泰山酸雨特征及影响因素分析

利用2006—2015年泰山气象站的降水pH、电导率、降水量和风向风速资料，统计分析了泰山酸雨特征和变化趋势，探讨了降水量和风向风速对酸雨的影响。结果表明，泰山降水年均pH变化范围为4.31～4.99，酸雨发生频率达到69.3%；pH随降水量的增加而趋于5.60（中性）；5月至次年1月的月均pH与月平均过程降水量的变化趋势一致；月均电导率与月平均过程降水量的变化趋势相反。泰山降水期间盛行西南风，在南风和东北风条件下，酸雨出现频率最高且酸性最强，这主要是风速风向因素和人为排放源分布共同导致的。近10 a泰山降水酸性程度有所减弱，酸雨频率明显下降，表明近年来酸雨污染情况有所改善，有利于保护泰山生态环境。

Characteristics and influencing factors of the acid rain at Mount Tai

The characteristics and variation trend of the acid rain from 2006 to 2015 at Mount Tai are statistically investigated based on the pH value, conductivity, amount of precipitation, wind direction, and wind speed, and the influence of the amount of precipitation, wind direction and wind speed on the acid rain at Mount Tai are also analyzed. The results show that the annual mean pH value of precipitation ranges from 4.31 to 4.99 and the frequency of acid rain is up to 69.3% at Mount Tai. As the amount of precipitation increases, the pH value tends to reach 5.60 (neutral). A similar variation trend is observed of the monthly mean pH value and the monthly process-averaged precipitation from May to next January, while the monthly mean conductivity presents an opposite trend with the monthly process-averaged precipitation. Southwesterly winds prevail during precipitation processes at Mount Tai. The southerly and northeasterly winds bring the highest frequency of acid rain and the highest acidity at Mount Tai, which could be attributed to the wind speed and wind direction as well as the distribution of anthropogenic emission sources. In the past decade, both the precipitation acidity and the frequency of acid rain at Mount Tai tend to decline, which indicates the improvement of acid rain pollution and is of significant importance for protecting the ecological environment of Mount Tai.