Abstract:

The Yellow River Basin is located in the arid， semi-arid and semi-humid transition zone， which is an important economic zone and ecological barrier in China. It's of great significance to study the spatio-temporal pattern of precipitation and its response to multiple driving factors. In this paper， the spatio-temporal pattern， multi-scale characteristics and response of precipitation to different factors are analyzed. The precipitation showed a decreasing trend， with a decreasing rate of -0.88 mm/10a， while the precipitation in the upper reaches showed an increasing trend. The annual time scale was significant and the cumulative variance contribution rate of ensemble empirical mode decomposition （EEMD） was 94.85%. The partial wavelet coherence （PWC） analysis showed that evaporation was the dominant meteorological factor， meteorological factors mainly affected the seasonal and annual periods and circulation factors mainly dominated the inter-annual and decadal periods of precipitation. The synergistic effects of different types of factors can enhance the explanatory ability of precipitation at all time scales. The study is significant for understanding the precipitation variability and promoting the ecological protection and high-quality development of the basin.

Key words: Yellow River Basin, precipitation, ensemble empirical mode decomposition, partial wavelet coherency, multi-scale