Weddell Sea Control of Ocean Temperature Variability on the Western Antarctic Peninsula

• Published in: Geophysical research letters 2023-08, Vol.50 (15), p.n/a
• Main Authors: Morrison, Adele K., England, Matthew H., Hogg, Andrew McC, Kiss, Andrew E.
• Format: Article
• Language: English
• Subjects: Ablation; Advection; Antarctic temperatures; Antarctica; Coastal flooding; Cold; Cold water; Continental shelves; Dense water; Glaciation; Ice; Ice sheets; Inflow; ocean modeling; Ocean models; Ocean temperature; Ocean temperature variability; Ocean warming; Oceans; Overflow; Temperature variability; Tracers; Variability; Water temperature
• ISSN: 0094-8276; 1944-8007
• DOI: 10.1029/2023GL103018

Recent ice loss on the western Antarctic Peninsula has been driven by warming ocean waters on the continental shelf. However, due to the short observational record, our understanding of the dynamics and variability in this region remains poor. High‐resolution ocean model simulations show that the temperature variability along the western Antarctic Peninsula is controlled by the rate of dense water formation in the Weddell Sea. Passive tracer advection reveals connectivity between the Weddell Sea and the coastline of the western Antarctic Peninsula and Bellingshausen Sea. During multi‐year periods of weak Weddell dense water formation, dense overflow transport in the Weddell Sea decreases, while the transport of cold water around the tip of the Antarctic Peninsula strengthens, driving a temperature decrease of 0.4°C along the western Antarctic Peninsula. This mechanism implies that western Antarctic Peninsula coastal ocean temperature may cool in the future if Weddell Dense Shelf Water production slows down. Plain Language Summary Melting of the ice sheet along the western Antarctic Peninsula has been driven by warming ocean waters that are in contact with the underside of the ice. It is therefore important that we understand what processes drive variation in ocean temperature. However, due to the short observational record, our understanding of the dynamics and variability in this region remains poor. Using a high‐resolution ocean model, we identify a new mechanism that controls the ocean temperature variability along the western Antarctic Peninsula that is linked to the formation of dense water to the east in the Weddell Sea. During years when dense water formation is weak in the Weddell Sea, there is an increased transport of cold waters westward around the tip of the Antarctic Peninsula that flood the coast of the western Antarctic Peninsula with cold waters. Conversely, when dense water formation is strong in the Weddell Sea, there is decreased inflow of cold waters and the ocean along the coast of the western Antarctic Peninsula warms. This mechanism implies that the ocean along the western Antarctic Peninsula may temporarily cool in the future if dense water formation in the Weddell Sea slows down. Key Points A high resolution ocean model reveals connectivity from the Weddell Sea to the western Antarctic Peninsula and Bellingshausen Sea When Weddell Sea dense water formation is weak, transport of cold water along the coastline of the western Antarcti