Snow grows by collecting supercooled water, and rain water is converted into graupel by collection of snow, and graupel melting is the main source of rain water.

• 冰晶繁生、雪的凝华和撞冻过冷云水增长、雨水撞冻雪转化为霰、霰融化成雨水是降水粒子的最主要源项微物理过程。