Interpreting greenhouse gas and air pollution surface measurements to quantify urban emissions

量化和监测城市温室气体(例如二氧化碳、甲烷、一氧化二氮)和空气污染物(例如一氧化碳、氮氧化物、臭氧、气溶胶)的排放，对于核实减排目标的实现和我们的空气质量保持在安全水平至关重要。为了直接从大气测量中量化城市排放，我们需要精确和准确地测量大气气体混合比率和它们混合到的大气高度。这项提案寻求购买微脉冲激光雷达的资金：一种将测量大气混合高度的仪器。到目前为止，我们对现有混合比测量结果的解释以及我们在多伦多产生准确排放值的能力一直受到城市上空混合高度的不确定性的限制。混合高度在昼夜、夏季和冬季之间变化，并随着天气的变化而变化。城市研究的另一个复杂性是城市形态对混合高度的影响，创造了一个比周围地区混合高度更高的“城市穹顶”。因此，所要求的仪器是一个时间分辨的、坚固的、便携的、最先进的系统。它将安装在多伦多大学麦克伦南物理实验室的屋顶上，与现有的痕量气体和气溶胶测量进行连续的并排测量，将定期移动到多伦多各地，以表征其他观测站的混合高度，并驱车穿过城市，准确地定义多伦多的城市穹顶。在大多伦多地区没有现有的仪器可以进行便携式混合层高度测量，因此这些测量将为那些对研究多伦多城市排放感兴趣的人创建一个独特的、非常有价值的数据集。

Quantifying and monitoring urban emissions of greenhouse gases (e.g., carbon dioxide, methane, nitrous oxide) and air pollutants (e.g., carbon monoxide, NOx, ozone, aerosols) is crucial for verifying that emission reduction targets are met and that our air quality remains at safe levels. To quantify urban emissions directly from atmospheric measurements, we require precise and accurate measurements of atmospheric gas mixing ratios and the height of the atmosphere into which they mix. This proposal seeks funds to purchase a micro-pulse LIDAR: an instrument that will measure the atmospheric mixing height. To date, our interpretations of the existing mixing ratio measurements and our ability to produce accurate emission values in Toronto has been limited by uncertainties in the mixing height over the city. The mixing height changes between night and day, summer and winter, and with changing weather. An additional complication for urban studies is the influence of the urban form on the mixing height, creating an “urban dome” with a higher mixing height than the surrounding area. Thus, the requested instrument is a time-resolved, robust, portable, state-of-the-art system. It will be be stationed on the McLennan Physical Laboratories rooftop at the University of Toronto for continuous side-by-side measurements with existing trace gas and aerosol measurements, will be periodically moved throughout Toronto to characterize mixing heights at other observing stations, and driven across the city to accurately define Toronto's urban dome. There is no existing instrumentation in the greater Toronto area that makes portable mixing layer height measurements, and thus these measurements will create a unique and highly valuable dataset for those interested in studying Toronto’s urban emissions.