La Plata basin precipitation variability in spring: Role of remote SST forcing as simulated by GCM experiments

An ensemble of nine experiments with the same interannually varying sea surface temperature (SST), as boundary forcing, and different initial conditions is used to investigate the role of tropical oceans in modulating precipitation variability in the region of La Plata Basin (LPB). The results from...

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Autores principales:	Cherchi, A., Carril, A.F., Menéndez, C.G., Zamboni, L.
Formato:	JOUR
Materias:	air-sea interaction atmosphere-ocean coupling atmospheric forcing El Nino-Southern Oscillation general circulation model precipitation (climatology) sea surface temperature spring (season) teleconnection Atlantic Ocean Atlantic Ocean (South) La Plata Basin
Acceso en línea:	http://hdl.handle.net/20.500.12110/paper_09307575_v42_n1-2_p219_Cherchi
Aporte de:	Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires

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spelling	todo:paper_09307575_v42_n1-2_p219_Cherchi2023-10-03T15:47:58Z La Plata basin precipitation variability in spring: Role of remote SST forcing as simulated by GCM experiments Cherchi, A. Carril, A.F. Menéndez, C.G. Zamboni, L. air-sea interaction atmosphere-ocean coupling atmospheric forcing El Nino-Southern Oscillation general circulation model precipitation (climatology) sea surface temperature spring (season) teleconnection Atlantic Ocean Atlantic Ocean (South) La Plata Basin An ensemble of nine experiments with the same interannually varying sea surface temperature (SST), as boundary forcing, and different initial conditions is used to investigate the role of tropical oceans in modulating precipitation variability in the region of La Plata Basin (LPB). The results from the ensemble are compared with a twentieth-century experiment performed with a coupled ocean-atmosphere model, sharing the same atmospheric component. A rotated empirical orthogonal functions analysis of South America precipitation shows that the dominant mode of variability in spring is realistically captured in both experiments. Its principal component (RPC1) correlated with global SST and atmospheric fields identifies the pattern related to El Niño Southern Oscillation and its large-scale teleconnections. Overall the pattern is well simulated in the tropical southern Pacific Ocean, mainly in the ensemble, but it is absent or too weak in other oceanic areas. The coupled model experiment shows a more realistic correlation in the subtropical South Atlantic where air-sea interactions contribute to the relationship between LPB precipitation and SST. The correspondence between model and data is much improved when the composite analysis of SST and atmospheric fields is done over the ensemble members having an RPC1 in agreement with the observations: the improvement relies on avoiding climate noise by averaging only over members that are statistically similar. Furthermore, the result suggests the presence of a high level of uncertainty due to internal atmospheric variability. The analysis of some individual years selected from the model and data RPC1 comparison reveals interesting differences among rainy springs in LPB. For example, 1982, which corresponds to a strong El Niño year, represents a clean case with a distinct wave train propagating from the central Pacific and merging with another one from the eastern tropical south Indian Ocean. The year 2003 is an example of a rainy spring in LPB not directly driven by remote SST forcing. In this case the internal variability has a dominant role, as the model is not able to reproduce the correct local precipitation pattern. © 2013 Springer-Verlag Berlin Heidelberg. Fil:Carril, A.F. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Menéndez, C.G. 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_v42_n1-2_p219_Cherchi
institution	Universidad de Buenos Aires
institution_str	I-28
repository_str	R-134
collection	Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic	air-sea interaction atmosphere-ocean coupling atmospheric forcing El Nino-Southern Oscillation general circulation model precipitation (climatology) sea surface temperature spring (season) teleconnection Atlantic Ocean Atlantic Ocean (South) La Plata Basin
