摘要:
基于1956~2009年实测径流、天然径流和面降水的月系列,选用集中度和不均匀系数,分析东江径流年内分配特征的时空变异规律。通过对比降水和径流年内分配特征指标的阶段变化差异,量化分解气候变化、土地利用/覆被变化、水利工程水量调节和用水消耗等主要因素对东江径流年内分配特征变化的影响贡献。结果表明:东江实测径流的集中度和不均匀系数年变化过程均有显著下降趋势,且1973年为时序变点。降水及天然径流的年内集中程度阶段变化较小,但2000~2009年降水及天然径流的年内不均匀性要明显大于20世纪80年代和90年代。降水及天然径流的年内集中度和不均匀系数由上游向下游逐渐增大,显示集水面积越大降水及径流的年内集中程度和不均匀性越大。水利工程水量调节和土地利用/覆被变化降低了径流的年内集中程度和不均匀性,而用水消耗和气候变化增加了径流的年内集中程度和不均匀性。水利工程水量调节、土地利用/覆被变化、用水消耗和气候变化,对东江径流分配特征的影响贡献率分别约为-33.5%、-9.0%、4.5%和1.0%,新丰江水库、枫树坝水库和白盆珠水库的影响贡献率分别约为-21%、-10%和-2%,且近30年来土地利用/覆被变化和用水消耗的影响贡献有逐渐增加趋势。
Abstract:
The spatial-temporal variability of streamflow annual distribution during 1956 to 2009 in the Dongjiang River is analyzed.Both monthly observed and naturalized streamflow data and the monthly regional precipitation data are used in the study.The trend and change-point analysis are performed on the data to reveal the characteristics of streamflow.Likely contributions from various factors to the streamflow annual distribution are quantitatively analyzed.These factors include the climate change,the land use and coverage changes,the regulation of water reservoirs and the water consumption.The results show that the significant decreasing trend and change points in 1973 can be identified on the concentration and the nonuniformity in the observed streamflow data.The average change of the concentration degree in the naturalized streamflow data and the regional precipitation change are marginal.However,the nonuniform coefficient during 2000 to 2009 is significantly larger than that during the periods 1980-1989 and 1990-1999.The bigger catchment area is,the greater the concentration and the nonuniformity will be.The decrease of the concentration and nonuniformity is due to the effect of the regulations of water reservoirs and the land use and coverage changes; while,the increase is the result the water consumption and the climate change.The contributions to the spatial-temporal variability of streamflow annual distribution from the regulation of water reservoirs,the land use and coverage changes,the water consumption,and the climate change are respectively -33.5%,-9.0%,4.5% and 1.0%.Among the contribution from the regulation of water reservoirs,the Xinfengjiang,Fengshuba,and Baipenzhu reservoirs contribute -21%,-10%,-2%,respectively.There is an upward tendency in the contribution from the land use and coverage changes and the water consumption in the past 30 years.
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