摘要
根据四川省气象部门所属6个酸雨观测站2006—2013年的资料,研究了四川省酸雨的时空变化特征。结果表明:6个酸雨观测站多年降水p H均值除成都属较强酸性外,其余5站多年p H均值都属弱酸性。成都多年酸雨出现频率最高,达到61.5%;安岳多年酸雨出现频率最低,仅为26.6%。安岳K值(电导率)多年平均值最高,达到82.9μs/cm;峨眉山K值多年平均值最低,仅为21.9μs/cm。四川近8 a降水p H平均值为4.74,2008—2010年为第一阶段,2011—2013年为第二阶段,总体看两个阶段年均p H值呈阶梯式上升,到2013年四川省酸雨p H值已上升至5.30,酸性降水出现频率已下降至35.2%,K值降至44.9μs/cm。由于四川春季平均风速较秋季偏高,更利于污染物扩散,故月均p H值变化呈现夏季的>春季的>秋季的>冬季的季节变化特征。月均K值则为冬季的>春季的>秋季的>夏季的,这是因为冬季、春季空气中排放的SO2、NOx和可溶性离子型化合物较多,在降雨较少的情况下增加了雨水的酸度,增强了可溶性离子型化合物的离子化,导致了电导率的增加。酸雨酸性强度呈两头小中间大,降水主要呈弱酸性,强酸性降水无明显季节性特征,累计降水量与强酸性降水也无明显联系。
Based on the acid rain data from six observation stations which belonged to the Sichuan Provincial Meteorological Bureau from 2006 to 2013, the temporal and spatial variation characteristics of acid rain of Sichuan province was studied. The results showed that except Chengdu, precipitation pH mean value of the other 5 stations belonged to weak acid. The acid rain frequency of Chengdu was the highest up to 61.5% , and that of Anyue was the lowest only 26.6%. The muhiannual mean K value （conductivity） of Anyue was the highest up to 82.9 μs/cm, but that of Mount Emei was the lowest only 21.9 μs/cm. The pH mean value of Sichuan precipitation was 4.74 in recent 8 years. The period of 2008 to 2010 was the first stage, and 2011 to 2013 was the second stage. Annual mean pH value of the two stages showed an ascending trend. The pH value of acid rain in Sichuan rose to 5.3 by the end of 2013, the acid rain frequency fell to 35.2% , and the K value fell to 44.9 μs/cm. Due to the average wind speed was higher in spring than in autumn, and the high wind speed was beneficial to pollutant diffusion, the seasonal precipitation pH value was in descending order from summer, spring, autumn to winter. The acid rain K value was in descending order from winter, spring, autumn to summer, because more SO2 , NOx and soluble ionic compounds sent into air in winter and spring, and it enhanced ionization of soluble ionic compounds, and led to the conductivity increase. Acid strength of acid rain was big in the middle and small at both ends, and the precipitation was mildly acidic. Strong acidic precipitation was not obviously season-related. There had no obvious relationship between strong acidic precipitation and accumulative precipitation.
出处
《气象与环境科学》
2015年第2期54-59,共6页
Meteorological and Environmental Sciences
基金
国家自然科学基金项目(51209024)资助
关键词
酸雨
PH值
电导率
酸性降水频率
acid rain
pH value
conductivity
acid rain frequency
