Page 115 - 《高原气象》2026年第2期

2 期 陈 凡等：雅安秋雨期冷暖两类云-降水的垂直结构和宏微观差异研究 415

Vertical Structure and Macro-Micro Differences of Cold and Warm
Cloud-Precipitation in Ya'an During Autumn Rainy Season

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CHEN Fan ， ZHENG Jiafeng ， WANG Hao ， DONG Yuanchang ， CHEN Shaojie ， YU Wenqian 1
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（1. College of Atmospheric Sciences， Chengdu University of Information Technology， Chengdu 610225， Sichuan， China；
2. College of Electronic Engineering/College of Meteorological Observation， Chengdu University
of Information Technology， Chengdu 610225， Sichuan， China；
3. Institute of Plateau Meteorology， China Meteorological Administration， Chengdu 610072， Sichuan， China；
4. Dianjiang Meteorological Service， Chongqing 408300， China）
Abstract： The Ya'an area has a typical "windward slope" and "trumpet" topography， the observation and study
of cloud-precipitation in the Ya'an area has always been one of the hot issues of mountain meteorology in China.
In this paper， using the observation data of Ka-band millimeter-wave cloud radar， K-band micro-rain radar and
DSG4 laser raindrop spectrometer during the autumn rainy season in Ya'an area in 2023， the two types of cloud-
precipitation in Ya'an during the autumn rainy period are studied and compared. The results show that （1） the fre‐
quency of warm cloud-precipitation （WCP） is higher than that of cold cloud-precipitation （CCP） during the au‐
tumn rainy period in Ya'an， but the intensity of precipitation is generally weaker and the cumulative rainfall is
less.（2） In terms of vertical structure and macroscopic features， there are obvious differences between WCP and
CCP： the radar echo reflectivity factor Z high-frequency region of CCP has a wider distribution and stronger
echo， and the magnitude of the slope of Z high-frequency region at different heights reflects the difference be‐
tween the ice-phase particles' growth mechanism and rate and that of WCP's liquid cloud raindrops' touch-and-go
growth rate； CCP's linear depolarization ratio， LDR， increases abruptly near the zero-degree layer due to the
melting of ice-phase particles. The mean Doppler velocity V has a smaller value in the high-frequency region
m
and the velocity spectral width W has a larger value in the high-frequency region， suggesting a larger mean drop‐
let scale and a wider concentration distribution. In terms of macroscopic parameters， the cloud base and cloud
top of the CCP are significantly higher， the cloud layer is thicker， and the distribution of values is more dis‐
persed.（3） In terms of microscopic characteristics， the raindrop spectra of the two types of cloud-precipitation
are different with altitude： the concentration of small raindrops in the CCP increases and then decreases with de‐
creasing altitude due to the melting of ice-phase particles and raindrops merging， whereas that in the WCP fluctu‐
ates due to the effects of evaporation， merging， water vapor transport， and updraft lifting altitude. The medium-
and large-sized raindrop concentrations of both types of cloud-precipitation increase with decreasing altitude on
the whole. In terms of the differences in raindrop concentrations at different heights， above 455 m， the concentra‐
tion of raindrops of all grain sizes in WCP is almost lower than that in CCP； below 455 m， the concentration of
small and large raindrops in WCP is higher than that in CCP， and the concentration of medium raindrops is low‐
er.（4） Comparison of the raindrop spectra under different precipitation intensities showed that when the precipi‐
tation is weak， the WCP had lower concentrations of raindrops of all particle sizes than the CCP， but when the
precipitation reached a certain intensity （rainfall intensity R≥5 mm·h ）， the WCP produced more small rain‐
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drops and a small number of larger raindrops. The few extreme values of Z， LDR， V and W of WCP are larger
m
than those of CCP at altitudes below 3 km due to the synergistic effect of low-altitude rapids and topographic up‐
lift in the region， which makes the small WCP raindrops repeatedly touch and form medium-to-large raindrops in
the re-uplift airflow.
Key words： Ya’an； cloud-precipitation； vertical structure； macro-micro differences