Research On NOx Emission Flux Acquisition Method Based On OMI Data Modified By DOAS Technique

With China’s industrialization and urbanization of fossil energy consumption,as well as the number of motor vehicles and the rapid expansion of the number of urban population.The concentration and growth rate of NO₂ in the main cities of the North China Plain have been kept at a high level,which has become the main research object of global key monitoring and control.As the NO₂ column concentration is susceptible to weather and other factors,it can not accurately reflect the actual NO₂ emission in the region.While NO₂ emissions not only have more direct and accurate display of regional emission changes,but also is an important indicator of monitoring,assessing and identifying pollution sources for each source.At present,the study of NO₂ emissions and emissions inventories is mainly fo-cused on the methods of satellite observations and satellite data combined model.How-ever,satellite observations are susceptible to factors such as clouds and aerosols,which are less sensitive to the airflow in the troposphere and have poor spatial resolution.When studying the emission of air pollutants in the urban scale area,neither of the above methods can accurately reflect the emission of the study area.In recent years,passive differential optical absorption spectroscopy（DOAS）based on vehicle platform has the advantage of high spatial resolution and more sensitive to near ground air pollutants,and can obtain more data in a satellite grid.In this paper,the method of estimating NO₂ lifetime and NOx emission flux based on vehicle DOAS data correction OMI satellite data is established.And the effectiveness of the method is verified by Shijiazhuang and its surrounding area.1.This paper studies the method of DOAS NO₂ data projection to wind field,the gridding method for vehicle DOAS data and OMI Level2 NO₂ data product,as well as the derivation and simplification of flux and life estimation methods.And based on these methods,the method of modifying satellite data based on DOAS technology is established to improve the accuracy of estimating NO₂ life and NOx emission flux by using satellite data.2.Based on the traditional method of estimating the life and emission flux of satellite observation data in Shijiazhuang City and its surrounding areas,the effect of the modified method on the NOx emission flux was evaluated.The NO₂ average life and NOx emission flux in the study area were 4.2h and 3.6h,195.8mol/s and 163.8mol/s,respectively,with the errors of 49%and 37%.In addition,the study found that if the compound pollution characteristics of the city is obvious or the pollution is more serious,the observation time is selected in summer and the wind velocity distribution is in the range of 5～15km/h.In this paper,it is shown that the method of using the vehicle DOAS technology to modify the satellite data and apply it to the NO₂ life and NOx emission in the urban scale,can make up for the shortcomings of the traditional use of satellite data can not accurately estimate the emission of the study area.And Is an effective means to improve the accuracy of estimating the life of NO₂ in cities and the accuracy of NOx emissions.