Ice Crystal Scavenging of C1 - C4 Alcohols and Ethylene Glycol

小行星9314358 过冷云滴被雪晶捕获（成霜）和沉积增长（来自蒸汽）是导致冰晶尺寸足以作为降水从中纬度对流层云中移除的机制。 在降雨过程中，云滴溶解的污染气体被合并到新生的降水颗粒中。 在这个过程中的气体清除效率已在实验室和现场实验进行了研究。在天然云在偏远的大陆山顶网站（麋鹿山天文台在东南部怀俄明州）和涉及亲水性化学物种，建议提供具体的信息在何种程度上痕量气体被纳入冰晶生长的气相沉积。 我们的实验策略是在水饱和的空气中生长附着在通风基底上的冰晶，该空气被预处理以去除过冷的云滴，并通过添加已知量的每种研究化合物（甲醇、乙醇或正丁醇）。 我们打算测量，作为在气相中的浓度的函数，量的研究化合物纳入样品冰晶。 所得的数据集将提供一个检查亲水性和取代基链长如何影响气体清除。 这些研究将得到补充的程度，环境量的这些正常的醇保留在冰形成的大米检查。 选择用于研究的化合物是感兴趣的，因为它们的寿命相对于冬季浓度的羟基自由基的反应一般是相当的估计寿命对应于在沉淀中去除。 因此，重要的是表征冰相水解物去除醇类以及其他亲水性化合物的效率。 此外，选择在大气中发挥重要作用的化合物。 除了这些研究，我们计划进行并行气相测量的xxx醇和无机物种xxxxxxxxxx使用无机气体作为示踪剂的空气污染的人为污染，生物和人为源过程的相对重要性，相应的低分子量醇将被检查。

9314358 Snider Capture of supercooled cloud droplets by snow crystals (riming) and depostion growth (from the vapor are the mechanisms which lead to ice crystal sizes sufficient for removal as precipitation from mid-latitude tropospheric clouds. During ricing, cloud-droplet-dissolved pollutant gases are incorporated into nascent precipitation particles. The efficiency of gas scavenging during this process has been studied in both laboratory and field experiments.conducted in natural clouds at a remote continental mountain-top site (Elk Mountain Observatory in southeastern Wyoming) and involving hydrophilic chemical species are proposed to provide specific information about the extent to which trace gases are incorporated into ice crystals growing by vapor deposition. Our experimental strategy is to grow ice crystals attached to a ventilated substrate in water-saturated air that is pre- conditioned to remove supercooled cloud droplets and by addition of known amounts of each study compound (either methanol, ethanol, or normal butanol). We intend to measur, as a function of concentrations in the gas-phase, the amount of study compound incorporated into the sampled ice crystal. The resulting data set will afford an examination of how both hydrophilic properties and substituent chain length affect gas scavenging. These studies will be complimented by an examination of the extent to which ambient amounts of these normal alcohols are retained in ice formed by ricing. The compounds selected for study are of interest because their lifetimes with respect to reaction with wintertime concentrations of hydroxyl radical are generally comparable to estimated lifetimes corresponding to removal in precipitation. Therefore, it is important to characterize the efficiency of removal for alcohols, as well as other hydrophilic compounds, by ice-phase hydrometeors. In addition, the selected compounds that play important roles in the atmosphere. In addition to these studies, we plan to conduct concurrent gas-phase measurements of the xxx alcohols and the inorganic species xxxxxxxxxx Using the inorganic gases as tracers of air contaminated by man-made pollution, the relative importance of biogenic and anthropogenic source processes corresponding to the low-molecular weight alcohols will be examined.