Application of Turbulent Diffusion Term of Aerosols in Mesoscale Model

Jia, Wenxing; Zhang, Xiaoye; Zhang, Hongsheng; Ren, Yan

doi:10.1029/2021gl093199

Cited by 8 publications

(6 citation statements)

References 77 publications

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“…Du et al (2020) revealed that increasing the threshold of turbulence mixing coefficient was helpful to the simulation of diurnal variation of PM 2.5 . Jia et al (2021) developed a turbulence diffusion term for aerosols and embedded it into a mesoscale model for the first time.…”

Section: Models and Analyses Methodsmentioning

confidence: 99%

Low-level jets and their implications on air pollution: A review

Wei

Zhang

et al. 2023

Front. Environ. Sci.

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Low-level jets (LLJ) are a common phenomenon in the atmospheric boundary layer and have been reported worldwide. Additionally, they have considerable relevance in a series of fields. This review aimed to document their implications on air quality, specifically particulate matter, mineral dust, and ozone in recent literature focus on i) generalizing long-range advection of pollutants by the low-level jets; ii) analysing vertical transport due to low-level jets-enhanced turbulence mixing and the corresponding mechanisms for different pollutants; and iii) introducing the performance of state-of-the-art numerical models. Finally, we suggest that high-resolution spatiotemporal observations of the pollutants and turbulence must be conducted, and current parameterization schemes should be improved to better represent the low-level jets and nocturnal boundary layer structures for reproducing the complicated interactions between the low-level jets and pollutants.

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Section: Models and Analyses Methodsmentioning

confidence: 99%

Low-level jets and their implications on air pollution: A review

Wei

Zhang

et al. 2023

Front. Environ. Sci.

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“…However, many studies have suggested that mesoscale models underestimate the mixing in SBL simulation and lead to the overestimation of PM2.5 simulation (Teixeira et al 2008, Du et al, 2020, Jia et al, 2021a. Therefore, two sets of experiments are designed in our research.…”

Section: Numerical Experimentsmentioning

confidence: 99%

“…Huang et al (2010) improved the turbulent fluxes in the SBL by redefining the closure constants and modifying the sensible heat flux prognostic equation. Jia et al (2021a) developed a novel formula for particle diffusion based on mixing-length theory. It has improved the simulation of aerosols in the SBL over eastern China.…”

Section: Introductionmentioning

confidence: 99%

Parameterized minimum eddy diffusivity in WRF-Chem(v3.9.1.1) for improving PM_2.5 simulation in the stable boundary layer over eastern China

Wen

Zhu

Yan

et al. 2023

Preprint

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Abstract. Weak turbulence often occurs during heavy pollution events in eastern China. However, existing mesoscale models cannot accurately simulate turbulent diffusion under weakened turbulence, particularly under the nocturnal stable boundary layer (SBL), often leading to significant turbulent diffusivity underestimation and surface aerosol simulation overestimation. In this study, based on the Weather Research and Forecasting model coupled with the Chemistry model (WRF-Chem 3.9.1), a new parameterization of minimum turbulent diffusivity (Kzmin) is tested and applied in PM2.5 simulations in eastern China under SBL conditions. Sensitivity experiments show that there are different value ranges of available Kzmin over the northern (0.8 to 1.3 m2·s-1) and southern (1.0 to 1.5 m2·s-1) regions of East China. The geographically related Kzmin could be parameterized by means of two factors: sensible heat flux (H) and latent heat flux (LE), which also exhibited a regional difference related to the climate and underlying surface. The revised Kzmin scheme obviously enhanced the turbulent diffusion (north: 0.88 m2·s-1, south: 1.17 m2·s-1 on average) under the SBL, simultaneously improving the PM2.5 simulations, with the PM2.5 relative bias decreasing from 43.0 % to 15.6 % on the surface. The improvement in the mean bias of the surface simulation was more noticeable in the north (54.01 to 3.79 ug·m-3) than in the south (37.05 to 17.99 ug·m-3). It also increased the PM2.5 concentration in the upper SBL. Furthermore, we discussed the physical relationship between Kzmin and two factors. Kzmin was inversely correlated with sensible heat flux (negative) and latent heat flux (positive) in the SBL. Process analysis showed that vertical mixing is the key process to improve PM2.5 simulations on the surface in the revised scheme. The increase in the PM2.5 concentration in the upper SBL was attributed to vertical mixing, advection, and aerosol chemistry. This study highlights the importance of improving turbulent diffusion in current mesoscale models under the SBL and has great significance for aerosol simulation research under heavy air pollution events.

