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摘要: |
以2008年南京北郊大气中O<sub>3</sub> 质量浓度观测资料和常规观测资料为基础,利用Matlab小波分析工具,对O<sub>3</sub>浓度的年时间序列进行分析,得出该地区的O<sub>3</sub> 日均浓度的变化特征:春、夏季节O3浓度大于秋、冬季节,最高浓度出现在春末夏初,最低浓度出现在冬季;并且全年共有5个突变点;弱高压的天气系统、较高的温度、较低的湿度和晴朗少云的天气是造成南京北郊O<sub>3</sub>浓度突变的主要气象因素。结合HYSPLIT气流后向轨迹模拟,对污染源来源进行追踪,结果表明:南京北郊O<sub>3</sub>高浓度污染来源主要分为本地局地污染和外来污染物输送两类;垂直方向上,O<sub>3</sub>的区域尺度或中尺度的输送主要稳定在混合层的底层。 |
关键词: O3浓度 时间序列 小波分析 后向轨迹 |
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基金项目:国家973项目(2009CB426313);教育部博士点基金项目(20093228180003) |
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Observational study of ozone concentrations in northern suburb of Nanjing based on Matlab wavelet analysis |
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Abstract: |
Based on the O<sub>3</sub> and meteorological data observed in northern suburb of Nanjing in 2008, the time series and the variation characteristics of the daily averaged O<sub>3</sub> was analyzed with a Matlab wavelet method, the results indicated that the O<sub>3</sub> concentration in spring and summer were higher than that in autumn and winter . And the daily maximum and minimum values were presented in late spring to early summer and winter respectively. There were five O<sub>3</sub> concentration mutation points during the whole year.. The mutational variation of the O<sub>3</sub> concentration was caused by the high-pressure system, high temperature, low humidity and the sunny and cloudless climate. The source of the pollutants was studied with a HYSPLIT-4 pollutant dispersion model, the results showed that the pollution source leaded to the higher level of O<sub>3</sub> concentration was mostly come form the local pollutant and transportation of outer pollutant, the transportation of the O<sub>3</sub> in regional scale or mesoscale was mainly stabilized at the bottom of mixing layer in the vertical direction. |
Key words: ozone concentrations Time series Wavelet analysis Back-trajectories |