Storm climate of the western Arctic and its impact on shelf-basin exchange

北极西部风暴气候及其对陆架-盆地交换的影响

• 批准号: 0731928
• 负责人: Robert Pickart
• 金额: $ 40.96万
• 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: 2007
• 资助国家: 美国
• 起止时间: 2007-09-15 至 2011-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0731928&HistoricalAwards=false
• 关键词: Storm; climate; western; Arctic; its

It is predicted that one of the consequences of a warmer climate will be an increase in the intensity and frequency of cyclones that influence the arctic domain. This carries with it strong ramifications, including increased precipitation, more severe coastal flooding and erosion, and enhanced transfer of momentum to the pack-ice and the water beneath it. At present it is not well understood how such changing atmospheric conditions would influence the communication between the shelves and the interior Arctic Ocean. There is increasing evidence that wind-forcing is a dominant driver of such exchange, and that the impacts of this forcing involve multiple aspects of the food web. However, wind-forced shelf-basin exchange is not simply a regional phenomenon, but one that involves a mix of time and space scales, including understanding the behavior and evolution of storm systems centered thousands of kilometers away from the areas in question. In addition, the pack-ice significantly modulates the oceanic response. Therefore, it is necessary to address simultaneously different aspects the of the atmosphere-ice ocean system -over a myriad of scale- to understand fully the causes and effects of storm-driven shelf-basin exchange.This project brings together multiple fields (meteorology, oceanography), disciplines (physics, biochemistry), and tools (atmospheric and oceanic modeling, data analysis) to enhance the understanding of the system-wide nature of wind-driven exchange and its impact on the ecosystem of the interior and coastal Arctic. The oceanic scope is the Chukchi/Beaufort Sea region, but the atmospheric connections extend into the North Pacific, which in this context clearly needs to be considered as part of the arctic system. The project will unfold in three phases. In phase I NCEP reanalysis fields, AMSR-E ice concentration data, and SBI mooring data will be used to investigate the present storm climate, elucidating the conditions (e.g. upper-level atmospheric currents, orography of Alaska, configuration of pack-ice) leading to the strongest upwelling and downwelling. In Phase II detailed case studies of three storm events will be performed using the MIT ocean/ice model, driven by output from the high-resolution WRF atmospheric model, and analyzed in tandem with the SBI physical mooring data and biochemical shipboard data. This will enable the understanding of how regional variations in the wind and ice fields, together with the topography, influence the shelf-basin exchange. Net fluxes of biochemically important properties for each of the storms will be computed, and scaled up to obtain annual fluxes. In Phase III automated cyclone tracking applied to the full NCEP data set, together with historical ice concentration data, will be used to investigate the storm climate and associated upwelling/downwelling over several decades that encompass different climatic regimes. This will allow an assessment of possible impacts of a future warmer climate.This research will strive to determine what factors dictate the development and evolution of storms that lead to strong shelf-basin exchange, how the distribution of pack-ice modulates this, and the detailed dynamics that accomplish the exchange. Obtaining quantitative estimates of the associated biochemical fluxes will enable us to address the ramifications on the ecosystems of the shelves and central Arctic.

据预测，气候变暖的后果之一将是影响北极地区的气旋强度和频率增加。这带来了很大的影响，包括降水增加，海岸洪水和侵蚀更加严重，动量转移到浮冰和它下面的水。目前还不清楚这种变化的大气条件如何影响冰架和北冰洋内部之间的联系。越来越多的证据表明，风的作用力是这种交换的主要驱动力，这种作用力的影响涉及食物网的多个方面。然而，风力驱动的陆架-盆地交换不仅仅是一个区域现象，而是一个涉及时间和空间尺度的混合体，包括了解以数千公里外的风暴系统为中心的行为和演变。此外，浮冰显著调节海洋的反应。因此，有必要同时解决大气-冰海洋系统的不同方面-在无数的尺度上-以充分了解风暴驱动的陆架-盆地交换的原因和影响。（气象学，海洋学），学科（物理学、生物化学）和工具（大气和海洋建模，数据分析），以加强对风的全系统性质的了解-驱动的交换及其对北极内陆和沿海生态系统的影响。海洋范围是楚科奇/博福特海区域，但大气连接延伸到北太平洋，在这种情况下，显然需要考虑作为北极系统的一部分。该项目将分三个阶段展开。在第一阶段NCEP再分析场，AMSR-E冰浓度数据和SBI系泊数据将用于调查目前的风暴气候，阐明导致最强上升流和下降流的条件（例如上层大气流，阿拉斯加的地形，浮冰的配置）。在第二阶段，将使用麻省理工学院的海洋/冰模型进行三个风暴事件的详细案例研究，由高分辨率WRF大气模型的输出驱动，并与SBI物理系泊数据和生化船上数据一起进行分析。这将有助于了解风场和冰场的区域变化以及地形如何影响陆架-海盆交换。将计算每个风暴的生物化学重要特性的净通量，并按比例放大以获得年度通量。在第三阶段，应用于完整NCEP数据集的自动气旋跟踪，以及历史冰浓度数据，将用于调查几十年来包括不同气候状况的风暴气候和相关的上升流/下降流。这将允许一个未来变暖的气候可能产生的影响进行评估。这项研究将努力确定哪些因素决定的发展和演变的风暴，导致强大的陆架盆地交换，如何分布的浮冰调制这一点，以及详细的动态，完成交换。获得相关的生化通量的定量估计将使我们能够解决对大陆架和北极中部生态系统的影响。