We investigate an unusual extensive ice-free feature (EIF) within the pack ice that developed in the central Weddell Sea in December 1980 on the edge of the multi-year sea ice off the east coast of the Antarctic Peninsula. The EIF was first apparent on satellite imagery on 8 December 1980 and expanded until it reached its largest areal extent of ~5.4 × 10⁵km² on 26 December. The combined influences of near-record strength ( ~ 15 ms⁻¹) cold winds from the Antarctic continent (transporting sea ice northward and creating an area of thin ice), increased shortwave radiation and net heat flux into the ocean, passage of deep polar storms, and the upwelling of high saline warm water led to the opening of this unique EIF. It is still the largest ice-free feature within the pack ice resembling a polynya observed in the central Weddell Sea during the satellite era, contributing significantly to the 1981 Weddell Sea sea ice extent minimum of 0.793 × 10⁶km², the lowest on record. The development mechanism of this EIF was different from the 1970’s Weddell open ocean polynya which occurred within the winter sea ice cover through enhanced ocean convection.

我们调查了 1980 年 12 月威德尔海中部在南极半岛东海岸多年海冰边缘形成的浮冰内异常广泛的无冰特征 (EIF)。 EIF 于 1980 年 12 月 8 日首次在卫星图像上出现，并不断扩大，直至 12 月 26 日达到最大面积范围约 5.4 × 10 ⁵ 公里 ² 。来自南极大陆的接近记录强度（〜15毫秒 ⁻¹ ）冷风（将海冰向北输送并形成薄冰区域）、增加的短波辐射和进入海洋的净热通量的综合影响、深层极地风暴的通过以及高盐度暖水的上涌导致了这个独特的 EIF 的开放。它仍然是卫星时代在威德尔海中部观测到的类似于冰间湖的浮冰中最大的无冰特征，对 1981 年威德尔海海冰范围最小值 0.793 × 10 ⁶ 公里做出了重大贡献 ² ，有记录以来的最低值。该EIF的发展机制与1970年威德尔公海冰湖不同，后者通过增强海洋对流而发生在冬季海冰覆盖范围内。