Bob has asked me to carry this post, and I’m happy to do so. For those who want to criticize without contributing anything but criticism, I offer this insight: The only real mistake is the one from which we learn nothing. ~John Powell
-Anthony
Revised Post – On Foster and Rahmstorf (2011)
Guest post by Bob Tisdale
ABOUT THE ERROR-LADEN FIRST VERSION OF THIS POST
I displayed my very limited understanding of statistics in my post On Foster and Rahmstorf 2011 – Global temperature evolution 1979–2010. This was pointed out to me a great number times by many different people in numerous comments received in the WattsUpWithThat cross post. My errors in that portion of the post were so many and so great that they detracted from the bulk of the post, which was about the El Niño-Southern Oscillation. For that reason, I have added a third update to my earlier post on Foster and Rahmstorf (2011), which asks readers to disregard that post and the cross post at WUWT. That update also includes a link that redirects readers here.
I learned a lot from my mistakes. Many of those who commented provided detailed explanations of the methods used by Foster and Rahmstorf (2011). Thanks go to them.
When an author of a blog post makes a major mistake, it needs to be acknowledged and/or corrected, and I have done this multiple times for that portion of my earlier post about Foster and Rahmstorf (2011). Now I’m reposting an expanded version of the discussion of ENSO. If you’d still like to discuss the errors I made in the earlier post, please comment on that thread, not this one.
OVERVIEW
This post discusses the assumption made in the paper Foster and Rahmstorf (2011) “Global Temperature Evolution 1979–2010”that the variations in the global temperature record due to El Niño-Southern Oscillation (ENSO) can be estimated from an ENSO index. This post excludes all discussions of the statistical methods used by Foster and Rahmstorf in their paper. Please limit the comments on this thread to ENSO and surface temperature responses to ENSO.
INTRODUCTION
Foster and Rahmstorf (2011) attempted to remove from 5 global temperature datasets the linear effects of 3 factors that are known to cause variations in global temperature. The paper covered the period of 1979 to 2010. The intent of their paper was to show that anthropogenic global warming continues unabated in all of those datasets. The independent variables listed in the abstract of Foster and Rahmstorf (2011) are El Niño-Southern Oscillation (ENSO), volcanic aerosols, and solar variations.
Foster and Rahmstorf (2011) used independent measures for these three factors. Total Solar Irradiance and aerosol optical depth data were used to estimate the effects of solar variability and volcanic aerosols on global surface temperatures. This post does not pertain to them. This post initially discusses the attempt by Foster and Rahmstorf (2011) to use an ENSO index as a measure of the effects of ENSO on global surface temperature. What will then be discussed and shown is that an ENSO index cannot account for the effects of ENSO on global surface temperatures.
Foster and Rahmstorf (2011) also makes two more assumptions that have little basis in reality. They assume the rise in surface temperatures since 1979 was linear and that it was due to anthropogenic factors. The sea surface temperature record of the global oceans since 1982 clearly disagrees with these assumptions.
ENSO IS NOT AN EXOGENOUS FACTOR
The following two papers discuss the problems with the assumption made by Foster and Rahmstorf (2011) about ENSO. One of the papers was cited by them in their paper.
Foster and Rahmstorf (2011) cited Trenberth et al (2002) Evolution of El Nino–Southern Oscillation and global atmospheric surface temperatures”as one of their ENSO references. But Trenberth et al (2002) include the following disclaimer in the second paragraph of their Conclusions, (their paragraph 52, my boldface):
The main tool used in this study is correlation and regression analysis that, through least squares fitting, tends to emphasize the larger events. This seems appropriate as it is in those events that the signal is clearly larger than the noise. Moreover, the method properly weights each event (unlike many composite analyses). Although it is possible to use regression to eliminate the linear portion of the global mean temperature signal associated with ENSO, the processes that contribute regionally to the global mean differ considerably, and the linear approach likely leaves an ENSO residual.
The ENSO “residuals” are a significant contributor to the rise in Global Sea Surface Temperatures during the satellite era, as will be shown later in this post. Did Foster and Rahmstorf (2011) consider these residuals in their analysis? No.
A more recent paper was overlooked by Foster and Rahmstorf (2011). Compo and Sardeshmukh (2010) “Removing ENSO-Related Variations from the Climate Record” seems to be a step in the right direction. They write (my boldface):
An important question in assessing twentieth-century climate is to what extent have ENSO-related variations contributed to the observed trends. Isolating such contributions is challenging for several reasons, including ambiguities arising from how ENSO is defined. In particular, defining ENSO in terms of a single index and ENSO-related variations in terms of regressions on that index, as done in many previous studies, can lead to wrong conclusions. This paper argues that ENSO is best viewed not as a number but as an evolving dynamical process for this purpose.
Note: While Compo and Sardeshmukh made a step in the right direction, they missed a very important aspect of ENSO. They overlooked the significance of the huge volume of warm water that is left over from certain El Niño events, and they failed to account for its contribution to the rise in global Sea Surface Temperature anomalies since about 1975/76.
ENSO IS A PROCESS NOT AN INDEX
I have discussed, illustrated, and animated the process of ENSO and its effects on global surface temperatures and lower troposphere temperatures for about three years. There are too many posts to list them all here. However, if the subject of ENSO is new to you, refer to the introduction post here. If you would prefer an introductory-level discussion about ENSO written by someone else, refer to the excellent answers to FAQ here by Bill Kessler of the NOAA Pacific Marine Environmental Laboratory. For those who believe La Niña events are the opposite of El Niño events refer to the posts here, here and here. And for those who believe ENSO is represented by an index, refer to the post here. I will provide a relatively detailed overview of the process of ENSO in the following.
