Precipitation trends in southeastern South America: Relationship with ENSO phases and with low-level circulation

Rainfall trends in subtropical South America east of the Andes during the period 1960-1999 were studied in connection with El Niño-Southern Oscillation (ENSO) phases. In addition, monthly mean sea level pressure (SLP) fields from the National Center for Environmental Prediction reanalysis were used...

Descripción completa

Guardado en:
Detalles Bibliográficos
Autores principales: Barros, V.R., Doyle, M.E., Camilloni, I.A.
Formato: JOUR
Materias:
atmospheric circulation
El Nino-Southern Oscillation
precipitation (climatology)
principal component analysis
rainfall
sea level pressure
trend analysis
Atlantic Ocean
South America
Acceso en línea:http://hdl.handle.net/20.500.12110/paper_0177798X_v93_n1-2_p19_Barros
Aporte de:
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires
id todo:paper_0177798X_v93_n1-2_p19_Barros
record_format dspace
spelling todo:paper_0177798X_v93_n1-2_p19_Barros2023-10-03T15:08:14Z Precipitation trends in southeastern South America: Relationship with ENSO phases and with low-level circulation Barros, V.R. Doyle, M.E. Camilloni, I.A. atmospheric circulation El Nino-Southern Oscillation precipitation (climatology) principal component analysis rainfall sea level pressure trend analysis Atlantic Ocean South America Rainfall trends in subtropical South America east of the Andes during the period 1960-1999 were studied in connection with El Niño-Southern Oscillation (ENSO) phases. In addition, monthly mean sea level pressure (SLP) fields from the National Center for Environmental Prediction reanalysis were used to look at the connection between rainfall trends and the interannual variability of the low-level atmospheric circulation. South of 22° S, annual rainfall trends were positive everywhere, and statistically significant over part of western subtropical Argentina. Over most of the region, trends resulted mostly from the warm semester (October-March) trends with little contribution from the cold semester (April-September). Under certain conditions, linear precipitation trends of each ENSO phase add up to the total rainfall trend. In northeastern Argentina, southern Brazil and Paraguay, half of the annual rainfall trend came from El Niño phase with a minor contribution from La Niña and the neutral phase. However, in most of subtropical South America, east of the Andes, precipitation trends during the extreme phases of the ENSO constitute only a small part of the trends. A Principal Component Analysis (PCA) was applied to the monthly SLP fields of the austral warm semester. The mode that advects humid air from the Atlantic Ocean over most of Argentina and Uruguay has grown at the expense of the one that favors the flow from the tropical forest over the eastern part of the continent. South of 30° S, annual rainfall trends took place predominantly during the neutral phase of the ENSO, and were related to the trends of the first two SLP leading modes. On the other hand, the annual trends were negative in the continental part of the South Atlantic Convergence Zone (SACZ), but with contributions from all ENSO phases. © Springer-Verlag 2008. JOUR info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar http://hdl.handle.net/20.500.12110/paper_0177798X_v93_n1-2_p19_Barros
institution Universidad de Buenos Aires
institution_str I-28
repository_str R-134
collection Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic atmospheric circulation
El Nino-Southern Oscillation
precipitation (climatology)
principal component analysis
rainfall
sea level pressure
trend analysis
Atlantic Ocean
South America
spellingShingle atmospheric circulation
El Nino-Southern Oscillation
precipitation (climatology)
principal component analysis
rainfall
sea level pressure
trend analysis
Atlantic Ocean
South America
Barros, V.R.
Doyle, M.E.
Camilloni, I.A.
Precipitation trends in southeastern South America: Relationship with ENSO phases and with low-level circulation
topic_facet atmospheric circulation
El Nino-Southern Oscillation
precipitation (climatology)
principal component analysis
rainfall
sea level pressure
trend analysis
Atlantic Ocean
South America
description Rainfall trends in subtropical South America east of the Andes during the period 1960-1999 were studied in connection with El Niño-Southern Oscillation (ENSO) phases. In addition, monthly mean sea level pressure (SLP) fields from the National Center for Environmental Prediction reanalysis were used to look at the connection between rainfall trends and the interannual variability of the low-level atmospheric circulation. South of 22° S, annual rainfall trends were positive everywhere, and statistically significant over part of western subtropical Argentina. Over most of the region, trends resulted mostly from the warm semester (October-March) trends with little contribution from the cold semester (April-September). Under certain conditions, linear precipitation trends of each ENSO phase add up to the total rainfall trend. In northeastern Argentina, southern Brazil and Paraguay, half of the annual rainfall trend came from El Niño phase with a minor contribution from La Niña and the neutral phase. However, in most of subtropical South America, east of the Andes, precipitation trends during the extreme phases of the ENSO constitute only a small part of the trends. A Principal Component Analysis (PCA) was applied to the monthly SLP fields of the austral warm semester. The mode that advects humid air from the Atlantic Ocean over most of Argentina and Uruguay has grown at the expense of the one that favors the flow from the tropical forest over the eastern part of the continent. South of 30° S, annual rainfall trends took place predominantly during the neutral phase of the ENSO, and were related to the trends of the first two SLP leading modes. On the other hand, the annual trends were negative in the continental part of the South Atlantic Convergence Zone (SACZ), but with contributions from all ENSO phases. © Springer-Verlag 2008.
format JOUR
author Barros, V.R.
Doyle, M.E.
Camilloni, I.A.
author_facet Barros, V.R.
Doyle, M.E.
Camilloni, I.A.
author_sort Barros, V.R.
title Precipitation trends in southeastern South America: Relationship with ENSO phases and with low-level circulation
title_short Precipitation trends in southeastern South America: Relationship with ENSO phases and with low-level circulation
title_full Precipitation trends in southeastern South America: Relationship with ENSO phases and with low-level circulation
title_fullStr Precipitation trends in southeastern South America: Relationship with ENSO phases and with low-level circulation
title_full_unstemmed Precipitation trends in southeastern South America: Relationship with ENSO phases and with low-level circulation
title_sort precipitation trends in southeastern south america: relationship with enso phases and with low-level circulation
url http://hdl.handle.net/20.500.12110/paper_0177798X_v93_n1-2_p19_Barros
work_keys_str_mv AT barrosvr precipitationtrendsinsoutheasternsouthamericarelationshipwithensophasesandwithlowlevelcirculation
AT doyleme precipitationtrendsinsoutheasternsouthamericarelationshipwithensophasesandwithlowlevelcirculation
AT camilloniia precipitationtrendsinsoutheasternsouthamericarelationshipwithensophasesandwithlowlevelcirculation
_version_ 1807323353303744512

Ejemplares similares