Hydro-climatic trends of the Yellow River basin for the last 50 years

Kendall's test was used to analyze the hydro-climatic trends of the Yellow River over the last half century. The results show that: ( 1) the runoff of the basin has decreased even after allowing for human uses, ( 2) the watershed has become warmer with a more significant increase in minimum temperature than in mean and maximum temperatures, and ( 3) no significant change in precipitation trend was observed. The major reasons for these results include human activities, global warming, land use/land cover change, and others, such as accuracy of natural runoff estimation, precipitation characteristics, groundwater exploitation, water transfer, and snowmelt. Homogeneity analysis indicated that precipitation, temperature, maximum temperature, and minimum temperature were all heterogeneous and the trends varied from region to region and from month to month. If the Intergovernmental Panel on Climate Change (IPCC) projections of continued warming in the region during the 21st century are correct, the present results then suggest that the trend towards reduced runoff is likely to lead to exacerbated problems for agriculture, industry, urban communities, and the overall regional environment.