Contribution of sea ice albedo and insulation effects to Arctic amplification in the EC-Earth Pliocene simulation

In the present work, we simulate the Pliocene climate with the EC-Earth climate model as an equilibrium state for the current warming climate induced by rising CO2 in the atmosphere. The simulated Pliocene climate shows a strong Arctic amplification featuring pronounced warming sea surface temperatu...

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Bibliographic Details
Published in:Climate of the Past
Main Authors: J. Zheng, Q. Zhang, Q. Li, M. Cai
Format: Article in Journal/Newspaper
Language:English
Published: Copernicus Publications 2019
Subjects:
geo
envir
Arctic
Baffin Bay
Greenland
albedo
Baffin
Greenland Sea
North Atlantic
Sea ice
Online Access:https://doi.org/10.5194/cp-15-291-2019
https://www.clim-past.net/15/291/2019/cp-15-291-2019.pdf
https://doaj.org/article/dd1c0575c59142a19c952b3b54b704fd
Description
Summary:In the present work, we simulate the Pliocene climate with the EC-Earth climate model as an equilibrium state for the current warming climate induced by rising CO2 in the atmosphere. The simulated Pliocene climate shows a strong Arctic amplification featuring pronounced warming sea surface temperature (SST) over the North Atlantic, in particular over the Greenland Sea and Baffin Bay, which is comparable to geological SST reconstructions from the Pliocene Research, Interpretation and Synoptic Mapping group (PRISM; Dowsett et al., 2016). To understand the underlying physical processes, the air–sea heat flux variation in response to Arctic sea ice change is quantitatively assessed by a climate feedback and response analysis method (CFRAM) and an approach similar to equilibrium feedback assessment. Given the fact that the maximum SST warming occurs in summer while the maximum surface air temperature warming happens during winter, our analyses show that a dominant ice-albedo effect is the main reason for summer SST warming, and a 1 % loss in sea ice concentration could lead to an approximate 1.8 W m−2 increase in shortwave solar radiation into open sea surface. During the winter months, the insulation effect induces enhanced turbulent heat flux out of the sea surface due to sea ice melting in previous summer months. This leads to more heat released from the ocean to the atmosphere, thus explaining why surface air temperature warming amplification is stronger in winter than in summer.

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