La Nina – The Underappreciated Portion Of ENSO
Guest post by Bob Tisdale
Perform a Google Scholar search for documents including “El Nino” in quotes and there will be more than 200,000 results. On the other hand, “La Nina” will only raise 26,000+. Granted, the formal name of the coupled ocean-atmosphere phenomenon in the tropical Pacific is “El Nino-Southern Oscillation”, but that in quotes only returns 28,000+ results. So it appears that El Nino events do get much more “press” from the scientific community than La Nina events.
Figure 1 is a time-series graph of NINO3.4 SST anomalies from January 1979 to January 2010. El Nino events are a warming of the central and eastern tropical Pacific so they are displayed as a Positive SST anomaly, where La Nina events are a Negative. Visually, is the eye drawn to the upward spikes more than it is to the downward troughs? El Nino events are viewed as being larger in magnitude than La Nina events. NINO3.4 SST anomalies peaked at approximately 2.8 deg C during the Super El Nino events of 1982/83 and 1997/98, while the La Nina events that followed them failed to reach -2 deg C. But the La Nina events of 1988/89 and 2007/08 were stronger than the El Nino events that preceded them. (Refer to the note about base years at the end of this post.)
http://i48.tinypic.com/dpikxz.png
Figure 1
El Nino events release heat from the tropical Pacific, and through ocean currents and changes in atmospheric circulation, they raise surface temperatures outside of the tropical Pacific. These upward spikes in global temperatures, Figure 2, call attention to El Nino events during periods when global temperatures are rising. During La Nina events, the tropical Pacific releases less heat than normal, and global temperatures decline, which doesn’t have the same visual impact.
http://i45.tinypic.com/28wjsdy.png
Figure 2
La Nina events are a vital portion of the El Nino-Southern Oscillation coupled ocean-atmosphere process. La Nina events recharge the heat released from the tropical Pacific during the El Nino. Figure 3 is a graph of Tropical Pacific Ocean Heat Content compared to scaled NINO3.4 SST anomalies. Note that most La Nina events do not fully recharge the heat released by the El Nino events. From 1976 to 1994, tropical Pacific Ocean Heat Content dropped almost continuously, with occasional major dips and rebounds as an El Nino discharged heat and the subsequent La Nina partially recharged it. Then, the 1995/96 La Nina event, one that was not particularly strong, replaced all of the heat that had been released (plus some) over that 18-year stretch.
http://i46.tinypic.com/2vja1z5.png
Figure 3
THE 1995/96 LA NINA PROVIDED THE FUEL FOR THE NEXT EL NINO
During a La Nina event, tropical Pacific trade winds rise above normal levels. The increase in trade winds reduces cloud cover. Reduced cloud cover allows more Downward Shortwave Radiation (visible light) to warm the tropical Pacific. These coupled ocean-atmosphere processes associated with La Nina events were discussed in the post More Detail On The Multiyear Aftereffects Of ENSO – Part 2 – La Nina Events Recharge The Heat Released By El Nino Events AND…During Major Traditional ENSO Events, Warm Water Is Redistributed Via Ocean Currents”.
As noted above, the 1995/96 La Nina was not a strong event, yet it recharged all of the ocean heat that had been released in almost two decades of El Nino events. In “Genesis and Evolution of the 1997-98 El Niño” [ Science 12 February 1999: Vol. 283. no. 5404, pp. 950 – 954, DOI:10.1126/science.283.5404.950], Michael McPhaden explains, “For at least a year before the onset of the 1997–98 El Niño, there was a buildup of heat content in the western equatorial Pacific due to stronger than normal trade winds associated with a weak La Niña in 1995–96.” Link to Science abstract:
http://www.sciencemag.org/cgi/content/abstract/283/5404/950
Link to NOAA copy of McPhaden (1999):
http://www.pmel.noaa.gov/pubs/outstand/mcph2029/text.shtml
So there was a short-term recharge of tropical Pacific Ocean Heat Content in 1995/96, which is very evident in Figure 3. And this short-term buildup of heat content provided the fuel for the 1997/98 El Nino. Contrary to the beliefs of anthropogenic warming proponents the 1997/98 El Nino was NOT fueled by a long-term accumulation of heat from manmade greenhouse gases.
