Rotational drift in Antarctic sea ice: pronounced cyclonic features and differences between data products

Abstract. Sea ice extent variability, a measure based on satellite-derived sea concentration measurements, has traditionally been used as an indicator to evaluate the impact of climate change polar regions. However, concentration-based measurements variability do not allow discrimination relative contributions made by thermodynamic and dynamic processes, prompting need use drift products develop methods quantify changes in dynamics that would indicate trends characteristics. Here, we present new method automate detection rotational features Antarctic from space at spatial temporal scales comparable weather. This analysis focusses Atlantic sector Southern Ocean period 2013–2020 using currently available satellite motion EUMETSAT OSI SAF. We observe large discrepancy between cyclonic anticyclonic features, with typically exhibiting larger intensity according all products. The mean 95th percentile is 1.5–2.0 times for than features. increased intensity, indicating most intense are also least homogenous. There good agreement detecting features; however, disagreement evident merged product showing threshold largest likely due more extended coverage valid vorticity points. A time series shows abrupt intensification 2014–2017, which coincides record decline since winter 2015. Our results systematic assessments against dedicated observational experiments weather-dominated sector. Such information will us confirm whether detected increase linked rapidly changing atmospheric driven establish potential weather-driven ice.