The early 1990s change in ENSO-PSA-SAM relationships and its impact on Southern Hemisphere climate
This study uncovers an early 1990s change in the relationships between El Niño-Southern Oscillation (ENSO) and two leading modes of the Southern Hemisphere (SH) atmospheric variability: the southern annular mode (SAM) and the Pacific-South American (PSA) pattern. During austral spring, while the PSA...
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ftcdlib:oai:escholarship.org/ark:/13030/qt9wc3q6hk 2023-05-15T14:01:12+02:00 The early 1990s change in ENSO-PSA-SAM relationships and its impact on Southern Hemisphere climate Yu, JY Paek, H Saltzman, ES Lee, T 9393 - 9408 2015-01-01 application/pdf https://escholarship.org/uc/item/9wc3q6hk unknown eScholarship, University of California qt9wc3q6hk https://escholarship.org/uc/item/9wc3q6hk CC-BY CC-BY Journal of Climate, vol 28, iss 23 Geographic location entity Antarctica Sea ice Circulation Dynamics Antarctic Oscillation ENSO Teleconnections Variability Interannual variability Meteorology & Atmospheric Sciences Atmospheric Sciences Oceanography Geomatic Engineering article 2015 ftcdlib 2021-04-16T07:10:16Z This study uncovers an early 1990s change in the relationships between El Niño-Southern Oscillation (ENSO) and two leading modes of the Southern Hemisphere (SH) atmospheric variability: the southern annular mode (SAM) and the Pacific-South American (PSA) pattern. During austral spring, while the PSA maintained a strong correlation with ENSO throughout the period 1948-2014, the SAM-ENSO correlation changed from being weak before the early 1990s to being strong afterward. Through the ENSO connection, PSA and SAM became more in-phase correlated after the early 1990s. The early 1990s is also the time when ENSO changed from being dominated by the eastern Pacific (EP) type to being dominated by the central Pacific (CP) type. Analyses show that, while the EP ENSO can excite only the PSA, the CP ENSO can excite both the SAM and PSA through tropospheric and stratospheric pathway mechanisms. The more in-phase relationship between SAM and PSA impacted the post-1990s Antarctic climate in at least two aspects: 1) a stronger Antarctic sea ice dipole structure around the Amundsen-Bellingshausen Seas due to intensified geopotential height anomalies over the region and 2) a shift in the phase relationships of surface air temperature anomalies among East Antarctica, West Antarctica, and the Antarctic Peninsula. These findings imply that ENSO-Antarctic climate relations depend on the dominant ENSO type and that ENSO forcing has become more important to the Antarctic sea ice and surface air temperature variability in the past two decades and will in the coming decades if the dominance of CP ENSO persists. Article in Journal/Newspaper Antarc* Antarctic Antarctic Peninsula Antarctica East Antarctica Sea ice West Antarctica University of California: eScholarship Antarctic Antarctic Peninsula Austral East Antarctica Pacific The Antarctic West Antarctica |
institution |
Open Polar |
collection |
University of California: eScholarship |
op_collection_id |
ftcdlib |
language |
unknown |
topic |
Geographic location entity Antarctica Sea ice Circulation Dynamics Antarctic Oscillation ENSO Teleconnections Variability Interannual variability Meteorology & Atmospheric Sciences Atmospheric Sciences Oceanography Geomatic Engineering |
spellingShingle |
Geographic location entity Antarctica Sea ice Circulation Dynamics Antarctic Oscillation ENSO Teleconnections Variability Interannual variability Meteorology & Atmospheric Sciences Atmospheric Sciences Oceanography Geomatic Engineering Yu, JY Paek, H Saltzman, ES Lee, T The early 1990s change in ENSO-PSA-SAM relationships and its impact on Southern Hemisphere climate |
topic_facet |
Geographic location entity Antarctica Sea ice Circulation Dynamics Antarctic Oscillation ENSO Teleconnections Variability Interannual variability Meteorology & Atmospheric Sciences Atmospheric Sciences Oceanography Geomatic Engineering |
description |
This study uncovers an early 1990s change in the relationships between El Niño-Southern Oscillation (ENSO) and two leading modes of the Southern Hemisphere (SH) atmospheric variability: the southern annular mode (SAM) and the Pacific-South American (PSA) pattern. During austral spring, while the PSA maintained a strong correlation with ENSO throughout the period 1948-2014, the SAM-ENSO correlation changed from being weak before the early 1990s to being strong afterward. Through the ENSO connection, PSA and SAM became more in-phase correlated after the early 1990s. The early 1990s is also the time when ENSO changed from being dominated by the eastern Pacific (EP) type to being dominated by the central Pacific (CP) type. Analyses show that, while the EP ENSO can excite only the PSA, the CP ENSO can excite both the SAM and PSA through tropospheric and stratospheric pathway mechanisms. The more in-phase relationship between SAM and PSA impacted the post-1990s Antarctic climate in at least two aspects: 1) a stronger Antarctic sea ice dipole structure around the Amundsen-Bellingshausen Seas due to intensified geopotential height anomalies over the region and 2) a shift in the phase relationships of surface air temperature anomalies among East Antarctica, West Antarctica, and the Antarctic Peninsula. These findings imply that ENSO-Antarctic climate relations depend on the dominant ENSO type and that ENSO forcing has become more important to the Antarctic sea ice and surface air temperature variability in the past two decades and will in the coming decades if the dominance of CP ENSO persists. |
format |
Article in Journal/Newspaper |
author |
Yu, JY Paek, H Saltzman, ES Lee, T |
author_facet |
Yu, JY Paek, H Saltzman, ES Lee, T |
author_sort |
Yu, JY |
title |
The early 1990s change in ENSO-PSA-SAM relationships and its impact on Southern Hemisphere climate |
title_short |
The early 1990s change in ENSO-PSA-SAM relationships and its impact on Southern Hemisphere climate |
title_full |
The early 1990s change in ENSO-PSA-SAM relationships and its impact on Southern Hemisphere climate |
title_fullStr |
The early 1990s change in ENSO-PSA-SAM relationships and its impact on Southern Hemisphere climate |
title_full_unstemmed |
The early 1990s change in ENSO-PSA-SAM relationships and its impact on Southern Hemisphere climate |
title_sort |
early 1990s change in enso-psa-sam relationships and its impact on southern hemisphere climate |
publisher |
eScholarship, University of California |
publishDate |
2015 |
url |
https://escholarship.org/uc/item/9wc3q6hk |
op_coverage |
9393 - 9408 |
geographic |
Antarctic Antarctic Peninsula Austral East Antarctica Pacific The Antarctic West Antarctica |
geographic_facet |
Antarctic Antarctic Peninsula Austral East Antarctica Pacific The Antarctic West Antarctica |
genre |
Antarc* Antarctic Antarctic Peninsula Antarctica East Antarctica Sea ice West Antarctica |
genre_facet |
Antarc* Antarctic Antarctic Peninsula Antarctica East Antarctica Sea ice West Antarctica |
op_source |
Journal of Climate, vol 28, iss 23 |
op_relation |
qt9wc3q6hk https://escholarship.org/uc/item/9wc3q6hk |
op_rights |
CC-BY |
op_rightsnorm |
CC-BY |
_version_ |
1766270796902170624 |