AND THAT 1997/98 EL NINO WAS CALLED THE EL NINO OF THE CENTURY
The 1997/98 El Nino was strong enough to temporarily raise Global Lower Troposphere Temperature anomalies ~0.7 deg C, as illustrated in Figure 4. Note: The period of 1995 to present was used in the following graphs because there have been no explosive volcanic eruptions since 1995 to add unwanted noise to the data.
http://i47.tinypic.com/21nnu4z.png
Figure 4
And referring to Figure 5, Lower Troposphere Temperature anomalies of the Mid-To-High Latitudes of the Northern Hemisphere rose, but remained at elevated levels that varied well above the value in late 1996. This upward step (and a similar but smaller one caused by the 1986/87/88 El Nino) was discussed in the post “RSS MSU TLT Time-Latitude Plots…Show Climate Responses That Cannot Be Easily Illustrated With Time-Series Graphs Alone”.
http://i48.tinypic.com/33p6nbn.png
Figure 5
Sea Surface Temperature anomalies for the Mid-To-High Latitudes of the Northern Hemisphere also rose and remained at an elevated level. Refer to Figure 6, which compares that dataset to scaled NINO3.4 SST anomalies. The latitudes used for the SST anomalies in this illustration are 20N-65N, which are latitudes that have little impact from polar ice. This upward step in the Sea Surface Temperature anomalies for the Mid-To-High Latitudes of the Northern Hemisphere will be discussed in a future post. I have, however, discussed the impacts of El Nino events on the North Atlantic in the post There Are Also El Nino-Induced Step Changes In The North Atlantic. And the North Atlantic is also impacted by the Atlantic Multidecadal Oscillation, but that appears to have peaked in 2005.
http://i46.tinypic.com/2ylpix3.png
Figure 6
And for those wondering how well the SST and TLT anomalies for the Mid-To-High Latitudes of the Northern Hemisphere correlate, I’ve prepared Figure 7. The SST anomaly data were scaled by a factor of 1.8. There are divergences from year to year, but keep in mind that the coverage areas are very different; the TLT anomalies also include data over continental land masses. One thing is certain; the 1997/98 El Nino caused upward steps in both datasets.
http://i49.tinypic.com/2uo2o8y.png
Figure 7
And there are the impacts of the 1997/98 El Nino on the East Indian and West Pacific Oceans (60S-65N, 80E-180), which I first discussed in a series of posts more than a year ago. The 1997/98 El Nino shifted Sea Surface Temperature anomalies upward in this area of the global oceans, too. Refer to Figure 8. The cause of this was discussed in the posts Can El Nino Events Explain All of the Global Warming Since 1976? – Part 1 and Can El Nino Events Explain All of the Global Warming Since 1976? – Part 2.
http://i48.tinypic.com/2qamu88.png
Figure 8
Basically, the warm water that was built up during the 1995/96 La Nina collected below the surface of an area in the western tropical Pacific known as the Western Pacific Warm Pool (to depths of 300 meters). During the 1997/98 El Nino, the warm water contained in the Western Pacific Warm Pool sloshed east and spread across the surface of the central and eastern tropical Pacific. The warmer-than-normal waters raised Sea Surface Temperatures and changed atmospheric circulation. Then, as the La Nina of 1998/99/00/01 progressed, the trade winds, Pacific Equatorial Currents, and a phenomenon known as a Rossby wave returned the remaining surface and subsurface warm water to the western Pacific. Some of the warm water returned to the Pacific Warm Pool, but a major portion of it remained on the surface and was redistributed by ocean currents to western North and South Pacific, and a portion of the warm water migrated to the Eastern Indian Ocean.
