Preconditioning, Formation, and Impact of Maud Rise and Weddell Sea Polynyas in a High-Resolution Earth System Model
Open ocean polynyas (OOPs) in the Southern Ocean are ice-free areas within the winter ice pack that are associated with deep convection, potentially contributing to the formation of Antarctic Bottom Water (AABW). To enhance the credibility of Earth System Models (ESMs), their ability to simulate OOP...
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fttexasamuniv:oai:oaktrust.library.tamu.edu:1969.1/187569 2023-07-16T03:52:48+02:00 Preconditioning, Formation, and Impact of Maud Rise and Weddell Sea Polynyas in a High-Resolution Earth System Model Kurtakoti, Prajvala Kishore Stoessel, Achim Chang, Ping Panetta, Lee Orsi, Alejandro 2020-03-10T20:44:10Z application/pdf https://hdl.handle.net/1969.1/187569 en eng https://hdl.handle.net/1969.1/187569 Open Ocean Polynyas Maud Rise Polynyas Weddell Sea Polynyas Southern Ocean Convection Taylor cap Bottom water formation Southern Hemisphere Westerlies Open ocean convection Thesis text 2020 fttexasamuniv 2023-06-27T22:49:26Z Open ocean polynyas (OOPs) in the Southern Ocean are ice-free areas within the winter ice pack that are associated with deep convection, potentially contributing to the formation of Antarctic Bottom Water (AABW). To enhance the credibility of Earth System Models (ESMs), their ability to simulate OOPs realistically is thus crucial. Here we investigate OOPs that emerge intermittently in a high-resolution (HR) pre-industrial simulation with the Energy Exascale Earth System Model (E3SMv0), an offspring of the Community Earth System Model (CESM). While low-resolution (LR) simulations with E3SMv0 show no signs of OOP formation, the preindustrial E3SMv0-HR simulation produces both small Maud Rise polynyas (MRPs) as well as large Weddell Sea polynyas (WSPs). The former is associated with a prominent seamount in the eastern Weddell Sea, and their preconditioning and formation is the focus of the first part of this dissertation. The second part of my dissertation is on the generation of WSPs in the same preindustrial E3SMv0-HR simulation. While the formation of MRPs requires HR to simulate the detailed flow around Maud Rise, a realistic simulation of WSPs requires the ability of a model to produce MRPs. Furthermore, WSP formation will not occur without a prolonged build-up of a heat reservoir at depth, and a prolonged period of less negative wind stress curl in association with the core of the southern hemisphere westerlies being located at an anomalously northward position. The third part of my dissertation discusses the potential effects of AABW anomalies due to WSPs on the Atlantic Meridional Overturning Circulation (AMOC). Earlier studies indicate these anomalies propagate relatively fast along the deep western boundary in the form of internal boundary waves. Since the simulation contains 2 major WSP events that prevail over several years, their impact on AABW anomalies along the deep western boundary can readily be traced. However, they do not seem to affect the outflow of North Atlantic Deep Water (NADW) to the ... Thesis Antarc* Antarctic ice pack NADW North Atlantic Deep Water North Atlantic Southern Ocean Weddell Sea Texas A&M University Digital Repository Antarctic Southern Ocean Weddell Sea Weddell Curl ENVELOPE(-63.071,-63.071,-70.797,-70.797) Maud Rise ENVELOPE(3.000,3.000,-66.000,-66.000) |
institution |
Open Polar |
collection |
Texas A&M University Digital Repository |
op_collection_id |
fttexasamuniv |
language |
English |
topic |
Open Ocean Polynyas Maud Rise Polynyas Weddell Sea Polynyas Southern Ocean Convection Taylor cap Bottom water formation Southern Hemisphere Westerlies Open ocean convection |
spellingShingle |
Open Ocean Polynyas Maud Rise Polynyas Weddell Sea Polynyas Southern Ocean Convection Taylor cap Bottom water formation Southern Hemisphere Westerlies Open ocean convection Kurtakoti, Prajvala Kishore Preconditioning, Formation, and Impact of Maud Rise and Weddell Sea Polynyas in a High-Resolution Earth System Model |
