Servizio Comunitario di Informazione in materia di Ricerca e Sviluppo - CORDIS

Better understanding of compensating regional variability of air-sea CO2 fluxes in the North Atlantic

Prior to the NOCES project there existed a large conflict between estimates for interannual variability for air-sea CO2 fluxes in the North Atlantic. Inverse atmospheric models predicted very large variability; ocean models predicted small variability. Moreover, a databased study agreed with the large variability predicted by atmospheric models. That data based study used data from 1 station in the subtropical gyre of the North Atlantic, considering it to be representative, and extrapolated across the entire basin. Analysis of results from the NOCES simulations revealed that the subtropical gyre is not representative of the entire North Atlantic.

The subpolar gyre and the inter-gyre region (the transition area between subpolar and subtropical gyres) also contribute with multipolar anomalies at multiple frequencies: these tend to cancel one another in terms of the basin-wide air-sea CO2 flux. That is, high and low anomalies extend throughout the North Atlantic and partially cancel one another, thereby damping total basin-wide air-sea CO2 flux. Thus it is not reasonable to assume that variability in the subtropical gyre, namely at BATS, is representative of that in the intergyre and subpolar gyre, neither at interannual nor decadal timescales.

The former atmospheric inverse model results have also been proved wrong by (1) comparison to observed seasonal variability, which is much lower and (2) a new state-of-the-art atmospheric inverse model that has much higher resolution and likewise simulates much lower varibility. In conclusion, the high air-sea CO2 flux variability over the North Atlantic predicted by the older inverse approaches are clearly wrong due to inadequate spatial resolution and thus "leakage" of high variability from adjacent terrestrial grid cells.

Informazioni correlate

Reported by

Bat. 712, l'Orme, Pt. courrier 132
91191 Gif-sur-Yvette
See on map