Fundamentals of winter precipitation: theory and measurements

冬季降水的基础知识：理论和测量

• 批准号: RGPIN-2019-06654
• 负责人: Thériault, Julie
• 金额: $ 2.62万
• 依托单位: Université du Québec à Montréal
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=765321
• 关键词: Fundamentals; winter; precipitation; theory; measurements

Near-freezing temperatures and a mixture of precipitation types such as snow, freezing rain and wet snow are often linked to cold season high-impact events. One example is the 1998 Ice Storm where up to 100 mm accumulated at the surface. The difficulty in both their simulation and their detection arises because the precipitation types reaching the surface depend on the atmospheric conditions and they can be formed of liquid, solid or a mixture. The long-term objective is to improve the fundamental representation of winter precipitation type formation into models, including their detailed characteristics, as well as their interactions with other particles and the environment. This research program will fund 11 highly qualified personals (HQPs). They will use a combination of numerical experiments using high-resolution atmospheric models, field measurements and theoretical approaches to address the following three key issues. First, the key formation processes will be studied theoretically and by using well-observed storms. In particular, the processes leading to the freezing of falling precipitation particles will be investigated to differentiate between ice pellets and freezing rain. Second, the detailed characteristics of precipitation particles in various regions of Canada will be assessed using information on the particles' sizes and fall speeds measured in the field by an optical detector of precipitation particles. Long-term datasets will be analysed to compare the characteristic of the particles in different climatic regions of Canada (ex: Alberta and southern Québec). This information will be used to determine the performance of automatic snow gauges. Third, the precipitation type characteristics in the context of climate change over southern Québec will be evaluated. Targeted high-resolution climate simulations, which include the formation of freezing rain, will be conducted. Threshold values of the precipitation particle characteristics such as their sizes and falls peed will be assessed and linked to the storms atmospheric conditions. Overall, the issue of winter precipitation is of major importance to Canada where winter storms are often experienced across the country. Precipitation is one of the most important factors as the specific type of precipitation and intensity can have catastrophic consequences on the environment and on infrastructures. Each weather event contributes to the regional climatology, hence, further investigation on winter storms and associated precipitation will be a key step to bridge the gap with climate studies and better anticipate their changes in the future. The outcome of this research program will serve to a broad community such as hydrology, policy makers for risk assessment, and the private sector, in particular electrical utilities, to develop mitigation plan.

接近冰点的温度和降雪、冻雨和湿雪等混合降水通常与寒冷季节的高影响事件有关，其中一个例子是 1998 年的冰暴，其中地表积雪量高达 100 毫米。它们的模拟和检测之所以出现，是因为到达地表的降水类型取决于大气条件，并且它们可以由液体、固体或混合物形成。长期目标是将冬季降水类型形成的基本表示改进为模型。 ，包括它们的详细特征，如该研究项目将资助 11 名高素质人员 (HQP)，他们将利用高分辨率大气模型、现场测量和理论方法进行数值实验来解决以下三个关键问题。首先，将从理论上研究关键的形成过程，特别是，将研究导致降落的降水颗粒冻结的过程，以区分冰粒和冻雨。加拿大各地区降水颗粒物将使用降水颗粒光学探测器在现场测量的颗粒尺寸和下落速度信息进行评估，并将分析长期数据集，以比较加拿大不同气候地区（例如：阿尔伯塔省和阿尔伯塔省）的颗粒特征。第三，将评估魁北克南部气候变化背景下的降水类型特征，其中包括冰冻的形成。将评估降水颗粒特征（例如其大小和降落速度）的阈值，并将其与风暴大气条件联系起来。总体而言，冬季降水问题对于冬季风暴多发的加拿大至关重要。全国各地经常经历的降水是最重要的因素之一，因为特定类型的降水和强度可能对环境和基础设施造成灾难性后果，因此需要对冬季风暴和基础设施进行进一步调查。相关降水将是弥合气候研究差距并更好地预测未来变化的关键一步，该研究计划的成果将为水文学、风险评估决策者和私营部门（特别是电力部门）等广泛社区服务。公用事业公司，制定缓解计划。