基于2012-2021年地面气象观测资料,采用无人机观测气温廓线,计算分别位于开阔盆地和狭长山谷地形的山西省孝义市和古县大气混合层厚度、大气自净能力指数、逆温层厚度;利用FLEXPART模型模拟两地不同时期(清洁期、重污染期)大气中颗粒物传输路径及高度.结果表明:孝义市和古县大气自净能力指数分别为13.4和6.2,大气自净能力等级分别为二级和四级,春季大气自净能力最强,冬季最弱.冬季古县逆温强度大于孝义市,不利于大气污染物的扩散.清洁时期,两地污染物均沿西北方向传输,孝义市大气中粒子传输高度较高,传输距离更远;重污染期,两地空气中粒子传输高度均偏低,传输距离受地形影响,易造成当地大气污染.因此,开阔盆地相较于狭长山谷地区,大气污染物更易清除;开阔盆地大气污染物传输高度高于狭长山谷地区,且传输距离也更远.
Based on ground meteorological observation data from 2012 to 2021,unmanned aerial vehicles(UAVs)were used to observe temperature profiles.The mixed layer depths,atmospheric self-purification capacity index,and inversion layer thickness were calculated for Xiaoyi City and Gu County,which are located in basin and valley terrains,respectively.Furthermore,the particle transport pathways and heights during different periods(clean period,heavy pollution period)in the two locations were simulated using the FLEXPART model.The results showed that the atmospheric self-purification capacity index for Xiaoyi City and Gu County were 13.4 and 6.2,respectively.The self-purification capacity was strongest in spring but weakest in winter for both locations.During winter,Gu County exhibited stronger inversion intensity compared to Xiaoyi City,which hindered the dispersion of atmospheric pollutants.During the clean period,the pollutants in both locations were transported in a northwest direction,and Xiaoyi City had higher particle transport heights and longer distances.During the heavy pollution period,the particle transport heights were low in both locations,and the transport distance influenced by the local terrain,which resulted in localized atmospheric pollution.Therefore,compared to narrow and elongated valley areas,atmospheric pollutants were more easily cleared in open basin areas.Additionally,the transport height of atmospheric pollutants was higher in open basin regions than in narrow and elongated valley areas,with a greater transport distance.