Reconstructing wind strength and atmospheric circulation in West Antarctica over the past 300 years

重建过去300年来南极洲西部的风力和大气环流

• 批准号: NE/J020710/1
• 负责人: Elizabeth Thomas
• 金额: $ 36.62万
• 依托单位: British Antarctic Survey
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2013
• 资助国家: 英国
• 起止时间: 2013 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FJ020710%2F1
• 关键词: Reconstructing; wind; strength; atmospheric; circulation

Southern Ocean winds drive exchanges of heat and carbon dioxide between the ocean and the atmosphere, acting as a principal driver in regulating the global meridional overturning circulation. It is claimed that winds over the Southern Ocean (circumpolar westerlies) have increased in strength and shifted closer to the Antarctic continent in recent decades and is one of the strongest trends in Southern Hemisphere climate over the last 30 years. The enhanced circumpolar westerlies, attributed to greenhouse warming and anthropogenic ozone depletion, has driven changes in the depth of the ocean surface mixed layer and led to enhanced upwelling of deep, carbon-rich water. Regionally, changes in wind strength and atmospheric circulation patterns have been linked to the observed warming and increased precipitation on the Antarctica Peninsula and to increased upwelling of warm circumpolar deep water onto the Antarctic continental shelf. Circumpolar deep water promotes accelerated melting and thinning at the base of ice shelves and is considered a major contributing factor in the recent collapse of many Antarctic Peninsula ice shelves and a threat to the stability of large ice shelves in the Bellingshausen and Amundsen Sea. Few instrumental records of Southern Ocean winds exist prior to the late 20th century making it hard to validate models which examine the roles of wind strength and circulation on upwelling and climate. Climate models predict a poleward shift and strengthening of surface winds in response to increased atmospheric CO2 and therefore it is imperative that we understand how Southern Ocean wind patterns have changed over longer timescales and their potential impact on regional and ultimately global climate.In this proposal we will produce the first ice-core multi-proxy reconstruction of past wind strength and atmospheric circulation in the Bellingshausen and Amundsen Seas. The innovative proxy records will be developed using two new ice cores drilled on the climatically sensitive Amundsen Sea coast, West Antarctica which cover the period 2010-1700 AD. The unique discovery of marine diatoms in these ice cores, uplifted from the surface of the Amundsen/ Bellingshausen Sea and transported to the ice core sites by onshore (northerly) winds, will be used to provide a record of local changes in wind strength. This will be combined with records of dust and continental ions measured in the ice cores, which are proven proxies for long-range (circumpolar westerly) wind strength and circulation. Additional isotopic measurements will be taken to assess changes in the moisture source regions and the location of the Southern Hemisphere wind belt and a proven ice core proxy for past sea ice extent (Methansulphonic acid) will be measured to determine how sea ice influences uplift and transport of the diatoms deposited in the ice core.This interdisciplinary study will be the first of its kind to incorporate marine, continental and atmospheric tracers, to reconstruct both regional and hemispheric wind strength and atmospheric circulation in the Amundsen/Bellingshausen Sea. We will have an enhanced set of proxies to establish the drivers governing climate variability and an opportunity to explore the true impact of Southern Ocean winds on regional climate and upwelling in West Antarctica and the Amundsen/ Bellingshausen Sea. The new reconstructions will provide a much needed record of decadal to centennial changes and a means to test the intrinsic variability of climate models currently used to predict future climate change in this region.

