DOI: 10.1016/j.atmosenv.2013.12.029
Scopus记录号: 2-s2.0-84892468294
论文题名: Diurnal variation of NOx and ozone exchange between a street canyon and the overlying air
作者: Kwak K ; -H ; , Baik J ; -J
刊名: Atmospheric Environment
ISSN: 0168-2563
EISSN: 1573-515X
出版年: 2014
卷: 86 起始页码: 120
结束页码: 128
语种: 英语
英文关键词: CFD model
; Diurnal variation
; NOx removal
; O3 entrainment
; Street canyon
; Surface heating
Scopus关键词: CFD modeling
; Computational fluid dynamics modeling
; Counter-rotating vortices
; Diurnal variation
; Reynolds averaged Navier-Stokes equation
; Street canyon
; Surface heating
; Surface temperatures
; Air entrainment
; Aspect ratio
; Atmospheric temperature
; Buildings
; Chemical reactions
; Computational fluid dynamics
; Computer simulation
; Navier Stokes equations
; Surface properties
; Turbulent flow
; Velocity
; Vortex flow
; Walls (structural partitions)
; nitrogen oxide
; ozone
; computational fluid dynamics
; diurnal variation
; estimation method
; heating
; Navier-Stokes equations
; nitrogen oxides
; numerical model
; ozone
; photochemistry
; pollutant removal
; surface temperature
; turbulent flow
; velocity
; vorticity
; air analysis
; article
; building
; circadian rhythm
; computational fluid dynamics
; dry deposition
; gas exchange
; priority journal
; surface property
; temperature
; turbulent flow
Scopus学科分类: Environmental Science: Water Science and Technology
; Earth and Planetary Sciences: Earth-Surface Processes
; Environmental Science: Environmental Chemistry
英文摘要: The diurnal variation of NOx and O3 exchange between a street canyon and the overlying air in two dimensions is investigated to understand reactive pollutant removal and entrainment across the roof level of the street canyon. The computational fluid dynamics (CFD) model used in this study is a Reynolds-averaged Navier-Stokes equations (RANS) model and includes the urban surface and radiation processes and the comprehensive chemical processes. The CFD model is used for the one-day simulation in which the easterly ambient wind blows perpendicular to the north-south oriented street canyon with a canyon aspect ratio of 1. In the morning when the surface temperature of the downwind building wall is higher than that of the upwind building wall, two counter-rotating vortices appear in the street canyon (flow regime II). In the afternoon when the surface temperature of the upwind building wall is higher than that of the downwind building wall, an intensified primary vortex appears in the street canyon (flow regime I). The NOx and O3 exchange is generally active in the region close to the building wall with the higher temperature regardless of flow regime. The NOx and O3 exchange by turbulent flow is dominant in flow regime II, whereas the NOx and O3 exchange by mean flow becomes comparable to that by turbulent flow in a certain period of flow regime I. The NOx and O3 exchange velocities are similar to each other in the early morning, whereas these are significantly different from each other around noon and in the afternoon. This behavior indicates that the exchange velocity is dependent on flow regime. In addition, the diurnal variability of O3 exchange velocity is found to be dependent on photochemistry rather than dry deposition in the street canyon. This study suggests that photochemistry as well as flow in a street canyon is needed to be taken into account when exchange velocities for reactive pollutants are estimated. © 2013 Elsevier Ltd. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/80723
Appears in Collections: 气候变化事实与影响
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作者单位: School of Earth and Environmental Sciences, Seoul National University, Seoul 151-742, South Korea
Recommended Citation:
Kwak K,-H,, Baik J,et al. Diurnal variation of NOx and ozone exchange between a street canyon and the overlying air[J]. Atmospheric Environment,2014-01-01,86