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: 2016
• 资助国家: 加拿大
• 起止时间: 2016-01-01 至 2017-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=616069
• 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.

降水影响着我们所有人，这项研究的重点是它的一个方面，冻雨，这往往是与冰球。这种降水的结冰可能导致灾难性的后果，例如2013年12月在多伦多期间。我们对这种降水仍有许多不确定性，从对它的基本特征和驱动机制的理解不足，到我们监测它和预测它未来发生的能力。我的整体研究计划的这一组成部分的目标是更好地了解冻雨/冰球，并通过四个子目标的检查应用这种见解。该研究将是1名博士生，3名硕士生和5名本科生的重点。 降水的特征将使用“动手”观测和模型模拟进行研究。将特别注意记录马尼托巴大学（温尼伯）和丘吉尔，马尼托巴（加拿大西部的冻雨首都）的冰球功能和聚集的冰球的形成将被模拟，以评估其在减少冻雨通过收集高空过冷滴的作用。 将使用观测和模型信息对三个地点导致冻雨/冰球的风暴条件进行对比和综合。发生在温尼伯和丘吉尔的事件将与影响多伦多的重大冻雨事件（包括2013年12月的事件）一起进行调查。此外，下降的轨迹，初始冰粒将被检查，以确定什么地形和锋面环流和温度场允许冻雨产生没有一个垂直的温度分布有一个以上的冻结层。 将利用业务表面和探测信息，同时结合对降水形成机制的认识，对冻雨/冰球发生的趋势和变化进行审查。一个关键的问题是将这些问题与气候变化联系起来，这将考虑到热带风暴系统在加拿大大草原上移动较慢的趋势以及附近湖泊/海洋冰盖变化的影响。 从上述三项活动中获得的见解将用于地面监测和遥感监测，用于预测危险的结冰情况，并用于预测气候变化的未来情况。 总的来说，我的研究计划的这一组成部分的冻雨/冰球的重点增强了我们对这种降水的形成，检测和发生的理解。这种知识有助于改进监测和预测，从而减少灾害发生的可能性。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许多未来与降水相关的挑战。