The unique 2009-2010 El Niño event: A fast phase transition of warm pool El Niño to La Niña

2011 ◽  
Vol 38 (15) ◽  
Author(s):  
WonMoo Kim ◽  
Sang-Wook Yeh ◽  
Joo-Hong Kim ◽  
Jong-Seong Kug ◽  
MinHo Kwon
Keyword(s):  
Phase Transition ◽  
El Niño ◽  
El Nino ◽  
Warm Pool ◽  
La Niña ◽  
Fast Phase ◽  
El Niño Event ◽  
La Nina

Successive marine heatwaves cause disproportionate coral bleaching during a fast phase transition from El Niño to La Niña

2020 ◽  
Vol 715 ◽  
pp. 136951 ◽  
Author(s):  
Steven J. Dalton ◽  
Andrew G. Carroll ◽  
Eugenia Sampayo ◽  
George Roff ◽  
Peter L. Harrison ◽  
...  
Keyword(s):  
Phase Transition ◽  
Coral Bleaching ◽  
El Niño ◽  
El Nino ◽  
La Niña ◽  
Fast Phase ◽  
La Nina

How Many ENSO Flavors Can We Distinguish?*

2013 ◽  
Vol 26 (13) ◽  
pp. 4816-4827 ◽  
Author(s):  
Nathaniel C. Johnson
Keyword(s):  
El Niño ◽  
El Nino ◽  
Warm Pool ◽  
Tropical Pacific ◽  
La Niña ◽  
Western Pacific ◽  
Western Pacific Warm Pool ◽  
La Nina ◽  
Pacific Warm Pool ◽  
Sst Anomalies

Abstract It is now widely recognized that El Niño–Southern Oscillation (ENSO) occurs in more than one form, with the canonical eastern Pacific (EP) and more recently recognized central Pacific (CP) ENSO types receiving the most focus. Given that these various ENSO “flavors” may contribute to climate variability and long-term trends in unique ways, and that ENSO variability is not limited to these two types, this study presents a framework that treats ENSO as a continuum but determines a finite maximum number of statistically distinguishable representative ENSO patterns. A neural network–based cluster analysis called self-organizing map (SOM) analysis paired with a statistical distinguishability test determines nine unique patterns that characterize the September–February tropical Pacific SST anomaly fields for the period from 1950 through 2011. These nine patterns represent the flavors of ENSO, which include EP, CP, and mixed ENSO patterns. Over the 1950–2011 period, the most significant trends reflect changes in La Niña patterns, with a shift in dominance of La Niña–like patterns with weak or negative western Pacific warm pool SST anomalies until the mid-1970s, followed by a dominance of La Niña–like patterns with positive western Pacific warm pool SST anomalies, particularly after the mid-1990s. Both an EP and especially a CP El Niño pattern experienced positive frequency trends, but these trends are indistinguishable from natural variability. Overall, changes in frequency within the ENSO continuum contributed to the pattern of tropical Pacific warming, particularly in the equatorial eastern Pacific and especially in relation to changes of La Niña–like rather than El Niño–like patterns.

scholarly journals On the Physics of the Warm Water Volume and El Niño/La Niña Predictability

2019 ◽  
Vol 49 (6) ◽  
pp. 1541-1560 ◽  
Author(s):  
Allan J. Clarke ◽  
Xiaolin Zhang
Keyword(s):  
El Niño ◽  
El Nino ◽  
Warm Pool ◽  
Equatorial Pacific ◽  
La Niña ◽  
Warm Water ◽  
Water Volume ◽  
La Nina ◽  
Eastern Equatorial Pacific ◽  
Warm Water Volume

AbstractPrevious work has shown that warm water volume (WWV), usually defined as the volume of equatorial Pacific warm water above the 20°C isotherm between 5°S and 5°N, leads El Niño. In contrast to previous discharge–recharge oscillator theory, here it is shown that anomalous zonal flow acceleration right at the equator and the movement of the equatorial warm pool are crucial to understanding WWV–El Niño dynamics and the ability of WWV to predict ENSO. Specifically, after westerly equatorial wind anomalies in a coupled ocean–atmosphere instability push the warm pool eastward during El Niño, the westerly anomalies follow the warmest water south of the equator in the Southern Hemisphere summer in December–February. With the wind forcing that causes El Niño in the eastern Pacific removed, the eastern equatorial Pacific sea level and thermocline anomalies decrease. Through long Rossby wave dynamics this decrease results in an anomalous westward equatorial flow that tends to push the warm pool westward and often results in the generation of a La Niña during March–June. The anomalously negative eastern equatorial Pacific sea level typically does not change as much during La Niña, the negative feedback is not as strong, and El Niños tend to not follow La Niñas the next year. This El Niño/La Niña asymmetry is seen in the WWV/El Niño phase diagram and decreased predictability during “La Niña–like” decades.

scholarly journals Why Do Similar Patterns of Tropical Convection Yield Extratropical Circulation Anomalies of Opposite Sign?

