Evolution of water mass transformation and overturning in the western Nordic Seas in a warming climate

气候变暖期间北欧西部海域水团转化和翻转的演变

• 批准号: 2241083
• 负责人: Michael Spall
• 金额: $ 68.67万
• 依托单位: Woods Hole Oceanographic Institution
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-02-01 至 2026-01-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2241083&HistoricalAwards=false
• 关键词: Evolution; water; mass; transformation; overturning

The Nordic Seas are a key region for water mass transformation associated with the Atlantic Meridional Overturning Circulation (AMOC). The warming atmosphere has shifted the wintertime sea ice edge westward by hundreds of kilometers over the past fifty years. Greatly enhanced heat loss from the ocean along the western margin of the Nordic Seas and a reduction of heat loss in the interior of the Greenland and Iceland Seas has been coincident with this shift. To improve understanding of the consequences on water mass transformation, convection, the regional circulation, north-south heat transport and overturning circulation, this project will apply several complementary tools. These include theoretical development, the application of an idealized configuration of a high-resolution coupled ocean/atmosphere/sea ice model and the analysis of a recently acquired observational dataset in the region. The model simulations will represent the transition from the large ice extent of the mid 20th century to the reduced ice of present day and then project into the future under predicted increasing CO2 scenarios. The work is directly relevant to climate science and there are also educational broader impacts. The project will support a postdoc for two years and provide training in physical oceanography, numerical methods, applied mathematics, climate dynamics, and data analysis. Participation will also be sought from undergraduate students through the WHOI Summer Student Fellow Program (at no cost to this proposal). The PI will also co-advise and host a PhD student from the Univ. of Bergen for an extended period. The project uses idealized modeling which allows for control and isolated study of the influences of the various forcing mechanisms and ocean dynamics expected to be important. The primary tool to address the influences of sea ice retreat on water mass transformation is the SKRIPS fully coupled ocean/atmosphere/sea ice model, with components including the MITgcm with sea ice package for the ocean and ice and the Polar Weather Research and Forecasting model (WRF) for the atmosphere. The modeling studies are motivated by, and will be carried out in parallel with, simplified analytic models of the convective basin/boundary current system with new consideration of ice cover, Ekman transport, and a finite heat capacity atmosphere. In addition, PI Spall will work with collaborator Vage at the U. Bergen to analyze the Resilient Northern Overturning in a Warming Climate (ROVER) observational dataset, in light of the high resolution modeling and theoretical development of this project. ROVER included a two-year mooring array across the boundary current, summertime surveys, an unprecedented wintertime survey, glider data, wintertime deployment of ARGO floats directly in the boundary current, in addition to routinely collected glider transects across the boundary and a historical climatological data base developed by Vage.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

北欧海域是与大西洋子午线翻转环流(AMOC)相关的水团转化的关键区域。在过去的50年里，大气变暖使冬季海冰边缘向西移动了数百公里。北欧海西部边缘海洋的热量损失大大增加，格陵兰海和冰岛海内部的热量损失减少，这与这种转变是一致的。为了更好地了解水团转化、对流、区域环流、南北热量输送和翻转环流的后果，该项目将使用几种补充工具。这些活动包括理论发展、应用高分辨率海洋/大气/海冰耦合模式的理想化配置以及对该区域最近获得的观测数据集进行分析。模型模拟将代表从20世纪中叶的大冰川到现在的冰川减少的过渡，然后在预测的二氧化碳增加的情况下预测未来。这项工作与气候科学直接相关，也有更广泛的教育影响。该项目将为博士后提供为期两年的支持，并提供物理海洋学、数值方法、应用数学、气候动力学和数据分析方面的培训。本科生也将通过世界卫生组织暑期学生伙伴计划寻求参与(这项提议是免费的)。国际和平研究所还将联合建议和接待一名来自大学的博士生。在很长一段时间内。该项目使用理想化的建模，从而能够控制和单独研究各种强迫机制和海洋动力学的影响，这些机制和海洋动力学预计是重要的。解决海冰退缩对水团转化影响的主要工具是SKRIPS完全耦合的海洋/大气/海冰模式，其组件包括海洋和冰的MITgcm和海洋和冰的极地天气研究和预报模式(WRF)。模拟研究是由简化的对流盆地/边界流系统的分析模式推动的，并将与之并行进行，新的分析模式考虑了冰盖、Ekman输送和有限热容大气。此外，根据该项目的高分辨率建模和理论发展，Pi Spall将与U卑尔根的合作者VGE合作，在变暖气候(ROVER)观测数据集中分析弹性北方倾覆。罗孚包括跨越边界流的两年系泊阵列，夏季调查，史无前例的冬季调查，滑翔机数据，冬季直接在边界流中部署ARGO浮标，以及定期收集的跨边界滑翔机横断面和由Vage开发的历史气候数据库。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。