Influence of the Madden Julian Oscillation on precipitation and surface air temperature in South America

The regional influence of the Madden–Julian oscillation (MJO) on South America is described. Maps of probability of weekly-averaged rainfall exceeding the upper tercile were computed for all seasons and related statistically with the phase of the MJO as characterized by the Wheeler–Hendon real-time...

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Autor principal: Vera, Carolina Susana
Publicado: 2016
Materias:
Impacts
Madden–Julian oscillation
Precipitation
South America
Surface air temperature
Acceso en línea:https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_09307575_v46_n1-2_p245_Alvarez
http://hdl.handle.net/20.500.12110/paper_09307575_v46_n1-2_p245_Alvarez
Aporte de:
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires
id paper:paper_09307575_v46_n1-2_p245_Alvarez
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spelling paper:paper_09307575_v46_n1-2_p245_Alvarez2023-06-08T15:52:46Z Influence of the Madden Julian Oscillation on precipitation and surface air temperature in South America Vera, Carolina Susana Impacts Madden–Julian oscillation Precipitation South America Surface air temperature The regional influence of the Madden–Julian oscillation (MJO) on South America is described. Maps of probability of weekly-averaged rainfall exceeding the upper tercile were computed for all seasons and related statistically with the phase of the MJO as characterized by the Wheeler–Hendon real-time multivariate MJO (RMM) index and with the OLR MJO Index. The accompanying surface air temperature and circulation anomalies were also calculated. The influence of the MJO on regional scales along with their marked seasonal variations was documented. During December–February when the South American monsoon system is active, chances of enhanced rainfall are observed in southeastern South America (SESA) region mainly during RMM phases 3 and 4, accompanied by cold anomalies in the extratropics, while enhanced rainfall in the South Atlantic Convergence Zone (SACZ) region is observed in phases 8 and 1. The SESA (SACZ) signal is characterized by upper-level convergence (divergence) over tropical South America and a cyclonic (anticyclonic) anomaly near the southern tip of the continent. Impacts during March–May are similar, but attenuated in the extratropics. Conversely, in June–November, reduced rainfall and cold anomalies are observed near the coast of the SACZ region during phases 4 and 5, favored by upper-level convergence over tropical South America and an anticyclonic anomaly over southern South America. In September–November, enhanced rainfall and upper-level divergence are observed in the SACZ region during phases 7 and 8. These signals are generated primarily through the propagation of Rossby wave energy generated in the region of anomalous heating associated with the MJO. © 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_n1-2_p245_Alvarez http://hdl.handle.net/20.500.12110/paper_09307575_v46_n1-2_p245_Alvarez
institution Universidad de Buenos Aires
institution_str I-28
repository_str R-134
collection Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic Impacts
Madden–Julian oscillation
Precipitation
South America
Surface air temperature
spellingShingle Impacts
Madden–Julian oscillation
Precipitation
South America
Surface air temperature
Vera, Carolina Susana
Influence of the Madden Julian Oscillation on precipitation and surface air temperature in South America
topic_facet Impacts
Madden–Julian oscillation
Precipitation
South America
Surface air temperature
description The regional influence of the Madden–Julian oscillation (MJO) on South America is described. Maps of probability of weekly-averaged rainfall exceeding the upper tercile were computed for all seasons and related statistically with the phase of the MJO as characterized by the Wheeler–Hendon real-time multivariate MJO (RMM) index and with the OLR MJO Index. The accompanying surface air temperature and circulation anomalies were also calculated. The influence of the MJO on regional scales along with their marked seasonal variations was documented. During December–February when the South American monsoon system is active, chances of enhanced rainfall are observed in southeastern South America (SESA) region mainly during RMM phases 3 and 4, accompanied by cold anomalies in the extratropics, while enhanced rainfall in the South Atlantic Convergence Zone (SACZ) region is observed in phases 8 and 1. The SESA (SACZ) signal is characterized by upper-level convergence (divergence) over tropical South America and a cyclonic (anticyclonic) anomaly near the southern tip of the continent. Impacts during March–May are similar, but attenuated in the extratropics. Conversely, in June–November, reduced rainfall and cold anomalies are observed near the coast of the SACZ region during phases 4 and 5, favored by upper-level convergence over tropical South America and an anticyclonic anomaly over southern South America. In September–November, enhanced rainfall and upper-level divergence are observed in the SACZ region during phases 7 and 8. These signals are generated primarily through the propagation of Rossby wave energy generated in the region of anomalous heating associated with the MJO. © 2015, Springer-Verlag Berlin Heidelberg.
author Vera, Carolina Susana
author_facet Vera, Carolina Susana
author_sort Vera, Carolina Susana
title Influence of the Madden Julian Oscillation on precipitation and surface air temperature in South America
title_short Influence of the Madden Julian Oscillation on precipitation and surface air temperature in South America
title_full Influence of the Madden Julian Oscillation on precipitation and surface air temperature in South America
title_fullStr Influence of the Madden Julian Oscillation on precipitation and surface air temperature in South America
title_full_unstemmed Influence of the Madden Julian Oscillation on precipitation and surface air temperature in South America
title_sort influence of the madden julian oscillation on precipitation and surface air temperature in south america
publishDate 2016
url https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_09307575_v46_n1-2_p245_Alvarez
http://hdl.handle.net/20.500.12110/paper_09307575_v46_n1-2_p245_Alvarez
work_keys_str_mv AT veracarolinasusana influenceofthemaddenjulianoscillationonprecipitationandsurfaceairtemperatureinsouthamerica
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