BLAME THE 1995/96 LA NINA FOR THE RECORD TEMPERATURES DURING THE 2000s AND IN 2010
So, if you’re wondering why the present moderate El Nino event of 2009/10 is raising global temperatures to record levels, you have to go back in time. The 1995/96 La Nina provided the build-up of warm waters that was then discharged by the 1997/98 El Nino and redistributed by the 1998/99/00/01 La Nina. The end results were upward steps in SST anomalies and TLT anomalies for major portions of the globe.
One of the methods anthropogenic global warming advocates (scientists and bloggers) use to illustrate the assumed effects of greenhouse gases on global temperatures is to illustrate the divergence between the linear trends of global temperatures and a scaled ENSO index such as NINO3.4 SST anomalies. Refer to Figures 9 and 10. But the upward steps illustrated in Figure 5 and 6 bias global temperature data upwards.
http://i46.tinypic.com/2vsl2mr.png
Figure 9
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http://i50.tinypic.com/2d7j0ux.png
Figure 10
And the biases created by those step changes in the SST and TLT anomalies of the Mid-To-High Latitudes of Northern Hemisphere are responsible for much of the differences between NINO3.4 SST anomalies and global temperature anomalies. We can illustrate this looking at the data for the rest of the world; that is, by comparing the linear trend of NINO3.4 SST anomalies with the linear trends the TLT and SST anomalies for the tropics and the Mid-To-High Latitudes of the Southern Hemisphere. Refer to Figures 11 and 12. As shown, the linear trends of the NINO3.4 SST anomalies are slightly negative, but the linear trends for the SST and TLT anomalies of the tropics and Mid-To-High Latitudes of the Southern Hemisphere are relatively flat–much flatter than the global datasets.
http://i50.tinypic.com/vsn97q.png
Figure 11
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http://i49.tinypic.com/11mcj7p.png
Figure 12
That would mean the ENSO-induced step increases in SST and TLT anomalies of the Mid-To-High Latitudes of the Northern Hemisphere caused the vast majority of the positive linear trends for the global SST and TLT anomaly datasets. See Figures 13 and 14, which show the strengths of the positive trends for those areas of the globe.
http://i47.tinypic.com/i4okg2.png
Figure 13
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http://i50.tinypic.com/35347qh.png
Figure 14
Figures 15 and 16 compare the SST and TLT anomalies for the Mid-To-High Latitudes of the Northern Hemisphere to the Global data and to the SST and TLT anomalies for the Mid-To-High Latitudes of the Southern Hemisphere. It should now be clear that the majority of the rises in Global SST and TLT anomalies since 1995 were caused by the 1997/98 El Nino-induced upward steps in the SST and TLT anomalies for the Mid-To-High Latitudes of the Northern Hemisphere.
http://i50.tinypic.com/33p64k1.png
Figure 15
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http://i47.tinypic.com/1zywv8k.png
Figure 16
In short, the effects of the La Nina- and El Nino-induced step changes in the SST and TLT anomalies of Mid-To-High Latitudes of the Northern Hemisphere are mistaken for, and misrepresented as proof of, anthropogenic global warming.
A BRIEF LOOK AT AN EARLIER LA NINA EVENT
The 1972/73 El Nino was a strong ENSO event. NINO3.4 SST anomalies, referring to Figure 17, peaked above 2 deg C. There were only two El Nino events stronger than the 1972/73 El Nino in the second half of the 20th Century, and they were the two Super El Nino events of 1982/83 and 1997/98.
http://i46.tinypic.com/29krqd2.png
Figure 17
But the 1972/73 El Nino shares another superlative with the 1997/98 El Nino. Both El Nino events were followed by La Nina events that lasted through not one ENSO season, not two ENSO seasons—they lasted through three consecutive ENSO seasons. The La Nina event of 1998/99/00/01 recharged the heat content released by the 1997/98 El Nino and returned the tropical Pacific Ocean Heat Content to the new higher levels established during the 1995/96 La Nina. Refer to Figure 18. The La Nina event of 1973/74/75/76 recharged the heat released from the Tropical Pacific by El Nino events during the decade of the early 1960s to the early 1970s. And it also added to the Tropical Pacific Ocean Heat Content.
