Formation of nitric acid/water ice particles in cirrus clouds
Formation of nitric acid/water ice particles in cirrus clouds
复制标题
卷云中硝酸/水冰颗粒的形成
DOI：
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发表时间：
2006
期刊：
影响因子：
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通讯作者：
Christiane Voigt
中科院分区：
文献类型：
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作者：
B. Kärcher;Christiane Voigt
在过去的十年里，在纬度53°S-68°N的空中实地活动中，测量了卷云冰晶中的硝酸（HNO 3）。在冰晶中的HNO 3含量，表示为HNO 3/H2O摩尔比，和HNO 3在冰中的分数从这些测量得到的表现出明显的上升趋势，随着温度的降低。观测解释了一种新的模型描述溶解的HNO 3在液体气溶胶粒子作为冻结核和随后的捕获HNO 3在冰晶生长过程中。捕集效率随温度的降低而增加。有效的捕获发生通过扩散掩埋的环境HNO 3低于约203 K，因为长停留时间的HNO 3分子在冰表面。这为HNO 3诱导的影响冰晶生长的过程的修改打开了可能性。在较温暖的温度下，冰表面层中的分子过程导致吸附的HNO 3越来越快地逃逸到气相中，尽管冰的生长速率更快，但捕获效率更低。
Nitric acid (HNO3) in cirrus ice crystals has been measured in the last decade during airborne field campaigns at latitudes 53°S–68°N. The HNO3 content in ice crystals, expressed in terms of HNO3/H2O molar ratio, and the fraction of HNO3 in ice derived from those measurements exhibit a clear upward trend with decreasing temperature. The observations are explained by a novel model describing dissolution of HNO3 in liquid aerosol particles serving as freezing nuclei and subsequent trapping of HNO3 during ice crystal growth. The efficiency of trapping increases with decreasing temperature. Efficient trapping occurs via diffusional burial of the ambient HNO3 below about 203 K, because of long residence times of HNO3 molecules at the ice surface. This opens the possibility for HNO3‐induced modifications of processes affecting ice crystal growth. At warmer temperatures, molecular processes in the ice surface layer cause an increasingly rapid escape of adsorbed HNO3 into the gas phase and render trapping less efficient despite faster ice growth rates.