沧州近地面臭氧浓度与气象条件关系

Correlation between Near-surface Ozone Concentration and Meteorological Conditions in Cangzhou

  • 摘要: 利用2013-2018年沧州市臭氧监测数据和气象数据,运用相关和百分位阈值法,分析了沧州市臭氧污染特征及气象因子对臭氧污染的影响。结果表明:沧州市臭氧浓度呈现明显的季节变化特征,春季和夏季最高;臭氧超标日数也集中在春夏季,臭氧浓度和超标日数均呈逐年增加趋势;在所有气象因子中气温与臭氧相关性最强,较高的气温是沧州市臭氧发生的必要条件,气温越高越容易导致高浓度的臭氧污染;绝大多数情况下,臭氧浓度与相对湿度呈负相关关系;降水量级及降水性质都会对臭氧浓度造成明显影响;风向与风速影响臭氧污染物的水平传输和垂直扩散,冬春季影响明显;春季臭氧浓度的增加与风速增大导致的混合层高度增加有重要的关系;颗粒物通过影响到达近地面的气象要素间接影响臭氧浓度。沧州地区臭氧超标日的出现伴随着一系列气象条件的共同改变,包括晴天少雨、混合层高度增加、风速增大、相对湿度降低及气温升高等气象特征,污染结束则伴随着相反的气象变化。

     

    Abstract: Based on the ozone monitoring data and meteorological data of Cangzhou from 2013 to 2018, the characteristics of ozone pollution and the influence of meteorological factors on ozone concentration in Cangzhou were analyzed. The results showed that the ozone concentration in Cangzhou had an obvious seasonal variation, with the highest in spring and summer. The days of ozone exceeding the standard value were also concentrated in spring and summer. The ozone concentration and days of ozone exceeding the standard value were increasing year by year. Among all meteorological factors, the air temperature had the strongest correlation with ozone. Higher air temperature was a necessary condition for the occurrence of ozone in Cangzhou city, and the higher the temperature, the more likely to lead to higher concentration of ozone pollution; In most cases, ozone concentration was negatively correlated with relative humidity. When the relative humidity was greater than 50%, the higher the relative humidity was, the lower the average ozone concentration and the 90th percentile ozone concentration were. The precipitation level and the precipitation nature both had a significant effect on ozone concentration. When the precipitation on the day was more than 10 mm, most of the precipitation was convective precipitation in spring and summer, and the ozone concentration was higher. Wind direction and speed affected the horizontal transmission and vertical diffusion of ozone pollutants, especially in winter and spring. When ozone pollution occurred, the prevailing wind changed from west-southwest wind or east-northeast wind to south-southwest wind, and as the wind speed increased, the average ozone concentration increased obviously. The increase of ozone concentration in spring and the increase of mixing layer height were caused by the increase of wind speed have important relationships. Particulate matter indirectly affected ozone concentration by affecting the Near-surface meteorological elements. From May to October, when ozone pollution was high and particulate concentration was relatively low, the meteorological characteristics were high temperature and strong sunshine, which were conducive to the occurrence of various photochemical reactions in the atmosphere. In autumn and winter, particulate matter affected the average ozone concentration by affecting the formation of foggy weather. Ozone pollution days in Cangzhou were accompanied by the changes of a series of meteorological conditions, including sunny days, higher mixing layer height, increasing wind speed, lower relative humidity and rising temperature. The end of pollution was accompanied by the opposite weather changes.

     

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