Variability of sea ice production in the Weddell and Ross Seas polynyas from AMSR-E observations, 2003-2007

Using an algorithm to estimate heat loss from the 36GHz polarization ratios of AMSR-E, Martin et al. [2007] found that the combined ice production from three largest coastal polynyas in the Ross Sea was ~500 km3/yr. They also showed that the polynya ice production approximately equaled the ice export. Using the same approach, we investigate the ice production of polynyas in the southern Weddell Sea. The study shows that the Weddell polynyas are much smaller in area than those in the Ross Sea and that the ice production is only a small fraction of the net ice export from the southern Weddell. The reason for the difference between ice production in the Ross and Weddell seas is that in the Ross, persistent polynyas are maintained by the strong, cold off-shore winds blowing off the Ross ice shelf, consistently producing ice and consequently high salinity shelf water throughout the winter; while in the southern Weddell, there are no comparable wind patterns. Driven by a large offshore low-pressure system, the winds circulate around the Weddell in a clockwise pattern. This results in mostly weak sporadic polynyas distributed along the coastline, primarily along the Coats Land coast. This paper discusses the winter ice production of the Weddell coastal polynyas, compares them both in magnitude and variability with the Ross polynyas, and discusses the implications on the formation of high salinity shelf water in the Weddell and Ross Seas. (Reference: Martin, S., R. Drucker, and R. Kwok. The areas and ice production of the western and central Ross Sea polynyas, 1992-2002, and their relation to the B-15 and C-19 iceberg events of 2000 and 2002. J. Mar. Syst. (2007), doi:10.1016/j.jmarsys.2006.11.008.)