JOURNAL OF NATURAL RESOURCES >
Spatiotemporal variation of extreme precipitation regimes in the Hanjiang River Basin during 1970-2015
Online published: 2019-06-20
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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.
WANG Cheng-bo , LI Shuang-shuang , YAN Jun-ping , WU Ya-qun . Spatiotemporal variation of extreme precipitation regimes in the Hanjiang River Basin during 1970-2015[J]. JOURNAL OF NATURAL RESOURCES, 2019 , 34(6) : 1209 -1222 . DOI: 10.31497/zrzyxb.20190607
Fig. 1 Spatial distribution of the weather stations in the Hanjiang River Basin图1 汉江流域气象站点分布 |
Fig. 2 Comparison of PCD and PCP between normal and extreme precipitation图2 极端降水与正常降水集中度和集中期识别结果对比 |
Fig. 3 Spatial pattern of EPCD and EPCP in the Hanjiang River Basin during 1970-2015图3 1970-2015年汉江流域年均极端降水集中度和集中期的空间特征 |
Fig. 4 Variation of EPCD and EPCP in the Hanjiang River Basin during 1970-2015图4 1970-2015年汉江流域极端降水集中期和集中期变化特征 |
Fig. 5 Intra-annual distribution of extreme precipitation in the Hanjiang River Basin图5 汉江流域极端降水量年内分布特征 |
Fig. 6 The variation of seasonal extreme precipitation ratio in the Hanjiang River Basin during 1970-2015图6 1970-2015年汉江流域不同季节极端降水量比例变化特征 |
Fig. 7 The correlation between EASMI, SASMI and summer precipitation in Hanjiang River Basin图7 东亚夏季风、南亚夏季风指数与汉江流域不同站点夏季极端降水的相关性 |
Table 1 Positive and negative anomaly year of EASMI and SASMI表1 东亚季风与南亚季风正负异常年份 |
季风类型 | 正异常年 | 负异常年 |
---|---|---|
东亚夏季风 | 1972、1974、1975、1978、1981 1984、1985、1990、1994、1997 1999、2002、2004、2006、2012 | 1971、1977、1980、1983、1987、1988、1989 1993、1995、1996、1998、2003、2007、2008 2010、2011、2013、2014、2015 |
南亚II区夏季风 | 1972、1978、1982、1985、1990 1994、2002、2012 | 1979、1983、1987、1988、1989、1992、1995 1996、1998、2000、2003、2004、2007、2008 2010、2014、2015 |
Fig. 8 The relationship between summer monsoon index and extreme precipitation in the Hanjiang River Basin图8 南亚季风指数与汉江流域夏季极端降水量合成分析的空间分布 |
Fig. 9 Influence of time scale on the PCD and PCP between normal and extreme precipitation图9 时间尺度对极端降水与正常降水集中度和集中期识别结果的影响 |
The authors have declared that no competing interests exist.
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