ENSO is a coupled ocean-atmosphere process that periodically discharges heat to the atmosphere during an El Niño. The phrase “coupled ocean-atmosphere process” refers to the fact that many ocean and atmospheric variables in the tropical Pacific interact with one another. For that reason, a number of tropical Pacific variables are impacted directly by ENSO, including sea surface temperature, sea level, ocean currents, ocean heat content, depth-averaged temperature, warm water volume, sea level pressure, cloud amount, precipitation, the strength and direction of the trade winds, etc. I have presented the effects of ENSO on each of those variables in past posts. And since cloud amount for the tropical Pacific impacts downward shortwave radiation (visible light) there, I’ve presented and discussed that relationship as well. In fact, the videos included in the post here presented ISCCP Total Cloud Amount data (with cautions about that dataset), CAMS-OPI precipitation data, NOAA’s Trade Wind Index (5S-5N, 135W-180) anomaly data, RSS MSU TLT anomaly data, CLS (AVISO) Sea Level anomaly data, NCEP/DOE Reanalysis-2 Surface Downward Shortwave Radiation Flux (dswrfsfc) anomaly data, and Reynolds OI.v2 SST anomaly data.
During an El Niño, warm water from the west Pacific Warm Pool can travel thousands of miles eastward across the equatorial Pacific. Keep in mind that the equatorial Pacific stretches almost halfway around the globe. So as the convection, cloud cover, and precipitation all accompany that warm water, their relocation causes changes in atmospheric circulation patterns worldwide. In turn, this causes temperatures outside of the eastern tropical Pacific to vary, some warming, some cooling, but in total, the areas that warm exceed those that cool and global surface temperatures rise in response to an El Niño. The spatial patterns of warming and cooling during a La Niña are similar to an El Niño, but of the opposite sign. And all that a paper such as Foster and Rahmstorf (2011) can only hope to account for are the changes in global temperature that respond linearly to the changes in the ENSO index used in the analysis. As confirmation, a paper cited by Foster and Rahmstorf (2011) acknowledged that there are ENSO-related factors that impact global temperatures that are overlooked by linear regression analysis. See Trenberth et al (2002) linked above.
Because global spatial patterns for El Niño and La Niña events are similar but opposite, many persons believe that all of the effects of El Niño and La Niña events oppose one another. This is far from reality. A La Niña event is basically an exaggeration of the “normal” (or ENSO-neutral) state of the tropical Pacific, while an El Niño event is an anomalous state.
An El Niño can carry huge volumes of warm water from the surface and below the surface of the west Pacific Warm Pool eastward to the central and eastern equatorial Pacific. That warm water is not consumed fully by the El Niño, so it returns to the west during the La Niña. One of the ways the La Niña accomplishes this return of warm water is through a phenomenon called a slow-moving Rossby wave, which forms in the northeast tropical Pacific at about 5N-10N. After the 1997/98 El Niño, the Rossby wave is plainly visible in ocean heat content anomaly animations, and better still in sea level residual animations from the Jet Propulsion Laboratory.
I’ve highlighted the Rossby wave in screen captures from the JPL video in Figure 1. The upper right-hand cell shows the formation of the Rossby wave and the lower left-hand cell captures the Rossby wave travelling from east to west at approximately 5N-10N, carrying leftover warm water back to the western Pacific during the transition from the 1997/98 El Niño to the multiyear La Niña that followed.
Figure 1
The Rossby wave can be seen in the first 10 to 15 seconds of Video 1. And as you will note, if you allow the video to play through, there are no comparably sized Rossby waves carrying cool waters back to the western tropical Pacific at 5N-10N after the La Niña.
Video 1
And to further confirm this basic difference between El Niño and La Niña events, there are also no comparably-sized Rossby waves carrying cool waters back to the western tropical Pacific at 5N-10N after any La Niña event seen in the full version of the JPL animation, Video 2, which runs from 1992 to 2002.
Video 2
There are no ENSO indices presently in use that can account for the return of the warm water to the West Pacific during a La Niña event that follows an El Niño.
As I’ve noted in numerous posts, ENSO is also a process that redistributes the warm water that was leftover from the El Niño itself and enhances the redistribution of the warm water that resulted from the El Niño in waters outside of the eastern tropical Pacific. The redistribution carries that warm water poleward and into adjoining ocean basins during the La Niña that follows an El Niño. The impacts of this redistribution depend on the strength of the El Niño and the amount of water that was “left over”. Lesser El Niño events that are not followed by La Niña events obviously would not have the same impacts. There are no ENSO indices that can account for this redistribution and these differences.
La Niña events also recharge part of the warm water that was released during the El Niño. They accomplish this through an increase in downward shortwave radiation (visible light), and that results from the reduction in tropical Pacific cloud amount caused by the stronger trade winds of a La Niña. Sometimes La Niña events “overcharge” the tropical Pacific, inasmuch as they recharge more ocean heat in the tropical Pacific than was discharged during the El Niño that came before it. That was the case during the 1973/74/75/76 La Niña. Refer to Figure 2. Tropical Pacific Ocean Heat Content rose significantly during the 1973/94/75/76 La Niña, and that provided the initial “fuel” for the 1982/83 Super El Niño and the multi-year 1986/87/88 El Niño. The La Niña events that followed those El Niño only recharged a portion of the heat discharged by them. Tropical Pacific Ocean Heat Content declined until 1995. Then the 1995/96 La Niña event “overcharged” the Tropical Pacific Ocean Heat Content again and that provided the fuel for the 1997/98 “El Niño of the Century”.
Figure 2
Refer also to the introductory level discussion in the post ENSO Indices Do Not Represent The Process Of ENSO Or Its Impact On Global Temperature.
