京津冀地区臭氧浓度时空变化特征

Spatio-temporal Change Characteristics of Ozone Concentration in Beijing-Tianjin-Hebei Region

为研究京津冀地区臭氧浓度的时空变化,文章利用2014年6月-2018年5月中国环境监测总站臭氧浓度数据进行分析。结果表明:(1)京津冀地区臭氧浓度平均水平不断增高,不同区域增速差异明显,高值区出现由单中心向双中心的转变且逐渐形成了日益明显的沿海臭氧高浓度分布带;(2)臭氧浓度的季节性差异显著,春、夏两季较秋、冬两季臭氧浓度高,其中夏季最高,冬季则缺乏高值区;(3)不同城市的年均臭氧浓度分布模式不同,大部分城市核密度估计峰值对应臭氧浓度<20μg/m^3;(4)臭氧浓度的日内变化基本遵循周期性单峰型变化规律;(5)不同城市臭氧浓度超标天数差异显著,变化趋势可分为稳定增长型、突变增长型和稳定型。

In order to study the spatio-temporal change of ozone concentration in Beijing-Tianjin-Hebei region,the hourly ozone concentration data of 13 cities and 327 sites from June 2014 to May 2018,which was provided by the the National Urban Air Quality Real-time Release Platform from China National Environmental Monitoring Centre,was statistically and cartographically analyzed.The results show that the average of ozone concentration in Beijing-Tianjin-Hebei region was continuously increasing,and the growth rate was obviously different in different regions.The low-value area maintained the distribution of two centers,while the high-value area turned a single-centre to double-centre and gradually formed a obviously high ozone concentration distribution belt in coastal zone.The seasonal variation of ozone concentration was significant.Compared with autumn and winter,the ozone concentration was higher in spring and summer.The highest concentration appears in summer,while there was a lack of high value in winter.The annual average distribution pattern of ozone concentration was various from various cities,and the concentration of ozone,which corresponded to the peak of kernel density estimation,in most city was less than 20μg/m3,except Zhangjiakou and Chengde.The intra-day change of ozone concentration basically followed the periodic unimodal pattern that the minimum concentration appeared before sunrise,and then the concentration gradually increased to the peak,after the afternoon and then decreased again.The number of ozone over-polluted days in different cities was varied significantly,and the change patterns could be divided into stable growth type,mutation growth type and stable type.