四川中东部地区2009年大气硫沉降模拟

摘要

采用第三代公共多尺度空气质量模型Models-3/CMAQ,对四川中东部地区2009年1月、4月、7月和10月SO2排放所产生的硫沉降分布进行数值模拟研究,并且将该模型输出的ρ(SO2)、SO42-湿沉降量分别与地面层的ρ(SO2)、降水中SO42-湿沉降量实测值进行相关分析,探讨硫沉降的季节、区域分布特征及湿沉降变化.结果表明:ρ( SO2)模拟值与实测值的R(相关系数)为0.445,SO42-湿沉降量模拟值与实测值的R为0.510;四川中东部地区夏季硫沉降量为2.2×104 t,高于其他三季,冬季最小,为1.0×104 t；硫沉降呈三大片区分布,宜宾、乐山、泸州为高值分布区,资阳、遂宁、南充、广安和达州均属于硫沉降低值区,成都、德阳、绵阳片区属硫沉降次高值区；于沉降中SO2沉降量在各季所占比例均在85％以上,湿沉降中各季SO42-沉降量所占比例均在99％以上.%Using the third Community Multiscale Air Quality Modeling System ( Models-3/CMAQ) ,the sullur deposition produced by sulfur dioxide emissions in the eastern and central regions of Sichuan in January,April,July and October of 2009 was simulated. Correlation analysis was performed between the modeling results and monitoring data for SO2 concentrations in the surface layer and for SO42+ wet deposition. The seasonal and regional sulfur deposition distribution characteristics were discussed. The results showed that; 1 ) the correlation coefficient between the modeling results and the daily SO,concentration monitoring data was 0.445,while that for SO4" deposition in precipitation was 0. 510; 2) the amount of sulfur deposition in summer was about 22,000 t,which was the highest among the seasons,and the least amount was found in winter (ca. 10,000 t) ; 3) Sulfur deposition was characteristically distributed in three regions,with the highest distribution in the Yibin-Leshan-Luzhou region,the second highest distribution in the Chengdu-Deyang-Mianyang region and the lowest distribution in the Ziyang-Suining-Nanehong-Guang' an-Dazhou region; 4) In every season,the proportion of SO,deposition to the total dry deposition amount was over 85% ,and the contribution of sulfate deposition to total wet deposition amount was over 99% .