This is when a layer is made up of very, very cold water droplets, and in one region they start to freeze, and this freezing sets off a chain reaction which spreads outwards with the ice crystals cascading and falling down below, giving the appearance of jellyfish tendrils down below.
这是当某个云层由非常寒冷的水滴组成， 在某个局部地区水滴开始结冰， 然后形成一种向外扩散的 伴随着冰晶向下坠落的链式反应， 使之呈现一种水母的须状表象。