THE TREND OF THE EAST PACIFIC SEA SURFACE TEMPERATURE ANOMALIES HAS BEEN RELATIVELY FLAT FOR 30 YEARS
The East Pacific Sea Surface Temperature anomalies from pole to pole, Figure 3, are dominated by the variations in tropical Pacific caused by ENSO, and as a result, the variations in the East Pacific Sea Surface Temperature anomalies mimic ENSO, represented by the scaled NINO3.4 Sea Surface Temperature anomalies. The trend of the East Pacific Sea Surface Temperature anomalies is relatively flat at 0.011 deg C/Decade.
Figure 3
The reason the trend is so flat: warm water from the surface and below the surface of the west Pacific Warm Pool is carried eastward during an El Niño and spread across the surface of the eastern tropical Pacific, raising sea surface temperatures there. And during the La Niña events that follow El Niño events, the leftover warm water is returned to the western tropical Pacific. Due to the increased strength of the trade winds during the La Nina, there is an increase in upwelling of cool subsurface waters in the eastern equatorial Pacific, so the Sea Surface Temperatures there drop. In other words, the East Pacific is simply a temporary staging area for the warm water of an El Niño event. Warm water sloshes into this dataset from the western tropical Pacific and releases heat, and then the warm water sloshes back out.
WHAT EFFECT DOES THE WARM WATER HAVE WHEN IT RETURNS TO THE WESTERN TROPICAL PACIFIC DURING THE SUBSEQUENT LA NIÑA EVENT?
The warm waters released from below the surface of the West Pacific Warm Pool during a major El Niño are not done impacting Sea Surface Temperatures throughout the global oceans when that El Niño has ended, and they cannot be accounted for by an ENSO index. Keep in mind, during an El Niño like the 1997/98 event, a huge volume of water from below the surface of the west Pacific Warm Pool was spread across the surface of the eastern tropical Pacific. Consequently, warm water that had once been excluded from the surface temperature record, because it was below the surface, is now included in the surface temperature record. At the end of the El Niño, the trade winds push the warm water that’s now on the surface back to the western Pacific where it remains in the surface temperature record. The Sea Surface Temperature in the western Pacific rises as a result. Add to that the effects of the Rossby wave. As illustrated earlier, at approximately 5N-10N latitude, a slow-moving Rossby wave also carries leftover warm water from the eastern tropical Pacific back to the western Pacific during the La Niña. Ocean currents carry all of the leftover the warm water poleward to the Kuroshio-Oyashio Extension (KOE) east of Japan and to the South Pacific Convergence Zone (SPCZ) east of Australia, and the Indonesian Throughflow (an ocean current) carries the warm water into the tropical Indian Ocean. And as noted above, due to the increased strength of the trade winds during the La Nina, there is an increase in upwelling of cool subsurface waters in the eastern equatorial Pacific, so the Sea Surface Temperatures there drop. But that cooler-than-normal water is quickly warmed during the La Niña as it is carried west by the stronger-than-normal ocean currents that are caused by the stronger-than-normal trade winds. And the reason that water warms so quickly as it is carried west is because the stronger-than-normal trade winds reduce cloud cover, and this allows more downward shortwave radiation (visible sunlight) to warm the ocean to depths of 100 meters. This additional warm water helps to maintain the Sea Surface Temperatures in the West Pacific and East Indian Oceans at elevated levels during the La Niña and it also recharges the West Pacific Warm Pool for the next El Niño event. Refer again to Figure 2. (Keep in mind that the graph in Figure 2 is for the Ocean Heat Content for the entire tropical Pacific, not just the Pacific Warm Pool.)
And what happens when a major El Niño event is followed by a La Niña event? The Sea Surface Temperature anomalies for the Atlantic, Indian, and West Pacific Oceans (the Rest-Of-The-World outside of the East Pacific) first rise in response to the major El Niño; the 1986/87/88 and 1997/98 El Niño events for example. Then the Rest-Of-The-World Sea Surface Temperatures are maintained at elevated levels by the La Niña; the 1988/89 and 1998/99/00/01 La Niña events to complete the example. The results are the apparent upward shifts in the Sea Surface Temperature anomalies of the Atlantic, Indian, and West Pacific Oceans from pole to pole (90S-90N, 80W-180), as illustrated in Figure 14. Some have described it as a ratcheting effect, where the redistribution of warm waters during the major El Niño and La Niña events drive the surface temperatures up a notch.
Figure 4
In Figure 4, the dip and rebound starting in 1991 is caused by the volcanic aerosols emitted by the explosive volcanic eruption of Mount Pinatubo. And the reason the Rest-Of-The-World Sea Surface Temperature anomalies respond so little to the 1982/83 Super El Niño is because that El Niño was counteracted by the eruption of El Chichon in 1982.
To assure readers that the upward shifts in Rest-Of-The-World Sea Surface Temperature anomalies coincide with the 1986/87/88 and 1997/98 El Niño events, I’ve included an ENSO index, NINO3.4 Sea Surface Temperature anomalies, in Figure 5. The NINO3.4 Sea Surface Temperature anomalies have been scaled (multiplied by a factor of 0.12) to allow for a better visual comparison, and shifted back in time by 6 months to account for the time lag between the variations in NINO3.4 Sea Surface Temperature anomalies and the response of the Rest-Of-The-World data.
Figure 5
But the ENSO Index data is visually noisy and it detracts from the upward shifts, so I’ve removed it in Figure 6. But in it, I’ve isolated the data between the significant El Niño events. To accomplish this, I used the NOAA Oceanic Nino Index (ONI) to determine the official months of those El Niño events. There is a 6-month lag between NINO3.4 SST anomalies and the response of the Rest-Of-The-World SST anomalies during the evolution phase of the 1997/98 El Niño. So the ONI data was lagged by six months, and the Rest-Of-The-World SST data that corresponded to the 1982/83, 1986/87/88, 1998/98, and 2009/10 El Niño events was excluded and left as black dashed lines. All other months of data remain and are represented by the blue curves.
