Polar ocean responses and feedbacks to a rapidly changing climate

极地地区是地球气候系统的关键。首先，它们对气候变化非常敏感。例如，在过去的几十年里，北极变暖的速度是世界其他地区的两倍。其次，极地地区形成海洋对流，这是一种海水由于热量损失而变得非常稠密（“重”）并下沉到深海的过程。当这些水团下沉时，它们携带着氧气，这将维持海洋深处的生命，并从大气中清除人为碳，减少温室效应。然后，冷水在深海被输送到低纬度地区，并被从热带输送到上层海洋的暖水（“轻”水）所取代，从而形成一个全球海洋环流，有效地将热量从赤道输送到两极。然而，由于全球变暖，这种环流可能会失去力量。不断上升的海洋温度和融化的冰川、冰帽和冰盖不断涌入的淡水使极地水域的密度降低（因为密度主要取决于温度和盐度），并降低了它们下沉和移动这条“传送带”的可能性。除了可能产生的大规模气候后果外，密度较低的水域还会影响海冰覆盖、海洋生产力和区域尺度上的海洋环流，所有这些都与加拿大北部社区的做法密切相关。此外，随着冰川流量的增加，会形成更多的冰山，直接影响航运和其他近海活动。因此，目前的研究计划建议评估海洋变暖和淡水涌入极地海洋的后果，重点关注北极、巴芬湾、哈德逊湾、加拿大北极群岛和北大西洋亚极地。与我的HQP一起，我们将使用计算机模型，结合实地观测，了解海洋环流的变化、海冰覆盖、冰山的存在、海洋生物的营养可用性以及加拿大北部和东部大气中的碳封存。通过提高对气候变化对极地海洋的影响及其对气候的反应的认识，该项目将帮助依赖狩猎和捕鱼的北方社区、依赖海洋运输的经济和军事活动，以及通过改进对近期海洋状况的预测来制定政策。当我以独立研究者的身份开始我的职业生涯时，我不仅会努力发展优秀的科学，而且会帮助培养高素质的科学家和人类。除了科学培训，我将引导我的HQP建立一个尊重的工作场所，在那里多样性不仅被接受，而且被庆祝。外联也将在我的研究计划中发挥重要作用，让来自不同背景的孩子接触海洋科学领域，并表明任何人都可以成为科学家。

The Polar regions are key to Earth's climate system. Firstly, they are very sensitive to climate change. The Arctic, for example, has warmed twice as rapidly as the rest of the world in the past decades. Secondly, Polar areas stage ocean convection, a process where waters get very dense ("heavy") due to heat loss and sink to the deep ocean. When these water masses sink, they carry with them oxygen that will sustain life in the deeper parts of the ocean, and remove anthropogenic carbon from the atmosphere, reducing the greenhouse effect. The cold waters are then exported at depth to lower latitudes and are replaced by warm ("light") waters transported in the upper ocean from the tropics, creating a global ocean circulation that effectively transports heat from the equator to the Poles. This circulation, however, might lose its strength due to global warming. Rising ocean temperatures and constant influx of freshwater from melting glaciers, ice caps, and ice sheets make Polar waters less dense (since density depends mainly on temperature and salinity), and reduce their potential to sink and move this "conveyor belt". Besides the large-scale climatic consequences this might have, less dense waters also affect sea ice cover, marine productivity, and ocean circulation at regional scales, all of which are intimately connected to Northern Canadian communities' practices. Moreover, as glaciers increase their discharge, more icebergs are formed, directly impacting navigation and other offshore activities. Therefore, the present research program proposes to assess the consequences of ocean warming and freshwater influx to the Polar oceans, with focus on the Arctic, Baffin Bay, Hudson Bay, Canadian Arctic Archipelago, and the Subpolar North Atlantic. Together with my HQP, we will use computer models, combined with field observations, to understand changes in ocean circulation, sea ice cover, presence of icebergs, nutrient availability for marine life and carbon sequestering from the atmosphere to the north and east of Canada. By improving the understanding of the impacts of climate change in Polar oceans and their response back to climate, this program will help Northern communities that rely on hunting and fishing, economic and military activities that depend on marine transportation, and policy-making by improving predictions of the ocean state in the near future. As I start my career as an independent researcher, I will strive not only to develop excellent science but to help forming highly-qualified scientists and human beings. Besides scientific training, I will guide my HQP towards a respectful workplace, where diversity is not only accepted but celebrated. Outreach will also play an important role in my research program, exposing children from a diverse background to the field of ocean sciences and showing that anyone can be a scientist.