Numerical Simulation Of The Upper Reaches Of The Yellow River During The Artificial Rainfall Cloud Physical Observations And Precipitation Processes

In the river bason of Huanghe, it is in more and more serious shortage of water resources in these years. This situation did bring great losses to the economic development of the areas along the Huanghe River, such as Qinghai province, Ganshu province. From 1998 to 2000, Qinghai Meteorological Administration organized the experiment of rain enhancement in the upriver area of Huanghe River. Based on the data observed there, the feature of cloud precipitation had been analyzed briefly in this paper .The main results are showed below: (1) The number contents of ice nuclei in the upriver area of Huanghe are close to the results of eastern plain observed in the 60s. It is nearly ten percent of that of Peking in the 90s. (2) The experimental results on heterogeneous freezing nucleation of supercooled liquids showed that water melting from hail fr^oze before other rainfalls under the same conditions, which is in consistent with Vali抯 conclusions. (3) Based on the result of the numerical simulations of 3-D convective cloud model, graupel play⁽ an important role in the growth of raindrops and hailstones. Auto-conversion of ice to graupel contributed most embryo of graupel, while frozen raindrops can rarely appear. This conclusion coincides with some observations before. That is, ice is also very important in the process of precipitation. The sensitivity test of number contents of ice nuclei had also proved it. (4) According to the analysis, cold rain process is much more important than warm rain process. (5) The result of the numerical simulations of 3-D convective cloud model showed that seeding properly number of ice particles can increase the amount of rainfall.