Multi-Temporal Variability Within Antarctic Coastal Polynyas and Their Relationships To Large-Scale Atmospheric Phenomena
Open water and thin ice areas, known as coastal polynyas, form along the Antarctic coastline and allow continued interaction between the ocean and atmosphere throughout the sea ice advance season. Coastal polynyas are the most productive locations of sea ice formation, Antarctic bottom water formati...
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ftcdlib:qt0tj68195 2023-05-15T13:24:19+02:00 Multi-Temporal Variability Within Antarctic Coastal Polynyas and Their Relationships To Large-Scale Atmospheric Phenomena Ward, Jason Michael 136 2018-01-01 application/pdf http://www.escholarship.org/uc/item/0tj68195 en eng eScholarship, University of California http://www.escholarship.org/uc/item/0tj68195 qt0tj68195 public Ward, Jason Michael. (2018). Multi-Temporal Variability Within Antarctic Coastal Polynyas and Their Relationships To Large-Scale Atmospheric Phenomena. UCLA: Geography 0396. Retrieved from: http://www.escholarship.org/uc/item/0tj68195 Geography Atmospheric sciences Antarctica atmosphere climatology ocean polynyas sea ice dissertation 2018 ftcdlib 2018-12-21T23:52:33Z Open water and thin ice areas, known as coastal polynyas, form along the Antarctic coastline and allow continued interaction between the ocean and atmosphere throughout the sea ice advance season. Coastal polynyas are the most productive locations of sea ice formation, Antarctic bottom water formation, and biological activity in the Southern Ocean. Changes in these elements are greatly controlled by polynya area variability. To carry out an in-depth study of polynya area variability, a 26-year 25-polynya daily area dataset was created and analyzed. The long term trend and the daily, monthly, seasonal, and annual variations are separated to analyze the multi-temporal variability of the polynyas and investigate their individual and regional responses to prominent large-scale atmospheric circulation patterns. Results indicate that most polynya variability occurs at the daily scale, followed by monthly and seasonal variations. Very little variability occurs interannually. Thus, studies done at the annual scale mask most of the polynya activity. Only five of the polynyas have long term trends, which are all non-linear and arise from abrupt changes in the icescape. Three of the significant trends occur within the top four most significant regions of sea ice and bottom water formation. Long term changes in polynya area cause long term changes in the overall productivity of the Southern Ocean. The Southern Annular Mode (SAM), El Nino-Southern Oscillation (ENSO), and the Amundsen Sea Low (ASL) significantly contribute to individual and regional coastal polynya variability. Influence from the SAM and the ASL is primarily driven at the monthly and seasonal scales. Influence from ENSO is driven at the annual scale. Using Pearson correlations, principal component analysis, gaussian mixture models, and hierarchical agglomerative clustering, six regional polynya groups are delineated based on the strength and direction of inter-polynya co-variability. The mean polynya variability within each region is significantly correlated, which is driven at the seasonal scale. While the SAM, ENSO, and ASL are not the primary drivers of regional polynya group delineations, they are significantly influential in the mean variability of each group. Doctoral or Postdoctoral Thesis Amundsen Sea Antarc* Antarctic Antarctica Sea ice Southern Ocean University of California: eScholarship Amundsen Sea Antarctic Southern Ocean The Antarctic |
institution |
Open Polar |
collection |
University of California: eScholarship |
op_collection_id |
ftcdlib |
language |
English |
topic |
Geography Atmospheric sciences Antarctica atmosphere climatology ocean polynyas sea ice |
spellingShingle |
Geography Atmospheric sciences Antarctica atmosphere climatology ocean polynyas sea ice Ward, Jason Michael Multi-Temporal Variability Within Antarctic Coastal Polynyas and Their Relationships To Large-Scale Atmospheric Phenomena |
topic_facet |
