What is rime?

Rime is a natural phenomenon similar to the first frost that can be seen in the cold northern winter, and it is actually a kind of frost. Granular frost crystals, called rime, are white opaque granular structure deposits formed by ice crystals on objects below freezing point. When supercooled water droplets (temperature below zero) collide with objects also below freezing point, rime will be formed. When water droplets are very small and freeze as soon as they touch objects, a rime layer or rime deposit will be formed. The rime layer is composed of small ice particles with pores between them, which leads to a typical white appearance and granular structure. Due to the rapid freezing of each supercooled water droplet, the cohesion between adjacent ice particles is poor and it is easy to fall off from the attachment. Rime is most likely to form at the top of the mountain surrounded by Leng Yun. This is also a common form of icing on airplanes. In cold weather, steam fog near springs, rivers, lakes or ponds can also form rime. According to the records of Jilin Meteorological Observatory, the rime season in Jilin generally starts from1late October 165438+ every year and ends in early March of the following year. There are two kinds of rime: one is that supercooled water droplets quickly freeze into small granular ice cubes after contacting cold ground objects, which is called granular rime and has a relatively compact structure. The other is the crystal rime formed by the condensation of supercooled droplets, which has a loose structure and will fall off with a little shaking. The place where rime occurs most frequently is Changbai Mountain in Jilin Province, with an annual average of 178.9 days, and the most frequent year is 187 days.