spellingShingle	air-sea interaction atmosphere-ocean coupling atmospheric forcing El Nino-Southern Oscillation general circulation model precipitation (climatology) sea surface temperature spring (season) teleconnection Atlantic Ocean Atlantic Ocean (South) La Plata Basin Cherchi, A. Carril, A.F. Menéndez, C.G. Zamboni, L. La Plata basin precipitation variability in spring: Role of remote SST forcing as simulated by GCM experiments
topic_facet	air-sea interaction atmosphere-ocean coupling atmospheric forcing El Nino-Southern Oscillation general circulation model precipitation (climatology) sea surface temperature spring (season) teleconnection Atlantic Ocean Atlantic Ocean (South) La Plata Basin
description	An ensemble of nine experiments with the same interannually varying sea surface temperature (SST), as boundary forcing, and different initial conditions is used to investigate the role of tropical oceans in modulating precipitation variability in the region of La Plata Basin (LPB). The results from the ensemble are compared with a twentieth-century experiment performed with a coupled ocean-atmosphere model, sharing the same atmospheric component. A rotated empirical orthogonal functions analysis of South America precipitation shows that the dominant mode of variability in spring is realistically captured in both experiments. Its principal component (RPC1) correlated with global SST and atmospheric fields identifies the pattern related to El Niño Southern Oscillation and its large-scale teleconnections. Overall the pattern is well simulated in the tropical southern Pacific Ocean, mainly in the ensemble, but it is absent or too weak in other oceanic areas. The coupled model experiment shows a more realistic correlation in the subtropical South Atlantic where air-sea interactions contribute to the relationship between LPB precipitation and SST. The correspondence between model and data is much improved when the composite analysis of SST and atmospheric fields is done over the ensemble members having an RPC1 in agreement with the observations: the improvement relies on avoiding climate noise by averaging only over members that are statistically similar. Furthermore, the result suggests the presence of a high level of uncertainty due to internal atmospheric variability. The analysis of some individual years selected from the model and data RPC1 comparison reveals interesting differences among rainy springs in LPB. For example, 1982, which corresponds to a strong El Niño year, represents a clean case with a distinct wave train propagating from the central Pacific and merging with another one from the eastern tropical south Indian Ocean. The year 2003 is an example of a rainy spring in LPB not directly driven by remote SST forcing. In this case the internal variability has a dominant role, as the model is not able to reproduce the correct local precipitation pattern. © 2013 Springer-Verlag Berlin Heidelberg.
format	JOUR
author	Cherchi, A. Carril, A.F. Menéndez, C.G. Zamboni, L.
author_facet	Cherchi, A. Carril, A.F. Menéndez, C.G. Zamboni, L.
author_sort	Cherchi, A.
title	La Plata basin precipitation variability in spring: Role of remote SST forcing as simulated by GCM experiments
title_short	La Plata basin precipitation variability in spring: Role of remote SST forcing as simulated by GCM experiments
title_full	La Plata basin precipitation variability in spring: Role of remote SST forcing as simulated by GCM experiments
title_fullStr	La Plata basin precipitation variability in spring: Role of remote SST forcing as simulated by GCM experiments
title_full_unstemmed	La Plata basin precipitation variability in spring: Role of remote SST forcing as simulated by GCM experiments
title_sort	la plata basin precipitation variability in spring: role of remote sst forcing as simulated by gcm experiments
url	http://hdl.handle.net/20.500.12110/paper_09307575_v42_n1-2_p219_Cherchi
work_keys_str_mv	AT cherchia laplatabasinprecipitationvariabilityinspringroleofremotesstforcingassimulatedbygcmexperiments AT carrilaf laplatabasinprecipitationvariabilityinspringroleofremotesstforcingassimulatedbygcmexperiments AT menendezcg laplatabasinprecipitationvariabilityinspringroleofremotesstforcingassimulatedbygcmexperiments AT zambonil laplatabasinprecipitationvariabilityinspringroleofremotesstforcingassimulatedbygcmexperiments
_version_	1807316497197957120

La Plata basin precipitation variability in spring: Role of remote SST forcing as simulated by GCM experiments

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