Intraseasonal variability of wintertime frontal activity and its relationship with precipitation anomalies in the vicinity of South America

The intraseasonal variability of the frontal activity and its connection with the variability of the atmospheric circulation and precipitation in the Southern Hemisphere is studied. The frontal activity is defined as the relative vorticity times the local temperature gradient. A band-pass filter was...

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Autores principales: Blázquez, J., Solman, S.A.
Formato: JOUR
Materias:
Frontal activity
Intraseasonal variability
Large scale circulation
Precipitation
Southern hemisphere
anomaly
atmospheric circulation
atmospheric front
precipitation (climatology)
seasonal variation
Southern Hemisphere
winter
Pacific Ocean
Pacific Ocean (South)
South America
Acceso en línea:http://hdl.handle.net/20.500.12110/paper_09307575_v46_n7-8_p2327_Blazquez
Aporte de:
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires
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spelling todo:paper_09307575_v46_n7-8_p2327_Blazquez2023-10-03T15:48:02Z Intraseasonal variability of wintertime frontal activity and its relationship with precipitation anomalies in the vicinity of South America Blázquez, J. Solman, S.A. Frontal activity Intraseasonal variability Large scale circulation Precipitation Southern hemisphere anomaly atmospheric circulation atmospheric front precipitation (climatology) seasonal variation Southern Hemisphere winter Pacific Ocean Pacific Ocean (South) South America The intraseasonal variability of the frontal activity and its connection with the variability of the atmospheric circulation and precipitation in the Southern Hemisphere is studied. The frontal activity is defined as the relative vorticity times the local temperature gradient. A band-pass filter was applied to retain the intraseasonal timescales. An empirical orthogonal function analysis was applied to the filtered frontal activity anomalies. The two main modes show positive and negative centers located mainly over the southern Pacific Ocean and South American sector and are in quadrature with each other. A similar pattern was found when the main modes of intraseasonal variability of the 500 hPa geopotential height were projected on the frontal activity, suggesting that the variability of fronts are influenced by the variability of the large scale atmospheric circulation. Moreover, the precipitation anomalies projected on the main modes of both frontal activity and 500 hPa geopotential height show similar structures, especially over the southern Pacific Ocean and South America, which may indicate that the variability of fronts controls the variability of precipitation. The lagged regression of the time series of the frontal activity areallyaveraged over one of the centers of action against the frontal activity anomaly field shows at lags −8 and 8 a similar pattern, suggesting a period of around 17 days for each mode. Moreover, lagged regression between times series of frontal activity and precipitation anomalies reveals an opposite pattern between southeastern South America and southern Chile, being precipitation anomalies over these two regions anti-correlated due to the frontal activity. © Springer-Verlag Berlin Heidelberg 2015. Fil:Blázquez, J. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Solman, S.A. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. JOUR info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar http://hdl.handle.net/20.500.12110/paper_09307575_v46_n7-8_p2327_Blazquez
institution Universidad de Buenos Aires
institution_str I-28
repository_str R-134
collection Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic Frontal activity
Intraseasonal variability
Large scale circulation
Precipitation
Southern hemisphere
anomaly
atmospheric circulation
atmospheric front
precipitation (climatology)
seasonal variation
Southern Hemisphere
winter
Pacific Ocean
Pacific Ocean (South)
South America
spellingShingle Frontal activity
Intraseasonal variability
Large scale circulation
Precipitation
Southern hemisphere
anomaly
atmospheric circulation
atmospheric front
precipitation (climatology)
seasonal variation
Southern Hemisphere
winter
Pacific Ocean
Pacific Ocean (South)
South America
Blázquez, J.
Solman, S.A.
Intraseasonal variability of wintertime frontal activity and its relationship with precipitation anomalies in the vicinity of South America
topic_facet Frontal activity
Intraseasonal variability
Large scale circulation
Precipitation
Southern hemisphere
anomaly
atmospheric circulation
atmospheric front
precipitation (climatology)
seasonal variation
Southern Hemisphere
winter
Pacific Ocean
Pacific Ocean (South)
South America
description The intraseasonal variability of the frontal activity and its connection with the variability of the atmospheric circulation and precipitation in the Southern Hemisphere is studied. The frontal activity is defined as the relative vorticity times the local temperature gradient. A band-pass filter was applied to retain the intraseasonal timescales. An empirical orthogonal function analysis was applied to the filtered frontal activity anomalies. The two main modes show positive and negative centers located mainly over the southern Pacific Ocean and South American sector and are in quadrature with each other. A similar pattern was found when the main modes of intraseasonal variability of the 500 hPa geopotential height were projected on the frontal activity, suggesting that the variability of fronts are influenced by the variability of the large scale atmospheric circulation. Moreover, the precipitation anomalies projected on the main modes of both frontal activity and 500 hPa geopotential height show similar structures, especially over the southern Pacific Ocean and South America, which may indicate that the variability of fronts controls the variability of precipitation. The lagged regression of the time series of the frontal activity areallyaveraged over one of the centers of action against the frontal activity anomaly field shows at lags −8 and 8 a similar pattern, suggesting a period of around 17 days for each mode. Moreover, lagged regression between times series of frontal activity and precipitation anomalies reveals an opposite pattern between southeastern South America and southern Chile, being precipitation anomalies over these two regions anti-correlated due to the frontal activity. © Springer-Verlag Berlin Heidelberg 2015.
format JOUR
author Blázquez, J.
Solman, S.A.
author_facet Blázquez, J.
Solman, S.A.
author_sort Blázquez, J.
title Intraseasonal variability of wintertime frontal activity and its relationship with precipitation anomalies in the vicinity of South America
title_short Intraseasonal variability of wintertime frontal activity and its relationship with precipitation anomalies in the vicinity of South America
title_full Intraseasonal variability of wintertime frontal activity and its relationship with precipitation anomalies in the vicinity of South America
title_fullStr Intraseasonal variability of wintertime frontal activity and its relationship with precipitation anomalies in the vicinity of South America
title_full_unstemmed Intraseasonal variability of wintertime frontal activity and its relationship with precipitation anomalies in the vicinity of South America
title_sort intraseasonal variability of wintertime frontal activity and its relationship with precipitation anomalies in the vicinity of south america
url http://hdl.handle.net/20.500.12110/paper_09307575_v46_n7-8_p2327_Blazquez
work_keys_str_mv AT blazquezj intraseasonalvariabilityofwintertimefrontalactivityanditsrelationshipwithprecipitationanomaliesinthevicinityofsouthamerica
AT solmansa intraseasonalvariabilityofwintertimefrontalactivityanditsrelationshipwithprecipitationanomaliesinthevicinityofsouthamerica
_version_ 1782031084806995968

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