Assessment of uncertainties of an aircraft-based mass balance approach for quantifying urban greenhouse gas emissions
Assessment of uncertainties of an aircraft-based mass balance approach for quantifying urban greenhouse gas emissions
复制标题
DOI：
10.5194/acp-14-9029-2014
复制
发表时间：
2014-01-01
影响因子：
6.3
通讯作者：
Richardson, S. J.
中科院分区：
文献类型：
--
作者：
Cambaliza, M. O. L.;Shepson, P. B.;Richardson, S. J.
城市环境是全球人为碳排放的主要贡献者。由于二氧化碳排放量的增长大部分来自城市，因此有必要开发、评估和改进测量和建模策略，以量化和监测大城市中心的温室气体排放。在这项研究中的不确定性，在飞机为基础的质量平衡的方法来量化二氧化碳和甲烷的排放量从城市环境中，专注于印第安纳州印第安纳波利斯，美国，进行了说明。印第安纳波利斯相对平坦的地形有利于在质量平衡方法中应用平均风场。我们研究了我们的飞机为基础的质量平衡方法的不确定性，（1）评估测量通量的敏感性，重要的测量和分析参数，包括风速，背景CO2和CH4，边界层深度，和插值技术，以及（2）确定距点源或面源两个或多个顺风距离处的通量（具有相对较大的源强度，如固体废物设施和发电站）的快速连续性，假设排放通量是恒定的。当我们量化的精度的方法，通过比较来自测量在两个或两个以上的顺风距离从一个区域或点源的估计排放量，我们发现，最小和最大的可重复性分别为12和52%，平均为31%。我们建议，在实验设计的改进，可以通过仔细确定的背景浓度，监测边界层的演变，通过测量期间，并增加在边界层内的多个高度的顺风水平断面测量的数量。
Urban environments are the primary contributors to global anthropogenic carbon emissions. Because much of the growth in CO2 emissions will originate from cities, there is a need to develop, assess, and improve measurement and modeling strategies for quantifying and monitoring greenhouse gas emissions from large urban centers. In this study the uncertainties in an aircraft-based mass balance approach for quantifying carbon dioxide and methane emissions from an urban environment, focusing on Indianapolis, IN, USA, are described. The relatively level terrain of Indianapolis facilitated the application of mean wind fields in the mass balance approach. We investigate the uncertainties in our aircraft-based mass balance approach by (1) assessing the sensitivity of the measured flux to important measurement and analysis parameters including wind speed, background CO2 and CH4, boundary layer depth, and interpolation technique, and (2) determining the flux at two or more downwind distances from a point or area source (with relatively large source strengths such as solid waste facilities and a power generating station) in rapid succession, assuming that the emission flux is constant. When we quantify the precision in the approach by comparing the estimated emissions derived from measurements at two or more downwind distances from an area or point source, we find that the minimum and maximum repeatability were 12 and 52%, with an average of 31 %. We suggest that improvements in the experimental design can be achieved by careful determination of the background concentration, monitoring the evolution of the boundary layer through the measurement period, and increasing the number of downwind horizontal transect measurements at multiple altitudes within the boundary layer.