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Evaluating multi-satellite chlorophyll-a datasets an ocean colour case study within the Southern Benguela
Chlorophyll-a (chl-a), a photosynthetic pigment that can be derived from satellite ocean colour, is often used as a proxy for phytoplankton biomass and to derive primary productivity. Initiatives such as the Ocean Colour Climate Change Initiative (OC-CCI) produce merged multi-satellite products to c...
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| Format: | Thesis |
| Language: | English English |
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Department of Biological Sciences
2026
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| _version_ | 1867613441979580416 |
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| access_status_str | Open Access |
| author | Oehley, Craig |
| author2 | CSIR, Smith |
| author_browse | CSIR, Smith Oehley, Craig |
| author_facet | CSIR, Smith Oehley, Craig |
| author_sort | Oehley, Craig |
| collection | Thesis |
| description | Chlorophyll-a (chl-a), a photosynthetic pigment that can be derived from satellite ocean colour, is often used as a proxy for phytoplankton biomass and to derive primary productivity. Initiatives such as the Ocean Colour Climate Change Initiative (OC-CCI) produce merged multi-satellite products to create consistent long-term time-series datasets for climate studies at a global scale. Their ability to handle variable in-water conditions is critical for their mission parameters. This study compares the performance of two European multi-satellite chl-a products, from the OC-CCI and GlobColour projects against a regionally tuned Sentinel-3 product within the Southern Benguela region. The three products were assessed against a collated database of coincident in situ chl-a matchups to derive a series of performance metrics. The regionally tuned Sentinel-3 product outperformed the two global products in terms of Mean Absolute Error but showed a slight consistent overestimation bias. Analysis of match-ups showed an underestimation of high chl-a concentrations and overestimation of lower chl-a concentrations by both global products. An application of the products within St.Helena bay during high biomass bloom events showed that the Sentinel-3 product's ability to capture extreme chl-a concentrations was far higher than both global products. Spatial mismatch between zones of high chl-a concentration also indicate differences in processing chains and flagging techniques. |
| format | Thesis |
| id | oai:open.uct.ac.za:11427/42589 |
| institution | University of Cape Town (South Africa) |
| language | English eng |
| last_indexed | 2026-06-10T12:36:12.591Z |
| license_str | Not specified — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from UCTD — University of Cape Town Open Access Repository |
| publishDate | 2026 |
| publishDateRange | 2026 |
| publishDateSort | 2026 |
| publisher | Department of Biological Sciences |
| publisherStr | Department of Biological Sciences |
| record_format | dspace |
| source_str | UCTD — University of Cape Town Open Access Repository |
| spelling | oai:open.uct.ac.za:11427/42589 Evaluating multi-satellite chlorophyll-a datasets an ocean colour case study within the Southern Benguela Oehley, Craig CSIR, Smith CSIR, Whittle Ocean colour Southern Benguela Chlorophyll-a (chl-a), a photosynthetic pigment that can be derived from satellite ocean colour, is often used as a proxy for phytoplankton biomass and to derive primary productivity. Initiatives such as the Ocean Colour Climate Change Initiative (OC-CCI) produce merged multi-satellite products to create consistent long-term time-series datasets for climate studies at a global scale. Their ability to handle variable in-water conditions is critical for their mission parameters. This study compares the performance of two European multi-satellite chl-a products, from the OC-CCI and GlobColour projects against a regionally tuned Sentinel-3 product within the Southern Benguela region. The three products were assessed against a collated database of coincident in situ chl-a matchups to derive a series of performance metrics. The regionally tuned Sentinel-3 product outperformed the two global products in terms of Mean Absolute Error but showed a slight consistent overestimation bias. Analysis of match-ups showed an underestimation of high chl-a concentrations and overestimation of lower chl-a concentrations by both global products. An application of the products within St.Helena bay during high biomass bloom events showed that the Sentinel-3 product's ability to capture extreme chl-a concentrations was far higher than both global products. Spatial mismatch between zones of high chl-a concentration also indicate differences in processing chains and flagging techniques. 2026-01-16T10:02:19Z 2026-01-16T10:02:19Z 2025 2026-01-15T11:54:32Z Thesis / Dissertation Masters MSc http://hdl.handle.net/11427/42589 en eng application/pdf Department of Biological Sciences Faculty of Science University of Cape Town |
| spellingShingle | Ocean colour Southern Benguela Oehley, Craig Evaluating multi-satellite chlorophyll-a datasets an ocean colour case study within the Southern Benguela |
| thesis_degree_str | Master's |
| title | Evaluating multi-satellite chlorophyll-a datasets an ocean colour case study within the Southern Benguela |
| title_full | Evaluating multi-satellite chlorophyll-a datasets an ocean colour case study within the Southern Benguela |
| title_fullStr | Evaluating multi-satellite chlorophyll-a datasets an ocean colour case study within the Southern Benguela |
| title_full_unstemmed | Evaluating multi-satellite chlorophyll-a datasets an ocean colour case study within the Southern Benguela |
| title_short | Evaluating multi-satellite chlorophyll-a datasets an ocean colour case study within the Southern Benguela |
| title_sort | evaluating multi satellite chlorophyll a datasets an ocean colour case study within the southern benguela |
| topic | Ocean colour Southern Benguela |
| url | http://hdl.handle.net/11427/42589 |
| work_keys_str_mv | AT oehleycraig evaluatingmultisatellitechlorophylladatasetsanoceancolourcasestudywithinthesouthernbenguela |