A parameterization of low visibilities for hazy days in the North China Plain

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Date
2012
Volume
12
Issue
11
Journal
Series Titel
Book Title
Publisher
München : European Geopyhsical Union
Abstract

Visibility degradation is a pervasive and urgent environmental problem in China. The occurrence of low visibility events is frequent in the North China Plain, where the aerosol loading is quite high and aerosols are strongly hygroscopic. A parameterization of light extinction (Kex) for low visibilities on hazy days is proposed in this paper, based on visibility, relative humidity (RH), aerosol hygroscopic growth factors and particle number size distributions measured during the Haze in China (HaChi) Project. Observational results show that a high aerosol volume concentration is responsible for low visibility at RH <90%; while for RH >90%, decrease of visibility is mainly influenced by the increase of RH. The parameterization of Kex is developed on the basis of aerosol volume concentrations and RH, taking into accounts the sensitivity of visibility to the two factors and the availability of corresponding data. The extinction coefficients calculated with the parameterization schemes agree well with the directly measured values.

Description
Keywords
aerosol composition, aerosol property, concentration (composition), parameterization, relative humidity, sensitivity analysis, size distribution, visibility
Citation
Chen, J., Zhao, C. S., Ma, N., Liu, P. F., Göbel, T., Hallbauer, E., et al. (2012). A parameterization of low visibilities for hazy days in the North China Plain. 12(11). https://doi.org//10.5194/acp-12-4935-2012
License
CC BY 3.0 Unported