Evolution characteristics of global land surface water resources

To explore the evolution characteristics of global land surface water resources in the changing environment is a hot and difficult issue in the current hydrological and water resources research. Improving the accuracy of hydrological forecast in the ungauged basins is important for accurate evaluation of global surface water resources. To solve this problem, we first divided the global climate ecological division, compared five parameter transplant methods, and found that the combination of inverse distance spatial interpolation method and physical similarity method has the highest simulation accuracy, and then analyzed the evolution characteristics of surface water resources in the world, continents and key regions from 1960 to 2016. The results are as follows:229 climate-ecological subareas are obtained based on 13 climate regions and ecological indictors, using the Köppen-Geiger classifications method and the unsupervised classification method. The global surface water resources is 41.06 trillion m³, showing a significant decrease trend. The surface water resources show significant decreaing trend in North America and Africa. The level 4 water resources zones with declining surface water resources trend are mainly distributed in North America, North of South America and Central Africa.