Impact of land use change on actual evapotranspiration in the Songnen Plain, China

Study region: the Songnen Plain, China Study focus: Actual evapotranspiration (AET) is an integral part of the terrestrial water cycle. Examining the attribution of AET in the Songnen Plain under varying conditions can aid in the comprehension of the response mechanisms of water cycle processes to climate change and human activities. We used the method of separating environmental variables to separate the effects of climate change and human activities on AET, and innovatively revealed the effects of different land use changes on the changes of AET. The study can support decision-making to improve the efficiency of soil and water resources use and optimize land resources management. New hydrological insights for the region: The average AET in the Songnen Plain over the past four decades was 421.61 mm, with a slight upward trend (0.09 mm per year) and the majority of the increase occurred in Heihe City, east-central Yichun City, and central Harbin City. Climate change has a greater impact on AET than human activities. As human activities intensifies, however, its impact on water cycle processes increases from 20 % to 30 %. Regarding the influence of various land use types, the order of increasing AET is as follows: paddy fields, water areas, forests, and drylands. Conversely, the order of decreasing AET is as follows: wetlands, unused land, and construction land.