Figure 6
And to help further highlight the upward shifts, the average Sea Surface Temperature anomalies between the major El Niño events are added in Figure 7.
Figure 7
Based on past posts where I’ve presented the data the same way, some readers have suggested the period average temperatures are misleading and have requested that I illustrate the linear trends. Figure 8 shows how flat the trends are between the 1986/87/88 and 1997/98 El Niño events and between the 1997/98 and 2009/10 El Niño events.
Figure 8
Back to the East Pacific data: If we adjust the East Pacific Sea Surface Temperature anomalies for the effects of volcanic aerosols, Figure 9, the linear trend is slightly negative. In other words, for approximately 33% of the surface area of the global oceans, Sea Surface Temperature anomalies have not risen in 30 years.
Figure 9
Note: The method used to adjust for the volcanic eruptions is described in the post Sea Surface Temperature Anomalies – East Pacific Versus The Rest Of The World, under the heading of ACCOUNTING FOR THE IMPACTS OF VOLCANIC ERUPTIONS.
And if we adjust the Rest-Of-The-World Sea Surface Temperature anomalies for volcanic aerosols, Figure 10, we reduce the effects of the dip and rebound caused by the 1991 eruption of Mount Pinatubo. And the trend of the Rest-Of-The-World data between the 1986/87/88 and 1997/98 El Niño drops slightly compared to the unadjusted data (Figure 8), making it even flatter and slightly negative.
Figure 10
Note: In the second part of a two part series (here), I further subdivided the Rest-of-the-World (90S-90N, 80W-180) sea surface temperature data to isolate the North Atlantic, due to its additional mode of natural variability. The sea surface temperatures for the remaining South Atlantic-Indian-West Pacific data decay between the major El Niño events. In other words, the sea surface temperatures there drop; the linear trends are negative, just as one would expect.
In summary, ENSO is a coupled ocean-atmosphere process and its effects on Global Surface Temperatures cannot be accounted for with linear regression of an ENSO index as attempted by Foster and Rahmstorf (2011)–and others before them. We can simply add Foster and Rahmstorf (2011) to the list of numerous papers that make the same error. Examples:
Lean and Rind (2009) How Will Earth’s Surface Temperature Change in Future Decades?
And:
Lean and Rind (2008) How Natural and Anthropogenic Influences Alter Global and Regional Surface Temperatures: 1889 to 2006
And:
Santer et al (2001), Accounting for the effects of volcanoes and ENSO in comparisons of modeled and observed temperature trends
And:
Thompson et al (2008), Identifying signatures of natural climate variability in time series of global-mean surface temperature: Methodology and Insights
And:
Trenberth et al (2002) Evolution of El Nino–Southern Oscillation and global atmospheric surface temperatures
And:
Wigley, T. M. L. (2000), ENSO, volcanoes, and record-breaking temperatures
IS THERE A LINEAR “GLOBAL WARMING SIGNAL”?
Foster and Rahmstorf (2011) assumed that the global warming signal is linear and that it is caused by anthropogenic factors, but those assumptions are not supported by the satellite-era Sea Surface Temperature record as shown above. The El Niño events of 1986/87/88 and 1997/98 are shown to be the cause of the rise in sea surface temperatures since November 1981, not anthropogenic greenhouse gases.
CLOSING COMMENTS
This post illustrated and discussed the error in the assumption that regression analysis can be used to remove the impacts of ENSO on Global Surface Temperature. ENSO is a process that is not fully represented by ENSO Indices. In other words, the ENSO indices only represent a small portion of the impacts of ENSO on Global Surface Temperatures. Attempting to use an ENSO index as Foster and Rahmstorf (2011) have done is like trying to provide the play-by-play for a baseball game solely from an overhead view of home plate.
The assumption made by Foster and Rahmstorf (2011) that a linear trend provides an approximate “global warming” signal was shown to be wrong using Sea Surface Temperature data. When broken down into two logical subsets of the East Pacific and the Atlantic-Indian-West Pacific Oceans, satellite-era Sea Surface Temperature data shows no evidence of an anthropogenic global warming signal. It only shows upward shifts associated with strong ENSO events.
If Foster and Rahmstorf (2011) were to exclude ENSO from their analysis, it is likely their results would be significantly different.
A closing note: I have also been illustrating, discussing, and documenting the ENSO-related processes behind these upward shifts for three years, using the East Indian-West Pacific subset (60S-65N, 80E-180). I first posted about it on January 10, 2008 in a two-part series here and here. The WattsUpWithThat cross posts are here and here.
ABOUT: Bob Tisdale – Climate Observations
SOURCES
The NODC OHC data is available through the KNMI Climate Explorer, on their Monthly observationswebpage.
The Reynolds OI.v2 Sea Surface Temperature data used in the ENSO discussion is available through the NOAA NOMADS website here.
The Aerosol Optical Thickness data used in the volcano adjustments of the Sea Surface Temperature data in Figures 9 and 10 is available from the GISS Stratospheric Aerosol Optical Thickness webpage here.
Part 2 of PDO basics, Geoff.
By definition, the PDO is “derived as the leading PC [Principal Component] of monthly SST anomalies in the North Pacific Ocean, poleward of 20N. The monthly mean global average SST anomalies are removed to separate this pattern of variability from any “global warming” signal that may be present in the data.”
And that means the PDO is a statistically manufactured dataset, and that it does not represent the sea surface temperature of the North Pacific, north of 20N, but is a statistical function of the detrended sea surface temperature anomalies of that location. Do you agree with that or disagree, Geoff?
