三江源地区对流云吸湿性催化的数值模拟

采用二维分档对流云模式,模拟研究了不同的云凝结核(CCN)背景下三江源地区对流云及其降水的发展,以及吸湿剂的催化效果。结果表明:该地区对流云以冰相过程为主,霰粒子在降水发展过程中具有支配性的作用;初始CCN数浓度增加使降水延迟、降水量减少;催化效果在初始CCN数浓度较高的环境下更好;在云发展的早期,于云底上升气流区播撒吸湿剂,能够获得较好的降水增加效果;对催化结果起决定作用的是粗粒子,小粒子对催化起到负作用。这些结果表明,在合理的催化方案下对该地区作吸湿性催化能得到较为理想的增雨效果。

Numerical simulation of hygroscopic seeding of convective clouds in the origin area of Three Rivers

A 2D slab-symmetric nonhydrostatic cloud model was used to simulate the evolution of convective clouds and precipitation under different CCN(Cloud Condensation Nuclei) conditions in the origin area of Three Rivers in Qinghai-Xizang Plateau.Furthermore,the effects of various hygroscopic seeding on the precipitations were also investigated.Results showed that:(1) with the initial concentration of CCN increasing,the initial time of precipitation delayed,and the total amount decreased;(2) the hygroscopic seeding in such conditions with high initial concentration of CCN would get more effective result of precipitation enhancement than others;(3) it can achieve the rainfall enhancement when seeding was conducted a few minutes after the cloud initiation and above the base of cloud.It was found that the most effective particles were those with radius larger than 1μm,the particle smaller than 1μm had a negative effect on the rain development.The result suggests that the hygroscopic seeding has a positive effect on the rainfall enhancement of convective clouds in the local area.