Abstract: Sea ice of the Southern Ocean plays an important role in global climate change, making the Weddell Sea—the biggest bay in the Southern Ocean—a hot spot for studying sea ice change in this area. Based on GLORYS12V1 sea ice density data from 1993 to 2017, this study analyzed the sea ice distribution in the Weddell Sea and its interannual variation. A strong seasonality to the sea ice concentration distribution of the Weddell Sea was found. The distributional differences of the wind field are the main reason that sea ice piles up on one side of Antarctic Peninsula. Under wind effects, the Queen Maud Land’s broad ocean sea ice drifts into the open ocean and melts, producing a spatial distribution with “low west–high east” and “high nearshore–low offshore” sea-ice concentrations. Fluctuations in sea-ice area occur at intervals of 27 months, 35 months, 75 months and 120 months, respectively. Seasonal changes in sea-ice area are not very obvious in spring, fall and winter, but in summer, there is an outstanding increase of around 0.15×10⁵ km²·a⁻¹. The interannual variation of Antarctic sea ice area is mainly affected by thermodynamic factors, including sea surface temperature, as well as temperature and shortwave radiation cycles related to periods of 27 months, 35 months, and 75 months. The general sea ice area has strong negative correlations with temperature and sea surface temperature in spring, summer, and fall, and has a strong negative correlation with solar short-wave radiation over the whole year.

Key words: Weddell sea, sea ice area, sea surface temperature, temperature, net solar short-wave radiation