The Comparation On The Precipitation Efficiency Between Windward Slope And High Altitude Region In The Eastern Tianshan Mountains

Mountain is one area of the most abundant cloud water resource on earth. The development of cloud water resource on mountain will become the focus of the development of water resources. Xinjiang is located in the center of the Eurasian continent, belongs to the typical arid and semi-arid continental climate, serious shortage of water resources, to develop upair water resources is an important measures. Understanding the characteristics of precipitation efficiency of Tianshan mountain in China is very important for the effective and reasonable development of upair water resources. On 16～17 April 2015, there was a heavy rain process in Tianshan mountain in Xinjiang province. Total 18h accumulated precipitation at wulumuqi station is 40.4 mm, to break the historical extremum.This case is the study case of this article. This article use NCAR FNL global analysis data to analysis atmospheric circulation background of this case. Research shows that:500 hPa isobaric surface, at the high latitude of Europe and Asia, has two trough and a ridge, the meridional circulation, there is a moving mesoscale short-wave trough at the balkhash lake, Tianshan mountain is located In front of the that trough, controlled by the southwest airflow. Ridge of the ural mountains development to the north, the same time this ridge bring the cold air supply to short-wave trough.700 hPa isobaric surface, there is one mesoscale short-wave trough near the balkhash lake, combinated of the northwest and southwest wind, tianshan is influenced by this short wave trough. As a cold front on the ground, at the same time the uplifting of the tianshan mountain terrain, provided the impetus for emergence of tianshan area heavy rain conditions.In this paper, using the mesoscale numerical model WRF V3.4 numerical simulation study on the precipitation process, mainly compared precipitation efficiency between the windward slope and the high altitude area. The results show that:the precipitation efficiency of the windward slope is more than that of the of high altitude region in this precipitation process, when the precipitation process is concentrated, precipitation efficiency is the most, about 60% and 60% respectively.when the precipitation process is concentrated, he column content of the total hydrometeors at the windward slop is lower than that of the high altitude region, the content of cloud water and rain at the windward slop are more than that of the high altitude region, the content of cloud ice and snow at the windward slop are less than that of high altitude region, the content of graupel difference is smaller.The comparation on the clouds between windward slope and high altitude region in the eastern Tianshan mountains results that the clouds of this precipitation is laminated hybrid cloud. The cloud of the high altitude region is more than that of the windward slope. The lower level of cloud are cloud water and rain, the middle of cloud is graupel, the top of cloud is cloud ice and snow, in clouds of two fifferent region. The biggest amount of different hydrometeors in clouds is snow. The precipitation mechanism of the windward slope is the melting snow and melting graupel. The precipitation mechanism of the high altitude region is snow.Because of the snow is far less than the falling speed of raindrops and graupel bead, so the precipitation efficiency and rainfall intensity of the windward slope is greater than that of the high altitude region.