气候变化及人类活动影响下的潮白河月水量平衡模拟

尽管分布式水文模型已有30多年的发展历史,但是迄今的应用还只是其潜力的很少一部分。Freeze-Harlan蓝图中由于理论上的深化带来了应用上的困难,同时也指出模型并不是越复杂越好。按照科学的建模原则,建立了一个简单的分布式月水量平衡模型(DTVGM);其中通过引入土壤湿度因子,改进后的Bagrov模型同时考虑了前期土壤湿度与降水对蒸散(发)的贡献;通过设置人类活动影响背景参数集,表述人类活动对水文过程的影响。将DTVGM月模型应用于华北地区密云水库以上潮白河流域,识别出白河流域气候变化对径流减少的贡献为44%,人类活动导致下垫面变化对径流减少的影响达54%;潮河流域气候变化的贡献率为24%,而人类活动的贡献率高达74%,是导致径流减少的主要原因。

A Distributed Monthly Water Balance Model for Identifying Hydrological Response to Climate Changes and Human Activities

A blueprint(FH69 blueprint) for a physically-based digitally simulated hydrologic response model was published by Freeze and Harlan in 1969,which initiated the studies on the distributed hydrological models(DHMs) at the watershed scale.Nevertheless,in spite of three decades of modeling development,distributed hydrological models are today being used in practice only at a fraction of their potential.The applications of DHMs based on the FH69 blueprint are confronted with difficulties because of deepening in theory,which simultaneously indicate that the complex models are not always good ones.According to the scientifically modeling protocol,a simple monthly subbasin-based water balance model is put forward,where the revised Bagrov evapotranspiration model is developed to parametrize the distinguishes between various land covers,and a parameter set is introduced to represent the impacts of human activities on runoff generation and evapotransipiration processes.In the case study of the Chaobai River Basin in North China,the model was used to quantificationally identify the impacts of climate changes and human activities on runoff.In the Bai River Basin,the annual mean precipitation of the 1980s(1980-1988) and 1990s(1989-2001) decreased by 9% and 5% com-pared with that of the 1970s(1961-1966 and 1973-1979),but the runoff reduced by 54% and 52% respectively.The simulation results indicate that the contribution rates of climate changes and human activities are 44% and 54% respectively.In the Chao River Basin,such contribution rates are 24% and 74%,i.e.,human activities are the main reason for runoff decrease.