中国环渤海地区SO2和NO2干沉降数值模拟及影响因子分析

摘要

利用耦合了Wesely大叶阻力干沉降模型的嵌套网格空气质量预报系统NAQPMS,对环渤海地区SO2和NO2的干沉降敏感因子、干沉降通量、空气质量进行模拟分析.结果表明,大气稳定度、太阳辐射、季节、下垫面类型为干沉降的主要敏感因子.大气越稳定,干沉降速率越小.太阳辐射越强,干沉降速率越大.SO2早秋干沉速率最小,冬季最大；NO2春、夏、早秋、晚秋的干沉降速率大致相同,冬季最小.SO2的干沉降速率在水面上较大,在沙漠上较小；NO2的干沉降速率在农田上较大,在水面上较小.由于不同敏感因子的共同作用,使得环渤海大部分地区SO2干沉降通量密度为0.05～0.25 μg/(m2.s),NO2干沉降通量密度均为0.05～0.30μg/(m2.s),高值区均主要分布在河北南部、山东西北部以及辽宁中部的部分地区.干沉降通量密度从大到小依次为秋季、春季、冬季和夏季,白天干沉降通量密度普遍大于夜间,且在渤海海面上也有一定的干沉降通量.由于干沉降、源排放、输送等作用的共同影响,使得环渤海地区SO2平均浓度为(5～20)×106,NO2平均浓度大致在(20～60)×10-6,高值区主要出现在河北南部、山东西北部以及辽宁中部的部分地区.夏季个别地区浓度较高,大部分地区浓度较低,春、秋、冬3季大部分地区浓度较高.%Nested air quality prediction modeling system (NAQPMS), had been coupled with the Wesely large leaf resistance dry deposition model from USA. The influencing factors of dry deposition and dry deposition flux of SO2 and NO2 in Bohai Rim area were simulated and analyzed. The main sensitive factors of dry deposition included atmospheric stabilities, solar radiation, seasons and surface pattern. The dry deposition velocity decreased with the increasing atmospheric stabilities and it rose more with intensive solar Radiation. The dry deposition velocity of SO2 had the minimum value in early autumn and the maximum value in winter. The dry deposition velocity of NO2 had the similar values during spring, summer, early autumn and late autumn, and reached its minimum value in winter. The dry deposition velocity of SO2 was maximum on the water surface while minimum in desert area. To dry deposition velocity of NO2 was lower on the water surface, while it remained higher on the farmlands. Because of the cumulative effect of different sensitive factors, the dry deposition flux of SO2 in the most of the research area remained between 0.05-0.25μg/(m2·s)whereas the dry deposition flux of NO2 was between 0.05-0.30μg/m2·s). The higher value were noted in the south of Hebei, north west of Shandong and middle of Liaoning province. For the four season the dry depositionrnflux was ranked as: autumn>spring>winter> summer. The dry deposition flux was larger in daytime than at night, it included some dry deposition flux of SO2 on the sea surface of Bohai region. In order of the effects of dry deposition, emission and transport, the concentration of SO2 in Bohai Rim was between (5-20)×l0-6, NO2 between (20-60)×l0-6. The maximum values of all the factors were observed in south of Hebei, north west of Shandong and the middle of Liaoning. The concentration was higher in summer in some area, while lower in most of the area, it remained higher during spring, autumn and winter.