The study of summer rainfall characteristics in the middle of the Qilian Mountains can provide weather background support for artificial precipitation enhancement by terrain clouds. Based on hourly surface meteorological observations and Temperature of Black Body (TBB) from FY-2G satellite during 2015-2017, the characteristics of rainfall and convection in summer and relationship between diurnal variation of rainfall and local circulation are investigated. The results show that the total rainfall amount of meteorological stations with an altitude less than 3.5 km in the middle of the Qilian Mountains increases linearly with the altitude, and in the eastern part (east of 99.2°E) it changes more sharply with the altitude than that in the western part. The diurnal variation of valley wind circulation and rainfall at Yeniugou and Qilian stations in the valley is more obvious than that at Gangcha Station near the Qinghai Lake. The maximum and sub-peak of rainfall at the two stations are in the evening and early morning, respectively, corresponding to the high frequency periods of the two main topographic clouds (cumulonimbus and stracumulus) in the region, and the average rainfall intensity is 2.0-2.3 and 1.0-1.3 mm·h^-1, respectively. Compared with Zhangye Station in Hexi Corridor, the peak value of TBB probability distribution at Qilian, Yeniugou and Gangcha stations in the Qilian Mountains changed from -22--12 ℃ to -32--22 ℃ under two kinds of rainfall intensity (less than 1.5 and more than or equal to 1.5 mm·h^-1). When the threshold of TBB <-32 ℃ is used to identify rainfall cloud, the coverage rate of rainfall cloud in the Qilian Mountains is lower than that in Hexi Corridor. The threshold of TBB <-22 ℃ is more suitable for the identification of weak convective rainfall clouds in the Qilian Mountains. In the study area, the high value areas of deep and shallow convection are distributed in the direction of north-south and northwest to southeast, respectively. The diurnal variation of shallow convective frequency based on TBB data can reflect some characteristics of diurnal variation of rainfall in this region.

After deducing external trajectory calculation method under non-standard atmospheric conditions for 37 mm anti-aircraft gun, which was widely used in the field of weather modification, the ballistic data in uniform cross wind and range wind field were simulated. The results show that the wind made a great influence on the flight path of projectile. The range wind can change the ballistic range by affecting the size and direction of air resistance. The cross wind can generate a lateral deviation of the trajectory along the wind by affecting the direction of the air resistance. On the same launch elevation angle, with the change of wind speed, the trajectory deviation correction caused by cross wind and the range correction caused by range wind showed a variation law that was similar to arithmetic progression. Through fitting analysis, the relationship among wind speed, elevation and trajectory correction was obtained，which can be used to estimate trajectory correction under arbitrary wind speed in actual operation.