Land-ocean-climate interactions in high northern latitudes

该研究项目涉及地质档案中记录的北方半球高纬度地区的晚新生代至近期气候变化。它解决了关于陆地-海洋-气候相互作用的三个互补问题。一个是亚北极太平洋、北极和北大西洋海洋之间的大规模交换，这种交换对淡水收支产生重要作用，从而影响盐度、水团分层、海冰以及通过海洋环流进行的热量重新分配。第二个重点是陆表环境，在陆地和海洋之间的过渡，陆地淡水排放影响水文条件。第三部分涉及季节性，季节性是气候的一个关键组成部分，也取决于海洋环境中水体的盐度和分层。 长期目标是了解和评估淡水在高纬度气候系统中从半球到区域范围的作用，而短期目标则以更具体的时间和空间为重点。在半球尺度上，它们包括：（1）北极西部海洋环境的重建（楚科奇海、白令海），其中来自北太平洋的淡水和营养物质输入对海冰和生产力起决定性作用，（2）阐明北极海冰变化模式与亚北极大西洋和太平洋交换之间的关系，（3）通过弗拉姆海峡和加拿大北极群岛的北冰洋外流对北大西洋北方海洋学的相对影响。在陆缘环境的区域尺度上，它们包括：（4）记录沿着格陵兰边缘的海洋和大陆冰稳定性或融化之间的相互作用;（5）重建沿着加拿大北方和东部边缘的气候和水文变化，特别是育空地区、哈德逊湾、拉布拉多大陆架和圣劳伦斯湾的海岸。 该研究计划主要依靠在国际合作框架内收集的海洋沉积物岩心。它是建立在过去几十年来开发的方法，但仍在进步。它们将微古生物学、地球化学和同位素代用指标联合收割机结合起来，同时重建气候、海面和深海条件的互补参数。 作为研究计划的一部分进行的项目涉及研究生的参与，并在国际倡议的框架内进行协调，将代用古气候和古生态数据采集/汇编与气候建模工作相结合。除了发展有关陆地-海洋-气候相互作用的基本知识，从千年到持续的“全球变化”尺度，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.