基于WRF-CAMx模式的近地面臭氧污染事件的个例分析

Case Analysis of Near-Surface Ozone Pollution Events Based on the WRF-CAMx Model

基于2020年11月8-9日莆田市地面气象站逐时气象数据及环境监测站逐时O_(3)监测数据,利用风廓线雷达资料和排放源数据,分析夜间出现O_(3)污染过程的气象特征,并结合WRF-CAMx模式进行O_(3)垂直分布模拟及来源分析。结果表明,莆田市夜间O_(3)污染峰值浓度为212μg·m-3,明显高于福州和泉州市的O_(3)峰值浓度。O_(3)污染前,温度出现升高现象,是冷空气南下锋前增温造成的。O_(3)污染期间,风廓线雷达资料显示,污染最严重的8日23时莆田市近地面到750 m的风速较20时的降低27.2%,加剧了O_(3)污染程度。Hysplit4模型结果显示,夜间O_(3)污染时段的气流经过NOX和VOCS排放量较大的长江三角洲地区,而非污染时段的气流主要来自东海洋面上空。WRF-CAMx模式结果显示,在夜间O_(3)污染严重的23时,O_(3)浓度的垂直分布可达到850 hPa(1500 m),宁德市在福建省各地市中对莆田O_(3)来源的贡献比达到94%。

Using the hourly meteorological data from the Putian meteorological station and hourly O_(3) data from the environmental monitoring station in November 89,2020,as well as the wind profiler radar data and emission source data,this article analyzes the meteorological characteristics of the nighttime O_(3) pollution process.Additionally,the WRF-CAMx model is employed for vertical distribution simulation and source analysis of O_(3).The results indicate that the nighttime peak concentration of O_(3) in Putian City was 212μg·m-3,significantly higher than that in Fuzhou and Quanzhou.Prior to the O_(3) pollution episode,the air temperature was on the rise,which was likely caused by the warming effect ahead of the southward-moving cold front.During the O_(3) pollution at night,the wind profiler radar data showed a 27.2%decline in wind speed from the near-surface to the 750 m height in Putian City,exacerbating the O_(3) pollution.The Hysplit 4 model results reveal that during the nighttime O_(3) pollution period,the airflow passed through the region with significant NO X and VOC S emissions,while during non-pollution periods,the airflow mainly originated from the East China Sea.WRF-CAMx model results demonstrate that during the heavy nighttime O_(3) pollution period(23:00),the atmospheric O_(3) concentration could reach the 1500 m height at 850 hPa.Ningde City contributed 94%to the nighttime O_(3) pollution in Futian City among various cities in Fujian Province.