Data/hora: 01/06/2024 03:46:04

Provedor de dados: | 5
País: | France
Título: | BOCATS 2016. CTD-O2 data report
Autores: | Branellec, Pierre; Lherminier, Pascale.
Data: | 2017-06
Ano: | 2017
Resumo: | The BOCATS cruise (Biennial Observation of Carbon, Acidification, Transport and Sedimentation) was carried out in the North Atlantic from Vigo (June 18) to Reykjavik (July 31). It was composed of 2 main sections: the OVIDE section coast to coast between Portugal and the south tip of Greenland, followed by the Reykjanes Ridge section, from 55 °N to Iceland. The classical hydrographic rosette was cast 137 times along the route. While the CTD-O2 probe acquired continuous profiles of the “physical” variables (pressure, temperature, salinity and dissolved oxygen), 28 Niskin bottles were closed at different levels during the upcast to provide samples for biogeochemical analysis. We report here an overview of the cruise operations and team, followed by a focus on the acquisition and calibration steps of the physical variables measured by the hydrographic CTD-O2 probe.  After calibration, we find precisions for pressure, temperature, salinity and dissolved oxygen that fit the GO-SHIP international quality requirements. Pressure and temperature were calibrated at the laboratory before and after the cruise, leading to a precision of 1 dbar and 0.002°C respectively. The calibration of salinity and dissolved oxygen data is obtained by applying polynomial correcting functions that are calculated to statistically minimize the differences between the probe data and the sample data analyzed on board in the chemistry container. These chemical data are also evaluated by the comparison of replicates. After calibration, the differences in salinity and oxygen follow a zero-centered Gaussian-like distribution which standard deviation is used to evaluate the probe precision for each variable. For salinity, we find a standard deviation of 0.001, and for oxygen, 0.027 ml/l (or 1.3 μmol/kg). Those numbers correspond to a 68 % confidence interval and must be doubled to reach a precision with a 95 % confidence interval.
Tipo: | Text
Idioma: | Inglês

Identificador:

https://archimer.ifremer.fr/doc/00480/59190/61877.pdf

DOI:10.13155/59190

https://archimer.ifremer.fr/doc/00480/59190/

Relação: | info:eu-repo/grantAgreement/EC/FP7/633211/EU//AtlantOS
Formato: | application/pdf

Fonte:

info:eu-repo/semantics/openAccess

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