Estimation and Spatiotemporal Variation Analysis of Net Primary Productivity in the Upper Luanhe River Basin in China From 2001 to 2017 Combining With a Downscaling Method. - Qinru Liu; Liang Zhao; Rui Sun 003; Tao Yu; Shun Cheng; Mengjia Wang; Anran Zhu; Qi Li (IEEE J. Sel. Top. Appl. Earth Obs. Remote. Sens., 2022)