El Nino Update
By Paul Homewood
Today I want to take a slightly different look at current ENSO conditions, and concentrate on subsurface temperature anomalies along the equator:
This is the latest situation:
http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/enso_advisory/
Despite positive, albeit weakening, anomalies on the surface, below the surface a huge pool of cold water has been building up in the last three months.
How does this compare to previous El Nino events? Unfortunately NOAA have no archived data for the 1998 event, but we can look at 2010, which was a much weaker one, but still the biggest since 1998 until the current El Nino.
In May 2010, the El Nino was already on the verge of petering out. Indeed, by June, La Nina conditions were in full swing. This was what subsurface temperatures looked like then:
Subsurface anomalies had only just started to go negative, but more significantly the cold pool of water below the surface was small and patchy, compared to the current situation.
We can see how this evolved over following months.
Warmer water quickly re-established itself in the western Pacific, as naturally occurs during La Ninas, with easterly winds pushing the warm surface water from east to west. This allows colder water to well up in the east.
The difference is that this time there is already a huge body of cold water below the surface across the whole of the equatorial Pacific. This is likely to mean that strong and long lasting La Nina conditions will follow.
Finally, let’s see how subsurface anomalies have developed over the last year:
A tremendous amount of heat that was built up below the surface of the east Pacific has been released into the atmosphere, causing the spike in temperatures. That will take time to dissipate, but that heat has now gone from the ocean.
There is a layman’s guide to how ENSO works here.
Sources
ENSO archives:
http://www.cpc.ncep.noaa.gov/products/expert_assessment/ENSO_DD_archive.shtml
Comments are closed.
NOT A LOT OF PEOPLE KNOW THAT 
Hot in India Why?
El Ninos tend to lead to droughts in India, because of jet stream changes.
Nice work Paul. I have to agree that the advancing La Nina is likely to be a strong one. It is already advancing faster than for the same time in 1998 as can be seen in the latest SSTA from the University of Maine below compared to 1998 for May 20.
I update these SSTA comparisons every few days here (along with SST comparisons):
“This allows colder water to well up in the east.” Perhaps this is a stupid and facetious question? But, if water wells up somewhere water has to down well somewhere else. Is that where warm water goes to “hide”…until next time?
We know that man-made CFCs were very quickly down welled to abyssal depths in the Weddell Sea (1987), so colder water must have well up.
Study the global thermohaline circulation. You will find your principal answer. The downwelling is cold salty water from polar sea ice formation, as brine is exuded. Because of the shape of the oceans in 3D, the major driver is the Arctic Atlantic. Antarctica drives the southern ocean, but not with as much global circulatory effect.
Oz… I have been tracking the ENSO 3.4 using the Hadley HadlSST1.1 database. After starting off quickly, the current data (through April) have tracked the 1997-98 path very closely but now look like they are about to drop more quickly. Might even reach La-Nina levels by the end of June?
We can hope. That way the pause might get reinstated in 2017.
Ristvan… The “pause” is alive and well, despite clumsy attempts to make it an artifact.
Broadlands, the ENSO 3-4 does not cover the 1997-98 El Nino very well because the most intense portion of that event was close to the coast of South America which is not covered by ENSO 3-4. You can see this in the SSTA map from 1998 May 20 that I posted. The 2015-16 event was stronger in the tropical Central Pacific and that is covered better by the ENSO 3-4. I have been looking at the NOAA Multivariate ENSO Index (MEI), but have not been able to determine what geographical area it covers.
Regardless, it’s very obvious from the SSTA maps that the current El Nino is fading faster than the 1997-98 El Nino and the the beginning of a La Nina is well under way now.
“We can hope. That way the pause might get reinstated in 2017.” Ristvan, give Karl a ring and ask him how he is going to eliminate the next La Nina temperature drop. Maybe Trump/Cruz will have got rid of him before his paper is published.
Reblogged this on Climate Collections.
A drastic decline in sunspot numbers such as we’re now seeing is usually associated with a downward trend in average global temperatures, so that could already be in play or if not, then it’s likely to be in the pipeline somewhere.
Wonder how this is going to play out with a cooling North Pacific and Atlantic working in tandem with low sunspot activity now and a lower and weakening sunspot cycle coming?
Paul, the lymens guide to ENSO link has a lot of pics missing, any chance you could fix that?
Thanks 🙂
Strange – it works on mine.
This is the original post from NOAA
http://www.srh.noaa.gov/jetstream/tropics/enso_patterns.html
Hi Paul – thanks for the original link.
Given that there was a strong El Nino, it seems reasonable that there will be a strong La Nina event to follow. The early signs are that this will be the case. The really interesting part will be in two to five years time on the longer term global warming trend.
A little light arithmetic:
130 degrees of equator is about 40,000 x 13/36 km, or ~14,400km
Assume a width of ~200km and average depth of ~0.1km, we have 288,000 km^3 of water that is say 2 Kelvin cooler at an SHC of 4 PJ/km^3/K, or ~2.3e21J
Energy content of atmosphere is ~5e21 J/K. The lower energy content of the water is equivalent to roughly half a degree off atmospheric temperatures, without allowing for any other effects.
No doubt all this razzmatazz is fully represented in Climate Models. The science is settled, remember.