福建惠安沿海大气扩散特性的数值分析与模拟

Numerical Analysis and Simulation of Characteristics of Atmospheric Diffusion in Coastal Area of Huian, Fujian

用福建惠安地区的实测气象资料, 结合风场诊断、轨迹分析和随机游走模拟方法, 分析惠安核电厂所在地小尺度 (40 km×40 km) 范围内的大气扩散特性, 并与现场扩散示踪实验数据比较。结果表明, 该地区的扩散输送总体受天气系统和海陆风环流二因子影响。研究范围内的风场, 在水平方向的空间变化不大, 扩散烟流基本平直。海陆风环流因子所致的风场时间变化和风向摆动对当地扩散有重要意义。随机游走模拟方法较好地反映出当地大气扩散的定量特征, 但复杂地形与海岸气象条件的联合作用, 仍使模拟结果与示踪实验结果的统计比较显得离散。

An analysis is carried out for properties of atmospheric diffusion over a relatively small region (40 km×40 km) where Huian nuclear power station will be located, by means of wind field diagnoses, trajectory analysis and random walk simulation. Transport and diffusion in this area are generally determined both by synoptic systems and land-sea breeze circulation. Spatial variation of wind field in horizontal is not serious in this area so transport plume of pollutants keeps straight in general. Temporal variation of wind field, particularly the wind direction transition caused by transient of land and sea breezes, plays an important role in atmospheric diffusion. Random walk simulation reveals properties of atmospheric diffusion in this area quantitatively in comparison with in situ tracer experiment data, though quite large scatter still exists in a statistical comparison between modeling and observation since a combined effect of complex terrain and coastal meteorological condition.