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“…It has long been considered that turbulence transports momentum and scalars similarly, which is referred to as the Reynolds analogy. The Reynolds analogy has primary implications in the turbulent‐exchange processes (Ishizuka et al., 2014; Nickling & Gillies, 1993; Zhang et al., 2008), turbulent flow simulations (Gray et al., 2001; Kang, 2016; Sang et al., 2018), and boundary‐layer parameterization schemes (Gatski & Bonnet, 2013; Jia et al., 2021). However, an increasing number of studies have shown that there is often the dissimilarity between the turbulent transport of momentum and scalars in the actual atmosphere, ranging from the natural landscapes (Dupont & Patton, 2012; Dupont et al., 2019; Jia et al., 2022; Li & Bou‐Zeid, 2011) to the urban areas (Moriwaki & Kanda, 2006; Wang et al., 2014; Zhang et al., 2022).…”

Section: Introductionmentioning

confidence: 99%

Dissimilarity of Turbulent Transport of Momentum and Heat Under Unstable Conditions Linked to Convective Circulations

Zhang

et al. 2023

JGR Atmospheres

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The dissimilarity between the turbulent transport of momentum and heat under unstable conditions and its physical mechanisms are investigated in this study, based on the multiple‐level turbulence observation from the Tianjin 255‐m meteorological tower. The transport dissimilarity is observed from the surface layer to the lower part of mixed layer as atmospheric instability increases. Although the transport dissimilarity is accompanied by the development of plumes and thermals under unstable conditions, plumes and thermals can produce intense transport both of momentum and heat simultaneously. It is convective circulations induced by vigorous thermals that cause transport dissimilarity. The horizontal divergence generated by convective circulations imposes a dominant large‐scale reduction in the along‐wind velocity component near the surface, which is related to increased counter gradient transport of momentum, while the temporal variations in temperature mainly reflect the role of plumes and thermals and thus the transport of heat is predominantly down‐gradient. This difference in respective physical processes subsequently leads to dissimilar transport between momentum and heat under unstable conditions. Therefore, it is of great interest to represent the influence of convective circulations on the momentum‐flux estimation in future investigations, aiming to improve the boundary‐layer parameterization schemes for mesoscale numerical weather models.

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Application of Turbulent Diffusion Term of Aerosols in Mesoscale Model

Abstract: Prosperous economic development and intensive expansion have led to a series of heavy aerosol pollution events in recent decades, which are characterized by high loadings of aerosol particles with an aerodynamic diameter less than 2.5 µm (PM 2.5 ) (

Cited by 8 publications

References 77 publications

Low-level jets and their implications on air pollution: A review

Low-level jets and their implications on air pollution: A review

Parameterized minimum eddy diffusivity in WRF-Chem(v3.9.1.1) for improving PM_2.5 simulation in the stable boundary layer over eastern China

Dissimilarity of Turbulent Transport of Momentum and Heat Under Unstable Conditions Linked to Convective Circulations

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Application of Turbulent Diffusion Term of Aerosols in Mesoscale Model

Abstract: Prosperous economic development and intensive expansion have led to a series of heavy aerosol pollution events in recent decades, which are characterized by high loadings of aerosol particles with an aerodynamic diameter less than 2.5 µm (PM 2.5 ) (

Cited by 8 publications

References 77 publications

Low-level jets and their implications on air pollution: A review

Low-level jets and their implications on air pollution: A review

Parameterized minimum eddy diffusivity in WRF-Chem(v3.9.1.1) for improving PM2.5 simulation in the stable boundary layer over eastern China

Dissimilarity of Turbulent Transport of Momentum and Heat Under Unstable Conditions Linked to Convective Circulations

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Product

Resources

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Parameterized minimum eddy diffusivity in WRF-Chem(v3.9.1.1) for improving PM_2.5 simulation in the stable boundary layer over eastern China