| Haze has become one of the major weather disasters to harm social security and human health in the recent years and it reduces visibility and air quality for it contains a large number of pollutants and affects seriously the natural environment,and human production and life. Satellite remote sensing data can make up for the shortage of manual field monitoring, which making full use of timeliness, reliability,wide range of satellite remote-sensing to monitor dynamically the distribution of a wide range of haze.In this paper, MODIS data was used to inverse the air aerosol optical thickness and the road visibility of different haze weather events occurred in Beijing and Nanjing regions. Based on this, the accuracy of remote sensing inversion was analyzed combined with the observation data of ground visibility and meteorological data to verify the rationality and applicability of the inversion methods in the two places; and compared similarities and differences of different haze and its causes in the different study areas. Finally, the reasonable control measures were tired to put forward combined with the local traffic situation against haze. It can be provide reference for haze weather monitoring and early warning and traffic safety operation in the future (Inversion Comparison process time matches the satellite transit time from 10: 00-12: 00).The main research results of this paper were showed as follows:(1) Based on MODIS data, the four cases of great haze events in spring and autumn of Beijing and Nanjing area were selected respectively to inverse temporal and spatial characteristics of atmospheric aerosol optical depth and visibility.Research results showed : the change of AOD in each haze process showed obvious characteristics of "single peak"; the temporal and spatial variation trends of the inversion visibility were consistent with the trends of the ground measured visibility;By verifying the accuracy of the inversion can be found that the linear correlation coefficient between the inversion visibility and the actual visibility is 0.5 or more,and they passed the significance test of p<0.01; The errors between the inversion values and actual values of the visibility was small (<0.5km) in the urban area and the inversion effect was better, but this error was large (>1km) in the suburban area and the inversion effect was poor.(2) The inversion and comparative analysis of spring and autumn haze events in Beijing area and Nanjing area were carried out and it was found that the visibility was larger, while the haze processes in autumn was longer and the visibility was smaller. The visibility of the haze processes in spring had a high consistency and there were large differences between the visibility of different regions in the autumn haze processes; The inversion accuracy of visibility was not only related to the coverage area, severity of the development of the haze processes, the geographical locations of the study area; The causes of the haze weather in Beijing and Nanjing were mainly due to terrain features of southeast low in Beijing and the dustpan terrain of Surrounded by mountains on three sides in Nanjing, which lead to the accumulation of pollutants in the two places. In addition, it was affected by different weather conditions, pollution sources, wind speed and other factors.(3) Based on the distribution of expressway, and combined with different degrees of haze in different regions of Beijing and Nanjing, it can be seen that the haze pollution in the southeastern part of Beijing is the most serious. The sections of the expressway in the area are respectively: Beijing-Harbin Expressway (G1),Beijing-Shanghai high-speed (G2), Beijing-Taiwan high-speed (G3) and Beijing-Hong Kong and Macao high-speed (G4). In addition, it also included the Fifth Ring Road in Beijing; more serious areas of the haze weathers occurred in Nanjing area were mainly distributed in the main city and the Qixia Chemical Industry Park, the traffic block of the G104, G205, S002, S104 highways in Nanjing section through these areas were more serious. |
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