近20年大、小凌河入海径流量和输沙量变化及其驱动力分析

利用大、小凌河1988—2007年的流量和输沙量资料,阐述了这2条河流入海径流量和输沙量的年内分配特征,应用Mann-Kendall秩检验法分析了其多年变化特征,并进一步探讨了2条河流入海径流和输沙量变化的驱动力.结果表明:大、小凌河入海径流量和输沙量的年内分配极不均衡,分别有60%和90%以上集中在汛期(6—9月);近20年来,大、小凌河入海径流量和输沙量年际变化趋势基本一致.1999年为2条河流入海径流量和输沙量年际变化的突变年,1999年前呈增大趋势,而从1999年开始明显减少.流域降水变化可能是促使大、小凌河入海径流量和输沙量变化的主要原因,同时人类活动的影响也起到了较大的促进作用.

Analysis of Driving Forces and Variations of the Runoff and Suspended Sediment Discharge of the Daling and Xiaoling Rivers into the Sea over the Past Twenty Years

Based on the data of suspended sediment discharge and runoff of the Daling and Xiaoling Rivers from 1988 to 2007, the intra-annual distributions of the runoff and the suspended sediment discharge into the coastal waters were evaluated, and variation characteristics in these years were analyzed with the Mann-Kendall method. Furthermore, the driving forces of these variations were studied. The results indicated that the intra-annual distributions of the runoff and the suspended sediment discharge of the Daling and Xiaoling Rivers were extremely uneven. More than 60 percent of the runoff and 90 percent of the suspended sediment discharge were concentrated during the flood season from June to September. In the past 20 years, the inter-annual variations of runoff and suspended sediment discharge of the Daling and Xiaoling Rivers were similar to each other. The turning point for runoff and suspended sediment discharge variations happened in 1999; the runoff and suspended sediment discharge increased before 1999, then decreased after 1999. The change of the runoff and suspended sediment discharge of the Daling and Xiaoling Rivers was mainly due to precipitation variation in the valley, as well as human activities.