Characteristics of Raindrop Spectrum in different areas of Ningxia during Summer

To investigate the microphysical characteristics of summer precipitation in the Northern Yellow River Irrigation Area, the Central Arid Zone, and the Southern Mountainous Area of Ningxia, this study analyzed disdrometer data collected from Yinchuan, Yanchi, and Liupanshan stations from 2022 to 2024. A comparative analysis of Raindrop Size Distribution (RSD) was conducted from the perspectives of the overall dataset, different rainfall rates, and precipitation types. The results indicate that the average RSD at Liupanshan station is broader with a higher number concentration of small raindrops, whereas the average RSD at Yinchuan station is narrower with a higher concentration of mid-size raindrops. Under different rainfall rates and precipitation types, the number concentrations of both small and large raindrops increase with rising altitude. Specifically, when the rainfall rate is less than 2mm·h^-1, the mass-weighted mean diameter (D_m) gradually decreases while the normalized intercept parameter (log₁₀N_W) increases with altitude. When the rainfall rate exceeds , the log₁₀N_W at Yanchi and Liupanshan stations surpasses that of Yinchuan station, whereas the D_m is smaller than that of Yinchuan. Furthermore, for a given shape parameter (µ), the slope parameter (⋀) increases with altitude. In convective precipitation events, the empirical relationships tend to overestimate the rainfall intensity at all three stations when the rainfall rate exceeds 20mm·h^-1.