Yet Even More Discussions About The Pacific Decadal Oscillation (PDO)

Guest post by Bob Tisdale

INTRODUCTION

I’ve written numerous posts that describe the Pacific Decadal Oscillation (PDO), what the PDO represents, and, just as important, what it does not represent. For those new to the PDO and for those needing a refresher, refer to An Introduction To ENSO, AMO, and PDO — Part 3An Introduction To ENSO, AMO, and PDO — Part 3.

IceCap recently published a post about the PDO. One of the illustrations in that post confirms a point I have been making: that the PDO does not represent the Sea Surface Temperatures of the North Pacific. And I’ve added a few additional comments and clarifications about the IceCap post.

In my post An Introduction To ENSO, AMO, and PDO — Part 3, the discussions of the PDO patternwere about the spatial pattern. But the word pattern can also be time-related and, therefore, it could pertain to the PDO’s “behavior in time”. A recent discussion on a blog thread gave me the impression that the multiple meanings of the word pattern could be the cause of some of the confusion about the PDO.

Also, much of the post An Introduction To ENSO, AMO, and PDO — Part 3discussed and illustrated the fact that the PDO does not represent the Sea Surface Temperature Anomalies of the North Pacific. There is another factor that may lead to some of the continued misunderstandings about the PDO. The PDO data is standardized. This could greatly exaggerate the magnitude of its variations. Could the standardization also inflate its perceived importance?

I had also wanted to include the errors in the SkepticalScience post It’s Pacific Decadal Oscillation . The SkepticalScience post was obviously written by someone who never plotted the Sea Surface Temperature anomalies of the North Pacific, who misunderstands how the PDO is calculated and what it represents, and who misunderstands or elects to misrepresent climate oscillations. But this post is long, so I’ll present the Skeptical Science errors in a separate post.

THE ICECAP PDO POST

Figure 1 is a screen cap of the opening of Joe D’Aleo’s post about the PDO at IceCap. I’ve included the screen cap because if you were to click on the post title Is the PDO real or a skeptic inventionat IceCap the link does not bring you to the post; it links to a .pdf document titled “THE PDO.” Most of the IceCap post and the linked .pdf document appear to be the same, but their opening paragraphs and the titles are different.

Figure 1

That aside, most of the IceCap post is intended to confirm the existence of the PDO, which is something I don’t dispute. If you’ve watched any of the SST .gif animations or videos I’ve prepared, the positive and negative PDO spatial patterns are very visible. And they should be; the PDO spatial pattern is the most prevalent of the many that form in the North Pacific SST anomalies. The IceCap post also mentions using the Pacific Decadal Oscillation in weather forecasts. Since there are a number of papers that describe weather patterns associated with the PDO, I imagine the PDO data is a useful index for meteorologists.

But one of the points that I have illustrated and discussed a number of times is that the PDO does not represent the Sea Surface Temperature anomalies of the North Pacific, north of 20N. The IceCap post includes a group of PDO- and ENSO-related maps, Figure 2. And those maps actually illustrate that the PDO does not represent the Sea Surface Temperature (SST) anomalies of the North Pacific.

Figure 2

I’ve modified the illustration, Figure 3, by highlighting the area used to calculate the PDO data and by covering the rest of the maps with text. The PDO is not calculated from the SST data south of 20N, so all of that additional visual information exaggerates the surface area represented by the PDO.

Figure 3

My text in Figure 3 reads: In The Positive (Warm) Phase Map Of The PDO Shown Above Left, The Sea Surface Temperature Anomaly For The North Pacific North Of 20N Appears To Be Negative. That Is, The Negative SST Anomalies Cover A Greater Surface Area And They Are More Intense Than The Positive Anomalies. The Opposite Holds True For The Map On The Right-Hand Side. How Then Could A Positive (Warm) Phase Of The PDO Raise Global Surface Temperatures, And Vice Versa?

Someone is bound to note that the IceCap post does not mention that the PDO has an impact on Global surface temperatures. Agreed. Their post doesn’t. This part of my discussion is about the common belief that the sign of the PDO dictates whether global temperatures rise or fall. Since the sign of the PDO does not represent the Sea Surface Temperature of the North Pacific the belief is unfounded.

In past posts, I’ve presented that there is an inverse relationship between the PDO and the Sea Surface Temperature (SST) Anomalies of the North Pacific. This can be shown with a graph that compares the PDO data and the difference between the SST anomalies of the North Pacific north of 20N and global SST anomalies. For simplicity sake, we’ll use the term “North Pacific Residual” for the data that’s calculated as the North Pacific SST anomalies minus the Global SST anomalies. Refer to Figure 4. We’ll use the North Pacific Residual in the comparison graph because one of the steps taken to calculate the PDO is to subtract Global SST anomalies from the SST anomalies of each 5 degree by 5 degree grid of the North Pacific north of 20N. Both datasets in Figure 4 have been smoothed with 121-month running average filters. Other than the agreement between the multidecadal variations in the two curves, there are a couple of things to note about the graph. First, the PDO data has been inverted; that is, it’s been multiplied by a negative number. Second, the PDO data has also been scaled by a factor of 0.2. That was an arbitrarily chosen round number I used to bring the variations of the PDO down into line with the North Pacific Residual data. But let’s look at the scaling in another way: the multidecadal variations in the PDO data are five times higher than the actual variations in the North Pacific Residual data in that graph. One might conclude the PDO data exaggerates the actual multidecadal variations in North Pacific SST anomalies. More on that later.

