Impacts of climate and vegetation on actual evapotranspiration in typical arid mountainous regions using a Budyko-based framework

Abstract

It is important to understand how actual evapotranspiration (ETa) changes occur and what the dominant contributing factors are. This study investigated the impacts of climatic factor and vegetation coverage on the variations of ETa using a Budyko-based framework. Climatic seasonal index and vegetation coverage index were selected as indicating factors. Two reservoir watersheds, i.e. the Wangkuai Reservoir Watershed and the Xidayang Reservoir Watershed, of the Daqing River Basin were selected as case studies. Also, relationships between the ETa and climatic and vegetation factors were analyzed. Results showed that the improved vegetation conditions positively contributed to the ETa changes, leading to an increase of 42.15 and 58.56 mm of ETa in the two watersheds, while the increasing climate seasonality had a negative effect, resulting in a drop of 11.48 and 13.47 mm of ETa. Vegetation coverage was recognized as the dominant factor to the changes of ETa, compared to the climatic factor. Our research could offer supporting information for water resources management, agricultural production improvement and eco-environment construction in arid regions. HIGHLIGHTS This study investigated the impacts of climatic factor and vegetation coverage on the variations of actual evapotranspiration using a Budyko-based framework.; The water-heat coupling controlling parameter of the Budyko-based framework was quantified by fitting the simulated actual evapotranspiration to observed actual evapotranspiration in a semi-empirical formula.;

Keywords

• actual evapotranspiration
• attribution
• budyko framework
• climatic factor
• vegetation coverage