典型城市不同湍流强度下的能见度变化特征

利用新研制的透射式大气能见度和湍流强度同步光学测量仪记录典型城市(南京)2017年冬夏两季的实验数据,计算并分析了不同污染条件下能见度与大气折射率结构常数之间的变化特征。结果发现,夏季大气能见度的变化趋势与湍流强度的变化趋势基本吻合,即湍流强度越大,相应的能见度越高,冬季亦如此。说明大气湍流对大气中污染的扩散起着重要作用,湍流扩散是污染物浓度降低的主要原因。该结论为研究不同季节下湍流强度对能见度的影响提供了科学依据。同时,该仪器也为研究边界层湍流与气溶胶粒子之间的相互作用提供了全新的手段。

Characteristics of visibility changes in typical city under different turbulence intensities

The experimental data of a typical city (Nanjing) in winter and summer of 2017 were recorded by a newly developed synchronous optical instrument for measuring atmospheric visibility and turbulence intensity. The variation characteristics between visibility and atmospheric refractive index structure constant under different pollution conditions are calculated and analyzed. The results show that the change trend of atmospheric visibility in summer is basically consistent with that of turbulence intensity, that is, the greater the turbulence intensity is, the higher the visibility is, and the same is true in winter, which shows that atmospheric turbulence plays an important role in the diffusion of atmospheric pollution, and turbulent diffusion is the main reason for the decrease of pollutant concentration. This conclusion provides a scientific basis for studying the influence of turbulence intensity on visibility in different seasons, and at the same time, the instrument provides a new method for studying the interaction between boundary layer turbulence and aerosol particles.