Figure 4

Figure 4 is taken from the post An Inverse Relationship Between The PDO And North Pacific SST Anomaly Residuals.

The SST anomaly data for the North Pacific is part of the Global Surface Temperature data, but the PDO data is not. This inverse relationship between the PDO and the SST anomaly data of the North Pacific directly contradicts the assumption that a positive (warm) PDO is responsible a rise in global temperatures or that a negative (cold) PDO is somehow responsible for a drop in global temperatures.

The IceCap post attempts to resurrect the argument that there is no clear evidence that ENSO drives the PDO. IceCap bases their brief discussion on a quote from the 14-year old Mantua et al (1997) paper “A Pacific interdecadal climate oscillation with impacts on salmon production.” The IceCap post reads, “The authors made no claim as to which (PDO or ENSO) was the chicken and which the egg.” And IceCap includes a quote from Mantua et al (1997):

“The ENSO and PDO climate patterns are clearly related, both spatially and temporally, to the extent that the PDO may be viewed as ENSO-like interdecadal climate variability (Tanimoto et al. 1993; ZWB). While it may be tempting to interpret interdecadal climatic shifts as responses to individual (tropical) ENSO events, it seems equally conceivable that the state of the interdecadal PDO constrains the envelope of interannual ENSO variability.”

That paragraph from Mantua et al (1997) appears to contradict a paper they reference. Mantua et al (1997) calculate the PDO using a method that was presented in Zhang et al (1997) ENSO-like Interdecadal Variability: 1900–93. In Zhang et al (1997), the PDO was identified as “NP”, and they use Cold Tongue Index SST anomalies (CT) as the El Niño-Southern Oscillation (ENSO) proxy. Zhang et al (1997) note:

“Figure 7 shows the cross-correlation function between CT and each of the other time series in Fig. 5. The lag is barely perceptible for TP and G and it increases to about a season for G – TP and NP, confirming that on the interannual timescale the remote features in the patterns shown in Fig. 6 are occurring in response to the ENSO cycle rather than as an integral part of it…”

It would be difficult for the PDO to drive ENSO if ENSO leads the PDO by a season and if the PDO spatial pattern is a “response to the ENSO cycle rather than…an integral part of it.”

In the 14 years since Mantua et al (1997) was published, there have been a number of papers that confirm that ENSO drives the PDO. In ENSO-Forced Variability of the Pacific Decadal Oscillation, Newman et al (2004) also found that the PDO lags ENSO. They describe cell d of their Figure 1 as:

“ENSO also leads the PDO index by a few months throughout the year (Fig. 1d), most notably in winter and summer. Simultaneous correlation is lowest in November– March, consistent with Mantua et al. (1997). The lag of maximum correlation ranges from two months in summer (r ~ 0.7) to as much as five months by late winter (r ~ 0.6). During winter and spring, ENSO leads the PDO for well over a year, consistent with reemergence of prior ENSO-forced PDO anomalies. Summer PDO appears to lead ENSO the following winter, but this could be an artifact of the strong persistence of ENSO from summer to winter (r = 0.8), combined with ENSO forcing of the PDO in both summer and winter. Note also that for intervals less than 1yr the lag autocorrelation of the PDO is low when the lag autocorrelation of ENSO (not shown) is also low, through the so-called spring persistence barrier (Torrence and Webster 1998).”

And the first sentence of the Conclusions of Newman et al (2004) reads (their italics):

“The PDO is dependent upon ENSO on all timescales.”

My post An Introduction To ENSO, AMO, and PDO — Part 3 included the same discussions of those two papers under the heading of DOES THE PDO DRIVE ENSO?

A more recent paper, Shakun and Shaman (2009) “Tropical origins of North and South Pacific decadal variability” also confirms that the PDO is an aftereffect of ENSO. In addition to the PDO, they use the acronym PDV for Pacific Decadal Variability.

The Shakun and Shaman (2009) Conclusions read:

“Deriving a Southern Hemisphere equivalent of the PDO index shows that the spatial signature of the PDO can be well explained by the leading mode of SST variability for the South Pacific. Thus, PDV appears to be a basin-wide phenomenon most likely driven from the tropics. Moreover, while it was already known PDV north of the equator could be adequately modeled as a reddened response to ENSO, our results indicate this is true to an even greater extent in the South Pacific.”

These papers confirm my statements from past posts that the PDO is an aftereffect of ENSO. And that brings us to the two tables from the IceCap post, which I have merged into one graphic, Figure 5. IceCap introduces the tables by stating:

“During the positive phase see the dominance of more frequent, stronger, longer La Ninas and the positive PDO mode, more frequent, stronger and longer El Ninos.”

