Air-ice exchange of CO2 and energy fluxes

Air-Ice fluxes of CO2 were measured over a Greenlandic fjord close to the town Kapisalik in a week in March 2010. The thickness of the ice was 0.5 – 1 meter and it had a thin layer of snow (1-5 cm) on top. We used eddy covariance, the dissipation technique and the cospectra peak method (Sørensen and Larsen, 2010) to estimate the fluxes from fast (20 Hz) data of CO2, water vapour, temperature and vertical wind speed. This is the first time these techniques have been used for CO2 and water vapour fluxes over ice. Using three different flux techniques will ensure higher confidence in the flux estimates.

The CO2 fluxes were small and averaged over the week the flux was downwards, however a few incidents of upward CO2 fluxes were observed. These upward CO2 fluxes occurred at high upward latent heat fluxes and downward but small sensible heat fluxes. It is speculated that upward CO2 fluxes from ice are associated with sublimation and high latent heat fluxes.

Here we present the observations and the results from the field campaign. Furthermore we discuss the analyses of the CO2 fluxes at different meteorological conditions and possible causes for upward fluxes of CO2.