Abstract:Based on the millimeter wave radar data and sounding temperature data obtained from the third Qinghai Tibet Plateau Atmospheric Scientific Experiment during July-August 2014, this study inverses the phase of cloud hydrometeor in summer in Nagqu, Tibet with the fuzzy logic method and conducts analysis research on its distribution features. Firstly, the typical cases of stratocumulus, nimbostratus, and deep convective clouds are analyzed, and it is found that the vertical distribution of reflectance factor, Doppler velocity, velocity spectrum width and depolarization factor of the three types of clouds are quite different, and the characteristics of radar measurements and distribution of hydrometeor phase are also quite different. Secondly, radar reflectivity characteristics of liquid, mixed and ice clouds are studied, which shows that both warm clouds and supercooled water have high value centers of reflectivity factor. The reflectivity distribution center of mixed clouds is invariable with height. The high reflectivity factor of ice cloud is mainly over 6 km and tends to concentrate with the increase of altitude. The high frequencies of the three phase clouds are concentrated at the heights of 1 km, 2-3 km and 3-4 km above the surface respectively. The frequency of liquid phase clouds is the highest in the morning, the frequency of mixed phase clouds is high in the afternoon and the frequency of ice phase clouds is the highest in the evening. The heights of three phase clouds in the morning are lower than that in the afternoon and evening, and the perpendicular range maximizes at night. The thickness of liquid phase clouds is generally less than 0.3 km, and the average thickness of ice phase clouds is the largest when the top of ice phase clouds is located at about 9 km height, while the thickness of mixed phase and ice phase in mid level clouds varies only a little.