2006—2019年山西省酸雨变化特征分析

利用2006-2019年山西省五台山、大同、太原、长治、侯马5个站酸雨观测资料，分析山西省不同时间尺度上酸雨次数和频率、降水pH、电导率K值的变化以及空间分布特征，不同酸度各雨量等级酸雨频率变化特征。结果表明：2006-2019年山西省酸雨次数和酸雨频率均呈下降趋势，年平均pH值范围为5.43-6.49，年平均电导率K值范围为73.4-120 μs·cm^-1；四季中，秋季平均pH最小，为5.70，春季最高，为6.11，电导率K值春季较高；各月相比，9月酸雨pH值最低，为5.58，4月最高，为6.20，月平均酸雨频次和降水pH值呈负相关，相关系数R为0.96。各站相比，太原降水年平均pH以及电导率K值均显著高于其他城市，酸雨pH值依次为太原（6.90）>长治（5.95）>大同（5.71）>侯马（5.57）>五台山（5.55）。不同等级降水酸雨发生频率差别较大，小雨（1.0-10.0 mm）时酸雨发生频率最大，强酸雨和弱酸雨频率分别为54.9%和67.0%，当降水量超过10.0 mm以后强弱酸雨发生的频率均随降水量增加而减小。

Analysis on changing trend characteristics of acid rain in Shanxi province from 2006 to 2019

Using the acid rain observation data from five stations at Wutai Mountain, Datong, Taiyuan, Changzhi, and Houma in Shanxi province from 2006 to 2019, the changes and spatial distribution characteristics of the number and frequency of acid rain, precipitation pH, conductivity K value on different time scales in Shanxi province were analyzed. The change characteristics of acid rain frequency with different acidity and rainfall levels were revealed. The results showed that the number and frequency of acid rain in Shanxi province from 2006 to 2019 show a downward trend. The annual average pH value ranges from 5.43 to 6.49, and the annual average conductivity K value ranges from 73.4 μs·cm^-1 to 120 μs·cm^-1. Among four seasons, the average pH is minimum in autumn, which is 5.70, and the highest in spring, which is 6.11. The conductivity K is higher in spring. Compared with each month, the pH value of acid rain is lowest in September, which is 5.58, and the highest in April, which is 6.20. The monthly average acid rain frequency is negatively correlated with the pH value of precipitation. The correlation coefficient R is 0.96. Compared with each station, the annual average precipitation pH and the conductivity K value in Taiyuan are significantly higher than in other cities. The acid rain pH value is Taiyuan (6.90) > Changzhi (5.95) > Datong (5.71) > Houma (5.57) > Wutai Mountain (5.55). The frequency of acid rain in different grades of precipitation varies greatly. The frequency of acid rain is the largest when it is light rain (1.0-10.0 mm). The frequency of strong acid rain and weak acid rain is 54.9% and 67.0%, respectively. When the precipitation exceeds 10.0 mm, the frequency of strong and weak acid rain decreases with the increase of precipitation.