Hailstone structures have been studied for over a century, but so far mainly by manual optical means. This paper presents new texture and microstructure data (i.e. crystal lattice orientations, grain sizes and shapes) measured with an Automatic Ice Texture Analyzer, which gives access to high spatial and angular resolutions. The hailstones show two main characteristics: (1) they are structured with several concentric layers composed of alternating fine equiaxed grains and coarse elongated and radially oriented grains, and (2) they show two texture types with c-axes oriented either parallel or perpendicular to the radial direction. Such textures are compared with the ones observed in lake S1 and S2 ices, respectively. The S1 texture type (with c-axes parallel to the columnar crystals that grew in the radial direction) may result from epitaxial growth from a polycrystalline embryo, while the S2 texture (c-axes in the plane perpendicular to the column direction) may result from the growth from an embryo made of a few crystals with mainly one crystallographic orientation. Our novel high-resolution maps and measurements of both microstructure and texture may help to shed new light on the long-term discussion on the growth mechanisms of large hailstones.

中文翻译：

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使用自动化技术对一些大型冰雹进行纹理表征

冰雹结构已经研究了一个多世纪，但到目前为止主要是通过手动光学手段。本文介绍了使用自动冰质地分析仪测量的新纹理和微观结构数据（即晶格取向、晶粒尺寸和形状），该分析仪可以获得高空间和角度分辨率。冰雹具有两个主要特征：（1）它们由多个同心层构成，由交替的细等轴晶粒和粗拉长和径向取向的晶粒组成；（2）它们显示出两种纹理类型：C-轴平行或垂直于径向方向。这些纹理分别与在湖 S1 和 S2 冰中观察到的纹理进行了比较。S1 纹理类型（与C-轴平行于径向生长的柱状晶体）可能是由多晶胚的外延生长产生的，而 S2 纹理（C垂直于列方向的平面中的轴）可能是由由少数晶体组成的胚胎生长产生的，这些晶体主要具有一个晶体学取向。我们新颖的高分辨率地图和微观结构和纹理测量可能有助于为长期讨论大型冰雹的生长机制提供新的思路。