<p>Here is a nice picture from <a href="http://www.nature.com/nature/journal/v461/n7263/fig_tab/461481a_F2.html" rel="nofollow noreferrer">Ashok &amp; Yamagata (2009)</a>:</p>

<p>It seems like the Kelvin wave is held back for some reason that I am not familiar with. From the figure below it looks analogous to a standing wave vs a freely propagating wave.  Interestingly, some authors argue that the frequency of these events has increased in recent years for anthropogenic reasons. i.e. climate change.</p>

<p><img src="https://i.sstatic.net/7IeD2.jpg" alt=""></p>

<blockquote>
  <p><strong>a</strong>, An El Niño event is produced when the easterly winds weaken; sometimes, in the west, westerlies prevail. This condition is
  categorized by warmer than normal sea surface temperatures (SSTs) in
  the east of the ocean, and is associated with alterations in the
  thermocline and in the atmospheric circulation that make the east
  wetter and the west drier. <strong>b</strong>, An El Niño Modoki event is an
  anomalous condition of a distinctly different kind. The warmest SSTs
  occur in the central Pacific, flanked by colder waters to the east and
  west, and are associated with distinct patterns of atmospheric
  convection. <strong>c</strong>, <strong>d</strong>, The opposite (La Niña) phases of the El Niño
  and El Niño Modoki respectively. Yeh et al.3 argue that the increasing
  frequency of the Modoki condition is due to anthropogenic warming, and
  that these events in the central Pacific will occur more frequently if
  global warming increases.</p>
</blockquote>

<p>The most concise definition i found is:</p>

<blockquote>
  <p>The peak warming of the sea surface temperature anomaly (SSTA) is confined to the  central equatorial Pacific until boreal winter instead of propagating to the east.</p>
</blockquote>

<p>You may already be familiar with this paper, but I found this passage interesting:</p>

<blockquote>
  <p>Because of the obvious distinction from the traditional El Niño
  [Rasmusson and Carpenter, 1982] and even from that defined by NOAA in
  2003, we refer to the SSTA pattern observed in 2004, namely, warming
  in the central Pacific (∼NINO4 region) flanked by colder SSTA to the
  west and east, as an El Niño Modoki (pseudo-El Niño) event; this term
  is now popular in Japan and east Asia. (The word Modoki was introduced
  by T. Yamagata during 2004 while explaining a probable cause behind
  the abnormal summer climatic conditions over Japan. It has been often
  used since then by various Japanese Mass Media. “Modoki” is a
  classical Japanese word which means “similar but different.” A news
  article also appeared in The Japan Times on 24 July 2004 under the
  heading “'Mock El Niño' culprit behind heat wave, floods: Professor,”
  which follows: “The heat wave and floods in various parts of Japan are
  being caused by an El Niño-like phenomenon in the central Pacific
  Ocean, a Japanese researcher said Friday. Toshio Yamagata, a professor
  at the University of Tokyo specializing in climate dynamics, said an
  increase in the sea surface temperature has activated convection
  currents and promoted a high-pressure ridge in the Pacific, bringing a
  hot summer to Japan …”</p>
</blockquote>

<p>(<a href="http://onlinelibrary.wiley.com/doi/10.1029/2006JC003798/full" rel="nofollow noreferrer">Ashok et al. 2007</a>)</p>

CC BY-SA 3.0
2014-11-18T13:13:33.897Z
Great answer but just to nitpick: instead of "Here is a nice picture from Nature:", why not saying "Here is a nice picture from Ashok & Yamagata (2009):"? Same thing for the final quote (Ashok et al. 2007). It's no biggie but i think it's nicer to the authors and in the end more useful to the reader.
plannapus
CC BY-SA 3.0
2014-11-18T18:32:06.820Z
@plannapus Thanks for the suggestion, I have changed it accordingly.
Isopycnal Oscillation
CC BY-SA 3.0
2014-11-18T06:52:44.707Z
2014-12-21T21:42:40.133Z
2014-12-21T21:42:40.133Z
Isopycnal Oscillation
<p>Central Pacific El Niños have different effects than Eastern Pacific El Niños. For example, Modoki El Niño tends to have more hurricanes in Atlantic and Gulf of Mexico regions. Modoki El Niños may have been around going back to the 13th century, possibly before. The El Niño which developed in 2015 is a Modoki version of the phenomenon.</p>

CC BY-SA 3.0
2015-04-18T22:01:01.103Z
2015-04-19T01:48:44.457Z
2015-04-19T01:48:44.457Z
Meg
<p>What are the characteristics that distinguishes a El Niño Modoki from a "normal" El Niño? </p>

<p>What are the effects of El Niño Modoki on atmospheric and oceanic processes? How does it affect weather systems? </p>

<p>What are the mechanisms that determine whether an El Niño event is a normal event or a Modoki event?</p>

CC BY-SA 3.0
2014-11-18T05:57:37.853Z
Thanks @gansub for the comment. I have altered the question accordingly
arkaia
<meteorology><atmosphere><ocean><enso>
What is El Niño Modoki?
arkaia
# What is El Niño Modoki?

