线与粉尘和甲烷发射模型耦合。该模型将用于研究与海因里希事件和相关地球系统变化相关的机制和时机。了解地球系统内的这些过程和反馈，并能够将建模结果与过去气候事件的数据进行比较，这将使我们有信心使用这些模型来预测地球系统的未来响应。

项目成果

ENSO in the Mid-Holocene according to CSM and HadCM3

• DOI: 10.1175/jcli-d-13-00251.1
• 发表时间: 2014-01
• 期刊: Journal of Climate
• 影响因子: 4.9
• 作者: W. Roberts;D. Battisti;A. Tudhope

Topography's crucial role in Heinrich Events.

地形在海因里希事件中起着至关重要的作用。

• DOI: 10.1073/pnas.1414882111
• 发表时间: 2014
• 期刊: Proceedings of the National Academy of Sciences of the United States of America
• 影响因子: 11.1
• 作者: Roberts WH

Dating, synthesis, and interpretation of palaeoclimatic records of the Last Glacial cycle and model-data integration: advances by the INTIMATE (INTegration of Ice-core, MArine and TErrestrial records) COST Action ES0907

• DOI: 10.1016/j.quascirev.2014.10.031
• 发表时间: 2014-12
• 期刊: Quaternary Science Reviews
• 影响因子: 4
• 作者: S. Rasmussen;H. H. Birks-H.;S. Blockley;A. Brauer;I. Hajdas;W. Hoek;J. Lowe;A. Moreno;H. Renssen;D. Roche;A. Svensson;P. Valdes;M. Walker

Abrupt Bølling warming and ice saddle collapse contributions to the Meltwater Pulse 1a rapid sea level rise.

• DOI: 10.1002/2016gl070356
• 发表时间: 2016-09-16
• 期刊: GEOPHYSICAL RESEARCH LETTERS
• 影响因子: 5.2
• 作者: Gregoire, Lauren J.;Otto-Bliesner, Bette;Valdes, Paul J.;Ivanovic, Ruza
• 通讯作者: Ivanovic, Ruza

Can energy fluxes be used to interpret glacial/interglacial precipitation changes in the tropics?

• DOI: 10.1002/2017gl073103
• 发表时间: 2017-06
• 期刊: Geophysical Research Letters
• 影响因子: 5.2
• 作者: W. Roberts;P. Valdes;J. Singarayer