There is an obvious error in that sentence. It should begin with “During the negativephase…”

Figure 5

Now I do realize that IceCap has not stated that the positive PDO is responsible for the more frequent, stronger and longer El Niño events and vice versa, but they implied it. And that contradicts the papers above. Since the PDO is an aftereffect of ENSO, a period when El Niño events dominated would cause the PDO to be positive, and vice versa for epochs when La Niña events dominate.

A SIMPLE DESCRIPTION OF HOW THE PDO SPATIAL PATTERN IS FORMED

To reinforce the discussion above, the following is a simple explanation of the processes that cause the PDO spatial pattern during ENSO events.

A positive PDO spatial pattern is characterized by SST anomalies in the eastern North Pacific that are higher than the SST anomalies in the central and western North Pacific. That positive PDO pattern is created by the response of the North Pacific SST anomalies to an El Niño event. Changes in coupled ocean-atmosphere processes, resulting from the El Niño, can cause an increase in the SST anomalies in the eastern North Pacific. Since the El Niño causes a reversal of trade winds in the western tropical Pacific, less warm water than normal is spun up into the western and central North Pacific (an area called the Kuroshio-Oyashio Extension or KOE), and SST anomalies of the western and central North Pacific drop. The initial drop in the western and central North Pacific is also driven by the changes in coupled ocean-atmosphere processes that are caused by the El Niño. The reverse holds true during a La Niña in the eastern North Pacific. For the western and central North Pacific during a La Niña, the leftover warm water from the El Niño also gets spun up into the KOE, adding to the warm waters being brought there by the increased strength of the trade winds, both of which raise SST anomalies there.

There are differences between the PDO and an ENSO proxy such as NINO3.4 SST anomalies from time to time. (NINO3.4 SST anomalies are a commonly used proxy for the frequency and magnitude of El Niño and La Niña events.) The reason for this is that other factors can impact how the North Pacific SST anomalies respond to ENSO events. These other factors include shifts in sea level pressure in the North Pacific and a phenomenon called The Reemergence Mechanismalong the Kuroshio-Oyashio extension (KOE). Aerosols from explosive volcanic eruptions should also account for some of the differences between the PDO and an ENSO proxy, though I have never seen this discussed in any papers.

CAN THE MULTIPLE MEANINGS OF THE WORD PATTERN ADD TO THE CONFUSION ABOUT THE PDO?

The Joint Institute for the Study of the Atmosphere and Ocean Joint Institute for the Study of the Atmosphere and OceanJoint Institute for the Study of the Atmosphere and Ocean (JISAO) Pacific Decadal Oscillation (PDO) webpage is a primary source for PDO information and data. Two maps are used by JISAO to illustrate the spatial patterns that can exist during the warm and cool phases of the PDO, Figure 6. I’ve highlighted the area of the North Pacific represented by the Pacific Decadal Oscillation. It is the area north of 20N, and only that area. The word “pattern” in the opening paragraph on that webpage refers to the “spatial climate fingerprint” of the North Pacific north of 20N, not the multidecadal variability of its data. As discussed previously in this post, when the PDO data is positive (warm phase), the SST anomalies in the eastern North Pacific are warmer than those in the western and central North Pacific, and when the PDO is negative (cool phase), the SST anomalies in the eastern North Pacific are cooler than the SST anomalies in the western and central north Pacific.

Figure 6

Farther down on the JISAO PDO webpage, the PDO is described as:

The “Pacific Decadal Oscillation” (PDO) is a long-lived El Niño-like pattern of Pacific climate variability. While the two climate oscillations have similar spatial climate fingerprints, they have very different behavior in time.

Again, the word pattern is being used to describe spatial characteristics of the SST anomalies.

As discussed in An Introduction To ENSO, AMO, and PDO — Part 3An Introduction To ENSO, AMO, and PDO — Part 3, the phrase “El Niño-like pattern” does NOT mean that the North Pacific (north of 20N) has a separate El Niño-like event.It refers to the fact that a typical El Niño event creates a spatial pattern in the North Pacific where it is warmer in the east than it is in the central and western portions, and a typical La Niña event will create the opposite pattern, cooler in the east than it is toward the center and west of the North Pacific.

Figure 7 is a time-series graph that compares the PDO and NINO3.4 SST anomalies (a commonly used proxy for the frequency and magnitude of El Niño and La Niña events). Both datasets have been smoothed with a 121-month filter. Keep in mind that the NINO3.4 SST anomalies represent exactly that, the SST anomalies of an area of the tropical Pacific called the NINO3.4 region, which is bordered by the coordinates of 5S-5N, 170W-120W, while the PDO does not represent the SST anomalies of the North Pacific. The PDO is a statistically manufactured dataset. As illustrated, the multidecadal variations in the PDO and the NINO3.4 SST anomalies are different. Both vary from positive to negative in the mid-1940s and rise from negative to positive in the late 1970s, but the NINO3.4 SST anomalies have an extra period of positive values in the 1960s. As discussed earlier in this post, the reason the PDO has a different “behavior in time” is because the PDO is also strongly impacted by other factors, including sea level pressure and volcanic eruptions.

Figure 7

In summary, on the main JISAO Pacific Decadal Oscillation (PDO) webpage, the word pattern always refers to the “spatial” characteristics of the North Pacific SST anomalies, not its behavior in time.