(Asked by: username_0 on 2014-11-18)

What are the characteristics that distinguishes a El Niño Modoki from a "normal" El Niño?

What are the effects of El Niño Modoki on atmospheric and oceanic processes? How does it affect weather systems?

What are the mechanisms that determine whether an El Niño event is a normal event or a Modoki event?

**Tags:** meteorology, atmosphere, ocean, enso

> **Comments:**
> **username_0**: Thanks @gansub for the comment. I have altered the question accordingly  

---

## 2 answers

### Answer by username_1 on 2014-11-18. Score: 11

Here is a nice picture from [Ashok & Yamagata (2009)](http://www.nature.com/nature/journal/v461/n7263/fig_tab/461481a_F2.html):

It seems like the Kelvin wave is held back for some reason that I am not familiar with. From the figure below it looks analogous to a standing wave vs a freely propagating wave. Interestingly, some authors argue that the frequency of these events has increased in recent years for anthropogenic reasons. i.e. climate change.

![](https://i.sstatic.net/7IeD2.jpg)

> **a**, An El Niño event is produced when the easterly winds weaken; sometimes, in the west, westerlies prevail. This condition is
> categorized by warmer than normal sea surface temperatures (SSTs) in
> the east of the ocean, and is associated with alterations in the
> thermocline and in the atmospheric circulation that make the east
> wetter and the west drier. **b**, An El Niño Modoki event is an
> anomalous condition of a distinctly different kind. The warmest SSTs
> occur in the central Pacific, flanked by colder waters to the east and
> west, and are associated with distinct patterns of atmospheric
> convection. **c**, **d**, The opposite (La Niña) phases of the El Niño
> and El Niño Modoki respectively. Yeh et al.3 argue that the increasing
> frequency of the Modoki condition is due to anthropogenic warming, and
> that these events in the central Pacific will occur more frequently if
> global warming increases.

The most concise definition i found is:

> The peak warming of the sea surface temperature anomaly (SSTA) is confined to the central equatorial Pacific until boreal winter instead of propagating to the east.

You may already be familiar with this paper, but I found this passage interesting:

> Because of the obvious distinction from the traditional El Niño
> [Rasmusson and Carpenter, 1982] and even from that defined by NOAA in
> 2003, we refer to the SSTA pattern observed in 2004, namely, warming
> in the central Pacific (∼NINO4 region) flanked by colder SSTA to the
> west and east, as an El Niño Modoki (pseudo-El Niño) event; this term
> is now popular in Japan and east Asia. (The word Modoki was introduced
> by T. Yamagata during 2004 while explaining a probable cause behind
> the abnormal summer climatic conditions over Japan. It has been often
> used since then by various Japanese Mass Media. “Modoki” is a
> classical Japanese word which means “similar but different.” A news
> article also appeared in The Japan Times on 24 July 2004 under the
> heading “'Mock El Niño' culprit behind heat wave, floods: Professor,”
> which follows: “The heat wave and floods in various parts of Japan are
> being caused by an El Niño-like phenomenon in the central Pacific
> Ocean, a Japanese researcher said Friday. Toshio Yamagata, a professor
> at the University of Tokyo specializing in climate dynamics, said an
> increase in the sea surface temperature has activated convection
> currents and promoted a high-pressure ridge in the Pacific, bringing a
> hot summer to Japan …”

([Ashok et al. 2007](http://onlinelibrary.wiley.com/doi/10.1029/2006JC003798/full))

> **Comments:**
> **username_2**: Great answer but just to nitpick: instead of "Here is a nice picture from Nature:", why not saying "Here is a nice picture from Ashok & Yamagata (2009):"? Same thing for the final quote (Ashok et al. 2007). It's no biggie but i think it's nicer to the authors and in the end more useful to the reader.  
> **username_1**: @username_2 Thanks for the suggestion, I have changed it accordingly.  

---

### Answer by username_3 on 2015-04-18. Score: 1

Central Pacific El Niños have different effects than Eastern Pacific El Niños. For example, Modoki El Niño tends to have more hurricanes in Atlantic and Gulf of Mexico regions. Modoki El Niños may have been around going back to the 13th century, possibly before. The El Niño which developed in 2015 is a Modoki version of the phenomenon.


---

