Water Mass Transformations Within Prydz Bay Coastal Polynyas from Clustered Drifters
Antarctic Bottom Water (AABW), a water mass that sinks to form the deepest limb of the meridional overturning circulation (MOC), is a key control on the ventilation of the Southern Ocean as well as global exchanges of heat, freshwater, and carbon. Sources of this water mass include latent heat polyn...
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2023
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ftunivhelsihelda:oai:helda.helsinki.fi:10138/357675 2023-10-09T21:46:45+02:00 Water Mass Transformations Within Prydz Bay Coastal Polynyas from Clustered Drifters Murakami, Margaret Helsingin yliopisto, Matemaattis-luonnontieteellinen tiedekunta University of Helsinki, Faculty of Science Helsingfors universitet, Matematisk-naturvetenskapliga fakulteten 2023 application/pdf http://hdl.handle.net/10138/357675 eng eng Helsingin yliopisto University of Helsinki Helsingfors universitet URN:NBN:fi:hulib-202305091913 http://hdl.handle.net/10138/357675 Lagrangian analysis Southern Ocean overturning water mass transformations oceanography Ilmakehätieteiden maisteriohjelma (Atmospheric Sciences) Master's Programme in Atmospheric Sciences Magisterprogrammet i atmosfärsvetenskaper Hydrosfäärin geofysiikka Geophysics of the Hydrosphere Hydrosfärens geofysik pro gradu -tutkielmat master's thesis pro gradu-avhandlingar 2023 ftunivhelsihelda 2023-09-13T23:00:50Z Antarctic Bottom Water (AABW), a water mass that sinks to form the deepest limb of the meridional overturning circulation (MOC), is a key control on the ventilation of the Southern Ocean as well as global exchanges of heat, freshwater, and carbon. Sources of this water mass include latent heat polynyas found in Prydz Bay, East Antarctica, which expose the Southern Ocean to the colder atmosphere and are important sources of high salinity shelf water (HSSW). This water mass is the precursor to Dense Shelf Water (DSW) which can be exported from the continental shelf to form Antarctic Bottom Water (AABW). In this study, Lagrangian particle tracking of water masses within Prydz Bay was used to investigate the roles of seasonality, bathymetry, and the presence of other water masses on the mechanisms of water mass transformation (WMT), a series of key processes in the MOC. Online particles were released weekly within the Prydz Bay polynya region in a 10 km resolution simulation of the Whole Antarctic Ocean Model (WAOM10) and their forward trajectories were tracked for one year. Results highlight the export of Prydz Bay water along the westward Antarctic Slope Current (ASC). Cluster analysis of the results shows a winter signal for bottom water forming particles. When advected beneath the ice shelf, polynya water can mix with fresh meltwater, becoming less dense and forming ice shelf water (ISW). After this polynya-originating water departs the ice shelf again, its increased buoyancy can make future AABW formation less likely. This study confirms that the presence of modified circumpolar deep water (mCDW) can play a controlling factor in rates of DSW export as bottom water. Results show export of DSW from the Prydz Channel and Cape Darnley, mixing either along or across isopycnals depending on the influence of other water masses and cross-slope flow. Interactions with the ASC and major topographic features including the Enderby Land projection and several underwater canyons appear to influence the export of water to the ... Master Thesis Antarc* Antarctic Antarctic Ocean Antarctica East Antarctica Enderby Land Ice Shelf Prydz Bay Southern Ocean Helsingfors Universitet: HELDA – Helsingin yliopiston digitaalinen arkisto Antarctic Southern Ocean East Antarctica Prydz Bay Antarctic Ocean Darnley ENVELOPE(69.717,69.717,-67.717,-67.717) Cape Darnley ENVELOPE(69.567,69.567,-67.738,-67.738) Prydz Channel ENVELOPE(73.000,73.000,-67.000,-67.000) |
institution |
Open Polar |
collection |
Helsingfors Universitet: HELDA – Helsingin yliopiston digitaalinen arkisto |
op_collection_id |
ftunivhelsihelda |
language |
English |
topic |
Lagrangian analysis Southern Ocean overturning water mass transformations oceanography Ilmakehätieteiden maisteriohjelma (Atmospheric Sciences) Master's Programme in Atmospheric Sciences Magisterprogrammet i atmosfärsvetenskaper Hydrosfäärin geofysiikka Geophysics of the Hydrosphere Hydrosfärens geofysik |
spellingShingle |
