Air‐sea gas transfer in high Arctic fjords. Issue 5 (4th March 2017)

• Record Type: Journal Article
• Authors: Andersson, A.; Falck, E.; Sjöblom, A.; Kljun, N.; Sahlée, E.; Omar, A. M.; Rutgersson, A.
• Is Part Of: Geophysical research letters. Volume 44:Issue 5(2017)
• Page Start: 2519
• Page End: 2526
• Publication Date: 2017-03-04
• Subjects: air‐sea gas exchange -- transfer velocity -- surface cooling -- water‐side convection -- CO2 flux -- Arctic; Geophysics -- Periodicals; Planets -- Periodicals; Lunar geology -- Periodicals; 550
• DOI: 10.1002/2016GL072373
• Languages: English
• ISSNs: 0094-8276

Abstract

Abstract: In Arctic fjords and high‐latitude seas, strong surface cooling dominates during a large part of the year, generating water‐side convection ( w * w ) and enhanced turbulence in the water. These regions are key areas for the global carbon cycle; thus, a correct description of their air‐sea gas exchange is crucial. CO2 data were measured via the eddy covariance technique in marine Arctic conditions and reveal that water‐side convection has a major impact on the gas transfer velocity. This is observed even at wind speeds as high as 9 m s −1, where convective motions are generally thought to be suppressed by wind‐driven turbulence. The enhanced air‐sea transfer of CO2 caused by water‐side convection nearly doubled the CO2 uptake; after scaled to open‐sea conditions the contribution from w * w to the CO2 flux remained as high as 34%. This phenomenon is expected to be highly important for the total carbon uptake in marine Arctic areas. Key Points: From Arctic EC CO2 data we show a dependence between water‐side convection w * w and the air‐sea gas transfer velocity up to wind of 9 m s −1 The relative contribution from w * w to the calculated total CO2 flux was as high as 34%, where the magnitude is clearly related to u * w / w * w The convectively enhanced transfer results in a significantly larger oceanic CO2 uptake by the sea in wintertime