THE WORD PATTERN CAN ALSO BE TIME RELATED

The second illustration on the main JISAO Pacific Decadal Oscillation (PDO) webpage is a time-series graph of the PDO data. It was missing from the website as I prepared this post. But there are copies posted at other websites. Refer to Figure 8.

Figure 8

On their PDO Index Monthly Values webpage, JISAO uses the phrase “the pattern of variability” to describe the PDO’s “behavior in time” or the periodicity of the PDO data. Refer to the description of the dataset at the top of the page. It reads (my boldface):

Updated standardized values for the PDO index, derived as the leading PC 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.

The uses of the word pattern are different, and their intents are different. Does the use of the word pattern in both instances add to the confusion about the PDO? I don’t have the answer. I’m asking the question. Clearly, the use of pattern in the JISAO description of “The ‘Pacific Decadal Oscillation’ (PDO) is a long-lived El Niño-like pattern” relates to its spatial characteristics. Likewise, the word pattern in the JISAO description of their maps, “Typical wintertime Sea Surface Temperature (colors), Sea Level Pressure (contours) and surface windstress (arrows) anomaly patternsduring warm and cool phases of PDO,” refers to the same thing, the spatial pattern.

Note: I mentioned above that there are no El Niño or La Niña events in the North Pacific north of 20N. I have shown, however, that there are secondary releases of heat in the North Pacific from the warm waters left over from an El Niño. These secondary releases of heat from the North Pacific occur along the Kuroshio-Oyashio Extension (KOE) and they occur during La Niña events that follow major El Niño events. Refer to The ENSO-Related Variations In Kuroshio-Oyashio Extension (KOE) SST Anomalies And Their Impact On Northern Hemisphere Temperatures.

DOES THE PDO DATA EXAGGERATE ITS RELATIVE SIGNIFICANCE?

Figure 9 compares the Pacific Decadal Oscillation (PDO) data and NINO3.4 SST anomalies. The scales are similar and that might lead one who is unaware of the differences between the two datasets to believe the two “signals” are similar in magnitude. That’s wrong for a number of reasons. First, the NINO3.4 SST anomalies represent the SST anomalies of an area in the equatorial Pacific, but the PDO data does not represent the SST anomalies of the North Pacific. The PDO data is a statistically manufactured dataset that represents an abstract form of the SST data there. Second, the NINO3.4 SST anomalies are presented in Deg C. The PDO data is not. The PDO data has been standardized.

Figure 9

Unfortunately, as far as I know, there is no PDO data available online that has not been standardized. So to illustrate the PDO data before standardization, one would have to duplicate the process JISAO uses to create it. Two of the three SST datasets JISAO uses are obsolete and the differences between those older datasets and the current spatially complete datasets are significant, so the results could be very different. And we really do not need to go through all of that trouble to show that the PDO exaggerates the variability of the North Pacific SST anomalies. We can show that other ways.

The inverse relationship between the PDO and the North Pacific Residual was illustrated in Figure 4. And as you’ll recall, the North Pacific Residual was calculated by subtracting Global SST anomalies from North Pacific SST anomalies, north of 20N. Both datasets in Figure 4 were smoothed with a 121-month running-average filter and the PDO data was scaled and inverted (multiplied by -0.2) to bring its variations into line with the North Pacific Residual data. For the next illustration, Figure 10, let’s leave the PDO data in its raw monthly form, and only invert (multiply by -1) the North Pacific Residual data. That is, we won’t scale either dataset. As shown in Figure 10, the actual variations in the North Pacific Residual are miniscule compared to those of the standardized PDO data.

Figure 10

The standard deviation of the North Pacific Residual data is 0.177, so to standardize that dataset we divide it by that value, or multiply it by its reciprocal of 5.65. Refer to Figure 11. Note how well the inverted and standardized North Pacific Residual data (using a different SST dataset, HADISST) captures the underlying multidecadal variations of the PDO data.

Figure 11

And we can detrend the North Pacific SST anomaly data to also show how the PDO exaggerates actual North Pacific Sea Surface Temperature variability. Again in this example, both datasets are in their “raw” form, and the detrended North Pacific SST anomalies are inverted (multiplied by -1.0). The PDO data as shown in Figure 12 greatly exaggerates the actual variations in the detrended North Pacific SST anomalies.

Figure 12

To standardize the detrended North Pacific SST anomalies, we’ll divide the data by its standard deviation (0.182), or multiply it by its reciprocal of 5.5. Once again, as shown in Figure 13, much of the multidecadal variability of the PDO can be captured by inverting and scaling the adjusted North Pacific SST anomalies.

Figure 13

Whether we present the North Pacific SST anomalies detrended or as a residual, the PDO data exaggerates the actual variations in North Pacific SST anomalies by a factor of at least 5.5. This may also lead to some the misunderstandings of the effects of the PDO on global temperatures.

CLOSING

The PDO is a useful index. Based on the IceCap post, it is used by meteorologists for weather predictions. The early papers about the PDO discussed its impact on salmon production, so it is also useful in those endeavors. But the PDO cannot be used to explain epochs of global warming or cooling because the PDO does not represent a process through which the North Pacific could raise or lower global temperatures.

