Frazil Ice Formation and Evolution

巴西冰粒是一种很小的圆盘状冰晶，一旦水温过冷到零下几度，就会在湍急的河流中形成。巴西冰粒在过冷水中具有很强的粘性，它们很容易相互粘在一起，形成浮力很强的巴西冰粒絮体，这些絮体上升到水面，在那里形成“巴西平底锅”，然后积聚形成一个完整的冰盖。巴西颗粒很容易附着在几乎任何表面，比如取水口上的屏风和垃圾架，切断了市政、工业和发电厂的供水。它还会粘在河床上，形成“锚冰”，这对鱼类非常有害。例如，在小河流中，锚冰可以在一夜之间填满整个河道，抑制幼鱼进入栖息地或阻止埋在河床中的卵的氧气供应。尽管巴西冰对河流的冻结过程及其形成的后果很重要，但人们对它的产生、运输和演变知之甚少。其中一个原因是我们目前无法准确测量河流中悬浮巴西的浓度和大小分布。拟议研究的长期目标是开发准确的方法来监测和预测河流中冰的形成及其随后在冻结期间的运输和演变。我的研究小组开发了一种独特的数字成像系统，设计用于在冻结的河流中部署水下，我们建议使用这项新技术首次精确测量阿尔伯塔三条河流中的冰的性质。我们还建议继续开发一种基于声纳的系统，可用于连续监测河流冰的过程。除此之外，我们将继续在实验室中使用我们独特的巴西冰生成罐来研究巴西冰的特性。我们收集的数据将产生巨大的影响，因为它将使我们和其他人能够严格评估河流冰数值模型的准确性并改进它们。在巴西，冰的形成和演变是冻结期间主要的河流冰过程，因此提高我们对河流冰的准确监测和预测能力将对沿河基础设施的规划设计、建设和运营产生重大影响

Frazil ice particles are small, disc-shaped ice crystals that form in turbulent rivers once the water temperature has supercooled to a few hundredths of a degree below zero. Frazil ice particles are very adhesive in supercooled water and they readily stick to each other forming buoyant frazil flocs that rise to the surface where they form `frazil pans' which then accumulate to form a full ice cover. Frazil particles easily adhere to almost any surface, such as screens and trash racks on water intakes, cutting off the water supplies to municipalities, industries, and power plants. It can also stick to the river bed, building up "anchor ice", which can be very harmful to fish. For example, in small rivers, anchor ice can fill up the entire channel in a single night, inhibiting habitat access for juvenile fish or blocking the oxygen supply to eggs buried in the stream bed. Despite the importance of frazil ice to the river freeze-up process and the consequences of its formation, little is known about its generation, transport and evolution. One reason for this is our current inability to accurately measure suspended frazil concentrations and size distributions in rivers. The long-term goal of the proposed research is to develop accurate methods for monitoring and predicting the formation of frazil ice in rivers and its subsequent transport and evolution during freeze-up. My research group has developed a unique digital imaging system that is designed to be deployed underwater in rivers at freeze-up and we propose to use this new technology to make the first accurate measurements of frazil ice properties in three Alberta rivers. We also propose to continue developing a sonar based system that can be used to continuously monitor river ice processes. In addition to this we will continue investigating the properties of frazil ice in the laboratory using our unique frazil ice generation tank. The data that we collect will have a tremendous impact because it will allow us and others to critically assess the accuracy of and improve numerical river ice models. Frazil ice formation and evolution is the dominant river ice process during freeze-up and therefore improving our ability to accurately monitor and predict it in rivers will have a significant impact on the planning design, construction and operation of infrastructure built along rivers.**