基于HYSPLIT后向轨迹模式判断河谷型城市大气污染物来源

Study of Air Pollution Transportation Source in Valley-City Based on The Hysplit Backward Trajectory Model

武威市天祝藏族自治县城位于河谷地形内,自河谷内大型碳化硅工业园区建成投产以来县城空气质量显著下降。为判断县城大气污染物的来源,利用HYSPLIT后向轨迹模式和NCEP气象再分析资料计算各个季节抵达县城的后向气流轨迹并进行聚类,结合同期的大气污染物监测数据,进一步分析影响天祝县空气质量的污染来源。结果显示:受不同来源气团影响下的县城污染物浓度有较大差异,当来自西北、偏西和偏南方向的气团过境时,县城大气污染物浓度较高。县城内PM10,PM2.5,SO2和CO的外来输送主要是来自西北和偏西方向,东北和东南方向的气团过境对污染物有清除作用,河谷地形内的大型工业园区无组织面源排放通过气流输送会影响县城的空气质量。

Tianzhu Tibetan autonomous county of Wuwei city is located in valley.Since the large-scale silicon carbide industrial park was built and put into production, the air quality of the county has decreased significantly.To judge the air pollutants source of the county, HYSPLIT backward track mode and NCEP meteorological reanalysis data were used to calculate the backward airflow track in each season and carry out clustering.Using the data of air pollutant monitoring in the same period, the pollution sources were further analyzed.The results show that the concentration of pollutants under the influence of air masses from different sources varies greatly.When the air mass from northwest, west and south transited, the county air pollutant concentration was higher.The external transport of PM10, PM2.5, SO2 and CO in the county was mainly from the northwest and west directions, and the transit of air masses in the northeast and southeast could clear pollutants.Unorganized surface source emissions from large industrial parks in the valley has a negative impact on the air quality of the county.