This post also illustrated how the PDO data is inversely related to North Pacific SST anomalies and how the PDO data greatly exaggerates the actual variations in the Sea Surface Temperatures of the North Pacific.

In a follow-up post, we’ll discuss the error-filled SkepticalScience post It’s Pacific Decadal Oscillation.

SOURCE

The PDO data and the HADISST anomalies presented in this post are available through the KNMI Climate Explorer:

http://climexp.knmi.nl/selectfield_obs.cgi?someone@somewhere

About these ads
This entry was posted in PDO and tagged , . Bookmark the permalink.

100 Responses to Yet Even More Discussions About The Pacific Decadal Oscillation (PDO)

  1. It's always Marcia, Marcia says:

    Bob

    I think it would help many readers if you made a video of things you present, like a lecture complete with a chalk board and graphs. It would be easier for many people to understand you with more than one of the five senses being used.

  2. Doug Proctor says:

    Earlier, I and others complained about criticisms without corrections. Now I, and the others, stand corrected. Well done. Mea culpa.

  3. Antony and other friends.
    I would like to buy a book of climatology. I am a civil engineer and want a suggestion on a good book without a biased view on the subject. What the suggestion of you.

  4. Brian H says:

    My eyeballs tell me the terms “positive” and “negative” PDO match the SST behaviour tight up against the Canadian and Alaskan coastline, the inverse of the bulk of the North Pacific. Is that correct?

  5. John F. Hultquist says:

    Bob T. has reported this information in several iterations over the last couple of years. With his supporting links and ever clearer explanations and diagrams it is about time for everyone to catch on. Please spread this widely.
    Thanks, Bob. Well done.

  6. edwardt says:

    Does ENSO impact global temperatures? By the warm pools moving from ocean basin to ocean basin in step changes? If so, is PDO not related to ENSO, either a representation of ENSO tendencies (more El Ninos than La Ninas and visa versa depending upon perceived PDO phase), or an initiator (either way, same thing). Seems like if ENSO effects global temps (which I believe is a theory or implication of yours, correct me if I’m wrong), then PDO either effects global temps or is a indicator of ENSO tendencies which effect global temperatures. I don’t understand the difference. There clearly seems to be a link between PDO states and global climate change points, regardless of the perceived mechanism (lack of SST anomaly or ENSO step change driven). Maybe it is an indicator of the state or activity of the THC? Just wondering aloud…agree it’s independent of the pacific sst anomaly, but it must represent something else going on, that apparently effects climate…just what is it? Local (meaning west coast of USA) climate, which has some impact on global anomalies, seems too small. Does it translate to the arctic area which seems to have a large impact on calculated global anomalies, there certainly appears to be correlation with alaska and other arctic areas. Maybe we could describe the PDO and it’s apparent effect on local areas (and how it might impact global anomalies) without getting into whether it represents the pacific sst or not? Maybe I should slow down and reread…probably a good idea.

  7. phil says:

    Ok I’m confused on something. In the “-PDO phase”, despite the ENSO phases, the overall PDO pattern seems to be relatively lower/more negative. Now I’m not saying that ENSO doesn’t effect the PDO significantly, as in, the reasoning for an apperent PDO lag to ENSO, but is that the entire story?

    In the Positive PDO phase, despite Changes in ENSO, the net PDO value is in the positive orientation, the -PDO phase, despite changes ENSO, still appear to be more negative…

    So could it go both ways? As in maybe they depend on Eachother?

    thanks :-)

  8. jorgekafkazar says:

    Nice material and a lot of it to consider. I’m not sure I understood all of it, and there are two areas where I particularly feel adrift:

    “Since the El Niño causes a reversal of trade winds in the western tropical Pacific…”

    Can you refer me to a data source showing that El Niños precede reversal of the trade winds? At what point do the trade winds go back to the previous direction set?

    “Figure 7 is a time-series graph that compares the PDO and NINO3.4 SST anomalies (a commonly used proxy for the frequency and magnitude of El Niño and La Niña events). Both datasets have been smoothed with a 121-month filter.”

    Lacking any proof to the contrary, my working assumption would be that El Niño/La Nina and PDO are independent cyclical phenomena. Figure 5 doesn’t make me want to change that assumption, since the correlation isn’t perfect. Their “frequencies,” insofar as they have any, may be similar, thus producing long periods (climatologically speaking) of reasonably good “wiggle matching.” Since El Niño/La Nina cycles have a periodicity that is significantly less than 10.1 years, wouldn’t the smoothing used in Figure 7 blur any putative relationships between PDO/El Niño? What is left over?