topic_facet |
Open Ocean Polynyas Maud Rise Polynyas Weddell Sea Polynyas Southern Ocean Convection Taylor cap Bottom water formation Southern Hemisphere Westerlies Open ocean convection |
description |
Open ocean polynyas (OOPs) in the Southern Ocean are ice-free areas within the winter ice pack that are associated with deep convection, potentially contributing to the formation of Antarctic Bottom Water (AABW). To enhance the credibility of Earth System Models (ESMs), their ability to simulate OOPs realistically is thus crucial. Here we investigate OOPs that emerge intermittently in a high-resolution (HR) pre-industrial simulation with the Energy Exascale Earth System Model (E3SMv0), an offspring of the Community Earth System Model (CESM). While low-resolution (LR) simulations with E3SMv0 show no signs of OOP formation, the preindustrial E3SMv0-HR simulation produces both small Maud Rise polynyas (MRPs) as well as large Weddell Sea polynyas (WSPs). The former is associated with a prominent seamount in the eastern Weddell Sea, and their preconditioning and formation is the focus of the first part of this dissertation. The second part of my dissertation is on the generation of WSPs in the same preindustrial E3SMv0-HR simulation. While the formation of MRPs requires HR to simulate the detailed flow around Maud Rise, a realistic simulation of WSPs requires the ability of a model to produce MRPs. Furthermore, WSP formation will not occur without a prolonged build-up of a heat reservoir at depth, and a prolonged period of less negative wind stress curl in association with the core of the southern hemisphere westerlies being located at an anomalously northward position. The third part of my dissertation discusses the potential effects of AABW anomalies due to WSPs on the Atlantic Meridional Overturning Circulation (AMOC). Earlier studies indicate these anomalies propagate relatively fast along the deep western boundary in the form of internal boundary waves. Since the simulation contains 2 major WSP events that prevail over several years, their impact on AABW anomalies along the deep western boundary can readily be traced. However, they do not seem to affect the outflow of North Atlantic Deep Water (NADW) to the ... |
author2 |
Stoessel, Achim Chang, Ping Panetta, Lee Orsi, Alejandro |
format |
Thesis |
author |
Kurtakoti, Prajvala Kishore |
author_facet |
Kurtakoti, Prajvala Kishore |
author_sort |
Kurtakoti, Prajvala Kishore |
title |
Preconditioning, Formation, and Impact of Maud Rise and Weddell Sea Polynyas in a High-Resolution Earth System Model |
title_short |
Preconditioning, Formation, and Impact of Maud Rise and Weddell Sea Polynyas in a High-Resolution Earth System Model |
title_full |
Preconditioning, Formation, and Impact of Maud Rise and Weddell Sea Polynyas in a High-Resolution Earth System Model |
title_fullStr |
Preconditioning, Formation, and Impact of Maud Rise and Weddell Sea Polynyas in a High-Resolution Earth System Model |
title_full_unstemmed |
Preconditioning, Formation, and Impact of Maud Rise and Weddell Sea Polynyas in a High-Resolution Earth System Model |
title_sort |
preconditioning, formation, and impact of maud rise and weddell sea polynyas in a high-resolution earth system model |
publishDate |
2020 |
url |
https://hdl.handle.net/1969.1/187569 |
long_lat |
ENVELOPE(-63.071,-63.071,-70.797,-70.797) ENVELOPE(3.000,3.000,-66.000,-66.000) |
geographic |
Antarctic Southern Ocean Weddell Sea Weddell Curl Maud Rise |
geographic_facet |
Antarctic Southern Ocean Weddell Sea Weddell Curl Maud Rise |
genre |
Antarc* Antarctic ice pack NADW North Atlantic Deep Water North Atlantic Southern Ocean Weddell Sea |
genre_facet |
Antarc* Antarctic ice pack NADW North Atlantic Deep Water North Atlantic Southern Ocean Weddell Sea |
op_relation |
https://hdl.handle.net/1969.1/187569 |
_version_ |
1771547247753822208 |