大同盆地复杂地形下近场大气污染物扩散模型选取研究

Study on the selection of near-field air pollutants diffusion model in complex terrain of Datong Bason

基于大同盆地地形和气象站数据对山区复杂地形下的近地面风场特征进行分析,发现大同盆地内特殊的地形构造所形成的气流通道对其主导风向存在明显影响。在不开展实地气象观测、仅引用周边气象站数据的条件下,CALPUFF模拟的电厂处西南、东北风向风频分别为40.5%、14.9%,AERMOD模拟的电厂处西南、东北风向风频分别为19.1%、8.2%,表明CALPUFF能更好地描述电厂受盆地东北—西南方向气流通道形成的主导风场影响。AERMOD存在低估重要敏感点环境影响的问题。因此,当山区盆地复杂地形下形成通道地形时,CALPUFF较AERMOD能更合理地模拟近场复杂地形及其风场对污染物扩散的影响。

The analysis of the characteristics of the near-surface wind field in complex terrain was analyzed based on the topography of the Datong Bason and the observation data of the weather stations.It was found that the airflow channel formed by the special topographic structure in the Datong Bason had significant impact on the dominant wind direction.Without on-site meteorological observation but only quoting the data of the surrounding weather stations,the southwest and northeast wind frequencies simulated by CALPUFF were 40.5%and 14.9%,respectively.Thosed simulated by AERMOD were 19.1%and 8.2%.Therefore,CALPUFF reflected the local dominant wind field formed by the northeast-southwest airflow channel better.However,AERMOD might result in underestimatation for important sensitive point.Overall,CALPUFF might be more reasonable than AERMOD to simulate the impact of complex terrain and its consequent wind field in the near-field on pollutants diffusion when the regional terrain formed a channel.