Sea surface temperature anomalies near South Georgia: Relationships with the Pacific El Niño regions

2002 ◽  
Vol 108 (C4) ◽  
Author(s):  
P. N. Trathan ◽  
E. J. Murphy
Keyword(s):  
Surface Temperature ◽  
Sea Surface Temperature ◽  
El Niño ◽  
El Nino ◽  
Sea Surface ◽  
South Georgia ◽  
Temperature Anomalies ◽  
The Pacific ◽  
Sea Surface Temperature Anomalies

scholarly journals Modelled Rainfall Response to Strong El Niño Sea Surface Temperature Anomalies in the Tropical Pacific

2015 ◽  
Vol 28 (8) ◽  
pp. 3133-3151 ◽  
Author(s):  
Christine T. Y. Chung ◽  
Scott B. Power
Keyword(s):  
Surface Temperature ◽  
Sea Surface Temperature ◽  
El Niño ◽  
El Nino ◽  
Tropical Pacific ◽  
Sea Surface ◽  
Precipitation Pattern ◽  
Convergence Zone ◽  
The Pacific ◽  
Sea Surface Temperature Anomalies

Abstract El Niño–Southern Oscillation strongly influences the interannual variability of rainfall over the Pacific, shifting the position and orientation of the South Pacific convergence zone (SPCZ) and intertropical convergence zone (ITCZ). In 1982/83 and 1997/98, very strong El Niño events occurred, during which time the SPCZ and ITCZ merged into a single zonal convergence zone (szCZ) extending across the Pacific at approximately 5°S. The sea surface temperature anomalies (SSTAs) reached very large values and peaked farther east compared to other El Niño events. Previous work shows that tropical Pacific precipitation responds nonlinearly to changing the amplitude of the El Niño SSTA even if the structure of the SSTA remains unchanged, but large canonical El Niño SSTAs cannot reproduce the szCZ precipitation pattern. This study conducts idealized, SST-forced experiments, starting with a large-amplitude canonical El Niño SSTA and gradually adding a residual pattern until the full (1982/83) and (1997/98) mean SST is reproduced. Differences between the canonical and strong El Niño SSTA patterns are crucial in generating an szCZ event. Three elements influence the precipitation pattern: (i) the local meridional SST maxima influences the ITCZ position and western Pacific precipitation, (ii) the total zonal SST maximum influences the SPCZ position, and (iii) the equatorial Pacific SST influences the total amount of precipitation. In these experiments, the meridional SST gradient increases as the SSTAs approach szCZ conditions. Additionally, the precipitation changes evident in szCZ years are primarily driven by changes in the atmospheric circulation, rather than thermodynamic changes. The addition of a global warming SST pattern increases the precipitation along the equator and shifts the ITCZ farther equatorward.

scholarly journals Influência dos Diferentes Tipos do Fenômeno El Niño na Precipitação da América do Sul

2021 ◽  
Vol 14 (2) ◽  
pp. 729
Author(s):  
Michelle Simões Reboita ◽  
Kelvem Rodrigo De Oliveira ◽  
Pedro Ygor Carvalho Corrêa ◽  
Renan Rodrigues
Keyword(s):  
South America ◽  
Surface Temperature ◽  
Sea Surface Temperature ◽  
El Niño ◽  
El Nino ◽  
Sea Surface ◽  
Temperature Anomalies ◽  
The North ◽  
Different Types ◽  
Sea Surface Temperature Anomalies

Nesse estudo foi aplicada uma metodologia de classificação dos eventos de El Niño em seus diferentes tipos (Central, Leste e, quando ambos ocorrem concomitantemente, MIX) no período de janeiro de 1950 a março de 2019. Além disso, os tipos de El Niño foram separados por estação do ano e considerando as diferentes condições de anomalias de temperatura da superfície do mar no oceano Atlântico Tropical Sul (neutras quando ocorrem anomalias de temperatura entre -0,5º e 0,5ºC; quentes quando as anomalias são superiores a 0,5ºC e frias quando as anomalias são inferiores a -0,5ºC). Com base nas combinações de ocorrência de cada tipo de EN e anomalias de temperatura da superfície do mar no Atlântico Tropical Sul, foram determinadas as anomalias de precipitação na América do Sul. Os diferentes tipos de El Niño são mais frequentes quando há condições neutras no Atlântico Tropical Sul. Com relação às anomalias de precipitação na América do Sul, os eventos de El Niño Leste e MIX, em geral, mostram padrão similar na distribuição espacial das anomalias, mas com os eventos MIX mostrando sinal mais fraco. As anomalias de temperatura da superfície do mar no Atlântico Tropical Sul quando negativas ajudam a fortalecer as condições secas entre o norte das regiões norte e nordeste do Brasil propiciadas pelos eventos de El Niño.  Influence of the Different Types of El Niño in the Precipitation over South America  A B S T R A C TIn this study, a specific methodology was applied to classify El Niño events into their different types (Central, East and when both occur at the same time, MIX) from January 1950 to March 2019. In addition, the types of El Niño were separated by season and considering the conditions of sea surface temperature anomalies on the South Tropical Atlantic Ocean (neutrality: temperature anomalies between -0.5º and 0.5ºC, warm: anomalies above 0.5ºC and cold:  anomalies below -0.5ºC). Based on in the combination of different types of El Niño and sea surface temperature anomalies on the South Atlantic Tropical Ocean, precipitation anomalies over South America were computed. The different types El Niño occur, in general, under neutral conditions on the Atlantic Ocean. The events of El Niño - East and MIX, in general, present a similar pattern in the spatial distribution of the precipitation anomalies over South America, but with the MIX events showing weaker signal. Sea surface temperature anomalies in the Tropical South Atlantic when negative, they help to strengthen the dry conditions between the north of the north and northeast regions of Brazil caused by the El Niño events.Keywords: atmospheric circulation, anomaly conditions, tropical oceans, climate

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