| With the continuous development of industrialization,haze pollution has become one of the serious air pollution phenomena.No matter in the whole country or Ningxia region,haze pollution has caused varying degrees of threat to traffic safety,people’s health,ecological environment and so on.Therefore,in the realization of haze pollution control,the design of haze early warning scheme is also very necessary.Studies have shown that haze particles are charged,and the charged polarity is different.This paper mainly studies the impact of haze pollution on electromagnetic wave attenuation,and then proposes a radar range equation considering electromagnetic wave attenuation.Based on the electromagnetic wave attenuation theoretical model and radar range equation,a haze early warning scheme is designed.In order to more accurately predict the attenuation coefficient of centimeter waves during haze,a dimensional analysis method is used to determine the dimensionless physical quantities that affect the attenuation of electromagnetic waves.That is,particle diameter,electromagnetic wave frequency,particle humidity,and particle surface charge density.Then,taking the core shell structure as the particle structure,the influence of the core shell structure on electromagnetic wave attenuation is analyzed.The results show that an increase in the volume fraction of haze particles with a core shell structure formed under high humidity will lead to an increase in the dielectric constant,thereby increasing the attenuation coefficient of electromagnetic waves.As electrons can move on the surface of the core shell structure,the surface conductance of particles increases,leading to an increase in the attenuation coefficient of electromagnetic waves.Through further analysis of the experimental data of Zhang Xiaobin et al.[1],it is found that the change in the attenuation coefficient of electromagnetic waves can be reflected by Hp-Hp0.The amount of charge of particles mainly affects the slope term of the electromagnetic wave attenuation coefficient that varies linearly with Hp-Hp0.Based on the experimental results of Zhang Xiaobin et al.[1],this paper presents an improved empirical model for predicting electromagnetic wave attenuation.In addition,in order to reflect the microscopic nature of the haze particle system,the ratio of electric quantity to mass of electrons is used for dimensionless processing,and the model in this paper introduces the interaction between particles.Based on the electromagnetic wave attenuation model in this paper,a formula for calculating the radar operating distance considering electromagnetic wave attenuation is proposed.It is obtained that the radar operating distance with and without electromagnetic wave attenuation has an exponential relationship.Based on the theoretical model of electromagnetic wave attenuation and the calculation formula of radar action distance in this paper,the forewarning scheme of external haze is designed.this paper combs the topography and wind environment of Shizuishan and Ningdong regions in Ningxia,and analyzes whether a wind channel can be formed between these two regions and Yinchuan City.The possible pollutants in Shizuishan City and Ningdong District were sorted out,and the possibility of haze pollution in these two areas was analyzed.Based on the foreign haze early warning scheme introduced in this paper,the application of haze pollution early warning scheme in Shizuishan city and Ningdong region of Ningxia was preliminarily discussed.It is discussed that in order to keep the radar operating range unchanged during haze pollution,the model of predicting electromagnetic wave attenuation coefficient is taken as the standard and the radar gain coefficient is changed to achieve the purpose of keeping the radar operating range unchanged. |
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