Error induced by neglecting subgrid chemical segregation due to inefficient turbulent mixing in regional chemical-transport models in urban environments

doi:10.5194/acp-2020-545

GSTDTAP > 地球科学

DOI	10.5194/acp-2020-545
	Error induced by neglecting subgrid chemical segregation due to inefficient turbulent mixing in regional chemical-transport models in urban environments
	Cathy W. Y. Li, Guy P. Brasseur, Hauke Schmidt, and Juan Pedro Mellado
	2020-07-24
发表期刊	Atmospheric Chemistry and Physics
出版年	2020
英文摘要	We employed direct numerical simulations to estimate the error on chemical calculation in simulations with regional chemical-transport models induced by neglecting subgrid chemical segregation due to inefficient turbulent mixing in an urban boundary layer with strong and heterogeneously-distributed surface emissions. In simulations of initially-segregated reactive species with an entrainment-emission configuration with an A–B–C second-order chemical scheme, urban surface emission fluxes of the homogeneously-emitted Tracer A result in a very large segregation between the tracers and hence a very large overestimation of the effective chemical reaction rate in a complete-mixing model. This large effect can be indicated by a large Damköhler number (Da) of the limiting reactant. With heterogeneous surface emissions of the two reactants, the resultant normalised boundary layer-averaged effective chemical reaction rate is found to be in a Gaussian function of Da, and is increasingly overestimated by the imposed rate with an increased horizontal scale of emission heterogeneity. Coarse-grid models with resolutions commensurable to regional models give reduced yet still significant errors for all simulations with homogeneous emissions. Such model improvement is more sensitive to the increased vertical resolution. However, such improvement cannot be seen for simulations with heterogeneous emissions when the horizontal resolution of the model cannot resolve emission heterogeneity. This work highlights particular conditions in which the ability to resolve chemical segregation is especially important when modelling urban environments.
领域	地球科学
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文献类型	期刊论文
条目标识符	http://119.78.100.173/C666/handle/2XK7JSWQ/286674
专题	地球科学
推荐引用方式 GB/T 7714	Cathy W. Y. Li, Guy P. Brasseur, Hauke Schmidt, and Juan Pedro Mellado. Error induced by neglecting subgrid chemical segregation due to inefficient turbulent mixing in regional chemical-transport models in urban environments[J]. Atmospheric Chemistry and Physics,2020.
APA	Cathy W. Y. Li, Guy P. Brasseur, Hauke Schmidt, and Juan Pedro Mellado.(2020).Error induced by neglecting subgrid chemical segregation due to inefficient turbulent mixing in regional chemical-transport models in urban environments.Atmospheric Chemistry and Physics.
MLA	Cathy W. Y. Li, Guy P. Brasseur, Hauke Schmidt, and Juan Pedro Mellado."Error induced by neglecting subgrid chemical segregation due to inefficient turbulent mixing in regional chemical-transport models in urban environments".Atmospheric Chemistry and Physics (2020).