Elperin Tov, Fominykh Andrew, Krasovitov Boris
Department of Mechanical Engineering, The Pearlstone Center for Aeronautical Engineering Studies, Ben-Gurion University of the Negev, P.O.B. 653, 84105 Beer-Sheva, Israel.
J Environ Radioact. 2015 May;143:29-39. doi: 10.1016/j.jenvrad.2015.02.001. Epub 2015 Feb 25.
We analyze effects of inhomogeneous concentration and temperature distributions in the atmosphere, rain droplet evaporation and radioactive decay of soluble gases on the rate of trace gas scavenging by rain. We employ a one-dimensional model of precipitation scavenging of radioactive soluble gaseous pollutants that is valid for small gradients and non-uniform initial altitudinal distributions of temperature and concentration in the atmosphere. We assume that conditions of equilibrium evaporation of rain droplets are fulfilled. It is demonstrated that transient altitudinal distribution of concentration under the influence of rain is determined by the linear wave equation that describes propagation of a scavenging wave front. The obtained equation is solved by the method of characteristics. Scavenging coefficients are calculated for wet removal of gaseous iodine-131 and tritiated water vapor (HTO) for the exponential initial distribution of trace gases concentration in the atmosphere and linear temperature distribution. Theoretical predictions of the dependence of the magnitude of the scavenging coefficient on rain intensity for tritiated water vapor are in good agreement with the available atmospheric measurements.
我们分析了大气中不均匀的浓度和温度分布、雨滴蒸发以及可溶性气体的放射性衰变对降雨清除痕量气体速率的影响。我们采用了一个放射性可溶性气态污染物降水清除的一维模型，该模型适用于大气中温度和浓度的小梯度以及非均匀初始高度分布情况。我们假设雨滴满足平衡蒸发条件。结果表明，降雨影响下浓度的瞬态高度分布由描述清除波前传播的线性波动方程决定。通过特征线法求解得到的方程。针对大气中痕量气体浓度呈指数初始分布且温度呈线性分布的情况，计算了气态碘 - 131 和氚化水蒸气（HTO）湿清除的清除系数。氚化水蒸气清除系数大小对降雨强度依赖性的理论预测与现有的大气测量结果吻合良好。
