Page 154 - 《高原气象》2025年第5期

高 原 气 象 44 卷
1272

Spatial and Temporal Characteristics of Extreme Hourly Precipitation in

Sichuan Province Based on Spatially Dense Rainfall Observation

ZHOU Qiuxue ， KANG Lan 1
1， 2
（1. Sichuan Meteorological Observatory， Chengdu 610072， Sichuan， China；
2. Heavy Rain and Drought-Flood Disasters in Plateau and Basin Key Laboratory
of Sichuan Province， Chengdu 610072， Sichuan， China）

Abstract： Based on the hourly precipitation data of 3454 stations with dense space in Sichuan Province and
DEM （Digital Elevation Model） data with horizontal accuracy of 30 m， the temporal and spatial distribution
characteristics of extreme hourly precipitation in 7 regions of Sichuan Province in recent 10 years were analyzed，
and the relationship between high frequency extreme precipitation and complex terrain was discussed. The results
showed that： （1） In recent 10 years， the frequency of extreme hourly precipitation with hourly rainfall ≥100 mm
in Sichuan Province has increased significantly with the growth rate of 6. 4 times·（10a） .（2） The sub-seasonal
-1
variation of extreme hourly precipitation frequency was more significant than that of extreme rainfall intensity，
with the maximum monthly increase of 3. 7 times and 0. 2 times， respectively. In addition， the occurrence time
of peak frequency was delayed with the increase of extreme hourly precipitation threshold.（3） The frequency of
extreme hourly precipitation was significantly higher at night than during the day， and the occurrence time of
peak-valley value and high-frequency concentration period were different in different regions， and the frequency
peak appears gradually from south to north and from west to east.（4） The diurnal variation of extreme rainfall in‐
tensity was much weaker than that of extreme hourly precipitation frequency， and the extreme rainfall intensity
of most stations in the basin was higher than the regional average， but the opposite was true in western Sichuan
Plateau and Panxi area.（5） The distribution characteristics of extreme hourly precipitation frequency and cumula‐
tive rainfall in different regions were closely related to topographic uplift and topographic convergence in this re‐
gion， and the increase of extreme hourly precipitation caused by topographic forced uplift in the western part of
the basin was roughly below 1400 m.（6） The slope of high frequency extreme hourly precipitation sites in the
basin was mainly eastward， and the slope of high frequency sites in the southwest of the basin was larger than
that in the northwest of the basin. The number of maximum extreme hourly cumulative rainfall sites in the West‐
ern Sichuan Plateau and Panxi area increased first and then decreased with the slope， and the peak value was lo‐
cated in the slope， but the decrease was more rapid in Panxi area than in the Western Sichuan Plateau.
Key words： extreme hourly precipitation； Sichuan； complex terrain； DEM