Further to that is the typical image of the PDO we often see presented:
http://www.atmos.washington.edu/~mantua/REPORTS/PDO/Figures/fig2.gif
The image in Figure 2a above is manufactured, “By regressing the records of wintertime SST and SLP upon the PDO index, the spatial patterns typically associated with a positive unit standard deviation of the PDO are generated (Fig. 2a).” Source:
http://www.atmos.washington.edu/~mantua/REPORTS/PDO/pdo_paper.html
Do you agree with that or disagree, Geoff?
The PDO is said to be, “dominant pattern of North Pacific sea surface temperature variability.” Source:
http://www.treesearch.fs.fed.us/pubs/34963
Do you agree with that or disagree, Geoff?
Bob Tisdale says:
January 17, 2012 at 8:37 pm
Right here and now, Geoff.
I am dubious you will maintain a professional non personal persona in this debate and would prefer a moderated public forum, but we will see how you go.
And that means the spatial pattern in the North Pacific, north of 20N, which is also called a PDO pattern, is caused by El Niño and La Niña events when those events are taking place. Do you agree with that or disagree, Geoff?
Disagree. This is probably the core of the debate. Your proposition of an El Nino led Rossby wave charging the next La Nina no doubt has merit, although I would like to see the Rossby wave in action after every El Nino, are you sure this happens during every El Nino? The ENSO process is not necessarily loading the neg PDO warm pool (NPWP…spatial area east of Japan). What drives the formation of the NPWP is an area of science not confirmed but there is no evidence that the 2010 El Nino provided the input to the NPWP that has lasted two years. If your logic is correct, dominate periods of El Nino during a pos PDO would load this area with warm water, which is actually observed in reverse, the pos PDO cold pool is formed in the same location. You need to answer this point.
And that means that the spatial patterns (cold in the east and warm in the central and western North Pacific similar to a La Niña pattern, and likewise, warm in the east and cool in the central and western North Pacific similar to an El Niño pattern) have different time periods. In other words, sometimes the spatial pattern associated with ENSO events in the North Pacific has a different schedule than the ENSO events themselves. The spatial pattern in the North Pacific can lead the ENSO event and sometimes it can lag the ENSO event, maintaining the ENSO-like pattern longer than the ENSO event itself. Do you agree with that or disagree,
Disagree, for the same reasons above, but agree the schedules can be non aligned, this describes the phase of the PDO. You have described a direct mechanism via a Rossby wave during El Nino, it either is there or is not. The double dip La Nina is a sober realization that other factors are involved. You also contend that the La Nina phase warms or charges the equatorial Pacific via reduced cloud cover for next El Nino. This did not occur during 2010/11 after a strong La Nina in 2010. If you are invoking another mechanism like a fluctuating Kuroshio Current or something similar this would be a different argument. I cannot see a direct relationship between ENSO and the NPWP.
A question for you.
Why did the double dip 2010/11 La Nina occur?
Bob Tisdale says:
January 17, 2012 at 9:04 pm
Part 2 of PDO basics, Geoff.
We can wait until part 1 is complete. You are not running the agenda here.
Geoff Sharpe: In response to a PDO basic question, you disagreed with what the PDO represented. You loose. You have no fundimental knowledge of what the PDO represents.
Good bye
Geoff Sharpe writes: “This is probably the core of the debate. Your proposition of an El Nino led Rossby wave charging the next La Nina no doubt has merit, although I would like to see the Rossby wave in action after every El Nino, are you sure this happens during every El Nino?”
Read what I wrote in the post and read what I wrote in reply to your earlier comments, Geoff. I never wrote anything that resembles “an El Nino led Rossby wave charging the next La Niña.” Please quote where I wrote anything to that effect. I also never said in this post or in any other post that a Rossby wave comparable to the one that formed after the 1997/98 El was formed after every El Niño event. In fact, in the post, I noted that the JPL animation showed that it had not happened in the rest of that video. You made an assumption that is not correct.
However, there was a Rossby wave after the 2009/10 El Niño, Geoff. It is visible in the following gif animation from the end of the 2009/10 El Niño. And as you’ll notice, one formed in the Southern tropics too. So there were Rossby waves in the North and South tropical Pacific after the 2009/10 El Niño.
http://i43.tinypic.com/mbu1ah.jpg
And here’s an animation of the NOAA GODAS x-z plots that show the recharge of the west Pacific Warm Pool during that time period:
http://i42.tinypic.com/zlt2wx.jpg
And here’s a graph that shows the Pacific Warm Pool OHC anomalies recharging after the 2009/10 El Niño. Keep in mind the NINO3.4 data in the graph is inverted:
http://i54.tinypic.com/23k7r5u.jpg
The graph is from the following post, which was linked in the post above:
http://bobtisdale.wordpress.com/2011/07/26/enso-indices-do-not-represent-the-process-of-enso-or-its-impact-on-global-temperature/
Do you agree with the data so far, Geoff, or do you disagree? The data doesn’t lie.
You wrote, “The ENSO process is not necessarily loading the neg PDO warm pool (NPWP…spatial area east of Japan). What drives the formation of the NPWP is an area of science not confirmed…”
It isn’t? Maybe the reason you can’t find any research about that area is because you insist on calling the area by the wrong name. I suggest you start researching the hundreds of papers that discuss the Kuroshio Extension and Kuroshio-Oyashio Extension.
You continued, “…but there is no evidence that the 2010 El Nino provided the input to the NPWP that has lasted two years.”
The data contradicts your statement. Maybe you should research before you write. The following is a comparison graph of NINO3.4 SST anomalies versus KOE (30N-45N, 150W-150E) SST anomalies. Both datasets are smoothed with a 13-month running average filter. The KOE begins to warm one month after the peak of the 2009/10 El Niño.
http://i40.tinypic.com/2u43803.jpg
Do you agree or disagree with the data, Geoff.