  9. Dan says:

    Not really sure this is actually worth much of an effort but having skimmed this ‘work’ and the similar icacap effort, have to say, you are joking aren’t you.
    This was at he bottom of the icecap story
    “Modelers and warmists will never admit to the PDO existence or importance as it would provide an alternative reason for the warming during the period from 1977 to 1998″
    What utter fiction, nobody is saying the PDO does not exist, that is (I’m sorry) a straight out lie. The role both the PDO and ENSO play in year to year climate are well documented, in fact a skeptical theory that cooling in the 40s through to the 70s (and their claim it proves AGW is not happening) when in fact it coincides with a large PDO cooling event that occurred over the same period even to the small reprieve around 1960, this is natural variability and despite repeated skeptic claims scientists have never said that natural variability is not happening, such a claim is in fact absurd as many of the same scientists are involved in researching both the PDO & ENSO.
    I realize skeptics are looking for any excuse to try and dismiss AGW (and they have tried many) but your own (fig 8) shows you can’t really blame the PDO. It has moved either side of a mean over the last 100 years and yes the warmests year do coincide with warmer years (adding to the effect of AGW) but the PDO has not had a long slow increase in the way the global temperature has, and certainly the PDO as the cause falls flat when you look at it’s phase in 2005 & 2010 the two warmest years on record.

  10. Bob Tisdale says:

    It’s always Marcia, Marcia says: “I think it would help many readers if you made a video of things you present, like a lecture complete with a chalk board and graphs.”

    My experience is that videos are about 10 times the work, but they get a small fraction of the traffic of a blog post. The return doesn’t seem to be worth all of the extra effort.

  11. Bob Tisdale says:

    Brian H says: “My eyeballs tell me the terms ‘positive’ and ‘negative’ PDO match the SST behaviour tight up against the Canadian and Alaskan coastline, the inverse of the bulk of the North Pacific. Is that correct?”

    I’m using the Kuroshio-Oyashio Extension SST anomalies in the following graph for the West and Central North Pacific SST anomalies.
    http://i55.tinypic.com/f3dgnp.jpg

    In general, your description holds true for the direction of the year-to-year variations, but not necessarily the magnitude. But the Eastern North Pacific and the KOE SST anomaly variations can occasionally run in the same direction.

  12. Bob Tisdale says:

    edwardt says: “If so, is PDO not related to ENSO, either a representation of ENSO tendencies (more El Ninos than La Ninas and visa versa depending upon perceived PDO phase), or an initiator (either way, same thing). Seems like if ENSO effects global temps (which I believe is a theory or implication of yours, correct me if I’m wrong), then PDO either effects global temps or is a indicator of ENSO tendencies which effect global temperatures. I don’t understand the difference.”

    First, the PDO is an aftereffect of ENSO, not an initiator. Second, the PDO does not represent the SST of the North Pacific; it is, in reality, inversely related to the North Pacific Residual (North Pacific SST anomaly minus Global SST anomaly). Refer to Figure 4 above. That is, over decadal time scales, when the PDO is rising, the North Pacific is contributing less to the rise in global temperatures and vice versa. Therefore, the PDO cannot be driving the global temperature variations. Third, if the PDO and an ENSO proxy can run out of synch occasionally, then the PDO is truly not a reasonable proxy for ENSO tendencies. You’re better off using an ENSO proxy.

  13. Geoff Sharp says:

    The PDO is a valuable tool that is a derived value. The pacific temperatures north of 20N are not important, when the north is cooler it allows the equatorial regions to warm. The PDO trend quite clearly follows the world temperature trend, and by adding solar variation all temperature measurement movements can be explained by natural variation.

    Positive PDO correlate with higher incidence of El Nino and vice versa. There is insignificant evidence to say what drives what, but I am with Erl Happ when it comes to the ENSO driver. The strength and direction of the Trades is the initiator of the ENSO cycle which is driven by changes in atmospheric pressure. What drives the changes in atmospheric pressure will be the key to understanding the most important oceanic region.

  14. Bob Tisdale says:

    jorgekafkazar says: “Can you refer me to a data source showing that El Niños precede reversal of the trade winds? At what point do the trade winds go back to the previous direction set?”

    A clarification: It is widely reported that a relaxation of the trade winds initiates an El Nino. But the relocation of the warm water from the Pacific Warm Pool to the central and eastern equatorial Pacific during the El Nino causes the trade winds in the western tropical Pacific to reverse, since the trade winds are responding to the relocation of the convection. The trade wind datasets are here:
    http://www.cpc.ncep.noaa.gov/data/indices/

    You asked, “Since El Niño/La Nina cycles have a periodicity that is significantly less than 10.1 years, wouldn’t the smoothing used in Figure 7 blur any putative relationships between PDO/El Niño?”

    The intent of the smoothing used in Figure 7 was to illustrate the similarities and differences on decadal time spans.

  15. Bob Tisdale says:

    Dan says: “Not really sure this is actually worth much of an effort but having skimmed this ‘work’ and the similar icacap effort, have to say, you are joking aren’t you…”

    What do you find in my post that you would consider to be a joke? You attacked the IceCap post with the rest of your comment but you never expanded on why you are referring to my post as a joke.

  16. AnonyMoose says:

    the common belief that the sign of the PDO dictates whether global temperatures rise or fall.

    The PDO does affect weather in regions where there are many thermometers, specifically North America and northern Europe. So it undoubtedly affects global temperature measurement, if not actual temperatures.

  17. paulhan says:

    When I look at a temperature chart, I see a lumpy 30 year sinusoidal wave superimposed on a larger cycle that is in a warming phase now. No-one as yet has come up with a reason for that sinusoidal wave. The solar and lunar cycles don’t explain it. Yet when a chart of the PDO phase and temperatures are combined, they make up a closer correlation to each other than any other known cycle compared to temps.

