Abstract: To systematically analyze the variations in the Qinghai Lake stage under climate change and the related influence mechanism, this paper presents a quantitative analysis of the spatiotemporal changes in the hydrological and meteorological factors of the lake basin, using a combination of time series analysis, a geostatistical interpolation method, and correlation analysis based on the data collected at the observation stations over the basin during 1956-2020. We use the global climate model to estimate the varying trends of precipitation and lake stage under different scenarios. The results show that during the past 50 years, the stage and surface area of the lake presented a general trend of decreasing first and then increasing, while an increasing trend occurred in runoff, precipitation and temperature, and a decreasing trend in evaporation. The lake stage was affected significantly by runoff, precipitation, temperature and evaporation; the correlation coefficients were as high as 0.95, 0.92, 0.88 and 0.81, respectively. We project that from 2021 to 2040, the lake stage will take a rising trend, showing an annual average rising rates of 0.218, 0.187, 0.125 and 0.132 m/a under four different scenarios. Quantitative analysis of the lake behaviors under climate change in this study lays a basis for future studies on the water cycling mechanism of plateau lakes.

Key words: climate change, hydrological factors, spatiotemporal changes, correlation, Qinghai Lake Basin