A new climatology for Southern Hemisphere blockings in the winter and the combined effect of ENSO and SAM phases
This study presents 53-year climatology of Southern Hemisphere (SH) blockings in the winter using daily 500-hPa geopotential height data from NCEP-NCAR reanalysis. The variability of SH blocking events and their relationships with combined phases of El Niño/southern oscillation (ENSO) and the southe...
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2014
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ftcdlib:oai:escholarship.org:ark:/13030/qt5913c9j2 2023-06-11T04:06:00+02:00 A new climatology for Southern Hemisphere blockings in the winter and the combined effect of ENSO and SAM phases Oliveira, Flavio NM Carvalho, Leila MV Ambrizzi, Tercio 1676 - 1692 2014-04-01 application/pdf https://escholarship.org/uc/item/5913c9j2 unknown eScholarship, University of California qt5913c9j2 https://escholarship.org/uc/item/5913c9j2 public International Journal of Climatology, vol 34, iss 5 blocking El Nino southern oscillation Antarctic oscillation austral winter Atmospheric Sciences Civil Engineering Environmental Engineering Meteorology & Atmospheric Sciences article 2014 ftcdlib 2023-05-29T17:58:00Z This study presents 53-year climatology of Southern Hemisphere (SH) blockings in the winter using daily 500-hPa geopotential height data from NCEP-NCAR reanalysis. The variability of SH blocking events and their relationships with combined phases of El Niño/southern oscillation (ENSO) and the southern annular mode (SAM) are examined. Conventional indices were revised and a slightly modified index is proposed to detect latitudinal variations of SH blockings. The South Pacific region is examined in detail. There is no statistically significant long-term trend in the SH blockings. During moderate El Niño, the preferred location SH blocking is observed over East Pacific, and we show that the blocking frequency increases during negative SAM phases. During moderate La Niña the SH blockings are significantly suppressed over Central Pacific, with lower blocking frequency during positive SAM phases. These results indicate that the daily variability of SH blocking is strongly modulated by both ENSO and SAM phases. © 2013 Royal Meteorological Society. Article in Journal/Newspaper Antarc* Antarctic University of California: eScholarship Antarctic Austral Pacific |
institution |
Open Polar |
collection |
University of California: eScholarship |
op_collection_id |
ftcdlib |
language |
unknown |
topic |
blocking El Nino southern oscillation Antarctic oscillation austral winter Atmospheric Sciences Civil Engineering Environmental Engineering Meteorology & Atmospheric Sciences |
spellingShingle |
blocking El Nino southern oscillation Antarctic oscillation austral winter Atmospheric Sciences Civil Engineering Environmental Engineering Meteorology & Atmospheric Sciences Oliveira, Flavio NM Carvalho, Leila MV Ambrizzi, Tercio A new climatology for Southern Hemisphere blockings in the winter and the combined effect of ENSO and SAM phases |
topic_facet |
blocking El Nino southern oscillation Antarctic oscillation austral winter Atmospheric Sciences Civil Engineering Environmental Engineering Meteorology & Atmospheric Sciences |
description |
This study presents 53-year climatology of Southern Hemisphere (SH) blockings in the winter using daily 500-hPa geopotential height data from NCEP-NCAR reanalysis. The variability of SH blocking events and their relationships with combined phases of El Niño/southern oscillation (ENSO) and the southern annular mode (SAM) are examined. Conventional indices were revised and a slightly modified index is proposed to detect latitudinal variations of SH blockings. The South Pacific region is examined in detail. There is no statistically significant long-term trend in the SH blockings. During moderate El Niño, the preferred location SH blocking is observed over East Pacific, and we show that the blocking frequency increases during negative SAM phases. During moderate La Niña the SH blockings are significantly suppressed over Central Pacific, with lower blocking frequency during positive SAM phases. These results indicate that the daily variability of SH blocking is strongly modulated by both ENSO and SAM phases. © 2013 Royal Meteorological Society. |
format |
Article in Journal/Newspaper |
author |
Oliveira, Flavio NM Carvalho, Leila MV Ambrizzi, Tercio |
author_facet |
Oliveira, Flavio NM Carvalho, Leila MV Ambrizzi, Tercio |
author_sort |
Oliveira, Flavio NM |
title |
A new climatology for Southern Hemisphere blockings in the winter and the combined effect of ENSO and SAM phases |
title_short |
A new climatology for Southern Hemisphere blockings in the winter and the combined effect of ENSO and SAM phases |
title_full |
A new climatology for Southern Hemisphere blockings in the winter and the combined effect of ENSO and SAM phases |
title_fullStr |
A new climatology for Southern Hemisphere blockings in the winter and the combined effect of ENSO and SAM phases |
title_full_unstemmed |
A new climatology for Southern Hemisphere blockings in the winter and the combined effect of ENSO and SAM phases |
title_sort |
new climatology for southern hemisphere blockings in the winter and the combined effect of enso and sam phases |
publisher |
eScholarship, University of California |
publishDate |
2014 |
url |
https://escholarship.org/uc/item/5913c9j2 |
op_coverage |
1676 - 1692 |
geographic |
Antarctic Austral Pacific |
geographic_facet |
Antarctic Austral Pacific |
genre |
Antarc* Antarctic |
genre_facet |
Antarc* Antarctic |
op_source |
International Journal of Climatology, vol 34, iss 5 |
op_relation |
qt5913c9j2 https://escholarship.org/uc/item/5913c9j2 |
op_rights |
public |
_version_ |
1768377726357471232 |