Frazil Ice Formation and Evolution

弗拉齐尔冰的形成和演化

• 批准号: RGPIN-2015-04670
• 负责人: Loewen, Mark
• 金额: $ 2.04万
• 依托单位: University of Alberta
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2019
• 资助国家: 加拿大
• 起止时间: 2019-01-01 至 2020-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=682384
• 关键词: Frazil; Ice; Formation; Evolution

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.**

弗拉齐尔冰粒是小的圆盘状冰晶，一旦水温过冷至零以下百分之几度，就会在湍急的河流中形成。冰晶冰颗粒在过冷水中具有很强的粘性，它们很容易相互粘在一起，形成有浮力的冰晶絮凝物，这些絮凝物上升到表面，形成“冰晶盘”，然后聚集起来形成完整的冰盖。 Frazile 颗粒很容易粘附在几乎任何表面上，例如进水口的滤网和垃圾桶，从而切断市政、工业和发电厂的供水。它还可以粘附在河床上，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，从而阻碍幼鱼进入栖息地或阻止埋在河床中的鱼卵的氧气供应。尽管碎冰对河流冻结过程及其形成的后果非常重要，但人们对其生成、运输和演化知之甚少。造成这种情况的原因之一是我们目前无法准确测量河流中悬浮的巴西石浓度和尺寸分布。该研究的长期目标是开发准确的方法来监测和预测河流中碎冰的形成及其在冻结过程中随后的运输和演化。我的研究小组开发了一种独特的数字成像系统，该系统设计用于在结冰的河流中部署在水下，我们建议使用这项新技术对艾伯塔省三条河流中的碎冰特性进行首次精确测量。我们还建议继续开发基于声纳的系统，可用于连续监测河冰过程。除此之外，我们将继续在实验室中使用我们独特的碎冰生成罐研究碎冰的特性。我们收集的数据将产生巨大影响，因为它将使我们和其他人能够批判性地评估河冰数值模型的准确性并改进数值河冰模型。巴西冰的形成和演变是冻结期间主要的河流冰过程，因此提高我们在河流中准确监测和预测它的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。**