 |
| Titel |
Seasonal to Inter-annual Variability of the Atlantic Ocean Carbon Sink |
| VerfasserIn |
Peter Landschützer, Ute Schuster, Dorothée Bakker, Nicolas Gruber |
| Konferenz |
EGU General Assembly 2013
|
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 15 (2013) |
| Datensatznummer |
250080849
|
|
|
|
|
|
| Zusammenfassung |
| The Atlantic Ocean is one of the most important sinks for atmospheric carbon dioxide (CO2),
but this sink is known to vary substantially from seasonal to multi-decadal time scales. Here
we use observations of the surface ocean partial pressure of CO2 (pCO2) to estimate this sink
and its temporal variations on a monthly basis from 1998 through 2007. We benefitted (i)
from a continuous strengthening of the observational underway network and (ii) from an
improved technique to interpolate the data in space and time. In particular, we combine two
artificial neural network methods to reconstruct basin-wide monthly maps of the sea surface
pCO2 at a resolution of 1Ë latitude x 1Ë longitude. From those, we then compute air-sea
CO2 flux maps using a standard gas exchange parameterization and high-resolution
wind speeds. The evaluation of our estimates with independent time series data
demonstrates that our method reconstructs the seasonal signal at these independent stations
well.
We estimate a decadal mean flux of 0.45±0.16 PgC*yr-1 for the Atlantic region from 44Ë
S to 79Ë N and west of 30Ë E, which is in good agreement with recent studies. We find the
strongest seasonal variability of the sea surface pCO2 and the CO2 air-sea fluxes within the
subtropics of the northern and southern hemisphere, i.e. the zones where the seasonal cycle of
the sea surface pCO2 is thermally driven.
Trends in sea surface pCO2 suggest the strongest increase from 1998 to 2007
polewards of 40Ë N along the Gulf Stream, the North Atlantic Current and the
Subpolar Gyre leading to a decreasing ocean carbon sink, whilst temporal trends in the
South Atlantic show an increasing sink. Our results show that the air-sea flux shows
only small inter-annual variability of 0.04 PgC*yr-1, with low variability both in
the South Atlantic (0.02 PgC *yr-1) and the North Atlantic (0.02 PgC *yr-1). |
|
|
|
|
|
|