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
##############
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
#####################
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
#####################
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
#####################
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
Discover more from Watts Up With That?
Subscribe to get the latest posts sent to your email.
Loud and clear as aways
Thanks Bob.
The only thing missing here is how this works when the system is seeking a long-term cooler state.
Everything we have kept track of pertains to a system seeking a long-term warmer state.
We know how the latter works.
What happens in the former scenario? (i.e. – a cooling state).
Half the world finds no surprise in your final comment.
==============================
Wonderful post.
So may I infer that this could be one of the natural positive energy events, that Prof. Jones has not been able to find yet?
If so, how much of the last 40 years of temperature rise would you be willing to attribute to this?
Thanx for sharing your expertise Bob!
I guess this answers my earlier question on trade winds and thermal expansion. Thanks again, Mr. Tisdale.
This is a concern as it means each time we have a warming period to reach a new and probably higher level of global mean temperature, the AGW scam will get stronger and stronger. So, in time they will win and we’ll be saddled with higher taxes. There’s only one way to stop this for sure – take the leading clowns of the AGW scam to court and try and prove them guilty then dish out suitable punishment.
Gotta love these Ads by Google showing up on your site:
Global Warming Myths
Read the myths and get the facts on the science of global warming
http://www.edf.org
Pure propagandists! Their link was right above your comment link, as if they were part of your post.
Enlightening. Thank you.
Chris
Norfolk, VA, USA
Stop Press – Dr Phil Jones admits no warming since 1995 and acknowledges the science was never settled:
http://www.dailymail.co.uk/news/article-1250872/Climategate-U-turn-Astonishment-scientist-centre-global-warming-email-row-admits-data-organised.html
I never imagined AGW would unravel so fast.
Bob, thanks for the clear essays.
Could you please comment in simmary on
(a) Is the El Nino/La Nina a conservative system wrt heat. That is, it it a cycle of redistributon of existing heat, or is heat taken from/added to the system?
(b) if the latter where does the excess heting/coolong report for measurement?
(c) has the mixture of observing stations in the two reference periods stayed about constant, or have we had a change like ‘the march of the thermometers’?
(d) Given the hypothesised connections with the Pacific Decadal Oscillation and the weather of West Australia being connected to snowfall at Law Dome, Antarctica, can we (or have we already) make a composite model of which global feature is connected to which other and with what confidence? (See David Stockwell’s Niche Modeling for the latter, at places like http://landshape.org/enm/droughts-and-antarctica/
and following.
Nice work, but I’m still not sure if the chicken comes before the egg.
Times ONline weighs in:
WORLD MAY NOT BE WARMING, SAY SCIENTISTS
http://www.timesonline.co.uk/tol/news/environment/article7026317.ece
You say higher Trade winds over open ocean is a warming effect. It seems sensible that for any level of insolation of the tropical sea surface that there should be a wind speed that evaporatively cools the surface at the same rate as the heating.
This hot damp air is the fuel for Willis E’s ITCZ super Cu-Nims which are certainly a cooling effect.
Just because satellites see open ocean under the Trade Winds, it does not follow that there is a net solar heating, especially during the night.
Great post Bob.
Summary: Pacific Ocean remains warm, but continues to cool
Central Pacific Ocean temperatures remain well above El Niño thresholds, with significant areas east of the date-line continuing to exceed their average by more than 2°C. However, the central to eastern Pacific has continued to cool since the peak of the El Niño warmth in late December and early January. The sub-surface of the equatorial Pacific has also cooled over the last month, which historically indicates that a return to neutral conditions may be under way.
http://www.bom.gov.au/climate/enso/
“Thumbnail (23:25:28) :
Times ONline weighs in:
WORLD MAY NOT BE WARMING, SAY SCIENTISTS
http://www.timesonline.co.uk/tol/news/environment/article7026317.ece
”
Rich. Read Kevin Trenberth’s response in the article.
“rbateman (21:04:36) :
The only thing missing here is how this works when the system is seeking a long-term cooler state.
Everything we have kept track of pertains to a system seeking a long-term warmer state.
We know how the latter works.