Lagrangian analysis Southern Ocean overturning water mass transformations oceanography Ilmakehätieteiden maisteriohjelma (Atmospheric Sciences) Master's Programme in Atmospheric Sciences Magisterprogrammet i atmosfärsvetenskaper Hydrosfäärin geofysiikka Geophysics of the Hydrosphere Hydrosfärens geofysik Murakami, Margaret Water Mass Transformations Within Prydz Bay Coastal Polynyas from Clustered Drifters |
topic_facet |
Lagrangian analysis Southern Ocean overturning water mass transformations oceanography Ilmakehätieteiden maisteriohjelma (Atmospheric Sciences) Master's Programme in Atmospheric Sciences Magisterprogrammet i atmosfärsvetenskaper Hydrosfäärin geofysiikka Geophysics of the Hydrosphere Hydrosfärens geofysik |
description |
Antarctic Bottom Water (AABW), a water mass that sinks to form the deepest limb of the meridional overturning circulation (MOC), is a key control on the ventilation of the Southern Ocean as well as global exchanges of heat, freshwater, and carbon. Sources of this water mass include latent heat polynyas found in Prydz Bay, East Antarctica, which expose the Southern Ocean to the colder atmosphere and are important sources of high salinity shelf water (HSSW). This water mass is the precursor to Dense Shelf Water (DSW) which can be exported from the continental shelf to form Antarctic Bottom Water (AABW). In this study, Lagrangian particle tracking of water masses within Prydz Bay was used to investigate the roles of seasonality, bathymetry, and the presence of other water masses on the mechanisms of water mass transformation (WMT), a series of key processes in the MOC. Online particles were released weekly within the Prydz Bay polynya region in a 10 km resolution simulation of the Whole Antarctic Ocean Model (WAOM10) and their forward trajectories were tracked for one year. Results highlight the export of Prydz Bay water along the westward Antarctic Slope Current (ASC). Cluster analysis of the results shows a winter signal for bottom water forming particles. When advected beneath the ice shelf, polynya water can mix with fresh meltwater, becoming less dense and forming ice shelf water (ISW). After this polynya-originating water departs the ice shelf again, its increased buoyancy can make future AABW formation less likely. This study confirms that the presence of modified circumpolar deep water (mCDW) can play a controlling factor in rates of DSW export as bottom water. Results show export of DSW from the Prydz Channel and Cape Darnley, mixing either along or across isopycnals depending on the influence of other water masses and cross-slope flow. Interactions with the ASC and major topographic features including the Enderby Land projection and several underwater canyons appear to influence the export of water to the ... |
author2 |
Helsingin yliopisto, Matemaattis-luonnontieteellinen tiedekunta University of Helsinki, Faculty of Science Helsingfors universitet, Matematisk-naturvetenskapliga fakulteten |
format |
Master Thesis |
author |
Murakami, Margaret |
author_facet |
Murakami, Margaret |
author_sort |
Murakami, Margaret |
title |
Water Mass Transformations Within Prydz Bay Coastal Polynyas from Clustered Drifters |
title_short |
Water Mass Transformations Within Prydz Bay Coastal Polynyas from Clustered Drifters |
title_full |
Water Mass Transformations Within Prydz Bay Coastal Polynyas from Clustered Drifters |
title_fullStr |
Water Mass Transformations Within Prydz Bay Coastal Polynyas from Clustered Drifters |
title_full_unstemmed |
Water Mass Transformations Within Prydz Bay Coastal Polynyas from Clustered Drifters |
title_sort |
water mass transformations within prydz bay coastal polynyas from clustered drifters |
publisher |
Helsingin yliopisto |
publishDate |
2023 |
url |
http://hdl.handle.net/10138/357675 |
long_lat |
ENVELOPE(69.717,69.717,-67.717,-67.717) ENVELOPE(69.567,69.567,-67.738,-67.738) ENVELOPE(73.000,73.000,-67.000,-67.000) |
geographic |
Antarctic Southern Ocean East Antarctica Prydz Bay Antarctic Ocean Darnley Cape Darnley Prydz Channel |
geographic_facet |
Antarctic Southern Ocean East Antarctica Prydz Bay Antarctic Ocean Darnley Cape Darnley Prydz Channel |
genre |
Antarc* Antarctic Antarctic Ocean Antarctica East Antarctica Enderby Land Ice Shelf Prydz Bay Southern Ocean |
genre_facet |
Antarc* Antarctic Antarctic Ocean Antarctica East Antarctica Enderby Land Ice Shelf Prydz Bay Southern Ocean |
op_relation |
URN:NBN:fi:hulib-202305091913 http://hdl.handle.net/10138/357675 |
_version_ |
1779309264208134144 |