Weather regimes in the South American sector and neighbouring oceans during winter
We classified 34 years of winter daily 500 hPa geopotential height patterns over the eastern South Pacific-South America-South Atlantic region using the K-means clustering method. We found a significant classification into five weather regimes (WRs) defined as the most frequent large-scale circulati...
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ftunibueairesbd:paper:paper_09307575_v21_n1_p91_Solman 2023-05-15T16:02:34+02:00 Weather regimes in the South American sector and neighbouring oceans during winter 2003 https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_09307575_v21_n1_p91_Solman https://hdl.handle.net/20.500.12110/paper_09307575_v21_n1_p91_Solman unknown https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_09307575_v21_n1_p91_Solman http://hdl.handle.net/20.500.12110/paper_09307575_v21_n1_p91_Solman atmospheric circulation cluster analysis regional climate Southern Hemisphere synoptic meteorology winter Atlantic Ocean Pacific Ocean South America 2003 ftunibueairesbd https://doi.org/20.500.12110/paper_09307575_v21_n1_p91_Solman 2023-02-16T02:08:11Z We classified 34 years of winter daily 500 hPa geopotential height patterns over the eastern South Pacific-South America-South Atlantic region using the K-means clustering method. We found a significant classification into five weather regimes (WRs) defined as the most frequent large-scale circulation anomalies: WR1 (trough centred downstream of the Drake Passage), WR2 (trough over the SW Pacific and ridge downstream), WR3 (ridge over the SE Pacific and NW-SE trough downstream), WR4 (trough over the SE Pacific and NW-SE ridge downstream) and WR5 (weak ridge to the west of southern South America). We also analysed their persistence and temporal evolution, including transitions between them and development around onsets and breaks of each regime. The preferred transitions, WR1 ← WR3 ← WR2 ← WR4 ← WR1 and also WR1 ← WR3 ← WR2 ← WR1, suggest the progression of a Rossby wave-like pattern in which each of the regimes resemble the Pacific-South America modes. Significant influence of the WRs on local climate over Argentina was found. The preferred transitions WR1 ← WR3 and WR3 ← WR2 induce sustained cold conditions over Patagonia and over northern Argentina, respectively. The most significant change in precipitation frequency is found for WR3, with wetter conditions over all the analysed regions. Finally, the interannual to interdecadal significant variations in the occurrence of these regimes were discussed. WR1 and WR3 are more frequent and WR2 is less frequent during El Niño, and WR2 and WR5 are more frequent and WR1 is less frequent during La Niña. A significant decrease in WR2 and increase of WR4 and WR5 during the 1970s and early 1980s were found. Other/Unknown Material Drake Passage Biblioteca Digital FCEN-UBA (Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires) Argentina Drake Passage Pacific Patagonia |
institution |
Open Polar |
collection |
Biblioteca Digital FCEN-UBA (Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires) |
op_collection_id |
ftunibueairesbd |
language |
unknown |
topic |
atmospheric circulation cluster analysis regional climate Southern Hemisphere synoptic meteorology winter Atlantic Ocean Pacific Ocean South America |
spellingShingle |
atmospheric circulation cluster analysis regional climate Southern Hemisphere synoptic meteorology winter Atlantic Ocean Pacific Ocean South America Weather regimes in the South American sector and neighbouring oceans during winter |
topic_facet |
atmospheric circulation cluster analysis regional climate Southern Hemisphere synoptic meteorology winter Atlantic Ocean Pacific Ocean South America |
description |
We classified 34 years of winter daily 500 hPa geopotential height patterns over the eastern South Pacific-South America-South Atlantic region using the K-means clustering method. We found a significant classification into five weather regimes (WRs) defined as the most frequent large-scale circulation anomalies: WR1 (trough centred downstream of the Drake Passage), WR2 (trough over the SW Pacific and ridge downstream), WR3 (ridge over the SE Pacific and NW-SE trough downstream), WR4 (trough over the SE Pacific and NW-SE ridge downstream) and WR5 (weak ridge to the west of southern South America). We also analysed their persistence and temporal evolution, including transitions between them and development around onsets and breaks of each regime. The preferred transitions, WR1 ← WR3 ← WR2 ← WR4 ← WR1 and also WR1 ← WR3 ← WR2 ← WR1, suggest the progression of a Rossby wave-like pattern in which each of the regimes resemble the Pacific-South America modes. Significant influence of the WRs on local climate over Argentina was found. The preferred transitions WR1 ← WR3 and WR3 ← WR2 induce sustained cold conditions over Patagonia and over northern Argentina, respectively. The most significant change in precipitation frequency is found for WR3, with wetter conditions over all the analysed regions. Finally, the interannual to interdecadal significant variations in the occurrence of these regimes were discussed. WR1 and WR3 are more frequent and WR2 is less frequent during El Niño, and WR2 and WR5 are more frequent and WR1 is less frequent during La Niña. A significant decrease in WR2 and increase of WR4 and WR5 during the 1970s and early 1980s were found. |
title |
Weather regimes in the South American sector and neighbouring oceans during winter |
title_short |
Weather regimes in the South American sector and neighbouring oceans during winter |
title_full |
Weather regimes in the South American sector and neighbouring oceans during winter |
title_fullStr |
Weather regimes in the South American sector and neighbouring oceans during winter |
title_full_unstemmed |
Weather regimes in the South American sector and neighbouring oceans during winter |
title_sort |
weather regimes in the south american sector and neighbouring oceans during winter |
publishDate |
2003 |
url |
https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_09307575_v21_n1_p91_Solman https://hdl.handle.net/20.500.12110/paper_09307575_v21_n1_p91_Solman |
geographic |
Argentina Drake Passage Pacific Patagonia |
geographic_facet |
Argentina Drake Passage Pacific Patagonia |
genre |
Drake Passage |
genre_facet |
Drake Passage |
op_relation |
https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_09307575_v21_n1_p91_Solman http://hdl.handle.net/20.500.12110/paper_09307575_v21_n1_p91_Solman |
op_doi |
https://doi.org/20.500.12110/paper_09307575_v21_n1_p91_Solman |
_version_ |
1766398233254297600 |