云下雨滴蒸发产生硫酸盐气溶胶速率的研究

云下雨滴蒸发是雨滴下降过程中重要的物理过程，特别是当云下相对湿度较低时更为明显。本文建立了考虑雨滴蒸发的云下雨水酸化的物理化学模式，用以研究云下雨滴蒸发作用对各种大小雨滴及雨水酸化的影响，并估算了由于小雨滴的完全蒸发进入到大气中的硫酸盐气溶胶的生成速率。计算结果表明:这种小雨滴的完全蒸发使雨滴内化学反应生成的硫酸盐结晶进入大气，在降水初期云下相对湿度较小时，形成硫酸盐气溶胶的速率可达1% h-1，与气粒转化速率相当。

A Study of the Production Rate of Sulfate Aerosol Resulting from the Evaporation of Raindrops Falling below the Cloudbase

The evaporation of raindrops falling below the cloudbase is an important physical process, especially under the condition of low relative humidity below cloudbase. A physico-chemical model of subeloud acidification of rainwater including the evaporation of raindrops is used to study the effect of evaporation on acidification of raindrops and rainwater and to estimate the production rate of sulfate aerosol resulting from the total evaporation of small raindrops. The results show that at the beginning of the predpitation, when the relative humidity below cloudbase is low, the conversion rate of sulfate acrosol by evaporation can reach 10 % h-1, which is comparable to gas-marticle conversion.