Relationships between autumn precipitation anomalies in southeastern South America and El Niño event classification
The classification of El Niño events was performed based on the time evolution of sea surface warming in the tropical Pacific Ocean during the period 1950-2000. Two sets of events were constructed: one in which the warming core migrates eastward along the tropical Pacific until April-June of the fol...
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paper:paper_08998418_v29_n5_p719_Antico2023-06-08T15:49:40Z Relationships between autumn precipitation anomalies in southeastern South America and El Niño event classification Antico, Pablo Luis El Niño Precipitation South America Tropical Pacific Ocean Autumn precipitation Circulation anomalies Cyclonic vorticity Event classification Heavy precipitation Low frequency Pacific decadal oscillation Precipitation Precipitation anomalies Sea surfaces South America Southeastern South America Subtropical jet Time evolutions Tropical Pacific Ocean Advection Moisture Nickel compounds Ocean engineering Tokamak devices Tropics Vorticity Oceanography advection atmospheric circulation autumn climate classification El Nino jet Pacific Decadal Oscillation precipitation (climatology) relative humidity sea surface vorticity warming Pacific Ocean Pacific Ocean (Tropical) South America The classification of El Niño events was performed based on the time evolution of sea surface warming in the tropical Pacific Ocean during the period 1950-2000. Two sets of events were constructed: one in which the warming core migrates eastward along the tropical Pacific until April-June of the following year, and another one in which it evolves westward until November-January. The first type has associated positive precipitation anomalies over southeastern South America during April-June. It results from a favourable combination of cyclonic vorticity advection and humidity convergence. At high levels, cyclonic vorticity advection is explained in terms of an eastward extension of the subtropical jet. Enhanced humidity advection takes place by an increased low-level northwesterly flow to the east of the Andes. It provides enough moisture availability that, in combination with the upper-level cyclonic vorticity advection, supports heavy precipitation during April-June. The second type of event exhibits slight negative or near-normal precipitation anomalies over the same region. Both low and high-level circulation anomalies are also weaker in this case. The 1997-1998 El Niño is analysed separately because it cannot be classified into any of the previously described event types. The observed distribution of both types of events along the analysed period changes after the 1970s. Comparison with other authors' results suggests the influence of low-frequency processes such as the Pacific Decadal Oscillation (PDO). Copyright © 2008 Royal Meteorological Society. Fil:Antico, P.L. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. 2009 https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_08998418_v29_n5_p719_Antico http://hdl.handle.net/20.500.12110/paper_08998418_v29_n5_p719_Antico |
| institution |
Universidad de Buenos Aires |
| institution_str |
I-28 |
| repository_str |
R-134 |
| collection |
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) |
| topic |
El Niño Precipitation South America Tropical Pacific Ocean Autumn precipitation Circulation anomalies Cyclonic vorticity Event classification Heavy precipitation Low frequency Pacific decadal oscillation Precipitation Precipitation anomalies Sea surfaces South America Southeastern South America Subtropical jet Time evolutions Tropical Pacific Ocean Advection Moisture Nickel compounds Ocean engineering Tokamak devices Tropics Vorticity Oceanography advection atmospheric circulation autumn climate classification El Nino jet Pacific Decadal Oscillation precipitation (climatology) relative humidity sea surface vorticity warming Pacific Ocean Pacific Ocean (Tropical) South America |
| spellingShingle |
El Niño Precipitation South America Tropical Pacific Ocean Autumn precipitation Circulation anomalies Cyclonic vorticity Event classification Heavy precipitation Low frequency Pacific decadal oscillation Precipitation Precipitation anomalies Sea surfaces South America Southeastern South America Subtropical jet Time evolutions Tropical Pacific Ocean Advection Moisture Nickel compounds Ocean engineering Tokamak devices Tropics Vorticity Oceanography advection atmospheric circulation autumn climate classification El Nino jet Pacific Decadal Oscillation precipitation (climatology) relative humidity sea surface vorticity warming Pacific Ocean Pacific Ocean (Tropical) South America Antico, Pablo Luis Relationships between autumn precipitation anomalies in southeastern South America and El Niño event classification |
| topic_facet |
El Niño Precipitation South America Tropical Pacific Ocean Autumn precipitation Circulation anomalies Cyclonic vorticity Event classification Heavy precipitation Low frequency Pacific decadal oscillation Precipitation Precipitation anomalies Sea surfaces South America Southeastern South America Subtropical jet Time evolutions Tropical Pacific Ocean Advection Moisture Nickel compounds Ocean engineering Tokamak devices Tropics Vorticity Oceanography advection atmospheric circulation autumn climate classification El Nino jet Pacific Decadal Oscillation precipitation (climatology) relative humidity sea surface vorticity warming Pacific Ocean Pacific Ocean (Tropical) South America |
| description |
The classification of El Niño events was performed based on the time evolution of sea surface warming in the tropical Pacific Ocean during the period 1950-2000. Two sets of events were constructed: one in which the warming core migrates eastward along the tropical Pacific until April-June of the following year, and another one in which it evolves westward until November-January. The first type has associated positive precipitation anomalies over southeastern South America during April-June. It results from a favourable combination of cyclonic vorticity advection and humidity convergence. At high levels, cyclonic vorticity advection is explained in terms of an eastward extension of the subtropical jet. Enhanced humidity advection takes place by an increased low-level northwesterly flow to the east of the Andes. It provides enough moisture availability that, in combination with the upper-level cyclonic vorticity advection, supports heavy precipitation during April-June. The second type of event exhibits slight negative or near-normal precipitation anomalies over the same region. Both low and high-level circulation anomalies are also weaker in this case. The 1997-1998 El Niño is analysed separately because it cannot be classified into any of the previously described event types. The observed distribution of both types of events along the analysed period changes after the 1970s. Comparison with other authors' results suggests the influence of low-frequency processes such as the Pacific Decadal Oscillation (PDO). Copyright © 2008 Royal Meteorological Society. |
| author |
Antico, Pablo Luis |
| author_facet |
Antico, Pablo Luis |
| author_sort |
Antico, Pablo Luis |
| title |
Relationships between autumn precipitation anomalies in southeastern South America and El Niño event classification |
| title_short |
Relationships between autumn precipitation anomalies in southeastern South America and El Niño event classification |
| title_full |
Relationships between autumn precipitation anomalies in southeastern South America and El Niño event classification |
| title_fullStr |
Relationships between autumn precipitation anomalies in southeastern South America and El Niño event classification |
| title_full_unstemmed |
Relationships between autumn precipitation anomalies in southeastern South America and El Niño event classification |
| title_sort |
relationships between autumn precipitation anomalies in southeastern south america and el niño event classification |
| publishDate |
2009 |
| url |
https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_08998418_v29_n5_p719_Antico http://hdl.handle.net/20.500.12110/paper_08998418_v29_n5_p719_Antico |
| work_keys_str_mv |
AT anticopabloluis relationshipsbetweenautumnprecipitationanomaliesinsoutheasternsouthamericaandelninoeventclassification |
| _version_ |
1768542419605782528 |