Full Text Available
Note: Clicking the button above will open the full text document at the original institutional repository in a new window.
An investigation into the sampling bias of Argo profiling floats in the Southern Ocean
Numerous Argo floats (approximately 3800 floats) have been deployed in the world's oceans to gather hydrographic and biogeochemical data from the upper 2000 m. However, limited research has been done on the spatial and temporal distribution and potential sampling bias of Argo profiling floats brough...
Saved in:
| Main Author: | |
|---|---|
| Other Authors: | |
| Format: | Thesis |
| Language: | English |
| Published: |
Department of Oceanography
2016
|
| Subjects: | |
| Tags: |
No Tags, Be the first to tag this record!
|
| _version_ | 1867611290779779072 |
|---|---|
| access_status_str | Open Access |
| author | Tsei, Senam Kofi |
| author2 | Backeberg, Björn |
| author_browse | Backeberg, Björn Tsei, Senam Kofi |
| author_facet | Backeberg, Björn Tsei, Senam Kofi |
| author_sort | Tsei, Senam Kofi |
| collection | Thesis |
| description | Numerous Argo floats (approximately 3800 floats) have been deployed in the world's oceans to gather hydrographic and biogeochemical data from the upper 2000 m. However, limited research has been done on the spatial and temporal distribution and potential sampling bias of Argo profiling floats brought on by the effects of bathymetric steering of currents, as well as oceanic features, such as meanders and eddies, that affect their distribution over the global ocean. This study investigates the sampling distribution of profiling floats and assesses the mechanisms that impact their trajectories and distribution in the Atlantic sector of the Southern Ocean. The study reveals that Argo floats are influenced and steered towards frontal jets, which in turn are steered by the underlying bathymetry. Argo floats have a 30 % higher probability of sampling regions where depths range from 4000 - 5000 m, rather than shallow regions of the oceans. Using bootstrapping, this result was shown to be statistically significant at the 95 % confidence interval. The sampling bias is associated with floats becoming entrained into deep reaching frontal jets that occur in the Southern Ocean and dominate the deeper waters. This is shown by analyzing the Argo float positions in relation to mean geostrophic currents which shows that there is a 40 % higher probability (statistically significant at the 95 % confidence level) of finding Argo floats in regions where geostrophic currents range from 0.1 - 0.22 m.s-1 even though the majority of surface currents in the Southern Ocean are found below 0.05 m.s-1. This indicates a non-uniform distribution of Argo floats in the Southern Ocean, which leads to a spatial sampling bias in the float data. This has implications for how we characterize the oceanography or understand the distribution and variability of oceanographic processes and its relation to climate. |
| format | Thesis |
| id | oai:open.uct.ac.za:11427/20017 |
| institution | University of Cape Town (South Africa) |
| language | eng |
| license_str | Not specified — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from UCTD — University of Cape Town Open Access Repository |
| publishDate | 2016 |
| publishDateRange | 2016 |
| publishDateSort | 2016 |
| 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:11427/20017 An investigation into the sampling bias of Argo profiling floats in the Southern Ocean Tsei, Senam Kofi Backeberg, Björn Applied Marine Science Numerous Argo floats (approximately 3800 floats) have been deployed in the world's oceans to gather hydrographic and biogeochemical data from the upper 2000 m. However, limited research has been done on the spatial and temporal distribution and potential sampling bias of Argo profiling floats brought on by the effects of bathymetric steering of currents, as well as oceanic features, such as meanders and eddies, that affect their distribution over the global ocean. This study investigates the sampling distribution of profiling floats and assesses the mechanisms that impact their trajectories and distribution in the Atlantic sector of the Southern Ocean. The study reveals that Argo floats are influenced and steered towards frontal jets, which in turn are steered by the underlying bathymetry. Argo floats have a 30 % higher probability of sampling regions where depths range from 4000 - 5000 m, rather than shallow regions of the oceans. Using bootstrapping, this result was shown to be statistically significant at the 95 % confidence interval. The sampling bias is associated with floats becoming entrained into deep reaching frontal jets that occur in the Southern Ocean and dominate the deeper waters. This is shown by analyzing the Argo float positions in relation to mean geostrophic currents which shows that there is a 40 % higher probability (statistically significant at the 95 % confidence level) of finding Argo floats in regions where geostrophic currents range from 0.1 - 0.22 m.s-1 even though the majority of surface currents in the Southern Ocean are found below 0.05 m.s-1. This indicates a non-uniform distribution of Argo floats in the Southern Ocean, which leads to a spatial sampling bias in the float data. This has implications for how we characterize the oceanography or understand the distribution and variability of oceanographic processes and its relation to climate. 2016-06-10T10:55:26Z 2016-06-10T10:55:26Z 2015 Master Thesis Masters MSc http://hdl.handle.net/11427/20017 eng application/pdf Department of Oceanography Faculty of Science University of Cape Town |
| spellingShingle | Applied Marine Science Tsei, Senam Kofi An investigation into the sampling bias of Argo profiling floats in the Southern Ocean |
| thesis_degree_str | Master's |
| title | An investigation into the sampling bias of Argo profiling floats in the Southern Ocean |
| title_full | An investigation into the sampling bias of Argo profiling floats in the Southern Ocean |
| title_fullStr | An investigation into the sampling bias of Argo profiling floats in the Southern Ocean |
| title_full_unstemmed | An investigation into the sampling bias of Argo profiling floats in the Southern Ocean |
| title_short | An investigation into the sampling bias of Argo profiling floats in the Southern Ocean |
| title_sort | investigation into the sampling bias of argo profiling floats in the southern ocean |
| topic | Applied Marine Science |
| url | http://hdl.handle.net/11427/20017 |
| work_keys_str_mv | AT tseisenamkofi aninvestigationintothesamplingbiasofargoprofilingfloatsinthesouthernocean AT tseisenamkofi investigationintothesamplingbiasofargoprofilingfloatsinthesouthernocean |