关中地区沙尘输送路径及潜在源区分析

Transport pathways and potential source regions of dust in Guanzhong region

利用MeteoInfo软件计算2016-2020年关中地区沙尘天气期间的逐时次后向气团轨迹,按季节进行聚类,结合PM10小时浓度数据,分析主要沙尘输送路径,并采用潜在源贡献因子法(PSCF)和浓度权重轨迹法(CWT)确定主要潜在沙尘源区及其贡献水平。结果表明:关中地区主要沙尘输送路径为西北路径,主要潜在沙源地包括蒙古国南部戈壁沙漠和我国古尔班通古特沙漠、巴丹吉林沙漠、腾格里沙漠、乌兰布和沙漠和毛乌素沙地。研究提出“沙源地边缘敏感区域”的概念,并指出这些区域城市可作为传输路径下游城市的沙尘预警指示城市,影响关中地区的沙源地边缘敏感区域主要分布在甘肃、宁夏、内蒙古西部、青海北部和陕西北部。关中地区春季沙尘影响频次多于冬季,春季沙尘源区分布范围比冬季广,但大部分源区贡献强度比冬季有所减弱。

The MeteoInfo software was used to calculate the hourly backward air mass trajectories during the dust weather in Guanzhong area from 2016 to 2020.The main dust transport pathways were analyzed in terms of seasonal clustering and combining with PM_(10)hourly concentration data,and the potential source contribution function(PSCF)analysis method and concentration-weighted trajectory(CWT)were introduced to determine the main potential dust source areas and their contribution levels.The results indicated that the northwestern pathways were the major pathways leading to the high PM_(10)values.The potential sand source areas mainly included the Gobi desert in southern Mongolia and the Gurbantunggut desert,Badain Jaran desert,Tengger desert,Ulan Buh desert and Mu Us sandland in China.The study puts forward the concept of"sand marginal sensitive areas",and points out that these regional cities can be used as dust warning and indication cities for the cities downstream of the transmission path,the sand marginal sensitive areas for Guanzhong are mainly distributed in Gansu,Ningxia,western Inner Mongolia,northern Qinghai and northern Shaanxi.The frequency of dust in spring was higher than that in winter in Guanzhong region,the dust transport pathways and the potential source areas also were widely distributed,while the contribution intensity in spring were more weakened than that in winter.