[1] Res Org Informat & Syst, Natl Inst Polar Res, Tokyo, Japan
[2] Stockholm Univ, Dept Phys Geog & Quaternary Geol, S-10691 Stockholm, Sweden
[3] Royal Inst Technol, Div Geodesy & Geoinformat, Stockholm, Sweden
[4] Kitami Inst Technol, Kitami, Hokkaido 090, Japan
[5] Nagoya Univ, Grad Sch Environm Studies, Nagoya, Aichi 4648601, Japan
[6] Fukuoka Univ, Fac Sci, Dept Earth Syst Sci, Fukuoka 81401, Japan
[7] Hokkaido Univ, Inst Low Temp Sci, Sapporo, Hokkaido 060, Japan
[8] Alfred Wegener Inst Polar & Marine Res, D-27515 Bremerhaven, Germany
[9] Stockholm Univ, Dept Appl Environm Sci, S-10691 Stockholm, Sweden
[10] Univ Ryukyus, Fac Sci, Dept Chem Biol & Marine Sci, Okinawa, Japan