http://i46.tinypic.com/2vja1z5.jpg
Figure 18
The Pacific Climate Shift of 1976/77 is a much-studied phenomenon. Trenberth et al (2002) discussed the differences in the evolution of El Nino events before and after the shift, and Trenberth et al (2002) referenced other papers that discussed effects of the Pacific Climate Shift on ENSO. Link to Trenberth et al (2002):
http://www.cgd.ucar.edu/cas/papers/2000JD000298.pdf
El Nino events became stronger after the Pacific Climate Shift. The frequency of El Nino events and El Nino Modoki increased. As noted in an early post, The 1976 Pacific Climate Shift, there were notable shifts in the SST anomalies and linear trends of Pacific Ocean basin subsets.
But I have yet to find a paper that attributes the Pacific Climate Shift of 1976/77 to the La Nina event of 1973/74/75/76 or one that even suggests that the 3-year-long La Nina played a role. Yet through known coupled ocean-atmosphere processes, the 1973/74/75/76 La Nina increased the warm water available for the additional El Nino events after 1976 and for the significant El Nino events of 1982/83 and 1986/87/88.
The explosive volcanic eruption of El Chichon may have counteracted the Super El Nino of 1982/83, but the 1986/87/88 El Nino was strong enough to cause upward shifts in the SST and TLT anomalies of the Mid-To-High Latitudes of the Northern Hemisphere, and the SST anomalies of the East Indian and West Pacific Oceans, similar to the shifts caused by the 1997/98 El Nino illustrated in this post.
A NOTE ABOUT BASE YEARS
Note: The relative strengths of El Nino versus La Nina events discussed early in this post would of course depend on the base years chosen for anomalies. And as illustrated in Figure 17 there is a minor difference depending on whether the base years of 1950 to 1979 or 1979 to 2000 are used. The significance of the difference would depend on how the data is being used. Example: A scaled running total of NINO3.4 SST anomalies will reproduce the basic global temperature anomaly curve as illustrated in Reproducing Global Temperature Anomalies With Natural Forcings if the base years are 1950 to 1979. If the base years of 1979 to 2000 are used, the result will not be similar to the global temperature curve.
http://i47.tinypic.com/2wlrkf4.png
Figure 19
CLOSING COMMENT
The La Nina event of 1973/74/75/76 provided the tropical Pacific Ocean Heat Content necessary for the increase in strength and frequency of El Nino events from 1976 to 1995. The 1995/96 La Nina furnished the Ocean Heat Content that served as fuel for the 1997/98 El Nino. And the 1998/99/00/01 La Nina recharged the tropical Pacific Ocean Heat Content after the 1997/98 El Nino, returning it to the new higher level established by the La Nina of 1995/96.
It would appear that La Nina events do all of the work, while El Nino events get all the glory—and the research.
SOURCE
All data for this post is available through the KNMI Climate Explorer:
http://climexp.knmi.nl/selectfield_obs.cgi?someone@somewhere
stephen richards (01:29:00) : You asked, “If the Niño/a are the major contributor to global temps, and there is no reason why they could not be, then for a cooler planet the La Niñas would need to be less cold or non existent ? Does that seem right to you.?”
The feedback from another variable such as the AMO may have an effect that is not accounted for in the discussion. Note that I research and illustrate the late 20th Century warming period for a number of reasons. It’s the warming period the AGW proponents say can only be caused by greenhouse gases, and the data shows they’re wrong. Second, before the satellite and buoys eras, a lot of the SST data is infilled, especially in the South Pacific.
A good summation of what we observe and a sensible general hypothesis but restricted very much to short term climate changes.
