Schmitgen, S. [P:(DE-Juel1)VDB1438] ; Geiss, H. [P:(DE-Juel1)16201] ; Ciais, Ph. [P:(DE-HGF)0] ; Neininger, B. [P:(DE-HGF)0] ; Brunet, Y. [P:(DE-HGF)0] ; Reichstein, M. [P:(DE-HGF)0] ; Kley, D. [P:(DE-Juel1)16204] ; Volz-Thomas, A. [P:(DE-Juel1)6742]