Abstract:
This study investigates the vertical structure characteristics of typhoon precipitation over three different terrains in Zhejiang East Plain, hilly areas, and mountainous regions, with a focus on convective and stratiform precipitation during the core precipitation phase and the outer circulation precipitation phase of typhoon. The results are as follows. (1) When the typhoon echo top height in Zhejiang East is below approximately 6 km (close to the freezing level), the height of the radar reflectivity factor center increases with the uplift of terrain, and there is a significant positive correlation between echo top height and precipitation rate; however, when the echo top height exceeds 6 km, the correlation between echo top height and precipitation rate weakens. The echo top height of convective precipitation in typhoons is more dispersed, while that of stratiform precipitation is relatively concentrated and distributed at higher altitudes. (2) The high-frequency center of convective precipitation in typhoons is mainly distributed in the lower and middle atmosphere, corresponding to larger maximum particle diameters and lower particle number concentrations, with strong raindrop collision and coalescence effects. The radar reflectivity factor of stratiform precipitation in typhoons is widely distributed in the vertical direction, with vigorous and tightly structured cloud systems, but smaller maximum precipitation particle diameters and weaker intensity than convective precipitation. As terrain height increases, the center height of the radar reflectivity factor of stratiform precipitation decreases, while that of convective precipitation gradually increases. (3) As the terrain uplifts, the maximum value of the radar reflectivity factor near the freezing level shows a significant increase in height, and the particle number concentration of both types of precipitation decreases. The precipitation particle diameter in mountainous and hilly terrains is significantly larger than that in the plain terrain, indicating that the terrain effect enhances atmospheric instability, strengthens the vertical transport of water vapor, and enhances the raindrop collision and coalescence effects.