Geography Atmospheric sciences Antarctica atmosphere climatology ocean polynyas sea ice |
description |
Open water and thin ice areas, known as coastal polynyas, form along the Antarctic coastline and allow continued interaction between the ocean and atmosphere throughout the sea ice advance season. Coastal polynyas are the most productive locations of sea ice formation, Antarctic bottom water formation, and biological activity in the Southern Ocean. Changes in these elements are greatly controlled by polynya area variability. To carry out an in-depth study of polynya area variability, a 26-year 25-polynya daily area dataset was created and analyzed. The long term trend and the daily, monthly, seasonal, and annual variations are separated to analyze the multi-temporal variability of the polynyas and investigate their individual and regional responses to prominent large-scale atmospheric circulation patterns. Results indicate that most polynya variability occurs at the daily scale, followed by monthly and seasonal variations. Very little variability occurs interannually. Thus, studies done at the annual scale mask most of the polynya activity. Only five of the polynyas have long term trends, which are all non-linear and arise from abrupt changes in the icescape. Three of the significant trends occur within the top four most significant regions of sea ice and bottom water formation. Long term changes in polynya area cause long term changes in the overall productivity of the Southern Ocean. The Southern Annular Mode (SAM), El Nino-Southern Oscillation (ENSO), and the Amundsen Sea Low (ASL) significantly contribute to individual and regional coastal polynya variability. Influence from the SAM and the ASL is primarily driven at the monthly and seasonal scales. Influence from ENSO is driven at the annual scale. Using Pearson correlations, principal component analysis, gaussian mixture models, and hierarchical agglomerative clustering, six regional polynya groups are delineated based on the strength and direction of inter-polynya co-variability. The mean polynya variability within each region is significantly correlated, which is driven at the seasonal scale. While the SAM, ENSO, and ASL are not the primary drivers of regional polynya group delineations, they are significantly influential in the mean variability of each group. |
format |
Doctoral or Postdoctoral Thesis |
author |
Ward, Jason Michael |
author_facet |
Ward, Jason Michael |
author_sort |
Ward, Jason Michael |
title |
Multi-Temporal Variability Within Antarctic Coastal Polynyas and Their Relationships To Large-Scale Atmospheric Phenomena |
title_short |
Multi-Temporal Variability Within Antarctic Coastal Polynyas and Their Relationships To Large-Scale Atmospheric Phenomena |
title_full |
Multi-Temporal Variability Within Antarctic Coastal Polynyas and Their Relationships To Large-Scale Atmospheric Phenomena |
title_fullStr |
Multi-Temporal Variability Within Antarctic Coastal Polynyas and Their Relationships To Large-Scale Atmospheric Phenomena |
title_full_unstemmed |
Multi-Temporal Variability Within Antarctic Coastal Polynyas and Their Relationships To Large-Scale Atmospheric Phenomena |
title_sort |
multi-temporal variability within antarctic coastal polynyas and their relationships to large-scale atmospheric phenomena |
publisher |
eScholarship, University of California |
publishDate |
2018 |
url |
http://www.escholarship.org/uc/item/0tj68195 |
op_coverage |
136 |
geographic |
Amundsen Sea Antarctic Southern Ocean The Antarctic |
geographic_facet |
Amundsen Sea Antarctic Southern Ocean The Antarctic |
genre |
Amundsen Sea Antarc* Antarctic Antarctica Sea ice Southern Ocean |
genre_facet |
Amundsen Sea Antarc* Antarctic Antarctica Sea ice Southern Ocean |
op_source |
Ward, Jason Michael. (2018). Multi-Temporal Variability Within Antarctic Coastal Polynyas and Their Relationships To Large-Scale Atmospheric Phenomena. UCLA: Geography 0396. Retrieved from: http://www.escholarship.org/uc/item/0tj68195 |
op_relation |
http://www.escholarship.org/uc/item/0tj68195 qt0tj68195 |
op_rights |
public |
_version_ |
1766378685708894208 |