Do El-Ninos signify global cooling?

[nikmb]

I've been thinking about El-Ninos.
When they appear we're talking about a lot of energy that's in the oceans. Where has this energy been accumlated from and for how long? Does all this heat get "recharged" by solar energy alone between El-Ninos or is this a net escaping of already accumulated heat?

I hope you can see where I'm coming from now.

So my question is:- Do frequent and bigger El-Ninos signify a net global cooling?

I would welcome all comments to help me get a better understanding of the dynamics involved.

[nautonnier]

Its not that simple

The top surface of the Pacific is blown westward by the trade-winds toward Indonesia the sea level is actually higher to the West because of this.

The trade-winds are caused by the air being 'sucked in' by the convection of the Hadley cells large convective patterns either side of the thermal equator or Inter-Tropical Convergence Zone. As the air is 'sucked in' the Coriolis Force causes it to veer and become more Easterly.

If the sea surface temperatures fall then the convection reduces and the trade-winds reduce. When this happens the sea level tries to equalize back and a 'Kelvin wave' is generated as the warm surface water from the higher Indonesian end washes back to the East. This is the EL Nino and it raises the temperature in the central Pacific toward the South American coast and the humidity and extra convection causes weather changes globally..... BUT it also spreads the hot surface water out and the heat escaping into the atmosphere as a state change of water vapor causing strong convection can rapidly cool the ocean. Dependent on how long the heat has been building up and how deep that heat is.

The extra convection increases the circulation of the Hadley cells and the trade-winds pick up - and reverse the process.

The strength of the winds can be assessed by looking at pressure differentials between Darwin and Tahiti (and other areas) and these can be used to generate what is called the Southern Oscillation Index

As the trade-winds pick up they drive the warm surface water back to the East and this surface water is replaced by cold water welling up along the West coast of South America, this cold water is carried along the surface and is the La Nina. The cold water is now warmed by the Sun.

So you will see that the El Nino thought to be a heating event is actually heat _escaping_ to the atmosphere then to space - LOWERING Ocean Heat Content. La Nina thought to be a 'cooling event' is cold ocean water being warmed by the Sun _raising_ Ocean Heat Content.

Also note that both sow the seeds of their own destruction by their effect on the convective patterns and therefore the winds that cause the sea surface changes. The entire El Nino Southern Oscillation (ENSO) is a complex feedback system that tends to normalize the sea surface temperatures.

The change to a negative Pacific Decadal Oscillation _may_ make the behavior of ENSO alter - that is what everyone is watching at the moment.

[poitsplace]

Indeed, this change is incredibly important to the whole AGW debate. ALL of what people THINK they know about anthropogenic global warming is tainted by the state of the PDO...as well as other long term cycles. Essentially all detailed information about the climate was obtained during what should have been a warming period anyway. Any assumption made of CO2's impact on climate based on this data is questionable at best.

This SHOULD be readily apparent to the AGW camp but the brainwashing campaign has gone so well that even some of the researchers themselves started to believe they knew it all...to the point that they trusted their own hypothesis over the actual data.

Nikmb, your best bet (imho) at understanding the impacts of El Nino and La Nina in the near future is to look to the past...back to the transition in the late 1940s and early 50s. This is what many of the meteorologists are doing now.

[nikmb]

Thanks

So El-Ninos are cooling and La-Ninas warming.
So the question now is now we had more of one than the other in the last 20-30 years?

[jurinko]

Yes, warm phase of PDO is marked by more El Ninos and vice versa. In a view of some, the PDO itself is an integrated effect of ENSO events.

El Nino warms things, but also releases a lot of heat; during the La Nina, heat is being absorbed. Here is some food for thoughts:

bobtisdale.blogspot.com/2010/02/la-nina-underappreciated-portion-of.html

[nikmb]

The Kaplan graph is interesting.
I counted squares which have 50% or more area for El-Ninos and La-Ninas and it gave 39 El-Ninos and 30 La-Ninas.

I know it's a very rough guesstimate but to me that shows a net global cooling since 1979.

[glc]

Mar 18, 2010 10:24:10 GMT nikmb said:

The Kaplan graph is interesting.
I counted squares which have 50% or more area for El-Ninos and La-Ninas and it gave 39 El-Ninos and 30 La-Ninas.

I know it's a very rough guesstimate but to me that shows a net global cooling since 1979.

Yes - you appear to have spotted the flaw in the warming/cooling La Nina/El Nino theory. El Nino does mean that some heat is leaving the oceans and entering the atmosphere. However this appears to be a short term effect and the oceans are rapidly being re-charged during the La Nina/neutral phase.

According to Easterbrook (who doesn't seem to be mentioned much recently) the PDO went 'negative' in 1999 meaning that we should get weaker and fewer El Ninos with stronger La Ninas.

[aj1983]

nikmb: no, more El Ninos don't show a net global cooling. They might show a larger release of LW radiation. That is, you've been looking at a (very crude) measure of outgoing LW radiation only. For the net energy budget you also need to look at the incoming energy.

[nautonnier]

Mar 18, 2010 13:16:32 GMT aj1983 said:

nikmb: no, more El Ninos don't show a net global cooling. They might show a larger release of LW radiation. That is, you've been looking at a (very crude) measure of outgoing LW radiation only. For the net energy budget you also need to look at the incoming energy.

And that is where it gets really interesting as the El Nino's tend to lead to more cloud and convection - as heat escapes with water vapor - which also has the effect of raising albedo reducing the incoming energy. This of course cools the surface and reduces the cloud and convection... decreasing albedo...

All of these have varying effects on the winds which of course are what drive ENSO.

It makes modeling turbulent flow in fluids simple.