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| Distribution and long-term variation of tropospheric NO2 over China during 2005 to 2013 |
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Abstract With the combination of NOx emission index of regional Emission inventory in Asia (REAS), the wind field at 10 meters height above surface which based on European Centre for Medium-Range Weather Forecasts (ECMWF) Real- Analysis data, and the relavant statistical data based on the China Statistical Yearbooks Database, the monthly tropospheric NO2 data over China acquired from the Ozone Monitoring Instrument (OMI) was analyzed with respect to spatial distribution and long-term trends between 2005 and 2013. The results showed that the high value areas of tropospheric NO2 columns over China were located on North China, the Yangtze River Delta, the Pearl River Delta and the Sichuan Basin. The trends of tropospheric NO2 columns were distinguished between east and west China. It was increased during 2005 to 2011 in east China, but decreased by 7.1% from 2011 to 2013. In west China, the tropospheric NO2 columns were increased continuously from 2005 to 2013. High value regions of NO2 tropospheric columns were decreased after 2011, which was strongly related to the cut of the NOx discharge of industry. The tropospheric NO2 columns reached their maximum in winter and minimum in summer. The anthropogenic emission of NOx was one of the important factors which influenced the seasonal mean tropospheric NO2 columns. In the mean time, seasonal means of 10-m winds also played an important role of influencing the seasonal distribution of tropospheric NO2 columns, which indicated that the impact of meteorological conditions should not be ignored.
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Received: 18 December 2014
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