The Water and Energy transfer Processes in Cold Regions (WEP-COR) model is an improved version of the Water and Energy transfer Processes in Large basins (WEP-L) model that integrates a multi-layer frozen soil model to simulate the hydrological processes in cold regions and the heat fluxes at different depths of frozen soil. The temperature, water content, freezing depth of the soil, and daily discharge were simulated and compared with observations. The simulated and observed data were used to analyze the runoff flow components. The results showed that the WEP-COR model can effectively simulate the distributions of the soil temperature and water content. The average root mean squared errors of the temperature, unfrozen water content, total water content, and freezing depth of the soil were 1.21 °C, 0.035 cm³/cm³, 0.034 cm³/cm³, and 17.6 cm, respectively. The mean Nash–Sutcliffe efficiency and relative error of the daily discharge were 0.64 and 6.58%, respectively. Compared with the WEP-L model, the WEP-COR model simulated the discharge with higher accuracy, especially during the soil thawing period. This improvement was mainly due to the addition of the frozen soil mechanism. The WEP-COR model can provide support for agricultural and water resources management in cold regions.

Climate projections obtained by running global climate models (GCMs) are subject to multisource uncertainties. The existing framework based on analysis of variance (ANOVA) for decomposing such uncertainties is unable to include the interaction effect between GCM and internal climate variability, which ranks only second to the main effect of GCM in significance. In this study, a three-way ANOVA framework is presented, and all main effects and interaction effects are investigated. The results show that, although the overall uncertainty (O) is mainly contributed by main effects, interaction effects are considerable. Specifically, in the twenty-first century, the global mean (calculated at the grid-cell level and then averaged, and likewise below) relative contributions of all main effects are 54% for precipitation and 82% for temperature; those of all interaction effects are, respectively, 46% and 18%. As the three-way ANOVA cannot investigate the uncertainty components resulting from uncertainty sources, it is improved by deducing the relationship between uncertainty components resulting from uncertainty sources and those resulting from the main effects and interaction effects. By the improved three-way ANOVA, O is decomposed into uncertainty components resulting from the emission scenario (S), GCM (M), and internal climate variability (V). The results reveal that O is mainly contributed by M in the twenty-first century for precipitation, and by M before the 2060s whereas by S thereafter for temperature. The robustness of the V characterization is explored by investigating the variation of V on the number of included ensemble members. The extent of the underestimation of the V contribution is roughly an average of 4% for precipitation and 1% for temperature.

An economic valuation of flood reductions arising from land use changes induced by the Conversion of Cropland to Forest and Grassland Program (CCFGP) in China is detailed in this paper. A distributed hydrologic model is used to analyze and predict changes in the probability of flood occurrences in the Yellow River Basin (YRB) due to revegetation activities under the CCFGP. The expected value of flood reductions due to the avoided flood damage potential is then estimated. Losses brought about by each type of flood in the YRB over time and the probability change in flood occurrences are used in the calculation. Results show that the economic benefits from flood reductions will total China Yuan 362 million during 2010–2020. The inclusion of this economic benefit into a benefit-cost analysis of the CCFGP provides a more comprehensive assessment of the program. Implications for prioritizing management options to mitigate flood disasters in the YRB are drawn.

The basin water cycle affected by human activities presents the duality of natural and human characteristics. The effect of human activities to hydrology is becoming point of focus in the world with the development of society. As a physically based distributed parameter model, soil and water assessment tool is deficient when applied to the area with more human activities. In areas of increased activities, monthly changes in irrigation and consumptive water use has been observed over the years. In the past, this module was applied to a system with very little human influence. In this study we revised the theory and made appropriate improvement on irrigation module and consumptive water use module in order to apply it to the water system in Tianjin City, China, where water cycle is strongly affected by the human activities. The watershed model has been calibrated and validated using measured data available for the main river. By comparing the simulation results between initial model and improved model, the Nash-Sutcliffe efficiency is adjusted from 0.62 to 0.89 and correlation coefficient is improved from 0.79 to 0.91. The resulting validated model improves the simulation precision, especially amends the peak value of runoff, and adequately describes the impact of consumptive water use and irrigation on the natural water cycle. The model developed in this paper can be used to study water resource and water environment management in area of high human activities.