对流云云中酸化的数值模拟——Ⅰ.模式建立和初步结果

发展了一维半、时变、微物理过程参数化处理的对流云云雨酸化的物理-化学模式,较为全面地考虑了污染气体向液水的质量传输过程以及液相化学反应动力学过程.通过初步模拟发现,垂直上升气流会很快把低层高浓度SO_τ气体输送到云的上层,从而使酸化过程得到加强;云滴与雨滴微物理结构的不同,对污染气体的吸收影响很大,小的云滴比雨滴更易酸化,云、雨水对污染气体的吸收和云、雨水的比含水量有关.因对流云云内外交换强烈,液水吸收掉的污染气体量相对于环境场而言是很小的.

NUMERICAL SIMULATION OF ACIDIFICATION PROCESS IN CUMULUS CLOUD I. Model Establishment and preliminary results

A one-dimensional, time-dependent cumulus cloud model was proposed to study acidification of cloud water and rain water. The processes of mass transfer from polluted gases to liquid water and kinetics of chemical reaction were considered. Owing to the effect of convective current, the great amount of SO2 gas is transported from surface level into cloud, so that the acidification process in cloud is intensified. The rain drops has an important effect on the absorption of polluted gases. The acidification of cloud droplets is stronger than rain drops. The absorption of polluted gases by cloud and rain water is mainly correlated to the cloud and rain water content. Because of the strong exchange of air in cloud and out cloud, the quantity of polluted gases absorbed by liquid water is very low comparing with the contents of polluted gases in the environment.