Abstract

A 2D slab-symmetric nonhydrostatic cloud model was adopted with a statistical sounding measured in the Three Rivers' Headstream regions as the initial thermal field to analyze the characteristics of development of clouds and precipitations under two kinds of aerosol distribution in continental and marine backgrounds. Meanwhile, the effect of increasing natural ice on cloud precipitation is also discussed. The effects of various hygroscopic seeding on the precipitations under the marine and continental backgrounds were also studied respectively. Results showed that: 1)Marine background CCN distribution, due to the high concentration of large particles, made more rainfall than the continental background CCN spectrum which is consist of small particles and the rain fell much earlier in appearance of the marine CCN. Precipitation and precipitation rate significantly appeared larger compared with the second one; 2) Due to the increased number of the natural ice crystals, the continental and marine background precipitation delayed and total amount of rainfall reduced. The larger the number of ice crystals was, the more obvious reduction in precipitation happened; 3) Hygroscopic seeding for the continental background of cloud has significant effect on increasing precipitation, however, had an negative effect on the maritime background. These results suggest that aerosol precipitation has a significant effect on the rainfall of convective clouds in the Three Rivers' Headstream regions. As a result, the hygroscopic seeding of the rainfall in the region has some theoretical feasibility of operation.

Figer1 the distribution of the drop mass and number in 24min and 44min