Mackenzie Delta river-ice breakup

淡水冰是北方河流的组成部分，也是相关生物、化学和物理过程的重要调节器。尽管人们对气候变化对冰盖系统的潜在影响表示了许多担忧，但我们的知识基础仍然相对薄弱，因此很难预测气候变化对冰盖系统影响的性质和程度。此外，即使是关于加拿大北部河冰系统的基本信息，也一直是正确评估开发的潜在环境影响的一个问题。包括麦肯齐河沿岸的石油和天然气开发，以及最近直接在麦肯齐河三角洲内的石油和天然气开发。尽管众所周知，河冰破裂是该三角洲一年中主要的水文事件，对其生态健康至关重要，但缺乏关于气候变化如何控制此类事件的时间、严重性和三角洲内空间维度的信息。此外，几乎没有人知道未来气候将产生什么影响。这个项目专注于填补我们一些最重要的知识空白，目标如下：i.量化麦肯齐河三角洲内河冰破裂的详细时空变化；二、确定破裂事件对三角洲内开阔水域条件下产生的年度径流事件的重要性，以震级和重复间隔来衡量；量化河冰破裂时间和严重程度的时间变化与影响驱动力(例如洪水)的主要水文和气候条件以及抵抗破裂的因素(例如冰厚度和机械强度)之间的关系。将主要控制水文气候条件与大气环流模式联系起来。拟议研究的相关长期目标是预测气候变化引起的主要温度和降水模式的改变将如何影响极端分裂事件的时间和规模。

Freshwater ice is an integral component of northern rivers and an important modifier of related biological, chemical and physical processes.   Although many concerns have been expressed about the potential impacts of climate change on ice-covered systems, our knowledge base remains relatively weak thereby making it difficult to predict the nature and magnitude of the effects of a changing climate on ice-covered systems.   Moreover, even basic information on river-ice systems in northern Canada has been a problem for proper assessment of the potential environmental impact of development, including  oil and gas development along the Mackenzie River and most recently directly within the Mackenzie River Delta.  Although river-ice breakup is known to create the dominant hydrologic event of the year in the Delta and is essential to its ecological health, there is a lack of information about how variations in climate have controlled the timing, severity and intra-delta spatial dimensions of such events.  Moreover, little is know what effects future climate will produce.This project focuses on filling some of our most important knowledge gaps with the following objectives:i. quantify the detailed spatial and temporal variations in river ice breakup within the Mackenzie River Delta;ii. establish the significance of breakup events, as measured by magnitude and recurrence interval, to annual flow events produced under open-water conditions within the delta;iii. quantify the relationship between temporal changes in river-ice breakup timing and severity with major controlling hydrologic and climatic conditions that affect the forces driving breakup (e.g., flood wave) and factors resisting breakup (e.g., ice thickness and mechanical strength), andiv. relate the major controlling hydro-climatic conditions to atmospheric circulation patterns.The related long-term objective of the proposed research is to predict how the timing and magnitude of extreme breakup events will be affected by climate-change induced modifications of major temperature and precipitation patterns.