Abstract:Statistical analysis was performed on 404 samples of three body scatter spike (TBSS) in 18 storm cells of 10 severe hailstorm processes in Changde and the surrounding areas, and the causes influencing TBSS observation were analyzed in detail. The conclusions can be drawn as follows. (1) Reflectivity intensity is the key factor for TBSS. As a factor causes TBSS features, the minimum reflectivity intensity should be 58 dBz. The more it is above this critical value, the easier TBSS will come into being. (2) The peak of TBSS can be reached under the following conditions: at altitude of 4 km or so, 1.5° elevation, distance of 90 km or so, and the vertical distribution of the storm core echo intensity is a predominant impact factor during this process. (3) The frequency of TBSS is the most from 180° to 360°. Usually, longer length echo area in the leeward direction of wind storms can cause TBSS to be covered. This is the basic factor affecting the TBSS observation. The storm cells relative to the position and moving direction of radar usually decide whether there are echoes influencing TBSS observations in the radial outer side. (4) If intensity of TBSS echo and storm radial outer side weak echo are quite strong, the TBSS features can be identified from the storm radial outer side weak echo.