Land-climate interactions and feedbacks in high-latitude regions

加拿大高纬度地区拥有数不清的湖泊、湿地、河流和永久冻土，以及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，但由于相关观察的缺乏和潜在过程和反馈的复杂性，很难进行调查。提出的研究计划的中心目标是通过区域气候模式和现有观测资料的数值试验，提高对高纬度陆地-气候相互作用和反馈的认识。将要解决的主要问题包括冻土、热岩溶湖、积雪和湖冰等冰冻圈元素变化对陆地-气候相互作用和从当前到未来气候反馈的影响，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。到目前为止还没有广泛的研究。大气与下垫面之间的相互作用是重要的，它决定了许多近地表场的演变。研究的结果将很容易转移到区域气候模型的操作实施中，这将支持对加拿大和北极地区地表和地下气候过程进行更实际的模拟，并可应用于气候变化评估研究，为政府和商业机构提供在大范围的时间范围内对未来气候条件的最准确预测。这将为加拿大省政府和联邦政府规划未来气候变化提供一个坚实的平台。

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.