湖南衡山春季一次酸雨过程气象条件的数值模拟研究

采用MM5中尺度气象模式对湖南衡山2009年3月22~24日一次典型酸雨过程的气象条件进行了详细的数值模拟研究.模式模拟的降水场、流场、温度场、边界层结构与酸雨实测、实际天气图、地面站观测记录的对比表明,模式模拟的变化趋势与实况非常一致.研究表明,与广东春季典型的酸雨过程相比,衡山春季北面冷空气的入侵过程受地形作用明显,低层流场受北风影响较快,中高层较晚.广东、衡山两地春季酸雨发生前后整个边界层层结相对稳定,边界层高度较低,同时伴随有逆温过程,均不利于污染物的扩散输送,衡山春季酸雨发生前后的逆温和逆湿层都相对更低.

Numerical simulation research on the meteorological fields in a spring acid rain event over Hengshan region

An investigation was carried out for the weather conditions facilitating acid rains based on the reasonable model outputs from the MM5 mesoscale model. The acid rain event of interest occurred in the Hengshan region of Hunan province on 24 March 2009. This investigation revealed that a stable planetary boundary layer (PBL) with poor diffusion conditions played an important role in the acid rain event. The topography in the Hengshan region maked the relatively low layer suffer from the cold air earlier than the relative high layer, leading to the formation of the stable PBL. The stable PBL in the Hengshan acid rain case was thinner than that in a Guangdong province acid rain case.