Impact of global climatic change on runoff in the upper reaches of the Yellow River

Drought and flood is a kind of the highest frequency and the most severe natural disaster in the world at present. The excessive and little amount of runoff will cause flood and drought. This paper studies the impact of solar activity and ocean-atmospheric interactivity on runoff change in the upper reaches of the Yellow River, using the measured runoff data from the Guide hydrological station. The relationship of between sunspot relative numbers and runoff change was analyzed with the grey correlation and cross spectrum method. Results show that there is a positive correlation between them; the impact of El Nino and La Nina phenomenon on high-low runoff change was analyzed statistically. These conclusions provide scientific ground for analyzing the physical cause of drought and flood disaster.