基于OMI卫星数据和车载DOAS技术对NO_x排放通量估算的修正

Modification of Estimates of NO_x Emissions Based on OMI Satellite Database and Mobile DOAS Technology

与搭载在EOS AURA卫星上的OMI(Ozone Monitoring Instrument)探测器相比,由车载被动差分吸收光谱(differential optical absorption spectroscopy,DOAS)技术获得的NO_2柱浓度数据空间分辨率更高,因而能够更准确地反映出NO_2时空分布情况,利用OMI NO_2 Level2数据产品重构2013年6月石家庄及周边区域的NO_2柱浓度分布,结合风场数据分析NO_2柱浓度沿风场方向的空间分布,同时,使用车载被动DOAS系统对西南通道即石家庄-保定-北京路段进行走航观测,获取车载DOAS NO_2柱浓度分布数据,使用指数修正高斯(exponentially-modified Gaussian,EMG)拟合方式,分别拟合OMI NO_2数据和经过地基DOAS数据修正后的OMI NO_2数据得到NO_x排放通量分别为195.8 mol/s、160.6 mol/s。经过地基DOAS数据修正的NO_x排放量小于卫星估算值,可能是由于卫星的空间分辨率较低导致的。

Compared with the tropospheric NO2 column concentration measured by the Monitoring Instrument Ozone（OMI） detector mounted on the AURA EOS satellite, the mobile passive differential optical absorption spectroscopy （DOAS） has higher spatial resolution. It can better reflect the distribution of NO2 pollution in a region. Therefore the distribution of NO2 column concentration over Shijiazhuang was reconstructed using data from OMI database（June 2013）, combined with the wind data, the variation of spatial and temporal patterns of the distribution of NO2 concentration under southwest wind in Shijiazhuang was obtained. At the same time, the mobile DOAS system was used to observe the distribution of NO2 concentration on the southwest transport channel （Shijiazhuang-Baoding-Beijing）. Finally, the exponentially-modified Gaussian （EMG） method was used to estimate the NOx emission rate over Shijiazhuang in June 2013. The results showed that, the emission fluxes of OMI NOx and emission fluxes modified by mobile DOAS was 195.8 mol/s and 160.6 mol/s, respectively. The reason why the latter is less than the former may be the low spatial resolution of the satellite.