Abstract:

Long-sequence Landsat remote sensing images were used to extract the fast ice information on Inexpressible Island. Changes in summer fast ice extent were determined for 2008 to 2018. Meteorological data for the same period from Manuela automatic weather station were used to analyze the driving forces of the fast ice changes. The results show that the amount of fast ice reaches its peak in November every year. The fast ice along the coast completely disappears from the end of December to early January and it begins to regenerate at the end of February. The increase in temperature is the main driving force for the reduction of fast ice. A daily average temperature of −10 ±2 ℃ is the critical value for the generation and dissipation of fast ice. When the average daily temperature is stable above −10 ℃, fast ice begins to decrease. Katabatic winds help sea ice drift away but during the period of fast ice reducing katabatic winds are at their weakest for the year, so katabatic winds are only a secondary driving force for the reduction of fast ice. Mastering the causes of interannual variations of fast ice is of great significance for Antarctic scientific research.

Key words: Inexpressible Island, fast ice, temperature, katabatic winds, driving force