南大洋风驱动海洋和大气之间的热量和二氧化碳交换，是调节全球经向翻转环流的主要驱动力。据称，近几十年来，南大洋（环极西风带）上空的风强度有所增强，并向南极大陆靠拢，是过去30年来南半球气候最强的趋势之一。由于温室变暖和人为臭氧消耗，环极地西风带增强，推动了海洋表面混合层深度的变化，并导致富含碳的深层水的上涌增强。从区域来看，风力强度和大气环流模式的变化与观测到的南极半岛变暖和降水增加以及温暖的环极地深水上涌到南极大陆架的增加有关。环极深水促进冰架底部加速融化和变薄，被认为是最近许多南极半岛冰架崩塌的主要因素，并对别林斯高晋和阿蒙森海大型冰架的稳定性构成威胁。 20 世纪末之前，南大洋风的仪器记录很少，因此很难验证研究风强度和环流对上升流和气候的作用的模型。气候模型预测，随着大气中二氧化碳含量的增加，地表风会向极地移动并增强，因此，我们必须了解南大洋风型在较长时间尺度上如何变化，以及它们对区域乃至全球气候的潜在影响。在本提案中，我们将首次对别林斯高晋海和阿蒙森海过去的风力和大气环流进行冰芯多代理重建。创新的代理记录将使用在气候敏感的西南极洲阿蒙森海岸钻探的两个新冰芯来开发，涵盖公元2010年至1700年。这些冰芯中海洋硅藻的独特发现，从阿蒙森/别林斯高晋海表面升起，并通过陆上（北风）风输送到冰芯地点，将用于提供当地风力变化的记录。这将与冰芯中测量的尘埃和大陆离子的记录相结合，这些记录已被证明是远程（环极西风）风强度和环流的代表。将进行额外的同位素测量，以评估水分源区域和南半球风带位置的变化，并将测量过去海冰范围的经过验证的冰芯替代物（甲磺酸），以确定海冰如何影响隆起和运输这项跨学科研究将是第一个将海洋、大陆和大气示踪剂纳入其中的跨学科研究，以重建阿蒙森/别林斯高晋地区的区域和半球风力和大气环流 海。我们将拥有一套增强的代理来确定控制气候变化的驱动因素，并有机会探索南大洋风对南极洲西部和阿蒙森/别林斯高晋海的区域气候和上升流的真正影响。新的重建将提供急需的十年至百年变化记录，并提供测试目前用于预测该地区未来气候变化的气候模型内在变异性的方法。

项目成果

Ice Core Chronologies from the Antarctic Peninsula: The Palmer, Jurassic, and Rendezvous Age-Scales

南极半岛的冰芯年表：帕尔默、侏罗纪和交会年龄尺度

• DOI: http://dx.10.17863/cam.81597
• 发表时间: 2022
• 作者: Emanuelsson B

Sea salt sodium record from Talos Dome (East Antarctica) as a potential proxy of the Antarctic past sea ice extent.

• DOI: 10.1016/j.chemosphere.2017.03.025
• 发表时间: 2017-06-01
• 期刊: Chemosphere
• 影响因子: 8.8
• 作者: M. Severi;S. Becagli;L. Caiazzo;V. Ciardini;Ester Colizza;F. Giardi;K. Mezgec;C. Scarchilli
• 通讯作者: C. Scarchilli

Preliminary Evidence for the Role Played by South Westerly Wind Strength on the Marine Diatom Content of an Antarctic Peninsula Ice Core (1980-2010)

西南风强度对南极半岛冰芯海洋硅藻含量影响的初步证据（1980-2010）

• DOI: http://dx.10.3390/geosciences10030087
• 发表时间: 2020
• 期刊: Geosciences
• 影响因子: 2.7
• 作者: Allen C

Regional Antarctic snow accumulation over the past 1000 years

过去1000年南极区域积雪

• DOI: http://dx.10.5194/cp-13-1491-2017
• 发表时间: 2017
• 期刊: Climate of the Past
• 影响因子: 4.3
• 作者: Thomas E

Accumulation in coastal West Antarctic ice core records and the role of cyclone activity

南极西部沿海冰芯记录的积累和气旋活动的作用

• DOI: 10.1002/2017gl074722
• 发表时间: 2017-09-16
• 期刊: Geophysical Research Letters
• 影响因子: 5.2
• 作者: J. Hosking;R. Fogt;E. Thomas;V. Moosavi;T. Phillips;Jack H. J. Coggins;D. Reusch
• 通讯作者: D. Reusch