An indicator of sea ice variability for the Antarctic marginal ice zone

Abstract. Remote-sensing records over the last 40 years have revealed large year-to-year global and regional variability in Antarctic sea ice extent. Sea area extent are useful climatic indicators of large-scale variability, but they do not allow quantification regions distinct concentration (SIC). This is particularly relevant marginal zone (MIZ), which a transitional region between open ocean pack ice, where exchanges ocean, atmosphere more intense. The MIZ circumpolar broader than Arctic. Its inferred from satellite-derived SIC using 15 %–80 % range, assumed to be indicative drift or partly closed conditions typical edge. proxy has been proven effective Arctic, it deemed less reliable Southern Ocean, type unrelated value, since wave penetration free-drift reported with 100 cover. aim this paper propose an alternative indicator for detecting can used quantify at climatological scale on ice-covered Ocean seasons, as well derive maps probability encountering certain degree expected monthly value. proposed based statistical properties SIC; tested available climate data distribution year compared threshold-based definition. results present revised view seasonal cycle, rapid increase saturation winter, opposed steady summer spring literature. It also reconciles discordant estimates threshold different algorithms. complements use fraction, allowing derivation exceeding planning observational networks navigation routes, changes when baselines periods.