Toward quantification and source sector identification of fossil fuel CO2 emissions from an urban area: Results from the INFLUX experiment
Toward quantification and source sector identification of fossil fuel CO2 emissions from an urban area: Results from the INFLUX experiment
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DOI：
10.1002/2014jd022555
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发表时间：
2015-01
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通讯作者：
J. Turnbull;C. Sweeney;A. Karion;T. Newberger;S. Lehman;P. Tans;K. Davis;T. Lauvaux;N. Miles;S. Richardson;M. Cambaliza;P. Shepson;K. Gurney;R. Patarasuk;I. Razlivanov
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作者：
J. Turnbull;C. Sweeney;A. Karion;T. Newberger;S. Lehman;P. Tans;K. Davis;T. Lauvaux;N. Miles;S. Richardson;M. Cambaliza;P. Shepson;K. Gurney;R. Patarasuk;I. Razlivanov
印第安纳波利斯通量实验 (INFLUX) 旨在开发和评估量化城市温室气体排放的方法。在这里，我们使用美国印第安纳波利斯周围高塔的 CO2、14CO2 和 CO 测量值来确定城市总 CO2、化石燃料衍生的 CO2 成分 (CO2ff) 以及相对于背景测量值的 CO 增强。当使用城市地区正上风向的当地背景时，印第安纳波利斯冬季二氧化碳总量的增加可以完全用城市二氧化碳排放来解释。相反，当使用大陆背景时，CO2ff 增强较大，仅占 CO2 增强总量的一半，有效代表印第安纳波利斯和更广泛地区的 CO2ff 增强的总和。在夏季，我们发现背景二氧化碳摩尔分数和共变垂直混合的日变化使得很难使用简单的迎风-顺风差异来可靠地确定城市二氧化碳总增量。我们使用特征 CO2ff 源部门 CO:CO2ff 排放比来检验 CO2ff 源部门对 CO2ff 总排放量的贡献。这种方法对产生大部分二氧化碳的移动部门非常敏感。我们表明，可以使用这种比率方法在整个昼夜周期中直接比较基于清单的排放产品（“自下而上”）和大气观测（“自上而下”）。对于印第安纳波利斯，自上而下的观测结果与自下而上的 Hestia 数据产品排放扇区模式在大部分昼夜周期内一致，但在夜间时段不一致。需要进一步检查自上而下和自下而上的假设，以评估差异的确切原因。
The Indianapolis Flux Experiment (INFLUX) aims to develop and assess methods for quantifying urban greenhouse gas emissions. Here we use CO2, 14CO2, and CO measurements from tall towers around Indianapolis, USA, to determine urban total CO2, the fossil fuel derived CO2 component (CO2ff), and CO enhancements relative to background measurements. When a local background directly upwind of the urban area is used, the wintertime total CO2 enhancement over Indianapolis can be entirely explained by urban CO2ff emissions. Conversely, when a continental background is used, CO2ff enhancements are larger and account for only half the total CO2 enhancement, effectively representing the combined CO2ff enhancement from Indianapolis and the wider region. In summer, we find that diurnal variability in both background CO2 mole fraction and covarying vertical mixing makes it difficult to use a simple upwind‐downwind difference for a reliable determination of total CO2 urban enhancement. We use characteristic CO2ff source sector CO:CO2ff emission ratios to examine the contribution of the CO2ff source sectors to total CO2ff emissions. This method is strongly sensitive to the mobile sector, which produces most CO. We show that the inventory‐based emission product (“bottom up”) and atmospheric observations (“top down”) can be directly compared throughout the diurnal cycle using this ratio method. For Indianapolis, the top‐down observations are consistent with the bottom‐up Hestia data product emission sector patterns for most of the diurnal cycle but disagree during the nighttime hours. Further examination of both the top‐down and bottom‐up assumptions is needed to assess the exact cause of the discrepancy.