A laboratory study of the uptake of HNO3 and HCl vapor by snow crystals and ice spheres at temperatures between 0 and −40°C
A laboratory study of the uptake of HNO3 and HCl vapor by snow crystals and ice spheres at temperatures between 0 and −40°C
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DOI：
10.1016/1352-2310(95)00022-q
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发表时间：
1995-05
影响因子：
5
通讯作者：
K. Diehl;S. Mitra;H. Pruppacher
中科院分区：
文献类型：
--
作者：
K. Diehl;S. Mitra;H. Pruppacher
描述了一个实验室实验，在该实验中，在ppbv和ppmv气体水平和0至−40°C的温度下，研究了树枝状雪晶以及单晶和多晶小冰球对HNO 3和HCl蒸气的吸收。在一项实验研究中，蒸汽被吸附在冰粒的表面上。在另一项实验研究中，在HNO 3和HCl蒸汽的存在下，允许冰粒从细纤维上的水蒸气生长。我们的实验结果表明，在这两种条件下，显着量的HNO 3和HCl成为清除的冰粒。在接近0°C的温度下，冰表面上存在准液体层，通过吸附对两种蒸气的清除作用最大。随着温度的降低，HNO 3和HCl蒸气的吸收量减少，并且随着温度的进一步降低，HCl蒸气的吸收量继续减少。相比之下，HNO 3的吸收在-18 °C附近达到最低值，随着温度的进一步降低再次强烈增加。的温度依赖性，这两种蒸汽的吸收的基础上，由蒸汽引起的表面熔化进行了解释。对于这种情况下，冰晶生长在相对于冰过饱和的气氛中，同时暴露于HNO 3或HCl蒸汽，我们注意到，气体清除是小于在简单的吸附由nongrowing晶体。我们的实验进一步表明，HNO 3一旦被冰粒吸收，如果冰粒保持在冰饱和状态，则不会解吸。我们的实验还表明，一些吸附的HNO 3和HCl扩散到冰粒。
A laboratory experiment is described during which the uptake of HNO3and HCl vapor by dendritic snow crystals and by single crystalline and polycrystalline small ice spheres was studied at ppbv and ppmv gas levels and at temperatures between 0 and −40°C. In one experimental investigation the vapor was allowed to be adsorbed onto the surface of the ice particles. During another experimental investigation the ice particles were allowed to grow from water vapor on fine fibers in the presence of the HNO3and HCl vapor. The results of our experiments show that under both conditions significant amounts of HNO3and HCl became scavenged by the ice particles. Scavenging by adsorption was maximum for both vapors at temperatures near 0°C where a quasi-liquid layer exists on the surface of ice. With decreasing temperature the uptake of HNO3and HCl vapor decreased and kept on decreasing for HCl with further decrease in temperature. In contrast, the uptake of HNO3reached a minimum near −18°C to increase again strongly with further decrease in temperature. The temperature-dependent ,uptake of both vapors were explained on the basis of surface melting caused by the vapors. For the case that the ice crystals were growing in an atmosphere supersaturated with respect to ice while simultaneously being exposed to HNO3or HCl vapor we noted that gas scavenging was less than during simple adsorption by a nongrowing crystal. Our experiments further showed that HNO3once taken up by an ice particle would not desorb if the ice particle remained at ice saturation. Our experiments also indicated that some of the adsorbed HNO3and HCl diffuses into the ice particle.