Brief communication: The anomalous winter 2019 sea-ice conditions in McMurdo Sound, Antarctica

• Published in: The Cryosphere
• Main Authors: Leonard, Greg H., Turner, Kate E., Richter, Maren E., Whittaker, Maddy S., Smith, Inga J.
• Format: Text
• Language: English
• Published: 2021
• Subjects: McMurdo Sound; Ross Sea; Antarc*; Antarctica; Sea ice
• Online Access: https://doi.org/10.5194/tc-15-4999-2021; https://tc.copernicus.org/articles/15/4999/2021/

McMurdo Sound sea ice can generally be partitioned into two regimes: (1) a stable fast-ice cover, forming south of approximately 77.6 ∘ S around March–April and then breaking out the following January–February, and (2) a more dynamic region north of 77.6 ∘ S that the McMurdo Sound and Ross Sea polynyas regularly impact. In 2019, a stable fast-ice cover formed unusually late due to repeated break-out events. We analyse the 2019 sea-ice conditions and relate them to a modified storm index (MSI), a proxy for southerly wind events. We find there is a strong correlation between the timing of break-out events and several unusually large MSI events.