Alessandro Cescatti¹, Ernest Koffi², Stephen J Vavrus³, Thomas Diehl¹, Jennifer Ann Francis⁴, Julienne Stroeve⁵ and Ramdane Alkama⁶, (1)European Commission Joint Research Centre, Ispra, Italy, (2)European Commission Joint Research Centre, Ispra Vey, Italy, (3)Univ Wisconsin, Madison, WI, United States, (4)Woods Hole Research Center, Falmouth, MA, United States, (5)University College London, Centre for Polar Observation and Modelling, London, United Kingdom, (6)European Commission, Joint Research Centre, Ispra, Italy