【摘要】 本文用三维K理论扩散方程对南京大厂地区污染物浓度分布特征进行了讨论。在K理论扩散方程中,输入的风速廓线、扩散系数廓线采用Businger通量廓线关系式。用塔层风资料求取了南京地区近地面特征量。用具有四阶精度的Chapeau函数方法对三维K理论扩散方程进行数值求解,计算了大厂地区SO₂年平均浓度分布,和实测值基本上吻合。本文还研究了忽略水平扩散系数、不考虑风速随高度变化,对污染物地面浓度分布的影响。结果表明:在点源的下风方1—5千米范围内,不管是较强的还是较弱的风,忽略水平扩散系数都会使计算的地面浓度估计过高;忽略风速随高度的变化,会给计算带来一定的误差。更多还原

【Abstract】 The distribution of air pollutants in the Dachang district is dis-cussed by using the three-dimensional K-theory diffusion equation,in which Businger flux profile relationships are adopted as the fedwind and diffusion coefficient profiles. The characteristic parameternear the surface in Nanjing is determined using the wind data fromthe tower-layer wind. The three-dimensional K-theory diffusion equa-tion is solved numerically in terms of Chapeau function having thefourth-order accuracy. The average annual SO₂ concentration distribu-tion thus computed corresponds quite well with the observationalvalue. The influence caused by the neglect of the horizontal diffusioncoefficient and the change of wind speed with height on the calcula-tion of the pollutant concentration distribution near the surface is alsoexamined. It is found that within the range of 1--5 kilometersfrom the point source downwind, whether the wind is strongor weak, negligence of the horizontal diffusion coefficient would leadto higher estimation of the surface concentration and errors in cal-culation would exist if the change in wind speed with height is over-looked.更多还原