Spatiotemporal changes in precipitation and drying-wetting patterns in the Yellow River Basin

Abstract

【Background and Objective】 The Yellow River Basin is the second largest river basin in China. Over the past 60 years, precipitation patterns in the basin have undergone both spatial and temporal changes due to the impact of climate change. This paper analyzes the precipitation characteristics and spatiotemporal alterations in dry-wet patterns in the basin. 【Method】 The study was based on meteorological data measured from 1960 to 2022 at weather stations across the basin. Spatiotemporal changes in precipitation, dry and wet spells were analyzed using regression analysis, correlation analysis, frequency percentage method, and the Mann-Kendall nonparametric statistical method. 【Result】 ① No significant change in total annual precipitation was identified in the basin from 1960 to 2022. However, a notable decrease in annual precipitation events (-1.95% per decade) and a significant increase in average precipitation intensity (+2.67% per decade) were observed. A sudden change in annual precipitation frequency occurred in 1978, while a shift in precipitation intensity happened in 1990. Since 1990, annual precipitation frequency has decreased markedly, while precipitation intensity has increased significantly. Regionally, the upper basin has become wetter, while the middle and lower reaches of the basin have become drier. Across the basin, light, moderate and medium-intensive rainfall events have declined, while heavy and extreme rainfall events have increased. Extreme rainfall event have become increasingly common, particularly in the middle and lower reaches of the basin. ② The risk of drought has increased in the upper and middle reaches of the basin, although drought intensity has decreased. Meanwhile, the likelihood and severity of drought in the lower reach has risen. Wet spells have shown heightened precipitation intensity during the wet season, corresponding to an increase in extreme precipitation events across the basin. The coexistence of drought and flooding highlights vulnerability of the basin to extreme weather events. ③ Changes in annual precipitation are primarily driven by intensive precipitation events, while changes in precipitation frequency ware influenced by low-intensive precipitation events. The distribution of wet days is affected by low-intensive precipitation, whereas wet-season precipitation is driven by high-intensive precipitation events. 【Conclusion】 In the context of climate change, the Yellow River Basin is increasingly vulnerable to both droughts and floods. The reduction in low-intensive precipitation events has prolonged dry periods, increasing drought risk. Simultaneously, the increase in precipitation intensity and extreme events during wet seasons raises flood risk. These findings underscore the urgent need for developing integrated water resource managements and new strategies to mitigate the impact of climate change.

Keywords

• the yellow river basin
• precipitation
• dry spells
• wet spells
• extreme precipitation