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

据预测，气候变暖的后果之一将是影响北极地区的气旋的强度和频率增加。这带来了强烈的后果，包括降水增加，更严重的沿海洪水和侵蚀，以及向浮冰及其下面的水转移的动量增强。目前还不清楚这种不断变化的大气条件将如何影响冰架和北冰洋内部之间的交流。越来越多的证据表明，风强迫是这种交换的主要驱动力，而且这种强迫的影响涉及食物网的多个方面。然而，风迫使大陆架-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现象，包括了解距离相关地区数千公里远的风暴系统的行为和演变。此外，浮冰显著地调节了海洋的反应。因此，有必要在无数尺度上同时处理大气-冰-海洋系统的不同方面，以充分了解风暴驱动的陆架-盆地交换的原因和影响。该项目汇集了多个领域（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），以加强对风驱动交换的全系统性质及其对北极内陆和沿海生态系统影响的理解。海洋范围是楚科奇/波弗特海区域，但大气联系延伸到北太平洋，在这种情况下，北太平洋显然需要被视为北极系统的一部分。该项目将分三个阶段展开。在第一期NCEP再分析领域，AMSR-E冰浓度数据和SBI系泊数据将用于研究当前的风暴气候，阐明导致最强上升流和下升流的条件（如高层大气流、阿拉斯加地形、浮冰结构）。在第二阶段，将使用MIT海洋/冰模型对三个风暴事件进行详细的案例研究，由高分辨率WRF大气模型的输出驱动，并与SBI物理系泊数据和船上生化数据一起进行分析。这将使人们能够了解风和冰原的区域变化以及地形如何影响陆架-盆地交换。将计算每个风暴具有重要生物化学性质的净通量，并按比例放大以获得年通量。在第三阶段，应用于NCEP完整数据集的自动气旋跟踪，连同历史冰浓度数据，将用于调查几十年来涵盖不同气候制度的风暴气候和相关的上升流/下升流。这将有助于评估未来气候变暖的可能影响。这项研究将努力确定是什么因素决定了风暴的发展和演变，导致强烈的陆架-盆地交换，浮冰的分布如何调节这种交换，以及完成交换的详细动力学。获得相关生物化学通量的定量估计，将使我们能够处理对冰架和北极中部生态系统的影响。

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.