Can it be extended to the longer term so as to explain the background temperature trend which has clearly been rising during the 20th century and possibly even since the depths of the LIA ?
We need something to account for the longer term cycling from MWP to LIA to date. That cycling with various fits and starts goes back to the last glaciation.
Many suggest solar variability for that aspect of the climate system but as we all know Leif Svalgaard is dismissive of that so what are we left with ?
My own opinion is an internal oceanic cycling independent of the ENSO/PDO mechanism. Is there anything else that could do it ?
Could such an independent internal oceanic cycling even cause the ENSO / PDO cycles with the effect on the Trade Winds being caused by global ocean/atmosphere changes rather than vice versa such that the effect on the Pacific warm pool is a regional consequence of more subtle global changes involving all the oceans combined ?
Is there some way to get the ocean salinity changes and correllate with them to these Ocean temperature changes?
Thanks
Joe
—
Prior to the onset of gender-balancing political correctness, the term for what is called “la nina” was actually “el viejo” (“the old man”).
That could in some way account for the lower number of hits on a Web search for the term “la nina.”
—
“stephen richards (01:29:00) : You asked, “If the Niño/a are the major contributor to global temps, and there is no reason why they could not be, then for a cooler planet the La Niñas would need to be less cold or non existent ? Does that seem right to you.?”
That is a matter of concern for me too. It is said that during a negative PDO phase the La Nina is stronger but the El Nino is weaker.
Yet Bob is saying that the La Nina needs to be strong or lengthy to fuel a subsequent strong El Nino. There seems to be a logical inconsistency there.
The most likely implication of the unlikeliness of that proposition is that something in the oceans on a larger scale is driving the ENSO and PDO phenomena.
Tucci (06:39:30) : Thanks for the reminder about El Viejo. If I Google Scholar search for “El Viejo”, there are ~68,000 returns, so the returns are still significantly smaller than the 200,000 from “El Nino”. It did help bridge the gap, though.
Regards
Joe (05:28:14) : You asked, “Is there some way to get the ocean salinity changes and correllate with them to these Ocean temperature changes?”
The Ocean Heat Content data also accounts for changes in salinity. I cannot isolate them. I also have not run into a website that offers halosteric sea level data in a user-friendly format. But there are studies that isolate the salinity (halosteric) component.
Where is it the Sun in this picture?, What happened years before with the Sun that triggered the big 98-98 El Nino?, Did it happen something different?.
If the 2010 El Nino were now to be named as such by the fishermen of north peruvian coasts it wouldn´t have received its name because it did not reach those coasts:
http://weather.unisys.com/surface/sst_anom.html
Stephen Wilde (05:10:27) : You said it “We need something to account for the longer term cycling from MWP to LIA to date.”
What about the two big solar events in 1989, one of which, impacted the Quebec´s electric grid. BTW, Piers Corbyn takes into account this kind of events, as these also change GMF:
http://www.vukcevic.talktalk.net/LOD-GMF.gif
http://www.vukcevic.talktalk.net/GeoMagField.gif
(Yes, I know this is a FORBIDDEN issue for the “Astrophysics´ Church of the 21th.millenium” and its inquisition´s friars 🙂 ), but freeing a little from beliefs and settled science, you intelligent guys, could think about these phenomena without censorship and give the world a more logical panorama indicating causes and not only descriptions.
So apply the socratic maieutics method of questioning.
Good piece of work, Bob, which I enjoyed reading.
Some interesting ideas regarding how this could be extended to correlate to longer-term climate change based on effects of the solar cycles hypothesised in a paper by Erl Happ and Carl Wolk – “Solar warming – Solar cooling” here:-
http://climatechange1.wordpress.com/2009ow /04/05/solar-warming-solar-cooling/
Here’s their conclusion –
“Solar activity has weakened the [polar] vortex in both hemispheres. Periodic change in 200hPa temperature in response to changing ozone content and changing short wave radiation change ice cloud density and prevalence. This drives the Southern Oscillation. By and large it is the sea that stores energy and transports it to higher latitudes producing warmer winters. Ultimately sea surface temperature depends upon the Quasi Biennial Oscillation in ultraviolet radiation and the solar wind. The change in the solar QBO is responsible for the waxing and waning of the Southern Oscillation as it changes between El Nino and La Nina dominance.”
