Analysis Of Temporal-spatial Characteristics Of Aerosol In Hangzhou Based On CE-318 And Satelliteremote Sensing Data

Along with the fast economic development in recent two decades, the Hangzhou district was experiencing rapid environmental changes. Recent studies had indicated that the aerosol particles play an important role in the environmental changes. However, there were some considerable uncertainties in estimating aerosol effects due to poor understanding of aerosol optical properties. In this study, CIMEL Sun/sky scanning spectral radiometers was installed in Hangzhou district. Continuous measurements were taken to analyze the diurnal and seasonal variations of aerosol optical properties in the different sites, and discussed the aerosol optical properties over this region.Firstly: Aerosol optical properties including Aerosol Optical Depth(AOD) and the ?ngstr?m exponent(α) were examined using ground-based measurements at three sites in the Hangzhou district: Hangzhou(120.01°E, 30.26°N), Linan(119.73°E, 30.26°N)and Qiandaohu(119.05°E, 29.55°N). The results from the observations showed that: AOD of Hangzhou station was the maximum. The AOD’s monthly mean peaks of Hangzhou station appeared in February June and September, and the maximum was in June. The AOD’s monthly mean of others stations were the same as the Hangzhou station. The seasonal mean of AOD of each stations changed greatly in different season. Fine particles contribution rate of AOD was highest in Linan station, coarse particle contribution rate of AOD was highest in Qiandaohu station, and the Hangzhou station was in the middle.Analyzing of the Aerosol optical properties of different underlying surfaces, we can found that: different underlying surfaces had the same change law in monthly changes, and the seasonal variation was the different in different underlying surfaces. The value of AOD was highest in unban, coarse particle contribution rate of AOD was highest in country.Secondly: Moderate resolution imaging spectro-radiometer(MODIS) aerosol product Collection 005 was used to characterize the distribution and seasonal variation trends of AOD over the Hangzhou district during 2007-2013. Results showed that: The yearly averaged AOD550 over the cities was larger than those over the mountainous area, and the AOD over urban was also larger than those of rural area. Seasonal variation analysis of AOD550 revealed that the peak values appear in spring and the lowest values appear in autumn and winter.Thirdly: The results of HYSPLIT backward trajectory model showed that: Due to the effect of monsoon, Hangzhou area had obvious seasonal change. The south airflow from offshore and the northeast flow from the inland were the typical transport ways of this area. The potential AOD pollution source had more correlation to local pollution than the long distance conveying pollution.