    Something is causing that, but nobody knows what it is, so we haven’t put a name on it.
    Instead people (including me) use the term “the PDO cycle” as a proxy for this phenomenon. ENSO, which is a roughly 3-5 year cycle, cannot cause this 30 year cycle, only reinforce it. To state otherwise would be to suggest that ENSO can remember that it is on its last cycle and that it should change now to a cooler or warmer regime as a result. How would it know this?

    Until we can come up with a name for this cycle, I think the confusion over “PDO” is going to persist.

  18. Geoff Sharp says:

    paulhan says:
    July 1, 2011 at 3:43 am

    When I look at a temperature chart, I see a lumpy 30 year sinusoidal wave superimposed on a larger cycle that is in a warming phase now. No-one as yet has come up with a reason for that sinusoidal wave. The solar and lunar cycles don’t explain it.

    Scafetta and Wilson might disagree with you.

    http://www.landscheidt.info/?q=node/180

  19. Buzz Belleville says:

    Wow, that’s a lot of information, and it’s going to take a while for my non-meteorology-trained brain to digest. But I appreciate the info, as the oceanic and atmospheric cycles are something I’ve been working to get my head around for a while.
    Question >> Does this undermine Dr. Spencer’s recent theory, espoused in his latest book and peer-reviewed articles? As I understand his theory (greatly oversimplified, as my brain requires), a positive PDO may be causing more cloud cover which in turn may cause warming. But this article seems to be saying that the PDO does not and cannot have any effect on mong term temp anomolies.

  20. Steve C says:

    Dan says: “I realize skeptics are looking for any excuse to try and dismiss AGW”. Au contraire, mon vieux. Most of us dismiss AGW (without even “trying”) simply because no convincing evidence has ever been produced to suggest that any such effect exists. Perhaps you would be so kind as to give us some links to something which offers us proof that:
    (1) Climatic conditions are currently in an “unprecedented” state;
    (2) This “unprecedented” state is “catastrophically dangerous“;
    (3) This “dangerous” condition is caused by manmade CO2 emissions.
    I think those three points constitute an adequately accurate summary of the AGW position.
    Show us, please do. That’s all it takes!

  21. Bob Tisdale says:

    paulhan says: “Until we can come up with a name for this cycle, I think the confusion over “PDO” is going to persist.”

    Due to the misunderstandings of what the PDO represents, at the end of the “AMO+PDO” post…
    http://bobtisdale.wordpress.com/2011/06/08/on-the-amopdo-dataset/
    …I suggested we come up with a name for the Pacific multidecadal oscillation that’s determined the same way as the Altantic Multidecal Oscillation:
    http://i53.tinypic.com/a0gf2g.jpg

  22. Bob Tisdale says:

    Buzz Belleville says: “Does this undermine Dr. Spencer’s recent theory, espoused in his latest book and peer-reviewed articles? As I understand his theory (greatly oversimplified, as my brain requires), a positive PDO may be causing more cloud cover which in turn may cause warming.”

    I’ve never seen any evidence in clud amount data that suggests the PDO causes variations in cloud cover.

  23. dallas says:

    Interesting piece of the climate puzzle. The PDO patterns appear to have a major impact on climate, but the changes in SST do not appear to be strong enough to make as significant a climate impact as indicated globally. The regional impacts are obvious, but then regional is not global :)

    Large land masses do tend to amplify the temperature variations. So to me it seems the “where” there is SST change is much more important than the “how much”.

  24. Geoff Sharp says:

    Bob Tisdale says:
    July 1, 2011 at 5:45 am

    I’ve never seen any evidence in clud amount data that suggests the PDO causes variations in cloud cover.

    When measured at the dateline the “cluds” generally are increased during an El Nino cycle. I am sure you are aware of this but lacking the PDO link to ENSO cycle understanding to appreciate?

  25. Dave Springer says:

    The problem with PDO, AMDO, ENSO, etc. is that we have no theory for them. All we know about them is the climatology. Just like with hurricanes we can only predict their behavior through statistical models of past behavior. So we have these semi-predictable SST oscillators running at various frequencies in various locations but no real understanding of what regulates the cycle length or peak intensities. Thus no one can categorically state what effect, if any, anthropogenic GHGs will have on them just like one can categorically state what AGHGs will have on hurricane formation. So far the climate boffins have a spectacular record of failure in their Katrina/Rita timeframe predictions that GHGs were causing more and more intense hurricane seasons. If anything the exact opposite appears to be the case.

  26. edwardt says:

    Does ENSO drive global temperatures in any appreciable way?

  27. Ninderthana says:

    You might want to look at figure 8 on page 15 of my paper. It shows that whenever there is a significant deviation of the Earth’ s rotation rate (as measured by the Length-Of-Day LOD) away from its long-term trend, the PDO is positive. What is not immediately apparent from this graph is the fact that the changes in LOD (i.e. the Earth’s rotation rate) occur seven years earlier than the
    changes in the PDO.

    http://www.wbabin.net/files/4424_wilson.pdf

    These changes in LOD are most likely due to long-term changes in the the Lunar Tides.

