Extreme Antarctic Cold of Late Winter 2023

• Published in: Advances in atmospheric sciences 2024-10, Vol.41 (10), p.1873-1880
• Main Authors: Tomanek, Anastasia J., Mikolajczyk, David E., Lazzara, Matthew A., Di Battista, Stefano, Ding, Minghu, Fontolan Litell, Mariana, Bromwich, David H., Norton, Taylor P., Keller, Linda M., Welhouse, Lee J.
• Format: Article
• Language: English
• Subjects: Aircraft; Anomalies; Antarctic meteorology; Atmospheric conditions; Atmospheric Sciences; Automatic weather stations; Climatology; Cold flow; Dynamic height; Earth and Environmental Science; Earth Sciences; Extreme cold; Extreme low temperatures; Flight operations; Fluid flow; Gels; Geophysics/Geodesy; Geopotential; Geopotential height; Height; Height anomalies; Hydraulics; Ice shelves; Land ice; Low temperature; Meteorology; News & Views; Stretching; Winter
• ISSN: 0256-1530; 1861-9533
• DOI: 10.1007/s00376-024-4139-1

Extreme cold temperatures were observed in July and August 2023, coinciding with the WINFLY (winter fly-in) period of mid to late August into September 2023, meaning aircraft operations into McMurdo Station and Phoenix Airfield were adversely impacted. Specifically, with temperatures below −50°C, safe flight operation was not possible because of the risk of failing hydraulics and fuel turning to gel onboard the aircraft. The cold temperatures were measured across a broad area of the Antarctic, from East Antarctica toward the Ross Ice Shelf, and stretching across West Antarctica to the Antarctic Peninsula. A review of automatic weather station measurements and staffed station observations revealed a series of sites recording new record low temperatures. Four separate cold phases were identified, each a few days in duration and occurring from mid-July to the end of August 2023. A brief analysis of 500-hPa geopotential height anomalies shows how the mid-tropospheric atmospheric environment evolves in relation to these extreme cold temperatures. The monthly 500-hPa geopotential height anomalies show strong negative anomalies in August. Examination of composite geopotential height anomalies during each of the four cold phases suggests various factors leading to cold temperatures, including both southerly off-content flow and calm atmospheric conditions. Understanding the atmospheric environment that leads to such extreme cold temperatures can improve prediction of such events and benefit Antarctic operations and the study of Antarctic meteorology and climatology.