WINTER PRECIPITATION TYPES AND THEIR OCCURRENCE

冬季降水类型及其发生情况

• 批准号: RGPIN-2016-06044
• 负责人: Stewart, Ronald
• 金额: $ 3.5万
• 依托单位: University of Manitoba
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2020
• 资助国家: 加拿大
• 起止时间: 2020-01-01 至 2021-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=709798
• 关键词: WINTER; PRECIPITATION; TYPES; THEIR; OCCURRENCE

Precipitation affects us all and this research focuses on one of its aspects, freezing rain which is often associated with ice pellets. The icing from this precipitation can lead to catastrophic consequences, such as during December 2013 in Toronto. We still have many uncertainties about such precipitation ranging from gaps in understanding its fundamental features and driving mechanisms to our ability to monitor it and to anticipate its future occurrence. The objective of this component of my overall research program is to better understand freezing rain/ice pellets and to apply this insight through an examination of four sub-objectives. The research will be the focus for 1 PhD student, 3 MSc students, and 5 undergraduate students. The features of the precipitation will be studied using hands on' observations and model simulations. Special attention will be paid to documenting ice pellet features at the University of Manitoba (Winnipeg) and Churchill, Manitoba (western Canada's freezing precipitation capital) and the formation of aggregated ice pellets will be modelled to assess their role in reducing freezing rain through collection of supercooled drops aloft. Storm conditions leading to freezing rain/ice pellets in three locations will be contrasted and synthesized using observational and model information. Events occurring over Winnipeg and Churchill will be investigated collectively with major freezing rain events affecting Toronto (including the December 2013 event). As well, the trajectories of falling, initial ice particles will be examined to determine what orographic and frontal circulations and temperature fields allow freezing rain to be produced without a vertical temperature profile having an above-freezing layer. Trends and variability in the occurrence of the freezing rain/ice pellets will be examined using operational surface and sounding information but also incorporating insight on precipitation formation mechanisms. A key issue is linking such issues with the changing climate and this will consider the tendency of extratropical systems to be moving slower over the Canadian Prairies and the impact of nearby lake/ocean ice cover variations. Insight from the preceding three activities will be applied to monitoring at the surface and through remote sensing, to the prediction of hazardous icing conditions, and to projections of future conditions in our changing climate. Overall, the freezing rain/ice pellet focus of this component of my research program enhances our understanding of the formation, detection and occurrence of this precipitation. This knowledge contributes to improved monitoring and prediction that reduce the likelihood of disasters. Students trained through this research will have expertise from precipitation science to its future occurrence so this next generation will be able to tackle the many future precipitation-related challenges.

降水影响我们所有人，这项研究集中在它的一个方面，冻雨，它经常与冰球联系在一起。这种降水的结冰可能会导致灾难性的后果，比如2013年12月的多伦多。关于这种降水，我们仍然有许多不确定因素，从对其基本特征和驱动机制的了解差距，到我们监测它并预测其未来发生的能力。我整个研究计划的这一部分的目标是更好地了解冻雨/冰球，并通过检查四个子目标来应用这一见解。这项研究的重点是1名博士生、3名硕士研究生和5名本科生。 将利用实际观测和模式模拟来研究降水的特征。将特别注意记录马尼托巴大学(温尼伯)和马尼托巴省丘吉尔(加拿大西部的冰冻降水之都)的冰球特征，并将对聚集的冰球的形成进行模拟，以评估它们通过收集高空过冷液滴减少冻雨的作用。 将利用观测和模式信息对比和综合三个地点导致冻雨/冰球的风暴条件。温尼伯和丘吉尔发生的事件将被集体调查，影响多伦多的主要冻雨事件(包括2013年12月的事件)。此外，还将检查下落的初始冰粒的轨迹，以确定在没有高于冰冻层的垂直温度分布的情况下，什么样的地形和锋面环流和温度场允许产生冻雨。 将利用业务面和探空信息，并结合对降水形成机制的洞察，审查冻雨/冰球发生的趋势和可变性。一个关键问题是将这些问题与不断变化的气候联系起来，这将考虑温带系统在加拿大草原上移动速度变慢的趋势以及附近湖泊/海洋冰盖变化的影响。 从上述三项活动中得到的见解将用于地面监测和通过遥感，预测危险的结冰情况，以及预测我们不断变化的气候中的未来情况。 总体而言，我的研究计划中这一部分的冻雨/冰球重点增强了我们对这种降水的形成、探测和发生的理解。这一知识有助于改进监测和预测，从而降低发生灾害的可能性。通过这项研究培训的学生将拥有从降水科学到未来发生的专业知识，因此下一代将能够应对未来与降水有关的许多挑战。