Page 264 - 《高原气象》2026年第1期

高 原 气 象 45 卷
260

Comparative Analysis of Precipitation Extremes in Two Major

Rainstorm Events at the Edge of the Subtropical High

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HUANG Wubin ， MA Li ， GUO Runxia ， DUAN Bolong ， TAN Dan ，
LI Jian ， JING Zhikun ， FAN Qiwei ， CUN Yu 2
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（1. Meteorological Bureau of Dunhuang City， Gansu Provincey， Jiuquan 735000， Gansu， China；
2. Lanzhou Central Meteorological Observatory， Lanzhou 730020， Gansu， China；
3. Jiuquan Meteorological Bureau， Jiuquan 735000， Gansu， China）
Abstract： This study conducts a systematic comparative analysis of two extreme heavy rainfall events in Gansu
Province， occurring in July 2022 （‘7·15’） and July 2024 （‘7·22’）， using multi-source observational data and
reanalysis datasets combined with various diagnostic methods. The key findings are as follows： （1） The two
events differed in 24-h cumulative precipitation， hourly rainfall intensity， and frequency of short-duration heavy
rainfall. The ‘7·15’ event had greater cumulative rainfall and stronger instantaneous intensity， but its spatial ex‐
tent of extreme rainfall （≥50 mm） and frequency of short-duration heavy precipitation were significantly lower
than those of ‘7·22’.（2） Both events exhibited extreme characteristics. The ‘7·15’ event broke historical re‐
cords for short-duration rainfall intensity at more stations than ‘7·22’， whereas the latter showed higher cumula‐
tive precipitation totals and more frequent short-duration heavy rainfall events.（3） Significant differences existed
in short-duration precipitation metrics. The ‘7·15’ event had substantially higher proportions of moderate and
heavy rainfall （44. 55% and 10. 68%， respectively）， with maximum 5-min and 1-h sliding precipitation reaching
30. 9 mm and 93. 6 mm. In contrast， ‘7·22’ was dominated by light rainfall （60. 70%）， with only 8. 68% heavy
precipitation events and maximum 5-min/1-h accumulations of 15. 3 mm and 83. 6 mm. The ‘7·15’ event dem‐
onstrated more extreme precipitation characteristics and greater disaster potential.（4） The two events exhibited
both similarities and differences in their dominant weather systems， moisture convergence， and thermodynamic/
dynamic lifting conditions. Both were warm-sector convective heavy precipitation events triggered by the cou‐
pling of upper- and lower-level systems including the subtropical high， mid-to-low-level vortex shear， and sur‐
face convergence lines. While the ‘7·15’ event showed significantly weaker values than‘7·22’ in moisture con‐
vergence intensity， vertical convergence depth， moist layer thickness， frontogenesis， vertical updraft intensity，
and CAPE， it demonstrated greater precipitable water throughout the atmospheric column at the rainfall core，
stronger convective instability during intense precipitation， and higher vertical ascent heights during peak rainfall
periods.
Key words： minute level precipitation； extreme precipitation； short-duration rainfall events； Gansu