Page 172 - 《高原气象》2022年第5期

5 期 左园园等：一次高原涡过境的不同云-降水垂直结构和特征研究 1265

Study on the Vertical Structures and Characteristics of Different Cloud-

Precipitation Types during a Qinghai-Xizang Plateau Vortex Transit

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ZUO Yuanyuan ，ZHENG Jiafeng ，HE Jingshu ，YIN Xiaoyan ，LI Boyong ，HU Zhiqun ，LEI Zhiyu 1
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（1. Plateau Atmosphere and Environment Key Laboratory of Sichuan Province，School of Atmospheric Science，
Chengdu University of Information Technology，Chengdu 610225，Sichuan，China；
2. State Key Laboratory of Severe Weather，Chinese Academy of Meteorological Science，Beijing 100081，China）
Abstract：Using measurements from a Ka-band cloud radar（Ka-MMCR），a K-band micro rain radar（K-
MRR），and a ground disdrometer of the Third Qinghai-Xizang Plateau Atmospheric Science Experiment，com‐
bined with data from a Doppler weather radar，ERA-Interim reanalysis，and FY-2E satellite images，the vertical
structures and characteristics of different cloud-precipitation types triggered by a Qinghai-Xizang Plateau vortex
process that happened over Nagqu on August 13-14，2015 were studied and compared in detail. Results indicate
that there exist three stages of cloud-precipitation including the deep and strong convection（DSP），the deep and
weak convection（DWP），and the shallow convection（SP）appeared successively over the Nagqu with different
macro and micro characteristics. Specifically，the DSP has the shortest time scale，the strongest convection，and
the highest echo top. The inner strong updraft makes ice crystals effectively collide with supercooled water and
facilitate forming large graupels，which then quickly settle and melt into heavy raindrops. The average profile of
radar reflectivity factor Z （mean particle terminal velocity V ）exhibit gradually increased（decreased）as height
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decrease. The DWP has the longest time scale，relatively weaker convection intensity，and lower echo top. The
growth of ice crystals is mainly dominated by the accretion or coalescence process. From 8 km to the melting lay‐
er，the Z increment of the DWP is larger than that of the DSP，but the V decrement is smaller. The SP has the
T
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weakest convection intensity and the lowest echo height and is composed of small-scale cumulus. The variation
trends of radar variables of SP are similar to the DWP. Comparisons also suggest that the DWP shows a clearest
radar bright band，followed by the SP，the bright band in the DSP is weakest，and the radar spectrum skewness
can also be a good indicator of the bright band. The ground rain spectra of the three stages are also different，the
spectral width and the number concentration magnitude both exhibit as DSP>DWP>SP.
Key words：Qinghai-Xizang Plateau vortex；cloud-precipitation vertical structure；raindrop spectra；millimeter-
wave cloud radar