What happens in the former scenario? (i.e. – a cooling state).”
That was exactly my first thought when I got to the end of this excellent article.
From BBC Q&A with Dr Jones:
Here are the trends and significances for each period:
Period Length Trend
(Degrees C per decade) Significance
1860-1880 21 0.163 Yes
1910-1940 31 0.15 Yes
1975-1998 24 0.166 Yes
1975-2009 35 0.161 Yes
What made global temperatures “sink” 1880-1910 and 1940-1975? I would think that lots of people would like an explanation as the above article only focuses on the upward trends in global temperatures. There must be some contrary mechanism consisting of more cloud cover and more long term accumulation of heat content in the oceans or whatever.
Jones finally makes admission to the BBC’s AGW fanatic Harrabin.
Instead of a long commentary, I have highlighted the most important bit with stars.
Contrast what Jones is saying with Harrabin’s insistence that AGW still exists. And this is the man who wants to interview working skeptic British scientists!
……………………………………
Climategate U-turn as scientist at centre of row admits: There has been no global warming since 1995
http://www.dailymail.co.uk/news/article-1250872/Climategate-U-turn-Astonishment-scientist-centre-global-warming-email-row-admits-data-organised.html
Jonathan Petre
14th February 2010
* Data for vital ‘hockey stick graph’ has gone missing
* There has been no global warming since 1995
* Warming periods have happened before – but NOT due to man-made changes
The academic at the centre of the ‘Climategate’ affair, whose raw data is crucial to the theory of climate change, has admitted that he has trouble ‘keeping track’ of the information. Colleagues say that the reason Professor Phil Jones has refused Freedom of Information requests is that he may have actually lost the relevant papers.
Professor Jones told the BBC yesterday there was truth in the observations of colleagues that he lacked organisational skills, that his office was swamped with piles of paper and that his record keeping is ‘not as good as it should be’. The data is crucial to the famous ‘hockey stick graph’ used by climate change advocates to support the theory.
***************************************************************************
Professor Jones also conceded the possibility that the world was warmer in medieval times than now – suggesting global warming may not be a man-made phenomenon.
***************************************************************************
And he said that for the past 15 years there has been no ‘statistically significant’ warming.
The admissions will be seized on by sceptics as fresh evidence that there are serious flaws at the heart of the science of climate change and the orthodoxy that recent rises in temperature are largely man-made.
Professor Jones has been in the spotlight since he stepped down as director of the University of East Anglia’s Climatic Research Unit after the leaking of emails that sceptics claim show scientists were manipulating data.
The raw data, collected from hundreds of weather stations around the world and analysed by his unit, has been used for years to bolster efforts by the United Nation’s Intergovernmental Panel on Climate Change to press governments to cut carbon dioxide emissions.
* MAIL ON SUNDAY COMMENT: The professor’s amazing climate change retreat
http://www.dailymail.co.uk/debate/article-1250813/The-professor-s-amazing-climate-change-retreat.html
Following the leak of the emails, Professor Jones has been accused of ‘scientific fraud’ for allegedly deliberately suppressing information and refusing to share vital data with critics.
Discussing the interview, the BBC’s environmental analyst Roger Harrabin said he had spoken to colleagues of Professor Jones who had told him that his strengths included integrity and doggedness but not record-keeping and office tidying. Mr Harrabin, who conducted the interview for the BBC’s website, said the professor had been collating tens of thousands of pieces of data from around the world to produce a coherent record of temperature change. That material has been used to produce the ‘hockey stick graph’ which is relatively flat for centuries before rising steeply in recent decades.
According to Mr Harrabin, colleagues of Professor Jones said ‘his office is piled high with paper, fragments from over the years, tens of thousands of pieces of paper, and they suspect what happened was he took in the raw data to a central database and then let the pieces of paper go because he never realised that 20 years later he would be held to account over them’. Asked by Mr Harrabin about these issues, Professor Jones admitted the lack of organisation in the system had contributed to his reluctance to share data with critics, which he regretted. But he denied he had cheated over the data or unfairly influenced the scientific process, and said he still believed recent temperature rises were predominantly man-made.
