Sea ice Processes and Mass Balance in the Bellingshausen Sea

别林斯高晋海的海冰过程和质量平衡

• 批准号: NE/H009582/2
• 负责人: Jeremy Wilkinson
• 金额: $ 7.16万
• 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%2FH009582%2F2
• 关键词: Sea; ice; Processes; Mass; Balance

Antarctic sea ice thickness is arguably the largest gap in our knowledge of the climate system. While rapid changes in ice extent are evident in satellite imagery collected over the last three decades, we have little information with which to assess the thickness of the ice. Knowledge of the thickness distribution of sea ice and its snow cover is critical in understanding a wide range of air-sea-ice interactions. It's evolution over time provides a sensitive measure of the response of the polar regions to climate change and variability, and it controls the fluxes of heat, salt, and freshwater that govern air-sea interactions and water mass transformation. Whilst we are moving closer to the 'holy grail' of measuring Arctic sea ice thickness from space, such methods are severely limited in the Antarctic due to the deep snow cover. Moreover, our understanding of the processes that control Antarctic snow and ice thickness is inadequate. This proposal has two complementary lines of investigation: (1) To determine robust statistical relationships between snow depth, ice thickness, and freeboard distribution for a range of ice classes. Understanding these relationships is critical if we are to be able to determine either snow depth or ice thickness from space - the only viable means of determining large-scale snow and sea ice thickness, trends, and variability. (2) To quantify the role that key Antarctic sea ice processes play in controlling the ice thickness evolution and its response to climate forcing. This can only be achieved through detailed simultaneous measurements of both the surface topography and ice underside. We will obtain, for the first time anywhere, coincident 3D topography maps of both the surface (from airborne Lidar) and underside (from AUV mounted multibeam sonar) for a variety of ice types and conditions. With over 1 million individual measurements per sampling station, the richness of the data set will be several orders of magnitude more than is possible with traditional methods. This will allow us to determine, for the first time, robust statistical relationships between snow depth and ice thickness spatial variability. These data will allow a definitive assessment of the feasibility and accuracy of satellite methods for estimating Antarctic sea ice thickness and snow depth for a range of ice conditions. In addition we will deploy an unprecedented number (20) of novel ice mass balance buoys (IMBs) to monitor the evolution of the snow and sea ice throughout the annual sea ice cycle. The large number of IMB deployments will allow the first regional assessment of snow accumulation rates and ice mass balance of Antarctic sea ice. To achieve these goals we have secured a 30-day dedicated cruise aboard the James Clark Ross, scheduled for November 2010, as well as use of a BAS Twin Otter for airborne Lidar missions over ice stations and the surrounding region. These platforms, provided as part of the BAS core programme, along with support and instrumentation provided by project partners at no cost, represent a unique opportunity, and a significant leverage of over £1,000,000 of in-kind contribution. This is an unprecedented opportunity for the UK to lead a coordinated campaign to produce a definitive picture of snow and sea ice thickness distribution, and to continuously monitor the processes that control these distributions throughout the annual cycle. Our programme will deliver a major step forward in our knowledge of the snow and ice thickness distribution. It will advance our understanding of Antarctic sea ice processes and improve our ability to monitor the evolution of the ice cover and air-ice-ocean interactions on a large scale. This will allow improved representation of sea ice in large-scale and global climate models, and ultimately improve our understanding of the response of the Antarctic ice cover to current and future climate change and variability.

南极海冰的厚度可以说是我们对气候系统知识的最大空白。虽然在过去三十年收集的卫星图像中，冰层范围的迅速变化是显而易见的，但我们几乎没有什么信息可以用来评估冰层的厚度。了解海冰及其积雪的厚度分布对于了解广泛的气-海-冰相互作用至关重要。它随时间的演变提供了极地地区对气候变化和可变性的敏感测量，它控制着热量，盐和淡水的通量，这些通量控制着海气相互作用和水团转化。虽然我们正在接近从太空测量北极海冰厚度的“圣杯”，但由于积雪很深，这种方法在南极受到严重限制。此外，我们对控制南极冰雪厚度的过程了解不足。该建议有两个互补的研究方向：（1）确定一系列冰类的雪深、冰厚和干舷分布之间的可靠统计关系。了解这些关系是至关重要的，如果我们能够确定雪的深度或冰的厚度从空间-唯一可行的手段，确定大规模的雪和海冰的厚度，趋势和变化。(2)量化关键的南极海冰过程在控制冰厚度演变及其对气候强迫的响应方面所起的作用。这只能通过同时对表面地形和冰底进行详细测量来实现。我们将获得，第一次在任何地方，同时三维地形图的表面（从机载激光雷达）和底面（从AUV安装多波束声纳）的各种冰类型和条件。由于每个采样站有100多万次单独测量，数据集的丰富程度将比传统方法可能达到的数量级多。这将使我们能够确定，第一次，雪深和冰厚的空间变异性之间的强大的统计关系。这些数据将使人们能够明确评估卫星方法在各种冰况下估计南极海冰厚度和积雪深度的可行性和准确性。此外，我们将部署数量空前的（20个）新型冰质量平衡浮标（IMB），以监测整个年度海冰周期中雪和海冰的演变。大量的IMB部署将允许对南极海冰的积雪速度和冰质量平衡进行第一次区域评估。为了实现这些目标，我们已经确保了詹姆斯·克拉克·罗斯号上为期30天的专门巡航，计划于2010年11月，以及使用BAS双水獭在冰站和周围地区执行机载激光雷达任务。这些平台是作为BAS核心方案的一部分提供的，沿着项目合作伙伴免费提供的支持和工具，代表了一个独特的机会，以及超过1，000，000英镑的实物捐助的重要杠杆作用。这是一个前所未有的机会，英国可以领导一个协调的运动，以产生雪和海冰厚度分布的明确图片，并在整个年度周期中持续监测控制这些分布的过程。我们的计划将使我们对冰雪厚度分布的了解向前迈出一大步。它将增进我们对南极海冰过程的了解，提高我们大规模监测冰盖演变和空气-冰-海洋相互作用的能力。这将使海冰在大规模和全球气候模型中的表现得到改善，并最终提高我们对南极冰盖对当前和未来气候变化和变异的反应的理解。

项目成果

Thick and deformed Antarctic sea ice mapped with autonomous underwater vehicles

• DOI: 10.1038/ngeo2299
• 发表时间: 2015
• 期刊: Nature Geoscience
• 影响因子: 18.3
• 作者: G. Williams;T. Maksym;J. Wilkinson;C. Kunz;Chris Murphy;Peter W. Kimball;Hanumant Singh