Separating runoff change by the improved Budyko considering effects of both climate change and human activities on Zoige Wetland Basin, Eastern Tibetan Plateau

This study analyzes runoff changes in the Zoige wetland basin from 1980 to 2018 using the Budyko hypothesis-based water-heat balance equation and the modified Penman-Monteith model. It quantifies the relative contributions of climate change and human activities to runoff changes and evaluates the elastic coefficients and absolute impacts of meteorological factors and land use changes. The results are as follows:(1) From 1980 to 2018, annual runoff in the Zoige Basin decreased at 7.4 x 10(8)m(3)/10a, with D1 and D2 contributing 17.0% and 35.6% of total runoff, respectively. Rising temperatures, increased evaporation, declining relative humidity, and reduced wind speed exacerbated runoff losses, despite fluctuating precipitation showing a positive correlation with runoff. (2) Across the entire basin, the sensitivity of runoff to meteorological factors ranked as follows: precipitation > land use/land cover change (LULC) > solar radiation > maximum temperature > wind speed > minimum temperature > relative humidity. LULC had the greatest absolute impact on runoff, followed by precipitation, wind speed, and solar radiation. (3) On a regional scale, D2 was more sensitive to climate change and human activities than D1. Climate change increased runoff in D1 but reduced it in D2, while human activities consistently reduced runoff in both regions. This study provides scientific support for water resource management, disaster prevention, and sustainable development in the Zoige wetland basin under the influence of climate change and human activities.