I’d be very interested to see if others think the paper is useful?
So, we start to worry about global cooling if El Niño is NOT followed by a La Niña? Or is followed by a short and mild one?
Stephen Wilde (05:10:27) :
“such that the effect on the Pacific warm pool is a regional consequence of more subtle global changes involving all the oceans combined”
Definitely global. The anomalies reverse all over: http://www.crces.org/presentations/dmv_ipwp/images/figure7.gif
from: http://www.crces.org/presentations/dmv_ipwp/
Bob Tisdale (01:41:10) :
rbateman (21:04:36): You wrote, “The only thing missing here is how this works when the system is seeking a long-term cooler state.”
During the cooling phase of the AMO, does the North Atlantic provide feedback to the tropical Pacific, suppressing the intensity and frequency of ENSO events? North Atlantic SST and OHC anomalies appear to have peaked in 2005. If that is an indication that the AMO has shifted into its cooling phase, then we’ll get to watch over the next 2.5 to 3 decades.
Great post as always Bob, thanks.
Regarding th post I quote, the question becomes then, what causes the warming and cooling phases of the oceans on multidecadal scales. Stephen Wilde seems to be taking Leif Svalgaard at his word, I don’t. The Sun’s variability is more than the up’s and downs of TSI, which may have been underestimated anyway by our limited dataset and it’s less than perfect splicing and interpretation. The SDO mission NASA has just launched will hopefully reveal more, though how much a 5 year mission will tell us about multidecadal variability remains to be seen.
http://tallbloke.wordpress.com/2010/02/08/to-boldly-go-with-sdo/
Bob,
Ruth Curry, oceanographer at Woods Hole Oceanographic Institute has done extensive salinity readings for a great many years.
There is a great amount of simularities when cross-referencing the different degree of changes from the north Atlantic to the Pacific.
Thanks Joe
Where’s the trolls, Bob? We can’t have you scaring them off. What fun is that. Surely you can intentionally make a baseless claim for ammunition. /sarc
Tenuc (07:36:00) : Regarding Erl Happ’s, “Solar warming – Solar cooling” post that you linked:
http://climatechange1.wordpress.com/2009/04/05/solar-warming-solar-cooling/
Refer to his Figure 2. I see no correlation between the solar cycles and equatorial temperatures at 20hPa and 200hPa. Based on it, the rest of the assumptions are just that, assumptions.
“…Yet Bob is saying that the La Nina needs to be strong or lengthy to fuel a subsequent strong El Nino. There seems to be a logical inconsistency there.
The most likely implication of the unlikeliness of that proposition is that something in the oceans on a larger scale is driving the ENSO and PDO phenomena.”
I don’t think one full ENSO cycle necessairily discharges/recharges all the available stored energy of the tropical Pacific. The events leading to the 1997/98 El Nino could have been decades in the making. We just don’t have the means to accurately measure such things. One thing I think should be considered is long term cloud cover of the tropical Pacific. This obviously would have a direct implication in how much insolation makes to the ocean’s surface.
Tenuc (07:36:00) : From the paper you quoted:
As solar activity ramped strongly after 1978 the rate of evaporation from the tropical oceans increased. The Earth and particularly the lower troposphere emitted more long-wave radiation. This promoted marked heating at 100hPa. This period of strong heating came to an end about 2005 and 100hPa temperature has since returned to pre 1978 levels. In the absence of further solar stimulus the tropical oceans should gradually cool.
http://climatechange1.wordpress.com/2009/04/05/solar-warming-solar-cooling/#comment-272
And…This period of strong heating came to an end about 2005 and 100hPa temperature has since returned to pre 1978 levels. In the absence of further solar stimulus the tropical oceans should gradually cool. As 100hPa temperature falls it promotes ice cloud formation reflecting solar radiation and cooling the surface
Remember that drop in Ap index in 2005, as pointed out by Anthony?
