Investigating the Southern Ocean Biogeochemical Divide
The Southern Ocean plays a crucial role in Earth's climate and biogeochemical (BGC) cycles due to its unique features, such as strong westerly winds, intense ocean circulation, and its high-latitude location. This study focuses on the Southern Ocean Biogeochemical Divide (SOBD), a region where...
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The University of Bergen
2024
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ftunivbergen:oai:bora.uib.no:11250/3138788 2024-09-15T17:46:54+00:00 Investigating the Southern Ocean Biogeochemical Divide Bumrungsri, Thanyaphon 2024-06-03T10:02:51Z application/pdf https://hdl.handle.net/11250/3138788 eng eng The University of Bergen GEOF399 0 O ORD 2024 VÅR https://hdl.handle.net/11250/3138788 Copyright the Author. All rights reserved Southern Ocean NorESM2 biogeochemical cycle 756213 Master thesis 2024 ftunivbergen 2024-07-09T23:48:57Z The Southern Ocean plays a crucial role in Earth's climate and biogeochemical (BGC) cycles due to its unique features, such as strong westerly winds, intense ocean circulation, and its high-latitude location. This study focuses on the Southern Ocean Biogeochemical Divide (SOBD), a region where distinct ocean circulation patterns significantly influence nutrient distribution, marine primary production, and carbon sequestration. Utilizing data from the Norwegian Earth System Model version 2 (NorESM2-MM) and observational data from the World Ocean Atlas 2018 (WOA18), we examine the spatial and temporal variability of key BGC tracers-phosphate (PO4), dissolved oxygen (DO), and silicate (Si). Our analysis reveals that PO4 concentrations show a clear latitudinal gradient with higher levels near the Antarctic continent. DO concentrations are higher near the Antarctic continent at the surface, decreasing with depth. Si concentrations display similar patterns to PO4 but with generally higher values. The SOBD is identified as a consistent feature of upwelling water at approximately 250m depth, where significant changes in nutrient concentrations align with the 1036.5 kg/m^3 isopycnal line, marking the transition between different water masses. This alignment helps identify the SOBD's location, which falls between the Polar Front (PF) and the Southern Boundary (SB) of the Antarctic Circumpolar Current (ACC). Time series analysis highlights significant temporal fluctuations in BGC tracer concentrations, with notable shifts around the mid-20th century. These shifts are associated with the Early Twentieth Century Warming (ETCW) and changes in the Southern Annular Mode (SAM) index, influencing the strength of westerly winds and upwelling processes. Despite these fluctuations, the SOBD location remains stable over the study period (1850 to 2014). Masteroppgave i meteorologi og oseanografi GEOF399 MAMN-GEOF Master Thesis Antarc* Antarctic Southern Ocean University of Bergen: Bergen Open Research Archive (BORA-UiB) |
institution |
Open Polar |
collection |
University of Bergen: Bergen Open Research Archive (BORA-UiB) |
op_collection_id |
ftunivbergen |
language |
English |
topic |
Southern Ocean NorESM2 biogeochemical cycle 756213 |
spellingShingle |
Southern Ocean NorESM2 biogeochemical cycle 756213 Bumrungsri, Thanyaphon Investigating the Southern Ocean Biogeochemical Divide |
topic_facet |
Southern Ocean NorESM2 biogeochemical cycle 756213 |
description |
The Southern Ocean plays a crucial role in Earth's climate and biogeochemical (BGC) cycles due to its unique features, such as strong westerly winds, intense ocean circulation, and its high-latitude location. This study focuses on the Southern Ocean Biogeochemical Divide (SOBD), a region where distinct ocean circulation patterns significantly influence nutrient distribution, marine primary production, and carbon sequestration. Utilizing data from the Norwegian Earth System Model version 2 (NorESM2-MM) and observational data from the World Ocean Atlas 2018 (WOA18), we examine the spatial and temporal variability of key BGC tracers-phosphate (PO4), dissolved oxygen (DO), and silicate (Si). Our analysis reveals that PO4 concentrations show a clear latitudinal gradient with higher levels near the Antarctic continent. DO concentrations are higher near the Antarctic continent at the surface, decreasing with depth. Si concentrations display similar patterns to PO4 but with generally higher values. The SOBD is identified as a consistent feature of upwelling water at approximately 250m depth, where significant changes in nutrient concentrations align with the 1036.5 kg/m^3 isopycnal line, marking the transition between different water masses. This alignment helps identify the SOBD's location, which falls between the Polar Front (PF) and the Southern Boundary (SB) of the Antarctic Circumpolar Current (ACC). Time series analysis highlights significant temporal fluctuations in BGC tracer concentrations, with notable shifts around the mid-20th century. These shifts are associated with the Early Twentieth Century Warming (ETCW) and changes in the Southern Annular Mode (SAM) index, influencing the strength of westerly winds and upwelling processes. Despite these fluctuations, the SOBD location remains stable over the study period (1850 to 2014). Masteroppgave i meteorologi og oseanografi GEOF399 MAMN-GEOF |
format |
Master Thesis |
author |
Bumrungsri, Thanyaphon |
author_facet |
Bumrungsri, Thanyaphon |
author_sort |
Bumrungsri, Thanyaphon |
title |
Investigating the Southern Ocean Biogeochemical Divide |
title_short |
Investigating the Southern Ocean Biogeochemical Divide |
title_full |
Investigating the Southern Ocean Biogeochemical Divide |
title_fullStr |
Investigating the Southern Ocean Biogeochemical Divide |
title_full_unstemmed |
Investigating the Southern Ocean Biogeochemical Divide |
title_sort |
investigating the southern ocean biogeochemical divide |
publisher |
The University of Bergen |
publishDate |
2024 |
url |
https://hdl.handle.net/11250/3138788 |
genre |
Antarc* Antarctic Southern Ocean |
genre_facet |
Antarc* Antarctic Southern Ocean |
op_relation |
GEOF399 0 O ORD 2024 VÅR https://hdl.handle.net/11250/3138788 |
op_rights |
Copyright the Author. All rights reserved |
_version_ |
1810495338646077440 |