By analyzing the dopp ler radar data of the strong convective weather p rocesses occurred in Zhangye city in 2006, the intensity characteristics of belt - shaped and block echoes are summarized. Radar echo characteristics of mesoscale system of strong convective weather p rocesses, including low - jet,warm advection, cold advection, contrary wind area and vertical wind shear, are analyzed. The echo features are quantified objectively, and the stability index is introduced. The concise criterion for feasibility short - time forecast is obtained.

The characteristics of Doppler radar echoes and products in the artificial rainfall enhancement operation in the middle section of the Qilian Mountain on July 1st，2005 were analyzed in this paper by using radar data. It shows that the large scale weather background which resulted in large range rainfall echoes keeping for long time，and weather modification caused this rainfall process together，and the intensity and the velocity fields present the mixed precipitation echo characteristics，especially remarkable during the rainfall enhancement phase. Results show that the convergence flow field on the velocity image，wind profile products and vertical integrated liquid water content（VIL）have specific instruction significance to prediction of rainfall area and rainfall moving system as well as ground precipitation；the 0 ℃ layer bright band on the base reflectivity image and the convergence flow field on the velocity image are important basis for rain enhancement opportunity and position. The spatial - temporal distribution characteristics of precipitation along the different heights above sea level in the mid - section of Qilian Mountain provide the study basis for examining the effects of rain enhancement. Additionally，the precipitation process was analyzed from the synoptic meteorology and physical quantity diagnoses in the paper.

In this paper, using annual precipitation data of 13 stations during 1960 to 2000, characteristics of spatial distribution of annual precipitation in Heihe field are analyzed and division of climate district is done with EOF and REOF methods. Tendency of annual pTCClpltatlOn  In  Helhe filled  1S  Stlldled by LISlng linear tendency eStlmatlOn.  On the base  Of ahOVe  analySlS,  pTCClpltatlOn Can  he pTedlCted In each dlVlded area and In dlffeTent SeaSOn .T1ITOLIgh Inarl}lng eXalnlmng,  It haS reached CCI'taln rate Of aCCLITaCy.  The TCSlllt of predlchon Is stahle,dependable and avallahle.

Climate characteristic of Heihe field was introduced in thispaper，the temperature and precipitation change in recent 40 years was analyzed also.  Results showed that Heihe field was changing warmer and its ecological environment was getting worse in strength of damage weather，woods area，soil desertification ,lake diminution andgrassland degradation.  Some suggestions about protecting ecolo乡cal environment of Heihe field were乡ven as well.