湖北省酸雨的时空分布规律及成因分析

根据多年来对湖北省酸雨的监测结果，报道了湖北省酸雨的时空分布规律。湖北省的酸雨主要分布在长江沿岸及以南和四川盆地以东的鄂西地区，降水的H^ 浓度由东向西、由北向南逐渐增大，酸雨的高峰期出现在夏秋两季。对降水中各离子成分的测定结果表明：致酸物质以SO2为主，各地的制酸机制和酸性物质来源与当地污染源排放情况和气象条件有关。由于接地逆温、大气稳定度和大气混合层高度在湖北东西部地区的明显差异，东部地区降水的酸性物质来源有大气输送和局地污染源排放两种，西部地区降水中酸性物质的来源以局地污染源排放为主。对1996—2000年的酸雨量比率和酸雨检出率进行Daniel趋势检验表明：湖北省的酸雨范围在逐渐扩大，污染程度有加重的趋势。

TEMPORAL AND SPATIAL DISTRIBUTION OF ACID RAIN IN HUBEI PROVINCE WITH A DISCUSSION ON THE CAUSE

The temporal and spatial distribution,cause and tendency of acid rain in Hubei province are studied according to recent ten years statistical monitoring results,the geographic conditions and acid gas emissions.The acid rain is distributed mainly in the areas along(mainly in south to)the Yangtze River and in Enshi prefecture.The pH in the rain decreases from north to south,from east to west.The acid rain is much more frequent in summer and autumn than in other seasons.It is certificated by the ionic monitoring that the acid rain in Hubei is sulphur-type acid rain.The acid rain formation is related mainly to local emission,remote transmission geographic condition and meteorological factors.For example acid rain in Enshi city is famous in whole province because of its local high-sulphur coal and mountain-valley topography.The rate of acid rain mass to total rain mass and acid rain frequency rate in recent five years is analysed by way of Danniel statistatics,indicating a polluting tendency.