Tropical Pacific relationships with Southern Hemisphere atmospheric circulation and Antarctic climate
Significant trends in high-latitude Southern Hemisphere atmospheric circulation and surface climate have been observed over recent decades, which are likely linked to teleconnections from the tropics. This study investigates how a recent shift in tropical Pacific climate toward increased La Niña con...
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ftvictoriauwfig:oai:figshare.com:article/17060840 2023-05-15T13:35:14+02:00 Tropical Pacific relationships with Southern Hemisphere atmospheric circulation and Antarctic climate Kyle Clem 2017-01-01T00:00:00Z https://doi.org/10.26686/wgtn.17060840.v1 https://figshare.com/articles/thesis/Tropical_Pacific_relationships_with_Southern_Hemisphere_atmospheric_circulation_and_Antarctic_climate/17060840 unknown doi:10.26686/wgtn.17060840.v1 https://figshare.com/articles/thesis/Tropical_Pacific_relationships_with_Southern_Hemisphere_atmospheric_circulation_and_Antarctic_climate/17060840 Author Retains Copyright Atmospheric Dynamics Climate Change Processes Climatology (excl. Climate Change Processes) Antarctica Climate Variability ENSO SAM Teleconnection El Niño-Southern Oscillation Southern Annular Mode School: School of Geography Environment and Earth Sciences 040104 Climate Change Processes 040102 Atmospheric Dynamics 040105 Climatology (excl. Climate Change Processes) 970104 Expanding Knowledge in the Earth Sciences Degree Discipline: Physical Geography Degree Level: Doctoral Degree Name: Doctor of Philosophy Text Thesis 2017 ftvictoriauwfig https://doi.org/10.26686/wgtn.17060840.v1 2021-11-25T00:04:03Z Significant trends in high-latitude Southern Hemisphere atmospheric circulation and surface climate have been observed over recent decades, which are likely linked to teleconnections from the tropics. This study investigates how a recent shift in tropical Pacific climate toward increased La Niña conditions has influenced the atmospheric circulation and surface climate across the high southern latitudes, and how variations in the El Niño-Southern Oscillation (ENSO) and Southern Annular Mode (SAM) influence the surface climate of Antarctica. Over 1979-2014, significant cooling of eastern tropical Pacific sea surface temperatures (SSTs) is detected in all seasons. The eastern tropical Pacific cooling is associated with: (1) an intensified Walker Circulation during austral summer and autumn; (2) a weakened South Pacific Hadley cell and sub-tropical jet during autumn; and (3) a strengthening of the circumpolar westerlies between 50 and 60°S during both summer and autumn. Observed cooling in the eastern tropical Pacific is linearly congruent with 60-80% of the observed positive zonal-mean zonal wind trend between 50 and 60°S during summer (~35% of the interannual variability), and around half of the positive zonal-mean zonal wind trend during autumn (~15% of the interannual variability), the latter being most marked over the South Pacific. Although previous studies have linked the strengthening of the tropospheric westerlies during summer and autumn to ozone depletion, results from this study indicate poleward momentum fluxes and strengthened lower-tropospheric baroclinicity associated with eastern tropical Pacific cooling also help to maintain a strengthened mid-latitude jet through the 21st century, especially across the South Pacific. The La Niña shift in tropical Pacific SSTs is also significantly related to several changes in Antarctic surface climate. During autumn, a regional pattern of cooling occurred along coastal East Antarctica after 1979, with the rate of cooling increasing at Novolazarevskaya, Syowa, ... Thesis Antarc* Antarctic Antarctica East Antarctica Open Access Victoria University of Wellington / Te Herenga Waka Antarctic East Antarctica Austral Pacific |
institution |
Open Polar |
collection |
Open Access Victoria University of Wellington / Te Herenga Waka |
op_collection_id |
ftvictoriauwfig |
language |
unknown |
topic |
Atmospheric Dynamics Climate Change Processes Climatology (excl. Climate Change Processes) Antarctica Climate Variability ENSO SAM Teleconnection El Niño-Southern Oscillation Southern Annular Mode School: School of Geography Environment and Earth Sciences 040104 Climate Change Processes 040102 Atmospheric Dynamics 040105 Climatology (excl. Climate Change Processes) 970104 Expanding Knowledge in the Earth Sciences Degree Discipline: Physical Geography Degree Level: Doctoral Degree Name: Doctor of Philosophy |
spellingShingle |
