Intraseasonal variability in South America during the cold season

Mostrar todas las versiones(2)

Intraseasonal (IS) variability in South America is analyzed during the cold season using 10-90 day bandpass filtered OLR anomalies (FOLR). IS variability explains a large percentage of variance with maximum values over Paraguay, northeastern Argentina, and southern Brazil. The leading pattern of FOL...

Descripción completa

Guardado en:
Detalles Bibliográficos
Autores principales: Alvarez, Mariano Sebastian, Vera, Carolina Susana
Publicado: 2013
Materias:
Intraseasonal variability
Outgoing longwave radiation
South America
Winter
Acceso en línea:https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_09307575_v_n_p1_Alvarez
http://hdl.handle.net/20.500.12110/paper_09307575_v_n_p1_Alvarez
Aporte de:
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires
id paper:paper_09307575_v_n_p1_Alvarez
record_format dspace
spelling paper:paper_09307575_v_n_p1_Alvarez2023-06-08T15:52:51Z Intraseasonal variability in South America during the cold season Alvarez, Mariano Sebastian Vera, Carolina Susana Intraseasonal variability Outgoing longwave radiation South America Winter Intraseasonal (IS) variability in South America is analyzed during the cold season using 10-90 day bandpass filtered OLR anomalies (FOLR). IS variability explains a large percentage of variance with maximum values over Paraguay, northeastern Argentina, and southern Brazil. The leading pattern of FOLR, as isolated from an EOF analysis, (Cold Season IS pattern, CSIS), is characterized by a monopole centered over southeastern South America (SESA) with a northwest-southeast orientation. CSIS induces a large modulation on daily precipitation anomalies, especially on both wet spells and daily precipitation extremes, which are favored during positive (wet) CSIS phases. Large-Scale OLR anomalies over the tropical Indian and west Pacific Oceans associated with CSIS exhibit eastward propagation along tropical latitudes. In addition, circulation anomalies in the Southern Hemisphere reveal the presence of an anticyclonic anomaly over Antarctica with opposite-sign anomalies in middle latitudes 10 days before CSIS is maximum as well as evidence of Rossby wave-like patterns. Positive precipitation anomalies in SESA are favored during wet CSIS phases by the intensification of a cyclonic anomaly located further south, which is discernible over the southeastern Pacific for at least 14 days before CSIS peaks. The cyclonic anomaly evolution is accompanied by the intensification of an upstream anticyclonic anomaly, which remains quasi-stationary near the Antarctica Peninsula before the CSIS peak. We speculate that the stationary behavior of the anticyclonic center is favored by a hemispheric circulation anomaly pattern resembling that associated with a negative southern annular mode phase and a wavenumber 3-4 pattern at middle latitudes. © 2013 Springer-Verlag Berlin Heidelberg. Fil:Alvarez, M.S. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. 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_v_n_p1_Alvarez http://hdl.handle.net/20.500.12110/paper_09307575_v_n_p1_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 Intraseasonal variability
Outgoing longwave radiation
South America
Winter
spellingShingle Intraseasonal variability
Outgoing longwave radiation
South America
Winter
Alvarez, Mariano Sebastian
Vera, Carolina Susana
Intraseasonal variability in South America during the cold season
topic_facet Intraseasonal variability
Outgoing longwave radiation
South America
Winter
description Intraseasonal (IS) variability in South America is analyzed during the cold season using 10-90 day bandpass filtered OLR anomalies (FOLR). IS variability explains a large percentage of variance with maximum values over Paraguay, northeastern Argentina, and southern Brazil. The leading pattern of FOLR, as isolated from an EOF analysis, (Cold Season IS pattern, CSIS), is characterized by a monopole centered over southeastern South America (SESA) with a northwest-southeast orientation. CSIS induces a large modulation on daily precipitation anomalies, especially on both wet spells and daily precipitation extremes, which are favored during positive (wet) CSIS phases. Large-Scale OLR anomalies over the tropical Indian and west Pacific Oceans associated with CSIS exhibit eastward propagation along tropical latitudes. In addition, circulation anomalies in the Southern Hemisphere reveal the presence of an anticyclonic anomaly over Antarctica with opposite-sign anomalies in middle latitudes 10 days before CSIS is maximum as well as evidence of Rossby wave-like patterns. Positive precipitation anomalies in SESA are favored during wet CSIS phases by the intensification of a cyclonic anomaly located further south, which is discernible over the southeastern Pacific for at least 14 days before CSIS peaks. The cyclonic anomaly evolution is accompanied by the intensification of an upstream anticyclonic anomaly, which remains quasi-stationary near the Antarctica Peninsula before the CSIS peak. We speculate that the stationary behavior of the anticyclonic center is favored by a hemispheric circulation anomaly pattern resembling that associated with a negative southern annular mode phase and a wavenumber 3-4 pattern at middle latitudes. © 2013 Springer-Verlag Berlin Heidelberg.
author Alvarez, Mariano Sebastian
Vera, Carolina Susana
author_facet Alvarez, Mariano Sebastian
Vera, Carolina Susana
author_sort Alvarez, Mariano Sebastian
title Intraseasonal variability in South America during the cold season
title_short Intraseasonal variability in South America during the cold season
title_full Intraseasonal variability in South America during the cold season
title_fullStr Intraseasonal variability in South America during the cold season
title_full_unstemmed Intraseasonal variability in South America during the cold season
title_sort intraseasonal variability in south america during the cold season
publishDate 2013
url https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_09307575_v_n_p1_Alvarez
http://hdl.handle.net/20.500.12110/paper_09307575_v_n_p1_Alvarez
work_keys_str_mv AT alvarezmarianosebastian intraseasonalvariabilityinsouthamericaduringthecoldseason
AT veracarolinasusana intraseasonalvariabilityinsouthamericaduringthecoldseason
_version_ 1768542995126157312

Ejemplares similares