Gao R S, Popp P J, Fahey D W, Marcy T P, Herman R L, Weinstock E M, Baumgardner D G, Garrett T J, Rosenlof K H, Thompson T L, Bui P T, Ridley B A, Wofsy S C, Toon O B, Tolbert M A, Kärcher B, Peter Th, Hudson P K, Weinheimer A J, Heymsfield A J
Aeronomy Laboratory, National Oceanic and Atmospheric Administration, Boulder, CO 80305, USA.
Science. 2004 Jan 23;303(5657):516-20. doi: 10.1126/science.1091255.
In situ measurements of the relative humidity with respect to ice (RHi) and of nitric acid (HNO3) were made in both natural and contrail cirrus clouds in the upper troposphere. At temperatures lower than 202 kelvin, RHi values show a sharp increase to average values of over 130% in both cloud types. These enhanced RHi values are attributed to the presence of a new class of HNO3-containing ice particles (Delta-ice). We propose that surface HNO3 molecules prevent the ice/vapor system from reaching equilibrium by a mechanism similar to that of freezing point depression by antifreeze proteins. Delta-ice represents a new link between global climate and natural and anthropogenic nitrogen oxide emissions. Including Delta-ice in climate models will alter simulated cirrus properties and the distribution of upper tropospheric water vapor.
在对流层上部的自然和凝结尾迹卷云中，对相对于冰的相对湿度（RHi）和硝酸（HNO₃）进行了原位测量。在低于202开尔文的温度下，两种云型中的RHi值均急剧增加，平均超过130%。这些增强的RHi值归因于一类新的含HNO₃冰粒子（δ-冰）的存在。我们提出，表面HNO₃分子通过一种类似于抗冻蛋白降低冰点的机制，阻止冰/汽系统达到平衡。δ-冰代表了全球气候与自然和人为氮氧化物排放之间的新联系。将δ-冰纳入气候模型将改变模拟的卷云特性和对流层上部水汽的分布。