Asked about whether he lost track of data, Professor Jones said: ‘There is some truth in that. We do have a trail of where the weather stations have come from but it’s probably not as good as it should be. There’s a continual updating of the dataset. Keeping track of everything is difficult. Some countries will do lots of checking on their data then issue improved data, so it can be very difficult. We have improved but we have to improve more.’
He also agreed that there had been two periods which experienced similar warming, from 1910 to 1940 and from 1975 to 1998, but said these could be explained by natural phenomena whereas more recent warming could not.
He further admitted that in the last 15 years there had been no ‘statistically significant’ warming, although he argued this was a blip rather than the long-term trend. And he said that the debate over whether the world could have been even warmer than now during the medieval period, when there is evidence of high temperatures in northern countries, was far from settled.
Sceptics believe there is strong evidence that the world was warmer between about 800 and 1300 AD than now because of evidence of high temperatures in northern countries. But climate change advocates have dismissed this as false or only applying to the northern part of the world.
Professor Jones departed from this consensus when he said: ‘There is much debate over whether the Medieval Warm Period was global in extent or not. The MWP is most clearly expressed in parts of North America, the North Atlantic and Europe and parts of Asia. For it to be global in extent, the MWP would need to be seen clearly in more records from the tropical regions and the Southern hemisphere. There are very few palaeoclimatic records for these latter two regions. Of course, if the MWP was shown to be global in extent and as warm or warmer than today, then obviously the late 20th Century warmth would not be unprecedented. On the other hand, if the MWP was global, but was less warm than today, then the current warmth would be unprecedented.’
Sceptics said this was the first time a senior scientist working with the IPCC had admitted to the possibility that the Medieval Warming Period could have been global, and therefore the world could have been hotter then than now.
Professor Jones criticised those who complained he had not shared his data with them, saying they could always collate their own from publicly available material in the US. And he said the climate had not cooled ‘until recently – and then barely at all. The trend is a warming trend’.
***************************************************************************
Mr Harrabin told Radio 4’s Today programme that, despite the controversies, there still appeared to be no fundamental flaws in the majority scientific view that climate change was largely man-made.
***************************************************************************
But Dr Benny Pieser, director of the sceptical Global Warming Policy Foundation, said Professor Jones’s ‘excuses’ for his failure to share data were hollow as he had shared it with colleagues and ‘mates’. He said that until all the data was released, sceptics could not test it to see if it supported the conclusions claimed by climate change advocates. He added that the professor’s concessions over medieval warming were ‘significant’ because they were his first public admission that the science was not settled.
The conscious form of cruelty inflicted on us by groups such as Greenpeace, PITA and the IPCC, who feel it is their right to do so , are the worst forms of cruelty inflicted on humanity. They have no idea what they are doing with their actions.
See this formal explanation at 75:00 in this movie;
Kymatica.
http://www
Wow, data overload. Maybe next time you could provide an abstract? That took me forever to read and required the consumption of two Starbucks Grande Caramel Macchiato’s, an Adderall, and one 5-hour energy drink.
Aside from that, I thought it was a very informative and compelling essay 🙂
Bob
Read this on your blog the other say and have been contemplating since.
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.?
I say that besause your piece here says that la niñas feed el niños and the deeper the niña the higher the niño
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.
Leo G (21:31:51): You asked, “If so, how much of the last 40 years of temperature rise would you be willing to attribute to this?”
I’ve reproduced the global temperature anomaly curve since about 1910 with natural variables :
http://bobtisdale.blogspot.com/2009/01/reproducing-global-temperature.html
Does that mean all of the rise in global temperatures could be attributable to natural effects?
