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Three cases of microphysical characteristics and kinematic structures in the negative temperature region of summer mesoscale cloud systems over the eastern Tibetan Plateau (TP) were investigated using X-band dual-polarization radar. The time-height series of radar physical variables and mesoscale horizontal divergence δ ¯ derived by quasi-vertical profiles (QVPs) indicated that the dendritic growth layer (DGL, −20°C to −10°C) was ubiquitous, with large-value zones of KDP (specific differential phase), ZDR (differential reflectivity), or both, and corresponded to various dynamic fields (ascent or descent). Ascents in the DGL of cloud systems with vigorous vertical development were coincident with large-value zones of ZDR, signifying ice crystals with a large axis ratio, but with no obvious large values of KDP, which differs from previous findings. It is speculated that ascent in the DGL promoted ice crystals to undergo further growth before sinking. If there was descent in the DGL, a high echo top corresponded to large values of KDP, denoting a large number concentration of ice crystals; but with the echo top descending, small values of KDP formed. This is similar to previous results and reveals that a high echo top is conducive to the generation of ice crystals. When ice particles fall to low levels (−10°C to 0°C), they grow through riming, aggregation, or deposition, and may not be related to the kinematic structure. It is important to note that this study was only based on a limited number of cases and that further research is therefore needed. [ABSTRACT FROM AUTHOR]

The Tibetan Plateau vortex (TPV), as an α-scale mesoscale weather system, often brings severe weather conditions like torrential rain and severe convective storms. Based on the detections from the Global Precipitation Measurement (GPM) Core Observatory's Dual-frequency Precipitation Radar (DPR) and the FY-4A satellite's Advanced Geostationary Radiation Imager (AGRI), combined with ERA5 reanalysis data, the precipitation characteristics of a TPV moving eastward during 8–13 July 2021 at different developmental stages are explored in this study. It was clear that the near-surface precipitation rate of the TPV during the initial stage at the eastern Tibetan Plateau (TP) was below 1 mm·h−1, implying overall weak precipitation dominated by stratiform clouds. After moving out of the TP, the radar reflectivity factor (Ze), precipitation rate, and normalized intercept parameter (dBNw) significantly increased, while the proportion of convective clouds gradually rose. Following the TPV movement, the distribution range and vertical thickness of Ze, mass-weighted mean diameter (Dm), and dBNw tended to increase. The high-frequency region of Ze appeared at 15–20 dBZ, while Dm and dBNw occurred at around 1 mm and 33 mm−1·m−3, respectively. Near the melting layer, Ze was characterized by a significant increase due to the aggregation and melting of ice crystals. The precipitation rate of convective clouds was generally greater than that of stratiform clouds, whilst both of them increased during the movement of the TPV. Particularly, at 01:00 on 12 July, there was a significant increase in the precipitation rate and Dm of convective clouds, while dBNw noticeably decreased. These findings could provide valuable insights into the three-dimensional structure and microphysical characteristics of the precipitation during the movement of the TPV, contributing to a better understanding of cloud precipitation mechanisms. [ABSTRACT FROM AUTHOR]