Land-ocean-climate interactions in high northern latitudes

该研究项目涉及地质档案中记录的北半球高纬度地区晚新生代至最近的气候变化。它解决了关于陆地-海洋-气候相互作用的三个互补问题。一个是关于亚北极太平洋、北冰洋和北大西洋之间的大规模交换，这些交换对淡水收支起着重要作用，因此盐度、水团分层、海冰和通过海洋环流进行的热量再分配。第二个重点是在陆地和海洋之间过渡的陆缘环境，在那里陆地淡水排放影响水文条件。第三个问题涉及季节性，这是气候的一个关键组成部分，也取决于海洋环境中水团的盐度和分层。 长期目标是了解和评估淡水在从半球到区域范围的高纬度气候系统中的作用，而短期目标则有更具体的时间和空间重点。在半球一级，这些活动包括：(1)重建北极西部(楚科奇、白令海)的海洋环境，来自北太平洋的淡水和营养物质输入是海冰和生产力的决定因素；(2)阐明北冰洋海冰变化模式与北冰洋次北极大西洋和太平洋交换之间的关系；(3)评估通过弗拉姆海峡与加拿大北极群岛流出的北冰洋对北大西洋北部海洋学的相对影响。在区域陆缘环境范围内，这些活动包括：(4)记录格陵兰边缘海洋和大陆冰稳定或融化之间的相互作用；(5)重建加拿大北部和东部边缘，特别是育空、哈德逊湾、拉布拉多大陆架和圣劳伦斯湾沿岸的气候和水文变化。 该研究计划主要依赖于获取在国际合作框架内收集的海洋沉积物岩心。它是从过去几十年发展起来的方法建立起来的，但仍在进步中。它们结合了微古生物、地球化学和同位素指标，同时重建了气候、海面和深海条件的互补参数。 作为研究方案的一部分，开展的项目涉及研究生的参与，并在将代理古气候和古生态数据获取/汇编与气候建模工作相结合的国际倡议框架内进行协调。除了发展千年尺度的陆地-海洋-气候相互作用的基本知识外，该研究计划的成果还包括开发环境问题评估工具。

The research program deals with late Cenozoic to recent climate changes at high latitudes of the Northern Hemisphere, as recorded in geological archives. It addresses three complementary questions about land-ocean-climate interactions. One concerns the large-scale exchanges between the subarctic Pacific, Arctic and North Atlantic oceans that exert an important role on the freshwater budget, thus salinity, water mass stratification, sea ice, and heat redistribution through ocean circulation. The second focuses on epicontinental environments, at the transition between land and ocean, where terrestrial freshwater discharge impacts hydrographic conditions. The third deals with seasonality, which is a critical component of climate that also depends upon salinity and stratification of water masses in marine environments. The long-term objective is the understanding and assessment of the role of freshwater in the climate system at high latitudes, from hemispheric to regional scales, while short-term objectives are defined with more specific temporal and spatial foci. At hemispheric scale, they include (1) the reconstruction of marine environments in the western Arctic (Chukchi, Bering seas) where freshwater and nutrient inputs from the North Pacific are determinant on sea ice and productivity, (2) the elucidation of the relationships between the modes of Arctic sea ice variability vs the exchanges with the subarctic Atlantic and Pacific seas, and (3) the evaluation of the relative impacts of Arctic Ocean outflows through Fram Strait vs the Canadian Arctic Archipelago, on the northern North Atlantic oceanography. At the regional scale of epicontinental settings, they include (4) the documenting of interactions between ocean and continental ice stability or melting along the Greenland margins, and (5) the reconstruction of climate and hydrography variabilities along the northern and eastern margins of Canada, in particular the coasts of Yukon, Hudson Bay, Labrador shelf and the Gulf of St. Lawrence. The research program mostly relies on access to marine sediment cores collected within the framework of international collaborations. It is built from methodologies developed over the last decades, but still in progress. They combine micropaleontological, geochemical and isotopic proxies to simultaneously reconstruct complementary parameters of climate, sea surface and deep marine conditions. The projects conducted as part of the research program involve participation of graduate students and are coordinated within the framework of international initiatives combining proxy paleoclimate and paleoecological data acquisition/compilation with climate modelling efforts. Beyond the development of fundamental knowledge about land-ocean-climate interactions at millennial to on-going "global changes" scales, the outcomes of the research program also include the development of tools for environmental issue assessments.