Observation And Study Of The Sea Ice And Its Optical Characteristics In Prydz Bay, Antarctica In Summer

The variations and trends of the monthly average Sea ice extent and sea ice area in Antarctica have been analyzed based on the sea ice index in the National Snow and Ice Data Center (NSIDC) during the 1979-2014. It has been found that the sea ice extents were expanding and sea ice areas were increasing, furthermore, the growth is greater in recent years. The variation of the sea ice at different Antarctic regions was analyzed briefly according to the sea ice concentration trend by months.In the basis of the sea ice concentration AMSR2 (a case study in 2013), this paper discussed the spatial distribution characteristics at different stages in one year of the sea ice in Prydz Bay, Antarctica. The sea ice in Prydz Bay is mainly seasonal, and changes a lot in one year. The bay is covered by sea ice in winter, the edge of sea ice can reach 57°S; sea ice smash and melt gradually from north to south in spring and summer; the landfast ice along the coastline melted in midsummer, and there is mainly the discontinuous sea ice belt.The optical characteristic of sea ice has been observed during navigations of R/V Xuelong in the Austral summer of 2013-2014 in Prydz Bay, Eastern Antarctica. Underway incident and reflected solar irradiance have been measured using RAMSES-ACC-VIS hyper-spectral radiometers, which have been set up in front of the port side of Xuelong. Albedo of seawater and sea ice can then been calculated from the data. Temporal variations of albedo were analyzed by comparing the observed results obtained from different navigation segments from late November to early March, which spanned from sea ice melt season to growth season. During the melt season, the relatively large water content within the snow cover can reduce spectral reflection for the near-infrared spectrum.The observed albedo has been linked to sea ice concentration derived from satellite remote sensing (AMSR 2) and visual observations from the bridge of Xuelong. The analyses show that regional average albedo depended mainly on sea ice concentration. However, it was also affected by the physics of underlying surface. For example, the albedo of new ice formed from late February to early March was 30-50% of that of the second-year pack ice. Therefore, the contribution of new ice to regional average albedo is not as strong as that to regional ice concentration. Thus, to establish a reasonable albedo parameterization for the mixing zone of sea ice and water, ice concentration is not enough. One should seriously consider the influence of ice type and the physics of snow over the ice, and the wavelength dependence of spectral albedo. Meanwhile, surface temperature of the sea ice or seawater has been measured by the infrared radiometer at the same position, and the temporal and spatial change at four different segments were calculated and the relationship between the surface temperature and the albedo were also analyzed and studied...