Intraseasonal variability in subtropical South America as depicted by precipitation data

Daily precipitation data from three stations in subtropical Argentina are used to describe intraseasonal variability (20-90 days) during the austral summer. This variability is compared locally and regionally with that present in outgoing longwave radiation (OLR) data, in order to evaluate the perfo...

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Autores principales: González, Paula L. M., Vera, Carolina Susana
Publicado: 2008
Materias:
Convection
Intraseasonal variability
Precipitation
South America
Warm season
atmospheric circulation
atmospheric convection
climate forcing
correlation
El Nino-Southern Oscillation
precipitation (climatology)
Rossby wave
seasonal variation
spatial variation
summer
variance analysis
Pacific Ocean
Acceso en línea:https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_09307575_v30_n7-8_p727_Gonzalez
http://hdl.handle.net/20.500.12110/paper_09307575_v30_n7-8_p727_Gonzalez
Aporte de:
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires
id paper:paper_09307575_v30_n7-8_p727_Gonzalez
record_format dspace
spelling paper:paper_09307575_v30_n7-8_p727_Gonzalez2023-06-08T15:52:38Z Intraseasonal variability in subtropical South America as depicted by precipitation data González, Paula L. M. Vera, Carolina Susana Convection Intraseasonal variability Precipitation South America Warm season atmospheric circulation atmospheric convection climate forcing correlation El Nino-Southern Oscillation precipitation (climatology) Rossby wave seasonal variation spatial variation summer variance analysis Pacific Ocean South America Daily precipitation data from three stations in subtropical Argentina are used to describe intraseasonal variability (20-90 days) during the austral summer. This variability is compared locally and regionally with that present in outgoing longwave radiation (OLR) data, in order to evaluate the performance of this variable as a proxy for convection in the region. The influence of the intraseasonal activity of the South American Seesaw (SASS) leading convection pattern on precipitation is also explored. Results show that intraseasonal variability explains a significant portion of summer precipitation variance, with a clear maximum in the vicinity of the SASS subtropical center. Correlation analysis reveals that OLR can explain only a small portion of daily precipitation variability, implying that it does not constitute a proper proxy for precipitation on daily timescales. On intraseasonal timescales, though, OLR is able to reproduce the main features of precipitation variability. The dynamical conditions that promote the development of intraseasonal variability in the region are further analyzed for selected summers. Seasons associated with a strong intraseasonal signal in precipitation variability show distinctive wet/dry intraseasonal periods in daily raw data, and are associated with a well defined SASS-like spatial pattern of convection. During these summers, strong large-scale forcing (such as warm El Niño/Southern Oscillation (ENSO) events and/or tropical intraseasonal convective activity), and Rossby-wave-like circulation anomalies extending across the Pacific Ocean, are also observed. © Springer-Verlag 2007. Fil:González, P.L.M. 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. 2008 https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_09307575_v30_n7-8_p727_Gonzalez http://hdl.handle.net/20.500.12110/paper_09307575_v30_n7-8_p727_Gonzalez
institution Universidad de Buenos Aires
institution_str I-28
repository_str R-134
collection Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic Convection
Intraseasonal variability
Precipitation
South America
Warm season
atmospheric circulation
atmospheric convection
climate forcing
correlation
El Nino-Southern Oscillation
precipitation (climatology)
Rossby wave
seasonal variation
spatial variation
summer
variance analysis
Pacific Ocean
South America
spellingShingle Convection
Intraseasonal variability
Precipitation
South America
Warm season
atmospheric circulation
atmospheric convection
climate forcing
correlation
El Nino-Southern Oscillation
precipitation (climatology)
Rossby wave
seasonal variation
spatial variation
summer
variance analysis
Pacific Ocean
South America
González, Paula L. M.
Vera, Carolina Susana
Intraseasonal variability in subtropical South America as depicted by precipitation data
topic_facet Convection
Intraseasonal variability
Precipitation
South America
Warm season
atmospheric circulation
atmospheric convection
climate forcing
correlation
El Nino-Southern Oscillation
precipitation (climatology)
Rossby wave
seasonal variation
spatial variation
summer
variance analysis
Pacific Ocean
South America
description Daily precipitation data from three stations in subtropical Argentina are used to describe intraseasonal variability (20-90 days) during the austral summer. This variability is compared locally and regionally with that present in outgoing longwave radiation (OLR) data, in order to evaluate the performance of this variable as a proxy for convection in the region. The influence of the intraseasonal activity of the South American Seesaw (SASS) leading convection pattern on precipitation is also explored. Results show that intraseasonal variability explains a significant portion of summer precipitation variance, with a clear maximum in the vicinity of the SASS subtropical center. Correlation analysis reveals that OLR can explain only a small portion of daily precipitation variability, implying that it does not constitute a proper proxy for precipitation on daily timescales. On intraseasonal timescales, though, OLR is able to reproduce the main features of precipitation variability. The dynamical conditions that promote the development of intraseasonal variability in the region are further analyzed for selected summers. Seasons associated with a strong intraseasonal signal in precipitation variability show distinctive wet/dry intraseasonal periods in daily raw data, and are associated with a well defined SASS-like spatial pattern of convection. During these summers, strong large-scale forcing (such as warm El Niño/Southern Oscillation (ENSO) events and/or tropical intraseasonal convective activity), and Rossby-wave-like circulation anomalies extending across the Pacific Ocean, are also observed. © Springer-Verlag 2007.
author González, Paula L. M.
Vera, Carolina Susana
author_facet González, Paula L. M.
Vera, Carolina Susana
author_sort González, Paula L. M.
title Intraseasonal variability in subtropical South America as depicted by precipitation data
title_short Intraseasonal variability in subtropical South America as depicted by precipitation data
title_full Intraseasonal variability in subtropical South America as depicted by precipitation data
title_fullStr Intraseasonal variability in subtropical South America as depicted by precipitation data
title_full_unstemmed Intraseasonal variability in subtropical South America as depicted by precipitation data
title_sort intraseasonal variability in subtropical south america as depicted by precipitation data
publishDate 2008
url https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_09307575_v30_n7-8_p727_Gonzalez
http://hdl.handle.net/20.500.12110/paper_09307575_v30_n7-8_p727_Gonzalez
work_keys_str_mv AT gonzalezpaulalm intraseasonalvariabilityinsubtropicalsouthamericaasdepictedbyprecipitationdata
AT veracarolinasusana intraseasonalvariabilityinsubtropicalsouthamericaasdepictedbyprecipitationdata
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