2003-2007年日照市酸雨变化特征与成因研究

根据2003-2007年日照市酸雨观测资料和气象观测资料，统计分析了近年日照市降水pH值的年变化、季节变化和强度月变化等，探讨了酸雨的变化特征，并对酸雨成因进行了初步分析。结果表明：日照市酸雨发生频率为20％，降水pH最低值为4．37，属较强酸雨，最高值为7．12，年平均值呈下降趋势，酸性逐渐增强；酸雨发生频率按季节呈冬、春、夏、秋季递减，月变化也表现出一定的规律性，月平均值未在酸雨标准以内，ESE风向、稳定性云系和轻雾天气现象容易产生酸雨；酸雨的出现与日照市当地地形、工业布局、外来源和自然源等因素有密切关系。

Characteristics of acid rain and its forming reason from 2003 to 2007 in Rizhao,Shandong province

Based on the acid rain observation data and the related meteorological data from 2003 to 2007 in Rizhao, annual, seasonal and monthly variations of precipitation pH were analyzed. The change characteristics of acid rain and its forming reason were discussed. The results indicate that the frequency of acid rain is about 20 %. The low- est pH value of precipitation is 4.37, and it belongs to the stronger acid rain. The highest pH value of precipitation is 7.12. The annual average values take on the descending trend, and pH value decreases gradually. The frequency of acid rain is the highest in winter, followed in spring, summer and autumn. The monthly changes also display some certain rules. The monthly average exceeds the standard of acid rain. Under the ESE wind direction, stable cloud system and light fog weather conditions, acid rain occurs easily. Acid rain weather is related to local topography, industry layout, outside source, natural source and so on.