[1] Chinese Acad Sci, Inst Geog Sci & Nat Resources Res, State Key Lab Resources & Environm Informat Syst, Beijing 100101, Peoples R China
[2] Univ Chinese Acad Sci, Beijing 100049, Peoples R China
[3] Humboldt Univ, Dept Geog, Unter Linden 6, D-10099 Berlin, Germany
[4] Leibniz Ctr Agr Landscape Res ZALF, Eberswalder Str 84, D-15374 Muncheberg, Germany