1960-2017年珠江流域下游径流年际与年内变化特征

目的]分析1960—2017年珠江三角洲顶点径流年际、年内变化,为合理利用流域水资源提供参考。方法]年际变化运用径流年际变差系数(C_v)、M-K趋势分析、Morlet小波分析等方法分析,年内变化运用集中度(期)、径流等值线法等方法分析。结果]珠江三角洲顶点主要水文站径流年际变率较小。1960年以来研究区主要水文站径流量总体并未发生显著变化;径流量距平百分率K_i显示西、东江流域旱涝灾害发生较均匀且发生率较低,北江流域易发生洪涝灾害;珠江流域西、北、东江径流基本存在25～32,10～20,4～10 a的周期变化。珠江流域径流年内分配极不均匀,年径流集中度(RCD_(year))北江和东江略低于西江,近年来集中度都有减小趋势。北江最大径流最早出现,在5,6月份交替,东江最大径流在6,7月份交替,西江最大径流主要出现在7月份。结论]珠江流域下游地区近60 a径流量并未发生明显的下降或上升趋势,但径流年际与年内变化仍十分明显,变化的主要原因为流域水库修建等剧烈的人类活动。

Interannual and Intra-annual Variation Characteristics of Runoff in Downstream Areas of Pearl River Basin During 1960-2017

Objective] Variations in the interannual and intra-annual runoff of the Pearl River basin from 1960 to 2017 were analyzed in order to provide reference for rational use of watershed resources.Methods] We used the interannual variation coefficient (C_v) of the runoff, the M-K trend analysis and the Morlet wavelet to analyze the interannual variations in runoff. Meanwhile, we used concentration (period) and runoff contour method for runoff within a year.Results] The interannual variability of runoff in the Pearl River basin was small and the runoff stability was high. The total runoff had not changed significantly. The change in runoff was coinciding with droughts and floods in the Xijiang and Dongjiang river basins were relatively uniform and the incidence was low, the Beijiang river basin was prone to flood disasters. The runoff in Xijiang, Beijiang, Dongjiang, rivers of the Pearl River basin was basically 25~32, 10~20, 4~10 years. The distribution of runoff in the Pearl River basin was extremely uneven during the year, and in the annual runoff concentration (RCD_year), the Xijiang river was slightly higher than Beijiang and Dongjiang rivers. In recent years, the RCD_year had decreased. The annual runoff concentration period (RCP_year) indicated that the maximum runoff of the Beijiang river alternated in May and June, and the maximum runoff of the Dongjiang river alternated in June and July, and the maximum runoff of the Xijiang river occurred mainly in July.Conclusion] There is no obvious decline or upward trend of runoff in the downstream areas of the Pearl River basin from 1960-2017, but the interannual and intra-annual changes in runoff are still obvious. The main reason for the change is the vigorous human activities such as the construction of river basin reservoirs.