The assumption in that post is that the global oceans integrate the effects of ENSO. For that to be, a small amount of each ENSO event would have to linger in the oceans. Newman et al (2003) discovered this to be the case in the Pacific. They write, “Furthermore, North Pacific SSTs have a multiyear memory during the cold season. Deep oceanic mixed layer temperature anomalies from one winter become decoupled from the surface during summer and then ‘reemerge’ through entrainment into the mixed layer as it deepens the following winter. Thus, over the course of years, at least during winter and spring, the North Pacific integrates the effects of ENSO.” And they use reemergence to explain the process. Refer to the following post for more on the reemergence mechanism, which exists in all oceans:
http://bobtisdale.blogspot.com/2009/06/reemergence-mechanism.html
The East Indian and West Pacific Oceans can and do warm during La Nina events due to an east-west dipole effect, which would also contribute to the appearance of a lingering El Nino signal. I illustrated the dipole in this post:
http://bobtisdale.blogspot.com/2009/12/more-detail-on-multiyear-aftereffects.html
Your posts are like a Christmas Present under a tree. Takes time to unwrap them, but well worth it.
I love the word “recharge.” It puts a great deal into a nut shell.
The Trade Winds are the “recharger.” They, in a La Nina, are sort of a Sisyphus, pushing a boulder up a hill and creating potential energy. Then, in a El Nino, the Trade Winds relax, which is analogous to Sisyphus watching the boulder roll back down the hill again, and the potential energy being released.
I’ve been thinking a lot lately about energy which isn’t measured by thermometers. Wind is interesting to think about. What holds more energy, a square foot of air at 34.0 degrees in a calm, or a square foot of air at 33.9 degrees moving 100 miles an hour in a hurricane?
I’d like to know more about what makes the Trade Winds stronger, and what makes them weaker, because it seems to be the difference between the Pacific “recharging” or “discharging.”
I may not come up with answers, but I sure do enjoy thinking about this stuff. It increases my sense of wonder. I’m very grateful for the thinking-tools that your charts and graphs create.
Keep up the great work.
Very clear – thank you – and fascinating. So La Nina, and the clearer, less cloudy conditions associated with the stronger trades allow more heat to the surface recharging the ocean heat. I never thought of it like that before. The redistribution is by the El Nino events is now very obvious.
It does explain rather well why the GCMs get things so wrong, or at least miss out a lot of importance.
Geoff Sherrington (23:05:09) : You asked, “Is the El Nino/La Nina a conservative system wrt heat. That is, it it a cycle of redistributon of existing heat, or is heat taken from/added to the system?”
El Nino events discharge and redistribute heat that exists since the previous La Nina. The La Nina that follows the El Nino returns part of the leftover warm water to the Pacific Warm Pool for the next El Nino, redistributes the rest of the warm water to nearby oceans, and recharges the heat released by the El Nino through increases in downward shortwave radiation. Over the long term, though, the typical La Nina does not recharge all of the heat discharged during the previous El Nino, and tropical Pacific declines for a decade or two.
You asked, “if the latter where does the excess heting/coolong report for measurement?”
Tropical Pacific Ocean Heat Content:
http://i46.tinypic.com/2vja1z5.png
You asked, “has the mixture of observing stations in the two reference periods stayed about constant, or have we had a change like ‘the march of the thermometers’?”
Please rephrase the question. I’m not sure what you’re asking.
And with respect to your PDO/rainfall in Australia question, I’ll have to say that I can’t answer your question. I haven’t studied the relationship.
Sandy (23:31:48) : You wrote, “You say higher Trade winds over open ocean is a warming effect. It seems sensible that for any level of insolation of the tropical sea surface that there should be a wind speed that evaporatively cools the surface at the same rate as the heating.”
Tropical Pacific SST (Surface) anomalies cool during La Nina events, correlating well with NINO3.4 SST anomalies. The following graph also includes tropical Pacific OHC.
http://i50.tinypic.com/24flpjs.png
Some of the surface cooling would be caused by an increase in evaporative cooling due to the higher trade winds, but the vast majority of the surface cooling is caused by the upward shift in the thermocline, which is also related to the increase in trade winds. Refer to:
http://faculty.washington.edu/kessler/occasionally-asked-questions.html
My statement in the post probably could have been clearer when I wrote, 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.” I should have added “…raising tropical Pacific Ocean Heat Content,” to eliminate the possibility of confusion. Note in the above graph how tropical Pacific OHC rises during the La Nina events of 1995/96 and 1998/99/00/01.