Abstract: Underway incident and reflected solar irradiance were measured onboard the R/V Xuelong during its navigations in Prydz Bay, Eastern Antarctica, during the Australian summer of 2013–2014. The albedo of seawater and sea ice was calculated from the observed data. Albedo obtained from different navigational segments from late November to early March was compared. This period spanned the seasons of sea ice melt to growth. Landfast ice covered by snow had the largest albedo (~0.70). The second highest was pack ice with snow (~0.55—0.65), while, the albedo of pack ice without snow cover could decrease to about 0.40. The albedo of new ice was very low (~0.15—0.30). However, snow cover would increase it to about 0.40, which was comparable with second-year ice without snow cover. The observed albedo was linked to sea ice concentration derived from AMSR2 data and visual observations from the bridge of the R/V Xuelong. Regional average albedo depended mainly on sea ice concentration, although it was also affected by the physics of the underlying surface. For example, the albedo of new ice formed from late February to early March was only 30%—50% that of second-year pack ice. Therefore, the contribution of new ice to the regional average albedo is not as great as to regional ice concentration. During the melt season, the relatively large water content within the snow cover can reduce near-infrared spectral reflection. Thus, ice concentration alone is insufficient to establish a reasonable albedo parameterization for the mixing zone of sea ice and water. Instead, the influences of ice and snow types should also be considered.

Key words: Antarctica, Prydz Bay, sea ice, concentration, Albedo, solar irradiance