Atmospheric Dynamics Climate Change Processes Climatology (excl. Climate Change Processes) Antarctica Climate Variability ENSO SAM Teleconnection El Niño-Southern Oscillation Southern Annular Mode School: School of Geography Environment and Earth Sciences 040104 Climate Change Processes 040102 Atmospheric Dynamics 040105 Climatology (excl. Climate Change Processes) 970104 Expanding Knowledge in the Earth Sciences Degree Discipline: Physical Geography Degree Level: Doctoral Degree Name: Doctor of Philosophy Kyle Clem Tropical Pacific relationships with Southern Hemisphere atmospheric circulation and Antarctic climate |
topic_facet |
Atmospheric Dynamics Climate Change Processes Climatology (excl. Climate Change Processes) Antarctica Climate Variability ENSO SAM Teleconnection El Niño-Southern Oscillation Southern Annular Mode School: School of Geography Environment and Earth Sciences 040104 Climate Change Processes 040102 Atmospheric Dynamics 040105 Climatology (excl. Climate Change Processes) 970104 Expanding Knowledge in the Earth Sciences Degree Discipline: Physical Geography Degree Level: Doctoral Degree Name: Doctor of Philosophy |
description |
Significant trends in high-latitude Southern Hemisphere atmospheric circulation and surface climate have been observed over recent decades, which are likely linked to teleconnections from the tropics. This study investigates how a recent shift in tropical Pacific climate toward increased La Niña conditions has influenced the atmospheric circulation and surface climate across the high southern latitudes, and how variations in the El Niño-Southern Oscillation (ENSO) and Southern Annular Mode (SAM) influence the surface climate of Antarctica. Over 1979-2014, significant cooling of eastern tropical Pacific sea surface temperatures (SSTs) is detected in all seasons. The eastern tropical Pacific cooling is associated with: (1) an intensified Walker Circulation during austral summer and autumn; (2) a weakened South Pacific Hadley cell and sub-tropical jet during autumn; and (3) a strengthening of the circumpolar westerlies between 50 and 60°S during both summer and autumn. Observed cooling in the eastern tropical Pacific is linearly congruent with 60-80% of the observed positive zonal-mean zonal wind trend between 50 and 60°S during summer (~35% of the interannual variability), and around half of the positive zonal-mean zonal wind trend during autumn (~15% of the interannual variability), the latter being most marked over the South Pacific. Although previous studies have linked the strengthening of the tropospheric westerlies during summer and autumn to ozone depletion, results from this study indicate poleward momentum fluxes and strengthened lower-tropospheric baroclinicity associated with eastern tropical Pacific cooling also help to maintain a strengthened mid-latitude jet through the 21st century, especially across the South Pacific. The La Niña shift in tropical Pacific SSTs is also significantly related to several changes in Antarctic surface climate. During autumn, a regional pattern of cooling occurred along coastal East Antarctica after 1979, with the rate of cooling increasing at Novolazarevskaya, Syowa, ... |
format |
Thesis |
author |
Kyle Clem |
author_facet |
Kyle Clem |
author_sort |
Kyle Clem |
title |
Tropical Pacific relationships with Southern Hemisphere atmospheric circulation and Antarctic climate |
title_short |
Tropical Pacific relationships with Southern Hemisphere atmospheric circulation and Antarctic climate |
title_full |
Tropical Pacific relationships with Southern Hemisphere atmospheric circulation and Antarctic climate |
title_fullStr |
Tropical Pacific relationships with Southern Hemisphere atmospheric circulation and Antarctic climate |
title_full_unstemmed |
Tropical Pacific relationships with Southern Hemisphere atmospheric circulation and Antarctic climate |
title_sort |
tropical pacific relationships with southern hemisphere atmospheric circulation and antarctic climate |
publishDate |
2017 |
url |
https://doi.org/10.26686/wgtn.17060840.v1 https://figshare.com/articles/thesis/Tropical_Pacific_relationships_with_Southern_Hemisphere_atmospheric_circulation_and_Antarctic_climate/17060840 |
geographic |
Antarctic East Antarctica Austral Pacific |
geographic_facet |
Antarctic East Antarctica Austral Pacific |
genre |
Antarc* Antarctic Antarctica East Antarctica |
genre_facet |
Antarc* Antarctic Antarctica East Antarctica |
op_relation |
doi:10.26686/wgtn.17060840.v1 https://figshare.com/articles/thesis/Tropical_Pacific_relationships_with_Southern_Hemisphere_atmospheric_circulation_and_Antarctic_climate/17060840 |
op_rights |
Author Retains Copyright |
op_doi |
https://doi.org/10.26686/wgtn.17060840.v1 |
_version_ |
1766063295060508672 |