Summary
Antarctic sea ice plays a crucial role in the global climate system and is highly sensitive to climate change and variability (Walsh 1983; Liu et al. 2002; Roach et al. 2020). Sea ice seasonally covers a vast area of the high-latitude Southern Ocean each year, expanding its extent from ~3 × 106 km2 in summer to 19–20 × 106 km2 in winter (Parkinson 2019). This seasonal cycle is driven by large-scale atmospheric and oceanic circulations and temperature, but on shorter time scales is highly sensitive to the frequent occurrence of high wind and wave events, and also serves as a physical buffer for those ice shelves vulnerable to the destructive effects of ocean swells (Massom et al. 2018). As a highly reflective, insulative blanket, the sea ice and its snow cover strongly modify ocean–atmosphere fluxes and interactions (Bourassa et al. 2013). In turn, sea ice processes are of high importance to the physical and chemical properties and dynamics of the high-latitude ocean and atmosphere, including global ocean overturning (thermohaline) circulation (Meredith and Brandon 2017). The modification of ocean salinity and stratification by sea ice growth/melt processes moderates climate change by regulating the Southern Ocean's capacity to take up and store anthropogenic heat and carbon from the atmosphere (Frölicher et al. 2015), while more locally these same sea ice processes modify warm ocean-water incursions to Antarctic outlet glaciers and ice shelves and thus basal melt rates (Timmermann and Hellmer 2013). Sea ice also forms a key habitat for a myriad of biota—ranging from micro-organisms to whales (Thomas 2017)—that are highly adapted to (and dependent on) its presence and seasonal changes (Massom and Stammerjohn 2010). Human activities around Antarctica such as the resupply of research stations and field experiments are also strongly affected by sea ice (COMNAP 2015). Given these factors, changes and variability in Antarctic sea ice have important ramifications.
Related projects
