Satellite observation of melting and break-up of fast ice in Lutzow-Holm Bay, East Antarctica

Lutzow-Holm Bay, East Antarctica is covered entirely by multi-year fast ice, almost every year, but this fast ice breaks up periodically, with several years between break up events. A large break-up started in March 1997, and reached its maximum at the end of March 1998. Two thirds of the fast ice in the bay was blown out. Melting features in the fast ice and surrounding ice sheet slope were observed by high resolution ADEOS AVNIR visible data in 1997.Since there are periodic break ups of the fast ice in Lützow-Holm Bay, warmer climate conditions and an increase in melting are investigated and compared with the occurrences of fast ice break up. The interannual variation of melting in the coastal zone was estimated by using the passive microwave brightness temperature. The gradient ratio of horizontal channels of 18/19 GHz to 37 GHz of SMMR and SSM/I was used to detect the melting duration of each summer from 1978/79 to 1998/99. A long melting period was estimated to have occurred in summer 1996/97 before the large break up; similar relationships were observed in the previous break-ups. The fast ice area has large variability in the number of melting days compared to the ice sheet slope zone, and it will be sensitive to the air temperature change in the coastal zone