Influence of South America orography on summertime precipitation in Southeastern South America
Impacts of the main South American orographic structures (the Andes, the Brazilian Plateau and the Guiana shield) on the regional climate and associated global teleconnection are investigated through numerical experiments in which some of these features are suppressed. Simulations are performed with...
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2016
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| Acceso en línea: | https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_09307575_v46_n11-12_p3941_Junquas http://hdl.handle.net/20.500.12110/paper_09307575_v46_n11-12_p3941_Junquas |
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paper:paper_09307575_v46_n11-12_p3941_Junquas2023-06-08T15:52:46Z Influence of South America orography on summertime precipitation in Southeastern South America Vera, Carolina Susana Global teleconnection processes Orography influence South America orography Summer precipitation Two-way nesting system atmospheric general circulation model orography precipitation (climatology) regional climate summer teleconnection South America Impacts of the main South American orographic structures (the Andes, the Brazilian Plateau and the Guiana shield) on the regional climate and associated global teleconnection are investigated through numerical experiments in which some of these features are suppressed. Simulations are performed with a ‘‘two-way nesting’’ system coupling interactively the regional and global versions of the LMDZ4 atmospheric general circulation model. At regional scale, the simulations confirm previous studies, showing that both the Andes and the Brazilian Plateau exert a control on the position and strength of the South Atlantic convergence zone (SACZ), mainly through their impact on the low-level jet and the coastal branch of the subtropical anticyclones. The northern topography of South America appears to be crucial to determine the leading mode of rainfall variability in eastern South America, which manifests itself as a dipole-like pattern between Southeastern South America and the SACZ region. The suppression of South America orography also shows global-scale effects, corresponding to an adjustment of the global circulation system. Changes in atmospheric circulation and precipitation are found in remote areas on the globe, being the consequences of various teleconnection mechanisms. When the Brazilian Plateau and the Andes are suppressed, there is a decrease of precipitation in the SACZ region, associated with a weakening of the large-scale ascendance. Changes are described in terms of anomalies in the Walker circulation, meridional displacements of the mid-latitude jet stream, Southern annular mode anomalies and modifications of Rossby wave train teleconnection processes. © 2015, Springer-Verlag Berlin Heidelberg. Fil:Vera, C.S. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. 2016 https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_09307575_v46_n11-12_p3941_Junquas http://hdl.handle.net/20.500.12110/paper_09307575_v46_n11-12_p3941_Junquas |
| institution |
Universidad de Buenos Aires |
| institution_str |
I-28 |
| repository_str |
R-134 |
| collection |
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) |
| topic |
Global teleconnection processes Orography influence South America orography Summer precipitation Two-way nesting system atmospheric general circulation model orography precipitation (climatology) regional climate summer teleconnection South America |
| spellingShingle |
Global teleconnection processes Orography influence South America orography Summer precipitation Two-way nesting system atmospheric general circulation model orography precipitation (climatology) regional climate summer teleconnection South America Vera, Carolina Susana Influence of South America orography on summertime precipitation in Southeastern South America |
| topic_facet |
Global teleconnection processes Orography influence South America orography Summer precipitation Two-way nesting system atmospheric general circulation model orography precipitation (climatology) regional climate summer teleconnection South America |
| description |
Impacts of the main South American orographic structures (the Andes, the Brazilian Plateau and the Guiana shield) on the regional climate and associated global teleconnection are investigated through numerical experiments in which some of these features are suppressed. Simulations are performed with a ‘‘two-way nesting’’ system coupling interactively the regional and global versions of the LMDZ4 atmospheric general circulation model. At regional scale, the simulations confirm previous studies, showing that both the Andes and the Brazilian Plateau exert a control on the position and strength of the South Atlantic convergence zone (SACZ), mainly through their impact on the low-level jet and the coastal branch of the subtropical anticyclones. The northern topography of South America appears to be crucial to determine the leading mode of rainfall variability in eastern South America, which manifests itself as a dipole-like pattern between Southeastern South America and the SACZ region. The suppression of South America orography also shows global-scale effects, corresponding to an adjustment of the global circulation system. Changes in atmospheric circulation and precipitation are found in remote areas on the globe, being the consequences of various teleconnection mechanisms. When the Brazilian Plateau and the Andes are suppressed, there is a decrease of precipitation in the SACZ region, associated with a weakening of the large-scale ascendance. Changes are described in terms of anomalies in the Walker circulation, meridional displacements of the mid-latitude jet stream, Southern annular mode anomalies and modifications of Rossby wave train teleconnection processes. © 2015, Springer-Verlag Berlin Heidelberg. |
| author |
Vera, Carolina Susana |
| author_facet |
Vera, Carolina Susana |
| author_sort |
Vera, Carolina Susana |
| title |
Influence of South America orography on summertime precipitation in Southeastern South America |
| title_short |
Influence of South America orography on summertime precipitation in Southeastern South America |
| title_full |
Influence of South America orography on summertime precipitation in Southeastern South America |
| title_fullStr |
Influence of South America orography on summertime precipitation in Southeastern South America |
| title_full_unstemmed |
Influence of South America orography on summertime precipitation in Southeastern South America |
| title_sort |
influence of south america orography on summertime precipitation in southeastern south america |
| publishDate |
2016 |
| url |
https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_09307575_v46_n11-12_p3941_Junquas http://hdl.handle.net/20.500.12110/paper_09307575_v46_n11-12_p3941_Junquas |
| work_keys_str_mv |
AT veracarolinasusana influenceofsouthamericaorographyonsummertimeprecipitationinsoutheasternsouthamerica |
| _version_ |
1768546499294134272 |