Details:

Journal Title:
Climate Dynamics
Personal Author:
Hu, Zeng-Zhen ; Huang, Bohua ; Zhu, Jieshun ; Kumar, Arun ; McPhaden, Michael J.
Hu, Zeng-Zhen ; Huang, Bohua ; Zhu, Jieshun ; Kumar, Arun ; McPhaden, Michael J. Less -
NOAA Program & Office:
OAR (Oceanic and Atmospheric Research) ; PMEL (Pacific Marine Environmental Laboratory) ; NWS (National Weather Service) ; NCEP (National Centers for Environmental Prediction)
OAR (Oceanic and Atmospheric Research) ; PMEL (Pacific Marine Environmental Laboratory) ; NWS (National Weather Service) ; NCEP (National Centers for Environmental Prediction) Less -
Description:
We examine the connection between interannual anomalies of sea surface temperature (SST) in the central and far-eastern equatorial Pacific associated with basin-scale and coastal El Niños. Variations of the SST anomalies in these two regions are largely coherent, meaning coastal El Niños mostly occur together with the commonly studied basin-scale El Niños. Of particular interest for this study though is the understanding of the coastal El Niños that are not accompanied by basin-scale El Niños or that follow basin-scale El Niños. Such coastal El Niños can have catastrophic societal consequences in western South America. We identify seven coastal El Niños during 1979–2017, namely 1983, 1987, 1998, 2008, 2014, 2015, and 2017. These coastal El Niños are driven by different mechanisms. The coastal El Niños in 1983, 1987 and 1998 occurred after basin-scale El Niños. A unique feature of such extreme basin-scale El Niños like in 1982–1983, 1986–1987, and 1997–1998 is an equatorially centered intertropical convergence zone during its decaying phase. As a result, positive SST anomalies persist, and sometimes even strengthen, in the eastern Pacific in the subsequent boreal spring/early-summer, leading to coastal El Niños. The coastal El Niños in 2014 and 2015 on the other hand resulted from westerly wind bursts in the western Pacific that forced downwelling Kelvin waves and a thermocline depression in the far eastern Pacific. The formation of coastal El Niños in 2008 and 2017 were associated with westerly surface wind anomalies in the eastern equatorial Pacific and largely driven by ocean surface heat flux anomalies. These two coastal El Niños occur during the warm phase of the seasonal cycle, so that warm SSTs are amplified and/or the warm season is extended along the west coast of South America. Thus, there is a wide variety of the coastal El Niños in terms of evolution, mechanism, and timing. 1 Introduction El Niño–Southern Oscillation (ENSO) originates in the trop-ical Pacific and is the strongest year-to-year fluctuation of the climate system on the earth. It is also the largest source of predictability in global climate on seasonal-to-interannual time scales (National Research Council 2010 ). Originally, El Niño was referred to as anomalous warming along the Peru-Ecuador coast every few years, which sometimes resulted in catastrophic rain and adverse impacts on regional ecology (see the review by Wyrtki 1975). Only later was it recog-nized that most El Niños (the warm phase of ENSO) and La Niñas (the cold phase of ENSO) are Pacific basin-wide phenomena associated with broad scale  ocean-atmosphere interactions that have significant global climate impacts (Rasmusson and Carpenter 1982; Deser and Wallace 1987; Davey et al. 2014; McPhaden et al. 2006). Rasmusson and Carpenter (1982) found that the sea sur - face temperature (SST) warming near the South America coast usually preceded that in the central equatorial Pacific during the El Niños from the 1950 to 1970s so that coastal
Keywords:
[+]
Atmospheric Science
Source:
Climate Dynamics, 52(12), 7537-7552
DOI:
https://doi.org/10.1007/s00382-018-4290-4
ISSN:
0930-7575;1432-0894;
Format:
PDF
Publisher:
Springer Science and Business Media LLC
Document Type:
Journal Article
Funding:
Grant no. NA14OAR4310160 ; Grant no. NA17OAR4310144
Grant no. NA14OAR4310160 ; Grant no. NA17OAR4310144 Less -
License:
https://creativecommons.org/publicdomain/zero/1.0/
Rights Information:
CC0 Public Domain
Rights Statement:
This is a U.S. government work and its text is not subject to copyright protection in the United States; however, its text may be subject to foreign copyright protection
Compliance:
Library
Main Document Checksum:
[+]
urn:sha256:2689171b9375df60ebbcb719ef210e2324a97abd3247bcd2f313ddb58eb8f3ee
Download URL:
https://repository.library.noaa.gov/view/noaa/53507/noaa_53507_DS1.pdf
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