The nature of the rainfall onset over central South America
The objective of this work is to provide a detailed description of the onset of the South American Monsoon based on precipitation observations available over tropical and subtropical South America. The analysis was also performed using outgoing longwave radiation (OLR) data in order to assess the ab...
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2007
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| Acceso en línea: | https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_01876236_v20_n4_p377_Gonzalez http://hdl.handle.net/20.500.12110/paper_01876236_v20_n4_p377_Gonzalez |
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paper:paper_01876236_v20_n4_p377_Gonzalez2023-06-08T15:19:42Z The nature of the rainfall onset over central South America Onset Rainfall South America Summer monsoon Tropical climate atmospheric convection climate conditions longwave radiation monsoon observational method precipitation assessment rainfall regional climate summer tropical meteorology Brazil South America The objective of this work is to provide a detailed description of the onset of the South American Monsoon based on precipitation observations available over tropical and subtropical South America. The analysis was also performed using outgoing longwave radiation (OLR) data in order to assess the ability of this particular dataset to reproduce the main features associated with precipitation evolution during austral spring. Results show that both OLR and precipitation data agree in describing the progression of convection from the northwest and southeast into central Brazil by the beginning of October. Moreover the assessment of available methods to identify onset dates shows that the method of Kousky (1988), based on the OLR evolution, provides the onset date in most of South America, without regionally adaptation, as the methods based on rainfall generally require. Composite fields show that rainfall in central Brazil begins with moderate rates, which are still lower than those observed over the northwestern and southeastern tropical regions. After the rainfall jump, that on average occurs three pentads later than the onset of rainfall, precipitation rates increase over central Brazil and similar rates are observed over the entire tropical region. It is suggested that transient activity, which occurs around the onset period when the atmospheric mean conditions are getting more unstable as they approach summer-like conditions, is the one that imprints a rainfall-jump feature in the precipitation evolution. The character of changes in the precipitation rate, as the rainy season develops, provides complementary information that can be used together with onset date. 2007 https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_01876236_v20_n4_p377_Gonzalez http://hdl.handle.net/20.500.12110/paper_01876236_v20_n4_p377_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 |
Onset Rainfall South America Summer monsoon Tropical climate atmospheric convection climate conditions longwave radiation monsoon observational method precipitation assessment rainfall regional climate summer tropical meteorology Brazil South America |
| spellingShingle |
Onset Rainfall South America Summer monsoon Tropical climate atmospheric convection climate conditions longwave radiation monsoon observational method precipitation assessment rainfall regional climate summer tropical meteorology Brazil South America The nature of the rainfall onset over central South America |
| topic_facet |
Onset Rainfall South America Summer monsoon Tropical climate atmospheric convection climate conditions longwave radiation monsoon observational method precipitation assessment rainfall regional climate summer tropical meteorology Brazil South America |
| description |
The objective of this work is to provide a detailed description of the onset of the South American Monsoon based on precipitation observations available over tropical and subtropical South America. The analysis was also performed using outgoing longwave radiation (OLR) data in order to assess the ability of this particular dataset to reproduce the main features associated with precipitation evolution during austral spring. Results show that both OLR and precipitation data agree in describing the progression of convection from the northwest and southeast into central Brazil by the beginning of October. Moreover the assessment of available methods to identify onset dates shows that the method of Kousky (1988), based on the OLR evolution, provides the onset date in most of South America, without regionally adaptation, as the methods based on rainfall generally require. Composite fields show that rainfall in central Brazil begins with moderate rates, which are still lower than those observed over the northwestern and southeastern tropical regions. After the rainfall jump, that on average occurs three pentads later than the onset of rainfall, precipitation rates increase over central Brazil and similar rates are observed over the entire tropical region. It is suggested that transient activity, which occurs around the onset period when the atmospheric mean conditions are getting more unstable as they approach summer-like conditions, is the one that imprints a rainfall-jump feature in the precipitation evolution. The character of changes in the precipitation rate, as the rainy season develops, provides complementary information that can be used together with onset date. |
| title |
The nature of the rainfall onset over central South America |
| title_short |
The nature of the rainfall onset over central South America |
| title_full |
The nature of the rainfall onset over central South America |
| title_fullStr |
The nature of the rainfall onset over central South America |
| title_full_unstemmed |
The nature of the rainfall onset over central South America |
| title_sort |
nature of the rainfall onset over central south america |
| publishDate |
2007 |
| url |
https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_01876236_v20_n4_p377_Gonzalez http://hdl.handle.net/20.500.12110/paper_01876236_v20_n4_p377_Gonzalez |
| _version_ |
1768545923434020864 |