Bob Tisdale:
I find your ideas interesting. However, in order to have an actual explanation for something we need two separate things. First, we need some plausible mechanism by which cause becomes effect, and then we need data to show that it actually occurs. Unless I am too block-headed to see this, I feel you show us the second part without having provided the first.
Someone earlier on this thread asked if this is a cyclic process? The answer is part of the first requirement. Someone else asked what is going on during the cooling phase? That’s also part of the mechanical hypothesis. I have long asked whether the attendant moistening of the atmosphere plays a significant role. That is also part of the mechanical explanation.
Please respond to my paraphrasing of your hypothesis here. ENSO is a heat engine. It absorbs heat from sunlight in the tropics, converts this to work needed to transport warm water all over the Pacific and Indian oceans, and then expels waste heat in higher latitudes. This waste heat exhibits itself as anomalously high lower tropospheric temperatures in polar and temperate regions — and this raises global mean temperature.
Now in order to explain how a cyclic engine manages to produce semi-permanent step increases and/or secular trends in temperature, something about the engine is causing it to run in a larger enclosed area in either its P-V diagram (indicator diagram in the terminology of engines) or equivalently in its T-S diagram.
Bob,
Here is my assessement and why to the evidence that I have been able to explore that we are into an Ice Age and the tipping point was when the salt in the ocean started to change. Salt being a crystal has the properties to reflect sunlight. The salinity started on the surface around the equator where it is the hotest and our atmosphere is the highest. Also this is the maximum of the planets own rotational energy exerts most. The time frame past this was extreme draught in the areas. Evaporation was surpressed.
The salt changes starting on the surface and no heavy evaporation to encourage this also suggests it to be atmospheric in nature. The only area we have not much exploration is rotation and how this would effect the pulling or stretching of the atmosphere. Changing the density in the atmosphere would change the speed of the atmosphere is being pulled along.
Atmospheric pressure due to pressure build-up and rotation would push up on our atmosphere and not down on the planets surface.
Pulling the salt to the surface of the oceans.
Now the big concern is that the north Atlantic now has very little salinity in this further change which now open the evaporation flood gates.
The changes of the currents you have shown opens the land mass now to massive precipitation.
Joe
Kevin Kilty (08:42:57) :
First, we need some plausible mechanism by which cause becomes effect, and then we need data to show that it actually occurs
If such a mechanism it is known then, and only then, forecasts are possible.
The big question still remains. What causes ENSO in the first place. The trade winds could be an effect of ENSO with the PWP heat rising leading to the trades increasing. Also, what causes the variation in El Nino (Modoki).
Could heat from geothermal activity be part of the equation. What about gravity? That is, Lunar, Sun, other planets and, possibly, changes in the density of the mantle/core as they move around inside the Earth. Not to mention salinity and density changes due to below surface oscillations. And, I probably missed several other possible components as well.
I think it will be some time before we know how to put it all together. However, I am very grateful to Bob for his efforts to start understanding one of the biggest climate engines on the planet.
tallbloke (08:13:12) :
Another interesting question is why didn’t all the other La-Ninas cause steps in OHC, why only the 75 and 95 Ninas? LOD changed from increasing to decreasing around 73 and 93 so I’ll bet those changes in earth rotation are the real cause of the step ups. Then all we need to get a cooling phase is a flip back to increasing LOD.
Stephen Wilde (07:00:11): Logical inconsistency?
You copied and pasted stephen richards’s question to me, but you must have missed my reply to him.
Then you wrote, “That is a matter of concern for me too. It is said that during a negative PDO phase the La Nina is stronger but the El Nino is weaker.”
