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A comparison of gas exchange models in the estimation of CO2 fluxes in the South Atlantic South of Africa for the summer season of 2008/2009

Includes bibliographical references.

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Bibliographic Details
Main Author: Ranier, Stephanie Megan
Other Authors: Monteiro, Pedro
Format: Thesis
Language:English
Published: Department of Oceanography 2014
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access_status_str Open Access
author Ranier, Stephanie Megan
author2 Monteiro, Pedro
author_browse Monteiro, Pedro
Ranier, Stephanie Megan
author_facet Monteiro, Pedro
Ranier, Stephanie Megan
author_sort Ranier, Stephanie Megan
collection Thesis
description Includes bibliographical references.
format Thesis
id oai:open.uct.ac.za:11427/9209
institution University of Cape Town (South Africa)
language eng
last_indexed 2026-06-10T12:34:20.437Z
license_str Not specified — see source repository
provenance_str_mv Harvested via OAI-PMH from UCTD — University of Cape Town Open Access Repository
publishDate 2014
publishDateRange 2014
publishDateSort 2014
publisher Department of Oceanography
publisherStr Department of Oceanography
record_format dspace
source_str UCTD — University of Cape Town Open Access Repository
spelling oai:open.uct.ac.za:11427/9209 A comparison of gas exchange models in the estimation of CO2 fluxes in the South Atlantic South of Africa for the summer season of 2008/2009 Ranier, Stephanie Megan Monteiro, Pedro Waldron, Howard Includes bibliographical references. There is a problem in the determination of air-sea CO2 fluxes because of the number of different relationships used in calculating gas transfer velocities. There is also a problem with the CO2 sink in the Southern Ocean being greatly underestimated. Data were collected underway using an autonomous pCO2 system during three separate relief cruises over the course of austral spring 2008 to austral autumn 2009 onboard the RV SA Agulhas in the South Atlantic Ocean. The wind speed product was extracted from QuikSCAT. Using the data we investigated the sensitivity of the five gas transfer velocity parameterisations to the uncertainty in the wind speed product of 2m.s-1. We found that the Stagnant Film Model was unresponsive. Liss and Merlivat’s (1986) linear model for three wind regimes showed a gradual increase in sensitivity with wind speed. The quadratic relationship developed by Nightingale et al., (2000) also showed a steady increase in sensitivity with an increase in wind speed. Wanninkhof’s (1992) quadratic relationship showed the greatest response at low wind speeds and then a continuing increase in response through medium to high wind regimes. The cubic relationship from Wanninkhof and McGillis (1999) showed the smallest response at low wind speeds but had the greatest response to the uncertainty in the wind speed product in medium and high wind regimes. We also calculated regional and seasonal averages of the CO2 flux with the five gas transfer velocities based on the different relationships between gas transfer velocity and wind speed. We found that there was a CO2 flux into the ocean ranging from 4mmol.m-2.day-1 to 12mmol.m-2.day-1 between 33.5 and 68°S, except during autumn between 45-50°S where there is a flux out of the ocean of 2mmol.m- 2.day-1. Between 68-70°S the flux into the ocean strengthens to between 28mmol.m- 2.day-1 and 52mmol.m-2.day-1. Gas transfer velocity is not dependant on wind speed alone, but currently it is the only variable that it measureable on a global scale. Further investigations are in place to measure gas transfer velocity in situ. 2014-11-05T03:58:08Z 2014-11-05T03:58:08Z 2011 Master Thesis Masters MSc http://hdl.handle.net/11427/9209 eng application/pdf Department of Oceanography Faculty of Science University of Cape Town
spellingShingle Ranier, Stephanie Megan
A comparison of gas exchange models in the estimation of CO2 fluxes in the South Atlantic South of Africa for the summer season of 2008/2009
thesis_degree_str Master's
title A comparison of gas exchange models in the estimation of CO2 fluxes in the South Atlantic South of Africa for the summer season of 2008/2009
title_full A comparison of gas exchange models in the estimation of CO2 fluxes in the South Atlantic South of Africa for the summer season of 2008/2009
title_fullStr A comparison of gas exchange models in the estimation of CO2 fluxes in the South Atlantic South of Africa for the summer season of 2008/2009
title_full_unstemmed A comparison of gas exchange models in the estimation of CO2 fluxes in the South Atlantic South of Africa for the summer season of 2008/2009
title_short A comparison of gas exchange models in the estimation of CO2 fluxes in the South Atlantic South of Africa for the summer season of 2008/2009
title_sort comparison of gas exchange models in the estimation of co2 fluxes in the south atlantic south of africa for the summer season of 2008 2009
url http://hdl.handle.net/11427/9209
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