长三角城市群污染输送相互影响的敏感性试验

利用WRF-Chem模式,对2013年11月29日至12月11日长江三角洲地区的严重空气污染事件进行数值模拟,研究长三角核心区不同污染物本地源和外来输送所占比重。分析长三角核心区排放源对本地不同污染物浓度的污染贡献。结果表明,在2013年12月的这一次污染事件中,颗粒物平均本地贡献与外来输送基本比重相当;而SO_2、CO、NH_3、NO_x这4种气体污染物则以本地贡献为主,本地贡献的差异与气体的化学反应活性有关,活性越强本地贡献比重越大。污染过程中12月7日至12月9日00:00为污染最严重的时段,污染物的本地贡献有明显上升。区域间输送的方向和强度与地面风向、风速有紧密的联系。在边界层高度范围内,大部分污染物越往高空本地排放源的贡献越弱,外来输送主导作用增强,而硝酸盐在地面、1 km和1.5 km的本地贡献差异远小于其他污染物。

A Sensitivity Experiment of the Air Pollution Transport in Urban Clusters over the Yangtze River Delta

In this paper,the numerical simulation of the severe air pollution case over the Yangtze River Delta from November 29th to December 11th 2013 was conducted with WRF -Chem model.The objective of the simulation was to analyze the contribution of local emission sources and foreign transport .The results indicated that the contribution of particulate matter from the core region of Yan -gtze River Delta was almost equal to which from foreign transport .On the other hand,SO2 ,CO,NH3 and NOx were mostly provided by local emissions.The higher chemical activity a kind of gaseous pollutant had ,the more it would be contributed by local emission sources.The local contribution of pollutants obviously rose to a higher level during the most serious period from December 7th to De-cember 9th .The direction and intensity of transportation had a close relationship with the wind direction and speed .Within the boundary layer,the local contribution of most pollutants got smaller when the altitude got higher .That means on the top of boundary layer,the effect of foreign'transport controlled the concentration of pollutants .However,the contribution of local emission sources for nitrate changed slightly on the ground ,at the height of 1km and 1.5 km.