Page 127 - 《高原气象》2026年第1期

1 期 刘旭东等：横断山区2001 -2020年小时极端降水时空分布特征 123

Spatial-Temporal Characteristics of Hourly Extreme Precipitation in the

Hengduan Mountain during 2001 --2020

1
1， 2
LIU Xudong ， LÜ Yaqiong ， BING Jiawei ， MING Guijia 1， 2
1， 2
（1. Institute of Mountain Hazards and Environment， Chinese Academy of Sciences， Chengdu 610229， Sichuan， China；
2. University of Chinese Academy of Science， Beijing 100049， China）

Abstract： Extensive research has been conducted on daily scale precipitation the Hengduan Mountain. The hour‐
ly scale data， which provides additional insights such as diurnal patterns， remains largely unexplored. There‐
fore， a fundamental study of the characteristics of extreme precipitation at the hourly scale is essential in the
Hengduan Mountain. In this study， we analyzed the spatial and temporal distribution characteristics of hourly ex‐
treme precipitation （95th percentile， R95） and very extreme precipitation （99th percentile， R99） using Multi-
Satellite Retrievals for Global Precipitation Measurement （IMERG） half-hourly satellite precipitation data from
2001 to 2020. Furthermore， we explored further the contribution to the whole year of rainy and non-rainy sea‐
sons periods. The results showed that the distribution pattern of hourly extreme precipitation and hourly very ex‐
treme precipitation thresholds， amount， intensity， and duration were decreasing from southeast to northwest in
the Hengduan Mountain， and the number was high in the east and west but less in the center. Hourly extreme pre‐
cipitation and hourly very extreme precipitation amounts occupied 29. 58% and 10. 15% of the annual total
amount， respectively. In the analysis of interannual variability， an increasing trend in the amount， number and
intensity were found for hourly extreme precipitation and hourly very extreme precipitation， while the duration is
generally showed a decreasing trend， with an increase in the amount of 4. 93 and 2. 83 mm annually， respective‐
ly. The amount experienced a significant increase in the northeastern part of the Hengduan Mountain. In terms of
diurnal variations， the hourly extreme precipitation and hourly very extreme precipitation amount and number
were concentrated at nighttime， with two peaks during 17: 00 （Beijing Time， same as after） -21: 00 and
00:00 -02:00. A discrepancy in the distribution of the maximum occurrence time were found in the northern and
southern regions in the Hengduan Mountain. The increasing trend in the hourly extreme precipitation amount was
primarily associated with an increase in number， which was more pronounced in the hourly very extreme precipi‐
tation. During the rainy season， the amount and frequency of hourly extreme precipitation and hourly very ex‐
treme precipitation accounted for over 90% and significantly influenced the annual pattern of characteristics. In
contrast， during the non-rainy season， the maximum occurrence time of amount and number were delayed by 1
hour in the main region compared to the annual pattern.
Key words： hourly extreme precipitation； Hengduan Mountain； spatial-temporal characteristics； diurnal varia‐
tions； IMERG