An Overview of the El Niño, La Niña,
and the Southern Oscillation Phenomena:
Theory, Observations, and Modeling
Links
Léo Siqueira, Enver Ramírez, and Rosio Camayo
1 Overview
The term El Niño, La Niña, and the Southern Oscillation, collectively ENSO, refers
to the large-scale ocean–atmosphere phenomenon linked to an occasional warming
(cooling) during El Niño (La Niña) in sea-surface temperatures (SST) across the
central and east-central equatorial Pacific (Fig. 1). It directly affects the equatorial
central and eastern Pacific region with signatures in and over the western Pacific and
Indian Ocean [31]. However, impacts of ENSO are experienced on a global scale [4,
45] through remote connections (teleconnections) with prominent implications over
diverse human activities, like energy generation, agriculture, infrastructure, public
health, transport, among others [31, 33, 35]. A typical pattern for El Niño (La Niña)
consists in an abnormal warming (cooling) of the SST along the coast of Peru which
is extended westward and forms an anomalous warm (cold) tongue shown in Fig. 1.
During an El Niño (La Niña) episode, changes in the oceanic heat content of
upper layers is also observed with a shallowing (deepening) to the west and a
deepening (shallowing) to the east. Regarding its temporal characteristics, ENSO
is a naturally occurring phenomenon and displays irregular interannual variations
(Fig. 3), with peak power between 3 and 7 years in SST, as highlighted in Fig. 2.
However, its variability can also be found in other variables, e.g., sea level
height, convective rainfall, surface air pressure, and atmospheric circulation. In
the atmosphere, El Niño (La Niña) episodes are associated with the anomalous
L. Siqueira
University of Miami, Rosenstiel School for Marine and Atmospheric Science, Miami, FL, USA
e-mail: lsiqueira@miami.edu
E. Ramírez () · R. Camayo
Center for Weather Forecasting and Climate Studies, National Institute for Space Research,
São Paulo, Brazil
e-mail: enver.ramirez@inpe.br; rosio.camayo@inpe.br
© Springer Nature Switzerland AG 2019
L. Bacelar Lima Santos et al. (eds.), Towards Mathematics, Computers and Environment:
A Disasters Perspective, https://doi.org/10.1007/978-3-030-21205-6_1
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