Abstract: The source region of Yangtze River is highly sensitive to climate change, leading to significant alterations in river runoff. According to hydro-meteorological data from Zhimenda hydrological station and five meteorological stations in the source region of Yangtze River spanning 1960 to 2022, we investigated the changes in annual and seasonal runoff in the source region of Yangtze River. Utilizing correlation analysis, cross-wavelet transform, and principal component analysis, we further examined the relationship between runoff fluctuations and key meteorological factors. Findings indicated a notable upward trend in annual runoff at Zhimenda station throughout 1960 to 2022, with a particularly substantial increase of runoff in the past two decades. The seasonal runoff trend in the source region remained relatively stable from 1960 to 2000, but exhibited an increasing trend from 2000 to 2022, persisting to the present day. Precipitation, temperature, and relative humidity emerged as the primary meteorological factors exerting the most significant influences on the runoff at Zhimenda station.

Key words: runoff, correlation analysis, cross wavelet transform, principal component analysis, source region of the Yangtze River