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The Fourth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC AR4) presents twenty-two global climate models (GCMs). In this paper, we evaluate the ability of 22 GCMs to reproduce temperature and precipitation over the Tibetan Plateau by comparing with ground observations for 1961~1900. The results suggest that all the GCMs(More)
Because of Boundary types and geologic conditions, which possess random and obscure characteristics, groundwater heads vary with the conditions. The prediction of groundwater level is one of the main work of hydraulic government, which is predicted based on the history data and the relative influence factors. Therefore, prediction precision depends on the(More)
At present, classic methods are often used to predict groundwater level, but the result is not ideal. Though GM(1,1) and neural network are applied in this field, some limits have been existed. In view of the difficulty to predict groundwater level, in this paper, a grey system-neural network united model is developed based on the grey theory and neural(More)
Contaminant transport in underground system usually occurs in varied flow fields and in anisotropic and heterogenous media. Because the applicability of analytical solutions is extremely limited for such conditions, and the distribution and transport of pollutants in groundwater are controlled by physical chemistry and biology courses, which include(More)
In view of the defect that the grey method can only predict the tendency approximately and artificial neural network can not predict the future tendency really, a new combined grey neural network model was proposed. This paper mainly analyses the groundwater quality and establishes their mathematical model based on the groundwater monitoring data of one(More)
With the development of social and economic, the pollution in river is worse. It is very important to study river pollution. In view of the uncertainty of river water pollution, Velocity and dispersion coefficient and attenuation in river are considered as uncertainty parameters and expressed as grey parameters. One dimensional gray numerical water quality(More)
The processes of soil freezing-thawing lead to soil water and heat movement in cold regions, which significantly influences the hydrological and energy cycles in the soil-plantatmosphere system. This research presented a soil water content coupled with heat transfer model based on physical processes of water and heat movement in frozen soil. The model was(More)
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