Impact of projected SST changes on summer rainfall in southeastern South America
Recent studies have shown that global warming and associated sea-surface temperature (SST) changes may trigger an important rainfall increase in southeastern South America (SESA) during the austral summer (December-January-February, DJF). The goal of this paper is to provide some insight into proces...
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| Acceso en línea: | https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_09307575_v40_n7-8_p1569_Junquas http://hdl.handle.net/20.500.12110/paper_09307575_v40_n7-8_p1569_Junquas |
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paper:paper_09307575_v40_n7-8_p1569_Junquas2023-06-08T15:52:42Z Impact of projected SST changes on summer rainfall in southeastern South America Vera, Carolina Susana Climate change Rainfall changes Sea surface temperature projections South America climate Two-way nesting system atmospheric modeling atmospheric transport climate modeling convergence global warming rainfall sea surface temperature summer twenty first century Atlantic Ocean Atlantic Ocean (South) Indian Ocean Indian Ocean (Equatorial) Pacific Ocean Pacific Ocean (Equatorial) South America Recent studies have shown that global warming and associated sea-surface temperature (SST) changes may trigger an important rainfall increase in southeastern South America (SESA) during the austral summer (December-January-February, DJF). The goal of this paper is to provide some insight into processes which may link global and SESA changes. For this purpose, a "two-way nesting" system coupling interactively the regional and global versions of the LMDZ4 atmospheric model is used to study the response to prescribed SST changes. The regional model is a variable-grid version of the global model, with a zoom focused over South America. An ensemble of simulations forced by distinct patterns of DJF SST changes has been carried out using a decomposition of full SST changes into their longitudinal and latitudinal components. The full SST changes are based on projections for the end of the twenty-first century from a multi-model ensemble of WCRP/CMIP3. Results confirm the presence of a major rainfall dipole structure, characterized by an increase in SESA and a decrease in the South Atlantic Convergence Zone region. Rainfall changes found in the WCRP/CMIP3 models are largely explained as a response of this dipole structure to the zonally-asymmetric (or longitudinal) component of SST changes. The rainfall response to the zonal-mean (or latitudinal) SST changes (including the global warming signal itself) shows an opposite contribution. The processes explaining the role of zonally-asymmetric SST changes involve remote effects of SST warming over the equatorial Indian and Pacific oceans inducing an atmospheric wave-train extended across the South Pacific into South America. © 2013 Springer-Verlag Berlin Heidelberg. Fil:Vera, C.S. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. 2013 https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_09307575_v40_n7-8_p1569_Junquas http://hdl.handle.net/20.500.12110/paper_09307575_v40_n7-8_p1569_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 |
Climate change Rainfall changes Sea surface temperature projections South America climate Two-way nesting system atmospheric modeling atmospheric transport climate modeling convergence global warming rainfall sea surface temperature summer twenty first century Atlantic Ocean Atlantic Ocean (South) Indian Ocean Indian Ocean (Equatorial) Pacific Ocean Pacific Ocean (Equatorial) South America |
| spellingShingle |
Climate change Rainfall changes Sea surface temperature projections South America climate Two-way nesting system atmospheric modeling atmospheric transport climate modeling convergence global warming rainfall sea surface temperature summer twenty first century Atlantic Ocean Atlantic Ocean (South) Indian Ocean Indian Ocean (Equatorial) Pacific Ocean Pacific Ocean (Equatorial) South America Vera, Carolina Susana Impact of projected SST changes on summer rainfall in southeastern South America |
| topic_facet |
Climate change Rainfall changes Sea surface temperature projections South America climate Two-way nesting system atmospheric modeling atmospheric transport climate modeling convergence global warming rainfall sea surface temperature summer twenty first century Atlantic Ocean Atlantic Ocean (South) Indian Ocean Indian Ocean (Equatorial) Pacific Ocean Pacific Ocean (Equatorial) South America |
| description |
Recent studies have shown that global warming and associated sea-surface temperature (SST) changes may trigger an important rainfall increase in southeastern South America (SESA) during the austral summer (December-January-February, DJF). The goal of this paper is to provide some insight into processes which may link global and SESA changes. For this purpose, a "two-way nesting" system coupling interactively the regional and global versions of the LMDZ4 atmospheric model is used to study the response to prescribed SST changes. The regional model is a variable-grid version of the global model, with a zoom focused over South America. An ensemble of simulations forced by distinct patterns of DJF SST changes has been carried out using a decomposition of full SST changes into their longitudinal and latitudinal components. The full SST changes are based on projections for the end of the twenty-first century from a multi-model ensemble of WCRP/CMIP3. Results confirm the presence of a major rainfall dipole structure, characterized by an increase in SESA and a decrease in the South Atlantic Convergence Zone region. Rainfall changes found in the WCRP/CMIP3 models are largely explained as a response of this dipole structure to the zonally-asymmetric (or longitudinal) component of SST changes. The rainfall response to the zonal-mean (or latitudinal) SST changes (including the global warming signal itself) shows an opposite contribution. The processes explaining the role of zonally-asymmetric SST changes involve remote effects of SST warming over the equatorial Indian and Pacific oceans inducing an atmospheric wave-train extended across the South Pacific into South America. © 2013 Springer-Verlag Berlin Heidelberg. |
| author |
Vera, Carolina Susana |
| author_facet |
Vera, Carolina Susana |
| author_sort |
Vera, Carolina Susana |
| title |
Impact of projected SST changes on summer rainfall in southeastern South America |
| title_short |
Impact of projected SST changes on summer rainfall in southeastern South America |
| title_full |
Impact of projected SST changes on summer rainfall in southeastern South America |
| title_fullStr |
Impact of projected SST changes on summer rainfall in southeastern South America |
| title_full_unstemmed |
Impact of projected SST changes on summer rainfall in southeastern South America |
| title_sort |
impact of projected sst changes on summer rainfall in southeastern south america |
| publishDate |
2013 |
| url |
https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_09307575_v40_n7-8_p1569_Junquas http://hdl.handle.net/20.500.12110/paper_09307575_v40_n7-8_p1569_Junquas |
| work_keys_str_mv |
AT veracarolinasusana impactofprojectedsstchangesonsummerrainfallinsoutheasternsouthamerica |
| _version_ |
1768543429707431936 |