论文标题
大气中冰的表面相变和晶体生长速率
Surface phase transitions and crystal growth rates of ice in the atmosphere
论文作者
论文摘要
随着气候建模预测到2100年至少提高2 C，冰的命运已成为一个严重的关注，但我们仍然不了解冰的生长（或融化）。在大气中，基础和棱镜面的晶体生长速率表现出神秘的温度依赖性，并且在0到-40 C之间的范围内最多三倍。在这里，我们使用大型计算机模拟来表征冰表面并识别冰晶主要方面上新型相变的序列。出乎意料的是，我们发现，随着温度的升高，晶体表面从随着步骤扩散的无序相变为平滑相，台阶密度较小。这会导致步骤自由能的异常增加，并为大气中发现的雪晶体生长速率的神秘跨越提供了长期寻求的解释。
With climate modeling predicting a raise of at least 2 C by year 2100, the fate of ice has become a serious concern, but we still do not understand how ice grows (or melts). In the atmosphere, crystal growth rates of basal and prismatic facets exhibit an enigmatic temperature dependence, and crossover up to three times in a range between 0 and -40 C. Here we use large scale computer simulations to characterize the ice surface and identify a sequence of novel phase transitions on the main facets of ice crystallites. Unexpectedly, we find that as temperature is increased, the crystal surface transforms from a disordered phase with proliferation of steps, to a smooth phase with small step density. This causes the anomalous increase of step free energies and provides the long sought explanation for the enigmatic crossover of snow crystal growth rates found in the atmosphere.
