Impacts of Changes in Sea Ice and Heat Flux on Arctic Warming

Abstract

The reduction of Arctic sea ice has enhanced the sea-ice-air interaction in the Arctic atmospheric boundary layer, especially the increase in sea-air heat flux in autumn. Changes in radiation and heat flux and the role of sea-ice-air interactions in climate change in the central Arctic were analyzed and evaluated on the basis of the observation data of ice stations during the six Chinese Arctic Research Expeditions. The albedo is high in the Arctic sea-ice surface except the melting process. Overall, the Arctic sea-ice surface can absorb radiation energy, which is much lower than that absorbed by mid-latitude surfaces. Consequently, a relatively weak turbulence exchange occurred between the sea-ice surface and the atmosphere. Further estimates of the surface heat budget in the Arctic are obtained using eddy correlation and flux-profile method. The results are representative of the heat balance and ice-air interactions in the central Arctic Ocean. In the Arctic, changes in heat flux displayed notable interdecadal characteristics, similar to the change of sea-ice extent. The heat flux in September of each year in 2001-2014 was considerably higher compared with that in 1979-2000, particularly at the edges of the central Arctic Ocean. In September of each year in 1979-2014, the sea-ice extent was remarkably negatively correlated to the heat flux (sensible heat flux + latent heat flux), and the heat flux was considerably positively correlated to the atmospheric temperature at 2 m above sea level. This result demonstrates that a reduction of Arctic sea ice will lead to changes in heat flux, thereby warming the atmosphere and increasing the temperature of the atmospheric boundary layer over the Arctic. In addition, this impact is long-lasting.