The Influence of Heat Transport on Arctic Amplification

Laura Fleming, S.M., 2019
Young-Oh Kwon, Advisor

The Arctic surface air temperature has warmed nearly twice as much as the global mean since the mid-20th century. Arctic sea ice has also been declining rapidly in recent decades. This thesis focuses mainly on the role of poleward heat transport on Arctic amplification in the Community Earth System Model version 1 (CESM1) Large Ensemble. In this thesis, we define the ocean heat transport as the heat transport across five sections surrounding the Arctic instead of using the zonally averaged ocean heat transport at 65∘N or 70∘N.

We find that CESM1 Large Ensemble projects a large increase towards the end of the 21st century in ocean heat transport into the Arctic, and that the increase in ocean heat transport is significantly correlated with Arctic amplification. The main contributor to the increase in ocean heat transport is the increase across the Barents Sea Opening. The increase in Barents Sea Opening ocean heat transport is highly correlated with the decrease in sea ice in the Barents-Kara Sea region. We propose that this is because the increase in ocean heat transport melts the ice at the sea ice margin, which results in increased surface heat flux from the ocean and further local feedback through decreased surface albedo and increased cloud coverage.