The influence of sea-ice cover on air-sea gas exchange estimated with radon-222 profiles

Michiel.Rutgers.v.d.Loeff [ at ]


Air-sea gas exchange plays a key role in the cycling of greenhouse and other biogeochemically important gases. Although air-sea gas transfer is expected to change as a consequence of the rapid decline in summer Arctic sea ice cover, little is known about the effect of sea-ice cover on gas exchange fluxes, especially in the marginal ice zone. During the Polarstern expedition ARK-XXVI/3 (TransArc, Aug/Sep 2011) to the central Arctic Ocean, we compared 222Rn/226Ra ratios in the upper 50m of 14 ice-covered and 4 ice-free stations. At three of the ice-free stations, we find 222Rn-based gas transfer coefficients in good agreement with expectation based on published relationships between gas transfer and wind speed over open water when accounting for wind history from wind reanalysis data. We hypothesize that the low gas transfer rate at the fourth station results from reduced fetch due to the proximity of the ice edge, or lateral exchange across the front at the ice edge by restratification. No significant radon deficit could be observed at the ice-covered stations. At these stations, the average gas transfer velocity was less than 0.1 m/d (97.5% confidence), compared to 0.5-2.2 m/d expected for open water. Our results show that air-sea gas exchange in an ice-covered ocean is reduced by at least an order of magnitude compared to open water. In contrast to previous studies, we show that in partially ice-covered regions, gas exchange is lower than expected based on a linear scaling to percent ice cover.

Item Type
Primary Division
Primary Topic
Publication Status
Eprint ID
DOI 10.1002/2013JC009321

Cite as
Rutgers van der Loeff, M. M. , Cassar, N. , Nicolaus, M. , Rabe, B. and Stimac, I. (2014): The influence of sea-ice cover on air-sea gas exchange estimated with radon-222 profiles , Journal of Geophysical Research-Oceans . doi: 10.1002/2013JC009321

[thumbnail of RvdLetalJGR2014.pdf]

Download (6MB) | Preview
Cite this document as:

Add to AnyAdd to TwitterAdd to FacebookAdd to LinkedinAdd to PinterestAdd to Email


Geographical region

Research Platforms

ARK > XXVI > 3

Edit Item Edit Item