 |
| Titel |
Spatiotemporal variability and drivers of pCO2 and air–sea CO2 fluxes in the California Current System: an eddy-resolving modeling study |
| VerfasserIn |
G. Turi, Z. Lachkar, N. Gruber |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
1726-4170
|
| Digitales Dokument |
URL |
| Erschienen |
In: Biogeosciences ; 11, no. 3 ; Nr. 11, no. 3 (2014-02-06), S.671-690 |
| Datensatznummer |
250117190
|
| Publikation (Nr.) |
 copernicus.org/bg-11-671-2014.pdf |
|
|
|
|
|
| Zusammenfassung |
We quantify the CO2 source/sink nature of the California Current System
(CalCS) and determine the drivers and processes behind the mean and
spatiotemporal variability of the partial pressure of CO2 (pCO2) in
the surface ocean. To this end, we analyze eddy-resolving, climatological
simulations of a coupled physical–biogeochemical oceanic model on the basis
of the Regional Oceanic Modeling System (ROMS).
In the annual mean, the entire CalCS within 800 km of the coast and from
∼33° N to 46° N is essentially neutral with regard
to atmospheric CO2: the model simulates an integrated uptake flux of
−0.9 ± 3.6 Tg C yr−1, corresponding to an average flux
density of −0.05 ± 0.20 mol C m−2 yr−1. This near zero
flux is a consequence of an almost complete regional compensation between (i)
strong outgassing in the nearshore region (first 100 km) that brings waters
with high concentrations of dissolved inorganic carbon (DIC) to the surface
and (ii) and a weaker, but more widespread uptake flux in the offshore region
due to an intense biological reduction of this DIC, driven by the nutrients
that are upwelled together with the DIC.
The air–sea CO2 fluxes vary substantially in time, both on seasonal and
sub-seasonal timescales, largely driven by variations in surface ocean
pCO2. Most of the variability in pCO2 is associated with the
seasonal cycle, with the exception of the nearshore region, where
sub-seasonal variations driven by mesoscale processes dominate. In the
regions offshore of 100 km, changes in surface temperature are the main
driver, while in the nearshore region, changes in surface temperature, as
well as anomalies in DIC and alkalinity (Alk) owing to changes in
circulation, biological productivity and air–sea CO2 fluxes dominate. The
prevalence of eddy-driven variability in the nearshore 100 km leads to
a complex spatiotemporal mosaic of surface ocean pCO2 and air–sea
CO2 fluxes that require a substantial observational effort to determine
the source/sink nature of this region reliably. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|