JOURNAL OF NATURAL RESOURCES ›› 2019, Vol. 34 ›› Issue (6): 1209-1222.doi: 10.31497/zrzyxb.20190607

• Resource Ecology • Previous Articles     Next Articles

Spatiotemporal variation of extreme precipitation regimes in the Hanjiang River Basin during 1970-2015

Cheng-bo WANG1,2(), Shuang-shuang LI1,2(), Jun-ping YAN1,2, Ya-qun WU1,2   

  1. 1. School of Geography and Tourism, Shaanxi Normal University, Xi'an 710119, China
    2. National Demonstration Center for Experimental Geography Education, Shaanxi Normal University, Xi'an 710119, China
  • Online:2019-06-20 Published:2019-06-20

Abstract:

With the rapid development of social economy and the continuous development of ecological construction, the change of water resources in the Hanjiang River Basin plays an important role in the sustainable development of trans-regional water transfer. Thus, it is worthy to analyze the variation characteristics and influencing factors of extreme precipitation in the Hanjiang River Basin, using the peaks-over-threshold approach, extreme precipitation concentration degree (EPCD) and extreme precipitation concentration period (EPCP). The results show that (1) In terms of the "10-day" scale, the extreme EPCD in the river basin is relatively high, and it shows the distribution characteristics of "high in the west and low in the east", which illustrated that the precipitation is more uniform in the eastern part than in the western. And the EPCD in the lower reaches of Hanjiang River has a decreasing tendency in recent years, which indicated that the precipitation tends to disperse. The annual average value of EPCP in the Hanjiang River is concentrated in late July, and it shows the spatial distribution features of "early in the east, and late in the west", that is, there is earlier arrival of the flood season in the east than in the west. (2) For the monthly scale, the extreme precipitation in the study basin is concentrated in May and September, and extreme precipitation rarely occurs during the period from October of the same year to April of the following year. (3) At the seasonal scale, since the start of the 21st century, the proportion of extreme precipitation in summer in the basin has decreased, and the summer extreme precipitation has mainly changed to spring in the upper reaches, which turned into autumn in the middle and lower reaches of the basin, indicating that summer is the key season that leads to the uneven variation of the extreme precipitation. (4) As for influencing factors, the East Asian summer monsoon and South Asia II have a negative correlation with the extreme precipitation. When the East Asian summer monsoon and South Asia II are strong, the extreme precipitation in the whole river basin decreases. However, when the East Asian monsoon and South Asia II are weak, the correlations with extreme precipitation present spatial difference. The weaker the East Asian monsoon, the increase of extreme precipitation varies from north to south, while in South Asia region II, the increase of extreme precipitation varies from east to west.

Key words: extreme precipitation, heterogenity, precipitation concentration degree, precipitation concentration period, Hanjiang River Basin