Hydrological process analysis of the Luanhe Mountain Basin based on trend test and empirical orthogonal approach

Trend Test, Empirical orthogonal function, Budyko sensitivity coefficient methods have been implemented in this study to analyze the variations of meteorological, hydrological and land use data in the Luanhe Mountain Basin and to investigate the hydrological responses under the changing environment. The findings were: ① There was an insignificant downward trend of the precipitation (–3.4 mm/10 a) and a significant downward trend of the potential evapotranspiration (–7.5mm/10 a), and their spatial variation directions were consistent. The streamflow decreased significantly and with an apparent dry-wet shifted phenomenon (–4.1×10⁸m³/10 a); ② Under the interference of anthropogenic activities, the streamflow decreased by 11.8×10⁸m³ during the entire period (1980—2018). ③ In terms of the attribution of streamflow change in the changing environment, the contribution rate of climate change took account to 27.2%, and the contribution rate resulted by anthropogenic activities was 69.6%. Therefore, the anthropogenic activities have been the main factors influencing the streamflow reduction in the Luanhe Mountain Basin.