Since the PDO is an aftereffect of ENSO, you should have no concern. Refer to:
http://bobtisdale.blogspot.com/2009/04/misunderstandings-about-pdo-revised.html
AND:
http://bobtisdale.blogspot.com/2009/05/revisiting-misunderstandings-about-pdo.html
You wrote, “Yet Bob is saying that the La Nina needs to be strong or lengthy to fuel a subsequent strong El Nino.”
Incorrect. The above post is very clear. Read the summary. Here it is again.
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The La Nina event of 1973/74/75/76 provided the tropical Pacific Ocean Heat Content necessary for the increase in strength and frequency of El Nino events from 1976 to 1995. The 1995/96 La Nina furnished the Ocean Heat Content that served as fuel for the 1997/98 El Nino. And the 1998/99/00/01 La Nina recharged the tropical Pacific Ocean Heat Content after the 1997/98 El Nino, returning it to the new higher level established by the La Nina of 1995/96.
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I can’t get much plainer than that. It’s based on the Tropical Pacific Ocean Heat Content and NINO3.4 SST anomaly data illustrated in Figure 3.
And I also referenced and provided links to McPhaden (1999) to confirm the 1995/96 La Nina made the additional heat content available for the 1997/98 El Nino.
You wrote, “There seems to be a logical inconsistency there.”
Maybe the “logical inconsistency” is based on your failure to accept that ENSO drives the PDO, not vice versa. Or maybe it’s based on your misinterpretation/misunderstanding of what I wrote in the post or your failure to refer back to Figure 3. The summary is based on it. Or maybe you didn’t read the referenced paper. Or maybe you didn’t read my reply to stephen richards.
But, in short, there is no “logical inconsistency” in my post.
You concluded with, “The most likely implication of the unlikeliness of that proposition is that something in the oceans on a larger scale is driving the ENSO and PDO phenomena.”
Sorry, Stephen, this post was about what fueled the El Nino events, not what drives them, or triggers them. For more information on what drives ENSO, refer to the ENSO Q&A post from NOAA:
http://faculty.washington.edu/kessler/occasionally-asked-questions.html
In case you’re referring to something other than the known coupled ocean-atmosphere ENSO processes, and if and when you find this mysterious something and can present data (something that eludes you) to show it is driving ENSO, please feel free to write a post or a paper. Otherwise, as always, your comment is based on speculation, and likely has no basis in reality since you do not rely on data.
Regards
tallbloke (08:13:12)
I’m taking Leif at his word purely as a logical exercise.
I’m not a scientist but I’m good with words and logic so I can take the science provided by others and look at it in new ways to try and formulate a coherent whole without a personal bias towards any specific outcome.
Bob’s work on ENSO is extremely fine and detailed but it’s only a small portion of the whole and I don’t think he has sorted out the ‘chicken and egg’ adequately as yet.
Erl Happ and Svensmark have some nice ideas on the response of the upper atmosphere from solar forcings which could be made to fit my proposition that the rate of energy loss to space is affected by the amount of turbulence on the solar surface which does have an effect on the thermosphere and possibly all the other portions of the atmosphere from stratosphere upwards.
Leif might well be right about the smallness of solar variation in terms of power output but his opinion that there is no other aspect of solar variation that might have a disproportionate effect on the rate of energy flow through the Earth system I find to be somewhat questionable given the variability we see in the satellite records of outward bound infra red.
AGW is now dead. There is lots of pent up science in the system that has been suppressed but which is now going to receive lots of attention.
I like the attention now being given to Dr. Miskolczi’s calculations because if correct those calculations provide a sound mathematical basis for my own propositions.
However there is lots to play for in the individual components of the climate system and for that reason I am loth to criticise the work of any other climate sceptics.
Let this site and other similar sites try to make up the scientific ground lost over the past 20 years of climatological nonsense.
Let Realclimate et al read and weep.