Land-climate interactions and feedbacks in high-latitude regions

加拿大的高纬度地区有无数的湖泊、湿地、河流和永久冻土，它们与大气的复杂相互作用给气候建模者带来了重大挑战。这些相互作用虽然重要，但由于相关观测的稀缺性以及潜在过程和反馈的复杂性，很难进行调查。拟议的研究计划的中心目标是通过区域气候模式和现有观测的数值实验，提高对高纬度陆地-气候相互作用和反馈的认识。将处理的主要问题包括不断变化的冰冻圈要素的影响，如永久冻土、热岩溶湖、积雪和湖冰对陆地-气候相互作用的影响以及从当前气候到未来气候的反馈，泥炭地在调节永久冻土演变中的作用，地下水-气候相互作用的重要性以及陆地-大气反馈在调节加拿大各地极端温度和降水事件中的作用，到目前为止还没有被广泛研究。大气和下垫面之间的相互作用很重要，决定着许多近地面场的演变。研究结果将很容易转移到区域气候模型的实际应用中，从而支持对加拿大和北极地区的地表和次地表气候过程进行更加实际的模拟，并可应用于气候变化评估研究，为政府和商业机构提供对广泛时间范围内未来气候条件的最准确预测。这将产生一个坚实的平台，加拿大的省和联邦政府可以在这个平台上规划未来的气候变化。

The Canadian high-latitude regions, with their innumerable lakes, wetlands, rivers and permafrost, and their complex interactions with the atmosphere offer significant challenges to climate modellers. These interactions, though important, are difficult to investigate due to the scarcity of relevant observations and the complexity of underlying processes and feedbacks. The central aim of the proposed research program is to improve understanding of the high-latitude land-climate interactions and feedbacks through numerical experiments with a regional climate model and available observations. The main questions that will be addressed include the impact of changing cryospheric elements such as permafrost, thermokarst lakes, snow cover and lake-ice on land-climate interactions and feedbacks from current to future climate, role of peatlands in modulating permafrost evolution, importance of groundwater-climate interactions and the role of land-atmosphere feedbacks in modulating extreme temperature and precipitation events across Canada, which have not been investigated extensively so far. Interactions between the atmosphere and the underlying surface are important and determine the evolution of many near-surface fields. The results of the research will be readily transferable for their operational implementation in regional climate models, which will then support more physically realistic simulations of surface and sub-surface climate processes over Canada and the Arctic region and can be applied in climate-change assessment studies to provide government and commercial agencies with the most accurate projections of future climate conditions, at a wide range of temporal horizons. This will yield a solid platform on which Canada's provincial and federal governments can plan for future climate change.