 |
| Titel |
Sensitivity of the air–sea CO2 exchange in the Baltic Sea and Danish inner waters to atmospheric short-term variability |
| VerfasserIn |
A. S. Lansø, J. Bendtsen, J. H. Christensen, L. L. Sørensen, H. Chen, H. A. J. Meijer, C. Geels |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
1726-4170
|
| Digitales Dokument |
URL |
| Erschienen |
In: Biogeosciences ; 12, no. 9 ; Nr. 12, no. 9 (2015-05-11), S.2753-2772 |
| Datensatznummer |
250117929
|
| Publikation (Nr.) |
 copernicus.org/bg-12-2753-2015.pdf |
|
|
|
|
|
| Zusammenfassung |
Minimising the uncertainties in estimates of air–sea CO2 exchange is an
important step toward increasing the confidence in assessments of the
CO2 cycle. Using an atmospheric transport model makes it possible to
investigate the direct impact of atmospheric parameters on the air–sea
CO2 flux along with its sensitivity to, for example, short-term temporal
variability in wind speed, atmospheric mixing height and atmospheric
CO2 concentration. With this study, the importance of high
spatiotemporal resolution of atmospheric parameters for the air–sea CO2
flux is assessed for six sub-basins within the Baltic Sea and Danish inner
waters. A new climatology of surface water partial pressure of CO2
(pCO2w) has been developed for
this coastal area based on available data from monitoring stations and
on-board pCO2w measuring
systems. Parameterisations depending on wind speed were applied for the
transfer velocity to calculate the air–sea CO2 flux. Two model
simulations were conducted – one including short-term variability in
atmospheric CO2 (VAT), and one where it was not included (CAT).
A seasonal cycle in the air–sea CO2 flux was found for both simulations
for all sub-basins with uptake of CO2 in summer and release of CO2
to the atmosphere in winter. During the simulated period 2005–2010, the
average annual net uptake of atmospheric CO2 for the Baltic Sea, Danish
straits and Kattegat was 287 and 471 Gg C yr−1 for the
VAT and CAT simulations, respectively. The obtained difference of 184 Gg C yr−1 was found to be significant, and thus ignoring short-term
variability in atmospheric CO2 does have a sizeable effect on the
air–sea CO2 exchange. The combination of the atmospheric model and the
new pCO2w fields has also made
it possible to make an estimate of the marine part of the Danish CO2
budget for the first time. A net annual uptake of 2613 Gg C yr−1 was
found for the Danish waters.
A large uncertainty is connected to the air–sea CO2 flux in particular
caused by the transfer velocity parameterisation and the applied
pCO2w climatology. However, as a
significant difference of 184 Gg C yr−1 is obtained between the VAT and
CAT simulations, the present study underlines the importance of including
short-term variability in atmospheric CO2 concentration in future
model studies of the air–sea exchange in order to minimise the uncertainty. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|