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Polar Amplification in Idealized Climates: The Role of Ice, Moisture, and Seasons
Author(s) -
Feldl Nicole,
Merlis Timothy M.
Publication year - 2021
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2021gl094130
Subject(s) - environmental science , ice albedo feedback , sea ice , climatology , albedo (alchemy) , atmospheric sciences , sea ice thickness , latent heat , polar , moisture , cryosphere , geology , meteorology , physics , art , astronomy , performance art , art history
The drivers of polar amplification are investigated by isolating the role of sea‐ice processes, moist energy transport, and the seasonal cycle of insolation in two models, an energy balance model and an idealized general circulation model. Compared to a simple ice‐albedo feedback (temperature‐dependent surface albedo), the addition of thermodynamic‐ice processes and the seasonal cycle of insolation profoundly affects seasonal polar warming. Climatologically limited‐extent ice in the warm season permits only small increases in absorbed solar radiation, producing weak warming, while thick, cold ice in the cold season enables a large radiatively forced response. Despite this enhanced winter warming, the annual‐mean polar amplification is modestly reduced by thermodynamic‐ice processes. When latent heat transport is disabled, polar amplification is further reduced by a factor of 1.8 across the range of ice representations, suggestive of a nearly additive warming by ice and moist‐transport processes.