And your entire comment fixates on Rossby waves. If you were to read the post and those linked, I have explained very clearly the parts of the ENSO process that contribute to the warming of the West Pacific, including the Kuroshio-Oyashio Extension. These include:
1. The changes in atmospheric circulation caused by an El Niño working their way eastward until they reach the West Pacific.
2. As the trade winds resume their normal direction and strength during the transition from an El Niño to a La Niña, the trade winds “sweep” the warm water left over from the El Niño to the west.
3. During the transition from an El Niño to a La Niña, a Rossby wave can form and carry warm water left over from the El Niño back to the western tropical Pacific.
4. During the La Niña, due to the increased strength of the trade winds, North and South Pacific gyres spin up and carry the warm water poleward.
5. Also as a result of the increased strength of the trade winds, tropical Pacific cloud cover decreases. This causes an increase in downward shortwave radiation which warms the tropical Pacific. The trade winds carry the warm water westward and the North and South Pacific gyres carry it poleward. This helps to maintain the SST in the west Pacific at elevated levels, especially in the KOE and SPCZ.
I’ve illustrated, discussed and animated the interrelationships of the above and their impacts on the Western Pacific, including the KOE. The links are there. If you fail to use those links and fail to read and learn from what is presented in those posts, that is your fault, not mine.
Have a nice day. I have other things to do today than to tutor you in ENSO basics.
Bob Tisdale says:
January 18, 2012 at 12:35 am
Geoff Sharpe: In response to a PDO basic question, you disagreed with what the PDO represented. You loose. You have no fundimental knowledge of what the PDO represents.
Good bye
So the spelling Nazi can’t spell my name correctly? You also had a drama with “fundamental”
I am fully aware of what constitutes the PDO index. There are many factors that make up the index, but at the end of the day the sea surface temps of the Pacific north west are the main outcome.
I am not surprised you have wimped it. You cannot answer the big questions that undermine your platform.
This is a science forum, you are incapable of dealing with confrontation of your theory. Good luck, you will need it.
Geoff Sharp says: “I am not surprised you have wimped it. You cannot answer the big questions that undermine your platform.
“This is a science forum, you are incapable of dealing with confrontation of your theory. Good luck, you will need it.”
Hmm. Look at the comment above yours. You must not have scrolled down far enough–or maybe there was a delay in the moderation. I’m sure you’ll choose the latter.
Geoff Sharp says: “I am fully aware of what constitutes the PDO index.”
Apparently you’re not since you disagreed with the basics.
You continued, “There are many factors that make up the index, but at the end of the day the sea surface temps of the Pacific north west are the main outcome.”
The PDO does not represent the sea surface temperatures of the Kuroshio-Oyashio Extension. The PDO is inversely related to the sea surface temperatures of the KOE. But don’t let reality get in the way of your troll-like comments on this thread.The data is available for you to research and prove that I’m right or wrong. I’m tired of creating graphs and gif animations for you that contradict your nonsense.
Geoff Sharp says: “This is a science forum, you are incapable of dealing with confrontation of your theory.”
While I’ve already responded to your comments, I just wanted to reply to you one last time. I do not present theories at my blog or on the cross posts that Anthony is kind enough to include here at WUWT. I present processes that have been known for decades and documented in numerous scientific studies. I present the results of those processes, their impacts, on surface temperatures using data. If and when you can document your understandings to the same depth that I have, I will welcome your comments. Until that time, I will continue to reply to your troll-like comments as I see fit.
Bob Tisdale says:
January 18, 2012 at 5:48 am
You can see why I wanted an open forum with a moderator. It did not take you long to revert to your childish ways. Persistent use of the word “troll” only weakens your position.
But let’s cut through the crap. The PDO is made up of several components, most of which are important to how ENSO can be affected. SST spatial patterns, SLP, wind direction all play an important role. I have been watching the daily global SST anomalies for 2 years (everyday), I also plot every month the JISAO raw PDO values. I have also looked back through the weekly achieves of global SST anomalies. I have a good understanding through first hand experience how the SST patterns play out in comparison to the PDO index. I understand it was originally set up to monitor fish stocks and comes with some inherent weaknesses like seen during Jan 2003 where unusual west coast of North America SST values can skew the record. But overall the area in the north west Pacific is an important part of the overall index as shown by the keepers of the record and authors like Easterbrook and Spencer.
Right now we are seeing a typical SST pattern when the PDO is highly neg. On average the lower the PDO value the more likely we are to see warm water moving from the North West Pacific down to the area above New Guinea. This was observed in 2011.
With that out of the way, can we get back to part 1 or do you wish to employ further sophist type tactics?
note; I will be away today and yes a lot of my comments tend to go in the sin bin and get stuck in the moderator queue.
Geoff Sharp says: “But let’s cut through the crap.”
Curiously, I have been doing that, but you keep adding to it.
Geoff Sharp says: “The PDO is made up of several components, most of which are important to how ENSO can be affected.”
Wrong! Once again, you expose your misunderstanding of the PDO. On the JISAO webpage I linked for you earlier and in the papers they’ve linked to it, JISAO explains how the PDO is calculated. There is only one component, and that component is SST. First they divide the North Pacific north of 20N into 5×5 grids. The SST for each grid is detrended. Then the leading Principal Component is determined. Then those results are standardized. The PDO is not made up of several components.
Geoff Sharp says: “SST spatial patterns, SLP, wind direction all play an important role.”
ENSO, SLP, wind direction and strength (don’t forget strength) all play a role on the spatial patterns in the North Pacific, which all cause variations in the numerical value of the PDO.
Geoff Sharp says: “I have been watching the daily global SST anomalies for 2 years (everyday), I also plot every month the JISAO raw PDO values.”
