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

南大洋风推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，南大洋上空的风（环极西风带）的强度有所增加，并向南极大陆靠近，这是过去30年来南半球气候最强烈的趋势之一。由于温室变暖和人为臭氧耗竭，环极西风带增强，推动了海洋表面混合层深度的变化，并导致深部富碳水的上涌增强。从区域来看，风力和大气环流型态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深水向南极大陆架上涌的增加有关。极地周围的深水加速了冰架底部的融化和变薄，被认为是最近许多南极半岛冰架崩塌的一个主要因素，并对别令斯豪森海和阿蒙森海的大型冰架的稳定性构成威胁。在20世纪后期之前，很少有关于南大洋风的仪器记录存在，这使得很难验证检查风强度和环流对上升流和气候的作用的模式。气候模型预测，由于大气中二氧化碳的增加，地面风会向极地移动，并会加强。因此，我们必须了解南大洋的风模式在更长的时间尺度上是如何变化的，以及它们对区域和最终全球气候的潜在影响。在这个建议中，我们将产生第一个冰芯多代理重建过去的风强度和大气环流在别令斯豪森和阿蒙森海。创新的代用记录将使用在气候敏感的南极洲西部阿蒙森海岸钻取的两个新的冰芯，这些冰芯覆盖了公元2010-1700年。这些冰芯中海洋硅藻的独特发现，从阿蒙森/别令斯豪森海的表面升起，被陆上（偏北风）吹到冰芯地点，将被用来提供当地风力变化的记录。这将与在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（绕极西风）风强度和环流的代表。将采取额外的同位素测量来评估湿气源区的变化和南半球风带的位置，并将测量一个已证实的过去海冰范围的冰芯代用物（甲磺酸），以确定海冰如何影响沉积在冰芯中的硅藻的隆升和运输。这项跨学科的研究将是同类研究中首次将海洋、大陆和大气示踪剂结合起来，重建阿蒙森/别林斯高森海的区域和半球风强度和大气环流。我们将有一组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区域气候和西南极洲和阿蒙森/别令斯豪森海上升流的真正影响。新的重建将提供一个非常需要的十年到百年变化的记录，并提供一种方法来检验目前用于预测该地区未来气候变化的气候模式的内在变异性。

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.