| Sulfur dioxide (SO2) is an important trace gas in the atmospheric, and is one of gaseous pollutants seriously impact on human. SO2acid deposition harms human health and ecological environment. SO2and other pollutants have been increasing constantly in the past20years because of rapid economic development in China. The eastern China was polluted as the most serious air dirty and acidic area in the world. A large number of emissions of acidic gaseous pollutants of SO2and NO2are the necessary condition for the formation of acid rain, so with the increase in SO2emission of SO2, acid rain pollution becomes increasingly serious. Acid rain areas are mainly distributed in Central China, East china, Southwest China, the coastal areas of South China, most areas of North China and southeast of the Northeast, showing a northeast-southwest trend. Acid rain areas which lie in south of the Yangtze River became the center of acid rain in the world. Acid rain polluted areas south of the Yangtze River is expanding to north and east, that include central of South China and Central China, as well as middle and lower reaches of the Yangtze River. Therefore, the study of the spatial and temporal variations of tropospherie SO2as well as the relationship between SO2and acid rain pollution in China is of great significance.This study aims to understand the spatial and temporal variations and pattrens of SO2on China by using tropospherie SO2column dataset retrieved from SCIAMACHY during January2004to December2010. The impact factors of SO2were analyzed using meteorological data, population density and GDP data, DEM as well as land cover data together with the satellite observations. And then, acid rain pattern and its relationship between tropospherie SO2were analyzed taking for Zhejiang Province as case. The results show that: (1) The spatial and temporal distribution of tropospheric SO2is very uneven in China, which the SO2vertical column densities were very high in North China and East China, and the densities were very low in the vast West China and in the north of Northeast China. The SO2column in economic zones of the Bohai Rim region, Yangtze River Delta and Pearl River Delta was much higher than the national averaged SO2density. The order of annual concentration of SO2columns was as follows:the Bohai Rim region>the Yangtze Delta> the Pearl Delta>the whole territory of China>Tibet region. Shandong Province, Tianjin City, Hebei Province, Henan Province and Jiangsu Province have the highest SO2concentrations while Xinjiang Uygur Autonomous Region, Tibet Autonomous Region, Taiwan Province, Hainan Province and Heilongjiang Province have the lowest SO2concentration.(2)32provinces can be broadly classified into five categories according to the characteristics of tropospheric SO2concentration trends based on cluster analysis. Human activities have a decisive impact on the spatial and temporal distribution and change of tropospheric SO2.Additionally, climate conditions, terrain together with land and sea location also have important roles on SO2distribution.(3) The seasonal variations of SO2columns is obvious, it has the highest concentration in January, November and December each year, and has the lowest concentration in March, April and May each year. However, Seasonal variations have differences in different regions of China.(4) The SO2vertical column density got to lowest in2004and measured up to highest in2010, showing a trend with increase-decrease-elevated. The SO2emission declined after2006because of strict implementation of sulfur emission restrictions, so tropospheric SO2changed in2007as a turning point.(5) The impact factors as climate conditions, terrain, land cover, population density and GDP will affect the spatial and temporal variations of tropospheric SO2. Analysis showed that the correlation coefficient between temperature and SO2is highest. While in the three economic zones, meteorological factors do different affects on SO2. And we found that the SO2column on article surface and farmland was highest revealing that SO2emissions are higher in human activities’areas.(6) As an important precursor for acid rain formation, SO2can affect the distribution and changes of acid rain. In this study, taking Zhejiang Province as a typical case, we analyzed the acid rain in Zhejiang and found that heavy acid rain area are located in central-north and east and west in Zhejiang, which are the densely populated and industrial-agricultural developed areas. Acid rain pollution changes seasonally with heaviest in the first quarter and lightest in the third quarter. In this research, negative correlation existed between acid rain pH values and tropospheric SO2column, and pollutant sources were both from local SO2emission and long-distance transmission. |
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