So you’ve looked at the maps of the decay phase of the 2009/10 El Nino and the two La Nina events that followed it. Did you make copies of the maps so that you can animate them? Did you animate them?
Did you also graph the Sea Surface Temperatures of the areas of the North Pacific that interest you? Since you’ve noted that SLP and wind direction can impact the PDO, did you also plot the monthly values of these variables? And of course there’s ENSO. Since the PDO pattern by definition is an “El Nino-like pattern” one would think you would also plot that data as well.
Please provide links to the comparison graphs of the North Pacific SST anomalies, ENSO index, PDO, SLP and wind direction data you use in your research.
Geoff Sharp says: “I have also looked back through the weekly achieves of global SST anomalies. I have a good understanding through first hand experience how the SST patterns play out in comparison to the PDO index.”
Have your written a blog post? Sorry if I’ve missed it. If not, we await your documentation, with data, of your “first hand experience”.
Geoff Sharp says: “But overall the area in the north west Pacific is an important part of the overall index as shown by the keepers of the record and authors like Easterbrook and Spencer.”
What “record” would that be, Geoff? Please clarify which “record” you’re discussing. The PDO? I’ve already provided a Wikipedia link on this thread that discussed the importance of the Kuroshio-Oyashio Extension on North Pacific SST.
Also, please provide links to papers by Easterbrook and Spencer in which they discuss the “the north west Pacific is an important part of the overall index”. I’ve done a quick review of their papers and I can’t find one in which they discuss the Kuroshio-Oyashio Extension. Please advise.
Geoff Sharp says: “Right now we are seeing a typical SST pattern when the PDO is highly neg. On average the lower the PDO value the more likely we are to see warm water moving from the North West Pacific down to the area above New Guinea. This was observed in 2011.”
The primary ocean current in the west Pacific, the Kuroshio Current (not the Kuroshio Extension), runs south to north. It is a western boundary current. It strengthens during a La Nina. This happens because the trade winds strengthen during a La Nina, which in turn increases the strength of the Equatorial Current of the North Pacific. In the northern hemisphere, all of that water needs to go somewhere when it gets to the western tropical Pacific, Geoff, so what doesn’t get picked up by the Indonesian Throughflow, goes northward.
There is eddying in the area of the western tropical Pacific south of Japan and as a result, there is a current called the Kuroshio Countercurrent, which circulates a small portion of the water southward again. But you have to keep in mind it’s re-circulating warm water that had once been in the tropics back down toward the tropics again.
Basically, water is driven west across the northern tropical Pacific by the Coriolis effect- and trade wind-driven Equatorial Current. During a La Nina, that water is warmed by the increased downward shortwave radiation caused by the decrease in cloud cover associated with the La Nina. That La Nina-warmed water is carried north toward Japan by the Kuroshio Current, and then eastward by the Kuroshio-Oyashio Extension, where shows up as a positive SST anomaly east of Japan. And, what it sounds like you’re describing, the Kuroshio Countercurrent carries a small portion of that warm water back to the south.
When I researched the Kuroshio-Oyashio Extension a couple of years ago, I looked for scientific papers that attempted to quantify any additional contribution the Kuroshio Countercurrent might have on the warm water volume of the west Pacific Warm Pool. While there are approximately 100 or so papers that discuss the Kuroshio Countercurrent, meaning it is a much-studied current, I could find none that documented its contribution. Do you have links to papers that document its contribution to the warm water volume and/or OHC of the PWP? All papers that describe the recharging of the PWP (for example, Trenberth et al [2002] linked in the post) discuss the process I have presented. They do not discuss the additional minor feedback contribution of the Kuroshio Countercurrent.
If YOU, Geoff, want to claim there is a significant additional contribution by the Kuroshio Countercurrent to the warm water volume and OHC of the Pacific Warm Pool, YOU need to document it with ocean current volumes, warm water storage volumes, heat content of those waters, etc. YOU might try to claim there’s a significant contribution, but YOU need to document it with data to prove it. You can’t just say, hey, look at what I’ve seen. But that’s all YOU have been doing. I understood this and so did everyone else reading this thread.
Have a nice day.
Bob Tisdale says:
January 18, 2012 at 2:52 am
Read what I wrote in the post and read what I wrote in reply to your earlier comments, Geoff. I never wrote anything that resembles “an El Nino led Rossby wave charging the next La Niña.”
I am afraid you did, but happy to see you now make this point clear. The El Nino Rossby wave is not a regular occurrence during El Nino which doesn’t surprise me. You need to be more careful in your choice of words.
You said:
An El Niño can carry huge volumes of warm water from the surface and below the surface of the west Pacific Warm Pool eastward to the central and eastern equatorial Pacific. That warm water is not consumed fully by the El Niño, so it returns to the west during the La Niña. One of the ways the La Niña accomplishes this return of warm water is through a phenomenon called a slow-moving Rossby wave, which forms in the northeast tropical Pacific at about 5N-10N. After the 1997/98 El Niño, the Rossby wave is plainly visible in ocean heat content anomaly animations, and better still in sea level residual animations from the Jet Propulsion Laboratory.
“One of the ways” could mean every El Nino has a Rossby wave AND other methods of moving warm water to the west (other methods are outlined by you), or it could mean it happens occasionally. By inference any moving warm water to the west Pacific warm pool is going to setup the conditions for a La Nina. Then a little further on after many animations of the Rossby wave you state:
Add to that the effects of the Rossby wave. As illustrated earlier, at approximately 5N-10N latitude, a slow-moving Rossby wave also carries leftover warm water from the eastern tropical Pacific back to the western Pacific during the La Niña. Ocean currents carry all of the leftover the warm water poleward to the Kuroshio-Oyashio Extension (KOE) east of Japan and to the South Pacific Convergence Zone (SPCZ) east of Australia
</There is no mention of the Rossby wave being an occasional phenomenon. The reader is led to believe it is a normal occurrence. You have either written it poorly or misled us
I think you need to amend your articles here and and your own blog to make this point very clear.
