Atmospheric stability and inverse temperature characteristics of Tianjin and its effect on PM2.5 pollution
YAO Qing1, LIU Jin-le2, CAI Zi-ying1, HAN Su-qin2, MA Zhi-qiang3
1. Tianjin Environmental Meteorology Center, Tianjin 300074, China;
2. Tianjin Institute of Meteorological Science, Tianjin 300074, China;
3. Environmental Meteorology Forecast Center of Beijing-Tianjin-Hebei, Beijing 100089, China
Temperature-velocity method was used to calculate the atmospheric stability in Tianjin and the frequency and intensity of the inversion of temperature were analysed based on the meteorological tower. In addition, we investigated the relationship between atmospheric stability and the temperature inversion, which had an influence on the monthly averaged mass concentration of PM2.5. The characteristics of atmospheric stability and temperature inversion were analysed during a heavy haze period. The results showed that the frequencies of atmospheric stability were 6.7%, 11.4%, 22.4%, 46.1%, 11.1% and 2.2%, respectively, from September 2015 to August 2017. The stagnant meteorological conditions occurred frequently during fall and winter. The unstable and neutral atmospheric stability dominated the daytime and nighttime of all year, respectively. The stable atmosphere contributed 30%~40% during nighttime in fall and winter. During the observation period, the frequency of temperature inversion was the highest in winter, which up to more than 90% during 5:00~8:00and 21:00~23:00. The intensity of temperature inversion was also the highest in winter. With the increase of the number of days of stable atmosphere, the monthly averaged mass concentration of PM2.5 and the number of polluted days increased. Meanwhile, the monthly averaged mass concentration of PM2.5 and the frequency of polluted day were all positively correlated with the frequency of inversion temperature. A heavy pollution process from December 16, 2016 to December 21, 2016 showed that the mass concentration of PM2.5 was effected by the atmospheric stability and the evolution of inversion temperature. The characteristics of atmospheric stability and temperature inversion during the formation of haze, fog-haze alternation and dissipation of haze had obvious difference. As the atmosphere continues to stabilize and the inversion temperature increases, it plays a very important role in the generation and maintenance of pollution. Fine analysis of atmospheric stability and inversion characteristics in the process of pollution will help to improve the prediction and warning level of heavy pollution weather.
姚青, 刘敬乐, 蔡子颖, 韩素芹, 马志强. 天津大气稳定度和逆温特征对PM2.5污染的影响[J]. 中国环境科学, 2018, 38(8): 2865-2872.
YAO Qing, LIU Jin-le, CAI Zi-ying, HAN Su-qin, MA Zhi-qiang. Atmospheric stability and inverse temperature characteristics of Tianjin and its effect on PM2.5 pollution. CHINA ENVIRONMENTAL SCIENCECE, 2018, 38(8): 2865-2872.
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