Upwelling and associated heat flux in the equatorial Atlantic inferred from helium isotope disequilibrium

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Hauptverfasser: Kock, Annette, Schafstall, Jens, Dengler, Marcus, Brandt, Peter, Bange, Hermann W
Format: Dataset Open Access
Sprache:en
Veröffentlicht: PANGAEA 2012
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author Kock, Annette
Schafstall, Jens
Dengler, Marcus
Brandt, Peter
Bange, Hermann W
author_facet Kock, Annette
Schafstall, Jens
Dengler, Marcus
Brandt, Peter
Bange, Hermann W
collection Datos científicos de ciencias marinas y ambientales
contents Sea-to-air and diapycnal fluxes of nitrous oxide (N2O) into the mixed layer were determined during three cruises to the upwelling region off Mauritania. Sea-to-air fluxes as well as diapycnal fluxes were elevated close to the shelf break, but elevated sea-to-air fluxes reached further offshore as a result of the offshore transport of upwelled water masses. To calculate a mixed layer budget for N2O we compared the regionally averaged sea-to-air and diapycnal fluxes and estimated the potential contribution of other processes, such as vertical advection and biological N2O production in the mixed layer. Using common parameterizations for the gas transfer velocity, the comparison of the average sea-toair and diapycnal N2O fluxes indicated that the mean sea-toair flux is about three to four times larger than the diapycnal flux. Neither vertical and horizontal advection nor biological production were found sufficient to close the mixed layer budget. Instead, the sea-to-air flux, calculated using a parameterization that takes into account the attenuating effect of surfactants on gas exchange, is in the same range as the diapycnal flux. From our observations we conclude that common parameterizations for the gas transfer velocity likely overestimate the air-sea gas exchange within highly productive upwelling zones.
format Dataset Open Access
id pangaea_https___doi_org_10_1594_PANGAEA_860359
institution PANGAEA
language en
publishDate 2012
publisher PANGAEA
record_format pangaea
spellingShingle Upwelling and associated heat flux in the equatorial Atlantic inferred from helium isotope disequilibrium
Kock, Annette
Schafstall, Jens
Dengler, Marcus
Brandt, Peter
Bange, Hermann W
SOPRAN; Surface Ocean Processes in the Anthropocene
Sea-to-air and diapycnal fluxes of nitrous oxide (N2O) into the mixed layer were determined during three cruises to the upwelling region off Mauritania. Sea-to-air fluxes as well as diapycnal fluxes were elevated close to the shelf break, but elevated sea-to-air fluxes reached further offshore as a result of the offshore transport of upwelled water masses. To calculate a mixed layer budget for N2O we compared the regionally averaged sea-to-air and diapycnal fluxes and estimated the potential contribution of other processes, such as vertical advection and biological N2O production in the mixed layer. Using common parameterizations for the gas transfer velocity, the comparison of the average sea-toair and diapycnal N2O fluxes indicated that the mean sea-toair flux is about three to four times larger than the diapycnal flux. Neither vertical and horizontal advection nor biological production were found sufficient to close the mixed layer budget. Instead, the sea-to-air flux, calculated using a parameterization that takes into account the attenuating effect of surfactants on gas exchange, is in the same range as the diapycnal flux. From our observations we conclude that common parameterizations for the gas transfer velocity likely overestimate the air-sea gas exchange within highly productive upwelling zones.
title Upwelling and associated heat flux in the equatorial Atlantic inferred from helium isotope disequilibrium
topic SOPRAN; Surface Ocean Processes in the Anthropocene
url https://doi.org/10.1594/PANGAEA.860359