The data contradicts your statement. Maybe you should research before you write. The following is a comparison graph of NINO3.4 SST anomalies versus KOE (30N-45N, 150W-150E) SST anomalies. Both datasets are smoothed with a 13-month running average filter. The KOE begins to warm one month after the peak of the 2009/10 El Niño.
http://i40.tinypic.com/2u43803.jpg
If you mean looking at your research I dont buy it. The correlations in you graph look extremely poor. Look at 1983 after the big El NIno, the KOE is hardly affected as you might expect during a pos PDO. You and others might like to call this region the KOE but I think it places too much emphasis on the current. The loading of this area for PDO purposes is definitely not an area of settled science.
The PDO does not represent the sea surface temperatures of the Kuroshio-Oyashio Extension. The PDO is inversely related to the sea surface temperatures of the KOE.
This is a pure example of a sophist at work. You know full well that the NPWP (KOE) needs to be inverted to match the PDO index and is direct proof of the solid link between the two datasets. Basically the NPWP (KOE) IS the PDO index which both you and I have shown.
http://tinyurl.com/2dg9u22/images/pdo_nwpac.png
To summarize:
1. The El Nino Rossby wave is not a normal phenomenon during each El Nino. (you need to make a public statement here and at your blog)
2. The north west Pacific SST’s are a very close fit (once inverted) to the PDO index.
Do you agree Bob? If not you will need to provide evidence.
Which brings us back to the main issue. Can the PDO (NPWP/KOE/ north west Pacific warm pool) influence ENSO? I have shown it can, which you are still yet to respond to. The main issue is still outstanding.
Bob Tisdale says:
January 19, 2012 at 3:23 am
There is nothing relevant to the discussion in this long winded rambling reply dated above.
Agree or disagree to my summary points in the previous post so we can move on. The summary points cover most of the last two days discussions. If not you are only creating smoke screens trying to avoid the real issue that is still not dealt with. “Is the PDO an after effect of ENSO”
Bob
Sorry about the late reply. The step is in 1976. Why do you ask?
http://virakkraft.com/76-shift.png
lgl says: “The step is in 1976. Why do you ask?”
Thanks for the confirmation. The Pacific Climate Shift is in 1976.
The end of the 1973/74/75/76 La Nina was in 1976 and ENSO is the dominant source of variability in the Pacific.
Regards
Geoff Sharp says: “Agree or disagree to my summary points in the previous post so we can move on.”
I replied to your comments one by one. The fact that you cannot understand whether they agree or disagree with your comment reflects on your lack of understanding on the subject matter. There is no reason to continue this discussion. I have been more than fair to you on this thread.
Good bye, Geoff.Sharp. [while I understand you are upset, that’s not in your jurisdiction – snip – Anthony]
Anthony: I understand your snip. My underlying thought was based on his comment on the Bastardi thread. I now have to search for his name on every thread to assure that he’s not throwing in off-topic comments directed at me.
Bob
The end of the 1973/74/75/76 La Nina was in 1976 and ENSO is the dominant source of variability in the Pacific.
Yes it is on the interannual scale, but on a decadal scale we need the NPI (or it’s driver)
The OHC increase in the tropics in the 70s is much larger than the ENSO variability.
http://virakkraft.com/ENSO-OHC-Tropics.png
http://virakkraft.com/PDO-tropical-OHC.png
lgl says: “Yes it is on the interannual scale, but on a decadal scale we need the NPI (or it’s driver)
The OHC increase in the tropics in the 70s is much larger than the ENSO variability.
http://virakkraft.com/ENSO-OHC-Tropics.png
http://virakkraft.com/PDO-tropical-OHC.png”
Or maybe the SOI as opposed to NINO3.4 SST anomalies would be better for discussions of OHC since the SOI would be a proxy for trade wind strength, which influences cloud cover, which dictates the DSR reaching the ocean. Regardlless, if a La Nina lasted for three full years, wouldn’t you expect the tropical Pacific OHC to rise over the entire La Nina due to the increase in DSR?
Bob
I can’t see using SOI makes much difference. http://virakkraft.com/SOI-OHC-Tropics-WH.png Still a step in the 70s.
A three year La Nina would cool the surface and since the ocean is heated/cooled from the top I would expect OHC to decrease. And according to Bill Illis the upward LW increases more than DSR.
lgl: Refer to Pavlakis et al (2008) regarding DSR:
http://www.atmos-chem-phys-discuss.net/8/6697/2008/acpd-8-6697-2008.pdf
And Pavlakis et al (2007) regarding DLR:
http://www.atmos-chem-phys-discuss.net/6/12895/2006/acpd-6-12895-2006.pdf
And now for my basic question: What coordinates are you using for your OHC graphs? It’s tough to read with the overlay. From what I can read, they’re 23.5S-23.5N, 180-360, or written another way 23.5S-23.5N, 180W-0, but that would be the eastern tropical Pacific and tropical Atlantic? Are those the coordinates you’re using? If so, why are you including the Atlantic? Why not the western tropical Pacific instead? Usng your latitudes of 23.5S-23.5N, the longitudes for the tropical Pacific would be 120E-80W, or 120E-280E.
Regards
Bob
Thank you for the links. I can’t find any conclusive regarding ULR, just a lot on DLR.
Yes, I do use 180W-0. It started with this http://virakkraft.com/ENSO-OHC-Tropics.png where I noticed the nice correlation/anti-corr. except the very odd step in the 70s without any similar step down in the other hemisphere, and I found it useful to include all tropics in the search of where did the heat come from. Besides, 120E is no natural boundary, Pacific is well connected with Indian.