2017 ◽  
Vol 74 (2) ◽  
pp. 487-511 ◽  
Author(s):  
Michael Goss ◽  
Steven B. Feldstein
Keyword(s):  
North America ◽  
El Niño ◽  
North Pacific ◽  
El Nino ◽  
Opposite Sign ◽  
Phase 1 ◽  
Warm Pool ◽  
Tropical Convection ◽  
La Niña ◽  
La Nina

Abstract Tropical precipitation anomalies associated with El Niño and Madden–Julian oscillation (MJO) phase 1 (La Niña and MJO phase 5) are characterized by a tripole, with positive (negative) centers over the Indian Ocean and central Pacific and a negative (positive) center over the warm pool region. However, their midlatitude circulation responses over the North Pacific and North America tend to be of opposite sign. To investigate these differences in the extratropical response to tropical convection, the dynamical core of a climate model is used, with boreal winter climatology as the initial flow. The model is run using the full heating field for the above four cases, and with heating restricted to each of seven small domains located near or over the equator, to investigate which convective anomalies may be responsible for the different extratropical responses. An analogous observational study is also performed. For both studies, it is found that, despite having a similar tropical convective anomaly spatial pattern, the extratropical response to El Niño and MJO phase 1 (La Niña and MJO phase 5) is quite different. Most notably, responses with opposite-signed upper-tropospheric geopotential height anomalies are found over the eastern North Pacific, northwestern North America, and the southeastern United States. The extratropical response for each convective case most closely resembles that for the domain associated with the largest-amplitude precipitation anomaly: the central equatorial Pacific for El Niño and La Niña and the warm pool region for MJO phases 1 and 5.

scholarly journals Percolation Phase Transition of Surface Air Temperature Networks: A new test bed for El Niño/La Niña simulations

2017 ◽  
Vol 7 (1) ◽  
Author(s):  
Lijuan Hua ◽  
Zhenghui Lu ◽  
Naiming Yuan ◽  
Lin Chen ◽  
Yongqiang Yu ◽  
...  
Keyword(s):  
Phase Transition ◽  
Air Temperature ◽  
El Niño ◽  
El Nino ◽  
Surface Air Temperature ◽  
La Niña ◽  
Test Bed ◽  
La Nina

scholarly journals Impacts of Two Types of El Niño and La Niña Events on Typhoon Activity

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Po-Chun Hsu ◽  
Chung-Ru Ho ◽  
Shin-Jye Liang ◽  
Nan-Jung Kuo
Keyword(s):  
Correlation Coefficient ◽  
El Niño ◽  
El Nino ◽  
Warm Pool ◽  
La Niña ◽  
El Niño Modoki ◽  
La Nina ◽  
Pacific Warm Pool ◽  
Highly Correlated ◽  
Hadley Centre

The HadISST (Hadley Centre Sea Ice and Sea Surface Temperature) dataset is used to define the years of El Niño, El Niño Modoki, and La Niña events and to find out the impacts of these events on typhoon activity. The results show that the formation positions of typhoon are farther eastward moving in El Niño years than in La Niña years and much further eastward in El Niño Modoki years. The lifetime and the distance of movement are longer, and the intensity of typhoons is stronger in El Niño and in El Niño Modoki years than in La Niña years. The Accumulated Cyclone Energy of typhoon is highly correlated with the Oceanic Niño Index with a correlation coefficient of 0.79. We also find that the typhoons anomalously decrease during El Niño years but increase during El Niño Modoki years. Besides, there are two types of El Niño Modoki, I and II. The intensity of typhoon in El Niño Modoki I years is stronger than in El Niño Modoki II years. Furthermore, the centroid position of the Western Pacific Warm Pool is strongly related to the area of typhoon formation with a correlation coefficient of 0.95.

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