气候变化领域集成服务门户(CCPortal): Evaluating the impact of storage-and-release on aircraft-based mass-balance methodology using a regional air-quality model

CCPortal

DOI	10.5194/acp-21-15461-2021
	Evaluating the impact of storage-and-release on aircraft-based mass-balance methodology using a regional air-quality model
	Fathi S.; Gordon M.; Makar P.A.; Akingunola A.; Darlington A.; Liggio J.; Hayden K.; Li S.-M.
发表日期	2021
ISSN	1680-7316
起始页码	15461
结束页码	15491
卷号	21 期号:20
英文摘要	We investigate the potential for aircraft-based top-down emission rate retrieval over- and under-estimation using a regional chemical transport model, the Global Environmental Multiscale-Modeling Air-Quality and CHemistry (GEM-MACH). In our investigations we consider the application of the mass-balance approach in the Top-down Emission Rate Retrieval Algorithm (TERRA). Aircraft-based mass-balance retrieval methodologies such as TERRA require relatively constant meteorological conditions and source emission rates to reliably estimate emission rates from aircraft observations. Avoiding cases where meteorology and emission rates change significantly is one means of reducing emissions retrieval uncertainty, and quantitative metrics that may be used for retrieval accuracy estimation are therefore desirable. Using these metrics has the potential to greatly improve emission rate retrieval accuracy. Here, we investigate the impact of meteorological variability on mass-balance emission rate retrieval accuracy by using model-simulated fields as a proxy for real-world chemical and meteorological fields, in which virtual aircraft sampling of the GEM-MACH output was used for top-down mass balance estimates. We also explore the impact of upwind emissions from nearby sources on the accuracy of the retrieved emission rates. This approach allows the state of the atmosphere used for top-down estimates to be characterized in time and 3D space; the input meteorology and emissions are "known", and thus potential means for improving emission rate retrievals and determining the factors affecting retrieval accuracy may be investigated. We found that emissions retrieval accuracy is correlated with three key quantitative criteria, evaluated a priori from forecasts and/or from observations during the sampling period: (1) changes to the atmospheric stability (described as the change in gradient Richardson number), (2) variations in the direction of transport, as a result of plume vertical motion and in the presence of vertical wind shear, and (3) the combined effect of the upwind-to-downwind concentration ratio and the upwind-to-downwind concentration standard deviations. We show here that cases where these criteria indicate high temporal variability and/or high upwind emissions can result in "storage-and-release"events within the sampled region (control volume), which decrease emission rate retrieval accuracy. Storage-and-release events may contribute the bulk of mass-balance emission rate retrieval under- and over-estimates, ranging in the tests carried out here from -25ĝ€¯% to 24ĝ€¯% of the known (input) emissions, with a median of -2ĝ€¯%. Our analysis also includes two cases with unsuitable meteorological conditions and/or significant upwind emissions to demonstrate conditions which may result in severe storage, which in turn cause emission rate under-estimates by the mass-balance approach. We also introduce a sampling strategy whereby the emission rate retrieval under- and over-estimates associated with storage-and-release are greatly reduced (to -14ĝ€¯% to +5ĝ€¯%, respectively, relative to the magnitude of the known emissions). We recommend repeat flights over a given facility and/or time-consecutive upwind and downwind (remote) vertical profiling of relevant fields (e.g., tracer concentrations) in order to measure and account for the factors associated with storage-and-release events, estimate the temporal trends in the evolution of the system during the flight/sampling time, and partially correct for the effects of meteorological variability and upwind emissions. © 2021 Sepehr Fathi et al.
语种	英语
scopus关键词	air quality; algorithm; atmospheric chemistry; carbon emission; chemical composition; computer simulation; mass balance; three-dimensional modeling; trace element
来源期刊	ATMOSPHERIC CHEMISTRY AND PHYSICS
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/246496
作者单位	Air Quality Research Division, Environment and Climate Change Canada, Toronto, Canada; Physics and Astronomy, York University, Toronto, Canada; Earth and Space Science, York University, Toronto, Canada; College of Environmental Science and Engineering, Peking University, Beijing, China
推荐引用方式 GB/T 7714	Fathi S.,Gordon M.,Makar P.A.,et al. Evaluating the impact of storage-and-release on aircraft-based mass-balance methodology using a regional air-quality model[J],2021,21(20).
APA	Fathi S..,Gordon M..,Makar P.A..,Akingunola A..,Darlington A..,...&Li S.-M..(2021).Evaluating the impact of storage-and-release on aircraft-based mass-balance methodology using a regional air-quality model.ATMOSPHERIC CHEMISTRY AND PHYSICS,21(20).
MLA	Fathi S.,et al."Evaluating the impact of storage-and-release on aircraft-based mass-balance methodology using a regional air-quality model".ATMOSPHERIC CHEMISTRY AND PHYSICS 21.20(2021).