资源环境科技发展态势分析平台

Gross primary production (GPP) and evapotranspiration (ET) are the key variables in global carbon and water cycle, respectively. Therefore, it is important to understand how they respond to land use and land cover change (LUCC). Northern China has experienced dramatic LUCC because of a large-scale ecological restoration project implemented since 1999. This study uses a diagnostic model (PML-V2) driven by satellite data to quantify LUCC-driven changes in GPP and ET, at 500 m resolution in northern China from 2004 to 2017. The results indicate that the GPP and ET of northern China has increased by 164 TgC year(-1) and 13 km(3) year(-1). The GPP and ET are strongly increased in the Loess Plateau and Northeast China Plain in the research period, especially after 2009. Cropland has the highest GPP change of 184 gC m(-2) year(-1) was in Loess Plateau, followed by the Northeast China Plain (128 gC m(-2) year-1) and then the Inner Mongolia Plateau (82 gC m(-2) year(-1)). The highest ET increase of 45 mm year(-1) occurs in shrubland in the Loess Plateau, followed by the increase of 20 mm year(-1) in the Northeast China Plain. The increase in leaf area index is the major cause of GPP and ET increases for these regions. Our results suggest that it is necessary to carefully plan the afforestation and other land use change patterns for sustainable water resources management.