WINTER PRECIPITATION TYPES AND THEIR OCCURRENCE

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，这通常与冰丸有关。这种降水造成的结冰会导致灾难性的后果，比如2013年12月在多伦多发生的情况。关于这种降水，我们仍有许多不确定因素，从对其基本特征和驱动机制的理解差距，到我们监测和预测其未来发生的能力。我整个研究计划的这个组成部分的目标是更好地理解冻雨/冰丸，并通过对四个子目标的检查来应用这一见解。该研究将成为1名博士生、3名硕士生和5名本科生的研究重点。******降水的特征将通过实际观测和模式模拟来研究。将特别注意在马尼托巴大学（温尼伯）和丘吉尔，马尼托巴（加拿大西部的冰冻降水之都）记录冰球的特征，并将模拟聚集的冰球的形成，以评估它们通过收集空中过冷滴来减少冻雨的作用。******将使用观测和模式信息对三个地点导致冻雨/冰球的风暴条件进行对比和合成。发生在温尼伯和丘吉尔的事件将与影响多伦多的主要冻雨事件（包括2013年12月的事件）一起进行调查。此外，还将检查初生冰粒的下落轨迹，以确定在没有具有冻结层的垂直温度剖面的情况下，何种地形和锋面环流以及温度场允许产生冻雨。******冻雨/冰丸发生的趋势和可变性将利用业务地面和探空信息进行研究，但也将纳入对降水形成机制的见解。一个关键问题是将这些问题与气候变化联系起来，这将考虑到温带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。******从前三项活动中获得的见解将应用于地面监测和遥感监测、危险结冰情况的预测以及对我们不断变化的气候的未来状况的预测。******总的来说，我的研究计划中这个组成部分的冻雨/冰颗粒重点增强了我们对这种降水的形成，检测和发生的理解。这些知识有助于改进监测和预测，从而减少发生灾害的可能性。通过这项研究培训的学生将拥有从降水科学到其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

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.**