Delayed Antarctic melt season reduces albedo feedback

• Published in: National Science Review
• Main Authors: Liang, Lei, Guo, Huadong, Liang, Shuang, Li, Xichen, Moore, John C, Li, Xinwu, Cheng, Xiao, Wu, Wenjin, Liu, Yan, Rinke, Annette, Jia, Gensuo, Pan, Feifei, Gong, Chen
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2023
• Subjects: Antarctic ice sheet; snowmelt; season delay; sea ice; solar irradiance; /dk/atira/pure/person/fieldofscience2010/1/17/2; name=Environmental sciences; Antarc*; Antarctic; Ice Sheet; Sea ice
• Online Access: https://research.ulapland.fi/fi/publications/de21c76f-8713-4927-afb0-b2927b94a1e0; https://doi.org/10.1093/nsr/nwad157; https://lacris.ulapland.fi/ws/files/38119572/nwad157.pdf

Antarctica's response to climate change varies greatly both spatially and temporally. Surface melting impacts mass balance and also lowers surface albedo. We use a 43-year record (from 1978 to 2020) of Antarctic snow melt seasons from space-borne microwave radiometers with a machine-learning algorithm to show that both the onset and the end of the melt season are being delayed. Granger-causality analysis shows that melt end is delayed due to increased heat flux from the ocean to the atmosphere at minimum sea-ice extent from warming oceans. Melt onset is Granger-caused primarily by the turbulent heat flux from ocean to atmosphere that is in turn driven by sea-ice variability. Delayed snowmelt season leads to a net decrease in the absorption of solar irradiance, as a delayed summer means that higher albedo occurs after the period of maximum solar radiation, which changes Antarctica's radiation balance more than sea-ice cover.