 |
| Titel |
Winter observations of CO2 exchange between sea ice and the atmosphere in a coastal fjord environment |
| VerfasserIn |
J. Sievers, L. L. Sørensen, T. Papakyriakou, B. Else, M. K. Sejr, D. Haubjerg Søgaard, D. Barber, S. Rysgaard |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
1994-0416
|
| Digitales Dokument |
URL |
| Erschienen |
In: The Cryosphere ; 9, no. 4 ; Nr. 9, no. 4 (2015-08-25), S.1701-1713 |
| Datensatznummer |
250116842
|
| Publikation (Nr.) |
 copernicus.org/tc-9-1701-2015.pdf |
|
|
|
|
|
| Zusammenfassung |
| Eddy covariance observations of CO2 fluxes were conducted during
March–April 2012 in a temporally sequential order for 8, 4 and 30 days,
respectively, at three locations on fast sea ice and on newly formed polynya
ice in a coastal fjord environment in northeast Greenland. CO2 fluxes
at the sites characterized by fast sea ice (ICEI and DNB) were found to
increasingly reflect periods of strong outgassing in accordance with the
progression of springtime warming and the occurrence of strong wind events:
FCO2ICE1 = 1.73 ± 5 mmol m−2 day−1 and
FCO2DNB = 8.64 ± 39.64 mmol m−2 day−1,
while CO2 fluxes at the polynya site (POLYI) were found to generally reflect uptake
FCO2POLY1 = −9.97 ± 19.8 mmol m−2 day−1. Values given are the
mean and standard deviation, and negative/positive values indicate
uptake/outgassing, respectively. A diurnal correlation analysis supports a
significant connection between site energetics and CO2 fluxes linked to
a number of possible thermally driven processes, which are thought to change
the pCO2 gradient at the snow–ice interface. The relative influence of
these processes on atmospheric exchanges likely depends on the thickness of
the ice. Specifically, the study indicates a predominant influence of brine
volume expansion/contraction, brine dissolution/concentration and calcium
carbonate formation/dissolution at sites characterized by a thick sea-ice
cover, such that surface warming leads to an uptake of CO2 and vice
versa, while convective overturning within the sea-ice brines dominate at
sites characterized by comparatively thin sea-ice cover, such that nighttime
surface cooling leads to an uptake of CO2 to the extent permitted by
simultaneous formation of superimposed ice in the lower snow column. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|