Variability and changes in high impact hydrometeorological events

气候变化是一个不可避免的全球现象，将强烈影响加拿大。在加拿大的北极和亚北极地区，与海冰和积雪的区域变化有关的反馈将放大预期的地表变暖，正如过去三十年在加拿大北部和东北部观测到的那样。这些变化还将影响当地和南部偏远地区的高影响天气事件，因为这些天气事件依赖于这些通过气象系统与向极地热输送强烈相互作用的区域反馈。然后，需要在区域尺度上更好地预测变化的气象（基于天气事件的发生、持续时间和强度），以及联合气候变量的相关变化，以提高我们对与大气环流驱动机制相互作用的局地或区域尺度影响之间耦合的理解。事实上，与单变量模拟有关的许多关键过程已被了解，但研究才刚刚开始集中于开发联合或组合变量的预测，特别是在涉及个别数量的极端或变异性时。在这种情况下，研究计划的总体目标是发展关于气候和天气极端事件以及水文气象灾害的新知识，并提高社会管理与这些事件未来变化相关的风险的能力。提出的科学方法将包括：1)配置当前和未来时期具有不同大气和海洋边界条件（来自再分析、全球气候模式、新的海面温度和高分辨率海冰产品）的新的区域气候模式运行；2)开发新的诊断变量和多变量标准。拟议研究的独创性和创新方面将是：1)改进我们目前对大尺度大气环流变率与区域地表条件变化之间的复杂联系的理解，以及它们对加拿大关键地区发生高影响风暴和极端事件的影响；2)根据大气变量对人类健康和自然或受扰动生态系统的特殊影响来定义综合大气变量；3)开发新的和定向的极端和水文气象灾害的区域尺度情景，用于加拿大各地的适应战略。***拟议的研究将有助于培养hqp（3名硕士，2名博士和2名博士后），以支持加拿大了解气候/天气极端事件或水文气象灾害如何影响加拿大的人类，社会经济和自然系统。这也将有助于利益攸关方和公共机构开发早期预警系统，减少因预期的恶劣天气条件造成的伤害，从而有助于降低风险

Climate change is an unavoidable global phenomenon that will strongly affect Canada. Over Arctic and subarctic regions of Canada, feedbacks associated with regional changes in sea-ice and snow cover will amplify anticipated surface warming, as observed over the last three decades in northern and northeastern Canada. These changes will also affect high impact weather events, locally and over remote southern regions, as those depend on these regional feedbacks that strongly interact with poleward heat transports through meteorological systems. Then, better projections of the changing meteorology (based on occurrence, duration and intensity of weather events) at regional scales are needed, as well as pertinent changes in joint climatic variables to improve our understanding on the coupling between local or regional-scale influences that interact with atmospheric circulation driven mechanisms. In fact, many of the key processes relevant to the simulation of single variables are understood, but studies are only starting to focus on developing projections of joint or combined variables, especially when extremes or variability in the individual quantities are concerned.***In this context, the overall objective of the research program is to develop new knowledge on climate and weather extremes and hydro-meteorological hazards, and to improve society's ability to manage risks associated with future changes of these events. The proposed scientific approach will consist to 1) configure new Regional Climate Models' runs with various atmospheric and oceanic boundary conditions (from reanalysis, global climate models, and new sea surface temperatures and sea-ice products available at high resolution) over current and future periods, and 2) develop new diagnostic variables and multivariate criteria. The originality and innovative aspects of the proposed research will be to 1) improve our current understanding on the complex links between the large-scale atmospheric circulation variability and the changes in regional surface conditions and their effects on the occurrence of high impact storms and of extreme events over key Canadian areas, 2) define combined atmospheric variables based on their particular impacts on human health and natural or perturbed ecosystems, and 3) develop new and oriented regional scale scenarios of extremes and hydro-meteorological hazards, for their uses in adaptation strategies across Canada.***The proposed research will contribute to train HQPs (3 Msc, 2 PhDs and 2 Post-Doctoral fellows) in order to support Canada's effort to understand how climate/weather extremes or hydro-meteorological hazards will affect Canada's human, socio-economic and natural systems. This will also help stakeholders and public institutions to develop early warning systems that could reduce injuries due to anticipated severe weather conditions, thus contributing to risk reduction.**