Direct measurement of greenhouse gas exchange in urban ecosystems

直接测量城市生态系统中的温室气体交换

• 批准号: 342029-2012
• 负责人: Christen, Andreas
• 金额: $ 2.33万
• 依托单位: University of British Columbia
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2015
• 资助国家: 加拿大
• 起止时间: 2015-01-01 至 2016-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=572444
• 关键词: Direct; measurement; greenhouse; gas; exchange

This research program will develop methods to measure, quantify and analyze emissions of greenhouse-gases (GHG) in cities. We will directly quantify emissions of carbon-dioxide (CO2), methane (CH4) and nitrous oxide (N2O) at scales of neighborhoods or land-use zones. At those scales, where most planning decisions are made, estimated emissions (from consumption statistics or aggregated by modeling) are associated with large uncertainties. There is a lack of in-situ methods and data to independently validate modelled emissions. We will use (i) mass flux measurements of GHGs on towers above urban surfaces, (ii) sample GHG emissions using closed-chambers over urban green-space, and (iii) use stable isotopes to partition selected emission and concentration measurements. We will quantify the contribution of uncertain diffuse sources (and sinks), in particular exchange by urban soils and vegetation. The program will use an existing 30 m research tower in Vancouver, BC, an existing laser spectroscopy system, and remotely sensed data of surface characteristics to address the following limitations and knowledge gaps: (A) Currently, direct measurements of CO2 emissions are limited to the net-exchange from all sources and sinks in an urban area (i.e. building emissions + transportation emissions + respiration - photosynthesis). Hence, a validation of sector-specific models is not possible. We will use direct flux and concentration measurements of stable isotopologues of CO2 to separate net-exchange into individual emission profiles of various sources (isotopic signatures differ for natural gas, gasoline and respiration). (B) We will quantify whether diffuse GHG sources and sinks related to urban land-use are relevant or not in Canadian cities. Specifically, the IPCC Guidelines for National Greenhouse Gas Inventories identify the lack of a methodology for estimating emissions of CH4 and N2O from settlements as an 'obvious' knowledge gap. We will measure CH4 and N2O emissions (and uptake) caused by primarily land-cover (lawns, soils), but also combustion. We will quantify emissions, attribute sources and determine controls.

该研究计划将开发测量，量化和分析城市温室气体（GHG）排放的方法。我们将直接量化二氧化碳（CO2），甲烷（CH 4）和一氧化二氮（N2 O）在社区或土地使用区的规模排放。在这些规模上，大多数规划决策都是在这些规模上做出的，估计的排放量（来自消费统计或通过建模汇总）与很大的不确定性有关。缺乏现场方法和数据来独立验证模拟排放量。 我们将使用（i）城市表面以上的塔上的温室气体的质量通量测量，（ii）使用城市绿地上的封闭室对温室气体排放进行采样，以及（iii）使用稳定同位素对选定的排放和浓度测量进行分区。我们将量化不确定的扩散源（和汇）的贡献，特别是城市土壤和植被的交换。该方案将利用不列颠哥伦比亚省温哥华现有的一座30米高的研究塔、现有的激光光谱系统和遥感地表特征数据，以解决以下局限性和知识空白： (A)目前，对CO2排放量的直接测量仅限于城市地区所有源和汇的净交换（即建筑物排放量+交通运输排放量+呼吸-光合作用）。因此，不可能验证具体部门的模型。我们将使用稳定的CO2同位素的直接通量和浓度测量，将净交换分离为各种来源的单独排放曲线（天然气，汽油和呼吸的同位素特征不同）。 (B)我们将量化扩散温室气体源和汇相关的城市土地利用是否相关或不在加拿大城市。具体而言，《气专委国家温室气体清单指南》指出，缺乏一种方法来估算住区的甲烷和一氧化二氮排放量，这是一个“明显的”知识差距。我们将测量主要由土地覆盖（草坪，土壤）引起的CH 4和N2 O排放（和吸收），但也包括燃烧。我们将量化排放，确定来源并确定控制措施。