Assessment of the synoptic variability of the Antarctic marginal ice zone with in situ observations

Abstract

Our knowledge of sea ice variability, which contributes to the detection of climate change trends, stems primarily from remotely sensed information. However, sea ice in the Southern Ocean is characterised by large variability that remains unresolved and limits our confidence on the remotely sensed products. Although one of the biggest seasonal changes on Earth is the annual advance and retreat of the Antarctic sea-ice cover, relatively little attention has been given to the processes by which the marginal ice zone (MIZ. edge forms and responds to synoptic events. The objective of this study was to compare sea-ice observations from the SA Agulhas II to high resolution satellite imagery when transecting the MIZ. Therefore, enhancing our understanding of the relationship between the MIZ and synoptic events. The location of the ship was tracked, allowing a more quantitative description of spatial sea-ice characteristics, specifically focusing on the MIZ edge. High resolution remotely sensed data were used to retrieve sea-ice properties. The Antarctic sea ice conditions were investigated to evaluate the quality of satellite retrievals with respect to on-board observational estimates, based on the Antarctic Sea Ice Processes and Climate (ASPeCt. protocol. To maximize the retrieval of information from previous cruises not specifically dedicated to sea-ice observations, an algorithm was developed to automatically retrieve sea ice concentration from still images and videos. This method can be used to obtain quantitative sea-ice data from vessels of opportunity without the need to have trained personnel on-board. - Abstract as displayed in the - Abstract booklet. The presentation on the day may differ from the - Abstract.