Analysis of Microphysical Characteristics near the Melting Layer in Stratiform Precipitation with Embedded Convection in East China

The microphysical characteristics of the melting layer in clouds have a critical impact on cloud structure and precipitation formation. Utilizing the Airborne Ka-Band Precipitation Cloud Radar (KPR) and in-situ observation instrument onboard the King Air 350 aircraft of the Weather Modification Center, CMA. This study analyzed the cloud microphysical characteristics near the melting layer during stratiform precipitation with embedded convection in east China on September 15, 2023. The results show that above 0℃, the particles in the cloud mainly gather and grow through rime, and the aggregated graupel particles are the main ones. When the ice phase particles falling and melting after 0℃, graupel particles and large ice crystals melting and gradually transform into small droplets. With the decreasing of the altitude, the radial velocity and spectrum width of KPR gradually increased, indicating that the size of precipitation particles in the cloud increased, the relative velocity of particles soared, and the particles are more likely to collide and grow, and then small droplets grow into large droplets through the collision process. By fitting cloud and precipitation particle spectrums, it is showed that Gamma distribution can fit cloud and precipitation particle spectrums well. Above the 0℃ layer, the slope of cloud droplets spectrum increases with decreasing-altitude, and the precipitation particle spectrum decreases with decreasing-altitude. However, below the 0°C layer, the slopes of both spectra initially increase and then decrease with decreasing-altitude.