Page 279 - 《高原气象》2026年第1期

1 期 黄玉霞等：甘肃“7·22”特大暴雨水汽来源及定量贡献分析 275

Moisture Sources and Quantitative Contribution Analysis of

the “7·22” Heavy Rainstorm in Gansu Province

2
1
1
HUANG Yuxia ， FAN Qiwei ， WANG Yong ， GUO Runxia ， LI Wenyao 1
3， 1
（1. Lanzhou Central Meteorological Observatory， Lanzhou 730020， Gansu， China；
2. Jiuquan Meteorological Bureau of Gansu Province， Jiuquan 735000， Gansu， China；
3. Heavy Rain and Drought - Flood Disasters in Plateau and Basin Key Laboratory of
Sichuan Province， Chengdu 610072， Sichuan， China）

Abstract： Based on automatic weather station observations of precipitation， ERA5 reanalysis data and NCEP
GDAS data， through methods such as water vapor budget analysis， HYSPLIT backward trajectory tracking and
water vapor transport contribution rate， this paper analyzed the water vapor transport characteristics of a severe
rainstorm event that occurred in the southeastern part of Gansu Province from July 22 to 24， 2024， and quantita‐
tively discussed its water vapor source and contribution rate. The results showed that the rainstorm area was locat‐
ed in the exit zone of the upper-level jet stream， where the airflow divergence enhanced the vertical transport of
low-level water vapor， causing the moist layer deeper. The continuous synergic influence of Typhoon " Prapir‐
oon" and the subtropical high transported water vapor over the South China Sea and the Bay of Bengal to the rain‐
storm area， providing sufficient water vapor， and the rainstorm area maintained a significant near-surface wet ar‐
ea and high precipitable water. The results of water vapor budget and tracking analysis showed that the inflow of
water vapor mainly occurred at the southern boundary of 800~500 hPa， with a maximum inflow of 1237 kg·m·s .
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Before the rainstorm， the water vapor mainly originated from the South China Sea and the Bay of Bengal， and
the water vapor channels accounted for 48% and 42% of all tracks respectively， and the water vapor transport
contribution rate was 51. 45% and 43. 31% respectively. When the rainstorm occurred， water vapor mainly origi‐
nated from the South China Sea， its water vapor channels accounted for 53% of all the tracks， and the contribu‐
tion rate of water vapor transport was 57. 98%. In addition， the water vapor transport in the Western Pacific and
Northwest Passage also contributed to the rainstorm. This would be conducive to understanding the formation
mechanism of the extraordinary rainstorm in Northwest China， and provided certain references for the future
forecast of extraordinary rainstorm in Gansu Province.
Key words： heavy rainstorm； water vapor transportation； quantitative contributions