安徽省酸雨分布特征和发展趋势及其影响因子

利用气象部门7个酸雨观测站资料、安徽及周边部分省份煤耗量、卫星观测的对流层NO2柱含量资料,分析了安徽酸雨的空间分布、发展趋势及酸雨发生频率上升的原因;同时,借助轨迹分析和聚类分析的方法分析了输送形势对各地酸雨的影响.2006～2008年间安徽酸雨频率表现为夏季低、秋季高,3 a降水均值呈酸性,其中合肥、安庆、马鞍山和蚌埠为中度酸性.在空间分布上表现为皖南到江淮之间最为严重,向北递减.阜阳、铜陵和黄山的降水pH值比较集中,各有75%以上位于6.00～7.50(阜阳)、5.00～6.00(铜陵)和5.00～6.50(黄山);其它测站的pH值分布范围比较大,峰值分别位于4.00～4.50(合肥和安庆)、5.00～5.50(马鞍山)和5.50～6.00(蚌埠).与10 a前相比,各地酸雨发生频率都大幅度上升.后向轨迹-聚类分析结果表明,酸雨发生频率与污染物的外来输送密切相关,各地都是来自偏东南到偏东北方向,尤其是经过江苏或浙江的气团对应着最高的中度以上酸雨发生频率,说明长江三角洲等经济发达地区的大气污染物排放对安徽酸雨有较大贡献.统计分析发现合肥酸雨变化趋势与安徽、浙江和江苏的煤耗量、对流层NO2柱含量的变化趋势都很一致(相关系数均大于0.7),再次说明该市酸雨增多、变强与区域污染物排放有密切联系.

Spatiotemporal Trends and the Impact Factors of Acid Rain in Anhui Province

The observational data of acid rain at seven stations in Anhui province operated by China Meteorological Administration (CMA), as well as the coal consumptions in Anhui and some surrounding provinces along with satellite measured tropospheric NO₂ columns, were used to analyze the spatiotemporal trends of acid rain in Anhui and the potential reasons of the increasing occurrence frequency of acid rain. In addition, the technique of back-trajectory-cluster analysis was used to examine the impacts of transport patterns on the precipitation acidity in Anhui. The occurrence frequency shows the lowest in summer and the highest in autumn, with 3-year average pH <5.6 during 2006-2008 at all stations, hereinto, pH values are between 5.0 and 4.5 in Hefei, Anqing, Maanshan and Bengbu. In spatial, acid rain were the most severe in southern to middle Anhui and mitigated to north. The distributions of pH were concentrative at Fuyang, Tongling and Huangshan, with more than 75% occurred between 6.00-7.50 (Fuyang), 5.00-6.00 (Tongling) and 5.00-6.50 (Huangshan); quite dispersive at other stations, with the maximum at 4.00-4.50 (Hefei and Anqing), 5.00-5.50 (Maanshan) and 5.50-6.00 (Bengbu). The occurrence frequencies of acid rain increased evidently at all stations comparing with those in the end of 1990s. The results of back-trajectories-cluster analysis show that the acid rain is closely related with the regional-range transport of acid rain precursors at each station. The air-masses from southeast and northeast, especially those passing through Jiangsu and Zhejiang, associated with the highest frequencies of acid rain with pH <5.0, indicating that the industrial emissions in the economy developed areas of Yangtze Delta play key roles in acid rain in Anhui province. In addition, statistics shows that the occurrence frequency of acid rain in Hefei was highly correlated with the trends of the provincial coal consumptions in Anhui, Jiangsu and Zhejiang, also tropospheric NO₂ column content over Anhui province and surrounding areas with all correlation coefficients >0.7, suggesting the close relationship between the quick increasing acid rain in Hefei and the regional pollutant emissions.