Analysis of the evolution and attenuation attribution of runoff in the LRB based on ESMD and Budyko framework

Study region The Laoha River Basin (LRB) in the typical semi-arid area of northeast China. Study focus Regarding the existing incomplete and unsystematic studies on runoff evolution and attribution analysis and to address the insufficient knowledge of the runoff evolution characteristics and the unclear dominant drivers of runoff attenuation in the LRB, this study proposed a novel framework of "evolution characteristics - sensitivity analysis - attenuation attribution - spatial contribution" integrating ESMD (Extreme-point Symmetric Mode Decomposition), EN (Elastic Net), Budyko theory, and LSTM network and apply it to the LRB (Laoha River basin) of Northeast China to analyze the evolution and attenuation attribution in runoff. New hydrological insights for the region The annual runoff in the LRB showed a significantly fluctuating downward trend, and two abrupt changes occurred in 1979 and 1998. Runoff sensitivity to CC (climate change) and HA (human activities) increased during the HIPs (human impact phases) compared to the BP (baseline period), and it was higher in the middle and lower reaches than in the upper reaches. HA have had the most significant impact on the runoff attenuation, with the contribution rate exceeding 80% across all phases, of which the human water use and the expansion of cropland were the most direct factors. The middle reaches were the key contributions area of runoff attenuation in the whole basin, with a contribution rate of 75% in the human impact phases, and playing a dominant role in runoff attenuation. These results are expected to offer important information for water resource management in the LRB.