AgI-seeding should be done before the activation of most ice nuclei start, so as to enhance rainfall through increasing ice crystals content, and deleting super-cooled cloud water.

• 结果表明，该地区秋季对流云降水主要为冷云降水，冰晶是霰产生的主要来源，冰霰自动转化是霰产生的最主要方式，冰晶与霰的碰并又促进了霰的进一步增长，霰是云中过冷水消耗的主要因素。