Page 119 - 《高原气象》2023年第1期

1 期 张天宇等：1998-2020年三峡库区小时极端降水时空变化特征分析 115

Temporal and Spatial Variation Characteristics of Hourly Extreme

Precipitation in the Three Gorges Region in 1998 -2020

2
1
2
ZHANG Tianyu ， WANG Yuxiao ， SUN Yingying ， LIU Bo ， JIANG Jiayi 2
2
（1. Chongqing Climate Center， Chongqing 401147， China；
2. College of Hydrology and Water Resources， Hohai University， Nanjing 210098， Jiangsu， China）
Abstract： Using the hourly precipitation data from 35 stations in the Three Gorges Reservoir Region （TGRR）
from 1998 to 2020， the spatial and temporal variation characteristics of extreme precipitation occurrence were an‐
alyzed around the total amount， frequency and intensity of hourly heavy precipitation （≥20 mm·h ） and hourly
-1
extreme heavy precipitation （≥50 mm·h ） in the TGRR in the past 23 years. The characteristics of hourly ex‐
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treme precipitation variation in the TGRR before and after 2010 are also compared and analyzed. The results indi‐
cate that the frequency and intensity of hourly heavy precipitation and extreme heavy precipitation in the TGRR
were abnormally high in 1998. If this year is excluded， the total number of hourly heavy precipitation and ex‐
treme heavy precipitation has no significant trend from 1999 to 2020. In recent 23 years， hourly heavy precipita‐
tion occurs 3. 8 times per station per year on average， and 3. 0~5. 0 times per year in most stations. The average
annual occurrence of hourly extreme heavy precipitation is 5. 5 times， and the average annual occurrence is less
than 0. 25 times in most stations. The average annual occurrence is more in the Jianshi-Xuanen area in the central
mountainous area. The spatial distribution of annual mean heavy precipitation and hourly heavy precipitation in
the TGRR is quite different. After 2010， the annual mean hourly heavy precipitation decreased by 10. 4 mm，
mainly in Chongqing area in the west of the TGRR， with an annual mean decrease of 15. 5 mm. The annual
mean hourly heavy precipitation and its occurrence frequency increased at 31. 4% stations， and the increase was
more obvious in the Jianshi-Laifeng area in central Hubei Province， and the annual heavy precipitation at five sta‐
tions increased by 16. 1 mm on average. And formed the distribution state with the beginning of construction as
the center. The "increase and decrease" of the average number of extreme heavy precipitation for many years be‐
fore and after 2010 presents an alternating southwest-northeast belt distribution. The average number of extreme
precipitation in most regions remained at 0. 0~0. 5， with little change on the whole. The stations with increasing
characteristics of heavy rainfall intensity accounted for 48. 6%， and the increasing range of heavy precipitation
rain intensity was further expanded. In the Wulong-Changyang area， the rainfall intensity of hourly heavy precipi‐
tation increased while the heavy precipitation decreased. On the whole， the increase of heavy precipitation in the
TGRR is mainly concentrated in the eastern area closer to the reservoir area， and the influence of hourly extreme
precipitation on incoming water in flood season needs to be paid attention to.
Key words： Three Gorges Reservoir Region； hourly heavy precipitation； hourly extreme heavy precipitation；
decadal variation