Monthly air temperatures, snow density and snow and ice thickness at Malcolm Ramsay Lake, North America

In northern regions where observational data is sparse, lake ice models are ideal tools as they can provide valuable information on ice cover regimes. The Canadian Lake Ice Model was used to simulate ice cover for a lake near Churchill, Manitoba, Canada throughout the 2008/2009 and 2009/2010 ice covered seasons. To validate and improve the model results, in situ measurements of the ice cover through both seasons were obtained using an upward-looking sonar device Shallow Water Ice Profiler (SWIP) installed on the bottom of the lake. The SWIP identified the ice-on/off dates as well as collected ice thickness measurements. In addition, a digital camera was installed on shore to capture images of the ice cover through the seasons and field measurements were obtained of snow depth on the ice, and both the thickness of snow ice (if present) and total ice cover. Altering the amounts of snow cover on the ice surface to represent potential snow redistribution affected simulated freeze-up dates by a maximum of 22 days and break-up dates by a maximum of 12 days, highlighting the importance of accurately representing the snowpack for lake ice modelling. The late season ice thickness tended to be under estimated by the simulations with break-up occurring too early, however, the evolution of the ice cover was simulated to fall between the range of the full snow and no snow scenario, with the thickness being dependant on the amount of snow cover on the ice surface.在观测数据稀缺的北部地区，湖冰模型（lake ice models）是理想的研究工具，可提供关于冰盖情势的宝贵信息。本研究采用加拿大湖冰模型，对加拿大马尼托巴省丘吉尔附近一处湖泊在2008/2009和2009/2010两个冰期的冰盖过程进行了模拟。为验证并优化模型模拟结果，研究团队通过安装于湖底的向上观测型浅水冰剖面仪（Shallow Water Ice Profiler, SWIP），在两个冰期内获取了冰盖的原位测量数据，该设备可识别封冻与解冻日期，并采集冰厚度相关测量值。此外，研究人员在湖岸架设了数码相机以记录整个冰期内的冰盖影像，同时开展野外实地测量，获取冰面积雪深度、雪冰（若存在）厚度及总冰盖厚度等数据。调整冰面积雪量以模拟潜在的积雪再分布过程后，模型模拟的封冻日期最大偏差可达22天，解冻日期最大偏差可达12天，这凸显了在湖冰模拟中准确表征积雪覆盖状态的重要性。模拟结果往往低估了季末冰厚，且解冻时间偏早，但冰盖的演化过程被限定在全积雪与无积雪两种情景的区间范围内，冰厚变化与冰面积雪量呈直接依赖关系。