  28. Ninderthana says:

    The main factor that Bob is ignoring in his investigation is is the long-term variations in the up welling of cool deep ocean water that is being regulated by the lunar tides.

  29. Bob Tisdale says:

    Ninderthana says: “The main factor that Bob is ignoring in his investigation is is the long-term variations in the up welling of cool deep ocean water that is being regulated by the lunar tides.”

    If and when you can provide documentation of this, I might not ignore it. Otherwise I will consider the eastern tropical Pacific upwelling to be functions of trade wind strength and of subsurface and surface ocean currents there.

  30. Bob Tisdale says:

    edwardt says: “Does ENSO drive global temperatures in any appreciable way?”

    Since the start of the satellite era of Sea Surface Temperatures, November 1981, one might conclude that ENSO drives all of the rise in global Sea Surface Temperatures. All you have to do is divide the global oceans into two subsets.

    The volcano-adjusted SST anomalies for the east Pacific Ocean (90S-90N, 180-180W) shows no increase since 1982:
    http://i51.tinypic.com/2a9snjt.jpg

    The SST anomalies for the Rest of the World (also volcano-adjusted) show upward steps in response to the 1986/87/88 and 1997/98 El Nino events, and multiyear periods afterwards with little change in temperature. And it appears the same thing is going to happen in response to the 2009/10 El Nino:
    http://i51.tinypic.com/ev9mhh.jpg

    I discussed this in the following post. It includes links to other posts that explain the processes that cause the upward steps:
    http://bobtisdale.wordpress.com/2011/03/03/sea-surface-temperature-anomalies-%e2%80%93-east-pacific-versus-the-rest-of-the-world/

  31. Bob Tisdale says:

    Geoff Sharp says: “When measured at the dateline the “cluds” generally are increased during an El Nino cycle. I am sure you are aware of this but lacking the PDO link to ENSO cycle understanding to appreciate?”

    “When measured at the dateline,” the cloud cover, which is caused by convection, accompanies the warm water eastward from the Pacific Warm Pool to the central and eastern equatorial Pacific during an El Nino, because of the El Nino, not because of the PDO. At the same time, cloud cover over the Pacific Warm Pool decreases. Also, Buzz Belleville referred to the Roy Spencer’s hypothesis about the PDO and global cloud cover. That was the basis for my reply.

  32. Ninderthana says:

    Bob,

    Please have a look at my latest posting on my blog.

    http://astroclimateconnection.blogspot.com/

    At least 1/3 of all the lunar tidal energy is deposited in the deep ocean as a result of friction between tides and deep-ocean ridges. This is a well accepted fact in Oceanography.
    The trade winds and surface ocean currents provide about 2/3 of the necessary energy to produce the observed up welling in the oceans. The remaining 1/3 is thought be provided by deep-ocean tidal dissipation. Oceanographers have directly measured the tidal dissipation along the Hawaiian Island ridges, confirming that this mechanism must play a significant role in powering the up welling of cool deep ocean water.

    You may want to have a look at a paper by Munk and Wunsch, Deep sea Research, issue 45, 1998. and look at the following two web pages.

    http://science.nasa.gov/science-news/science-at-nasa/2000/ast15jun_2/
    http://www.seafriends.org.nz/niue/ecology.htm

  33. Bob Tisdale says:

    dallas says: “Large land masses do tend to amplify the temperature variations. So to me it seems the ‘where’ there is SST change is much more important than the ‘how much’.”

    I assume you’re referring to the agreement between the SST anomalies in the eastern North Pacific and the land surface temperatures in western North America. You also have to consider that eastern Asia is following the SST anomalies of the western North Pacific, which often oppose the rise in the eastern North Pacific.

  34. Pamela Gray says:

    There is a fabulous video of the lava-lampish way in which the ocean currents move around vast pools of warm/cool water. These pools most definitely affect weather parameters in that they interact with over-the-ocean weather systems as they bare down on landfall.

    The oceans are the elephant (or better, woolly mammoth) in the room and AGW’rs are standing knee deep in it, completely blind to that fact. They search in vain through the very natural steaming woolly mammoth evidence for tiny little heat units of anthropogenic far infrared.

  35. Tim Clark says:

    Bob said, “…when the PDO is rising, the North Pacific is contributing less to the rise in global temperatures and vice versa. Therefore, the PDO cannot be driving the global temprature variation”.

    Bob, Read that again, its illogical. If a variation exists in the PDO dataset, and its contribution to global temperatures also varies, then you are admitting it is influencing global temperatures. When you consider the alarming increase in global temps aledgely amounts to less than a degree, any alteration in oceanic input can be quite significant. Are you hung up on the word “driving”? Is that where the fallacy exists?

  36. Brian D says:

    I truly believe the atmosphere is the driver of the the PDO/Enso cycles. The strength and position of the high pressure ridges dictating the winds and storm tracks. So I agree with Geoff on that (although i don’t know who this Erl fellow is).

  37. Paul Vaughan says:

    Every now & then a bright spark:

    dallas wrote (July 1, 2011 at 6:05 am)
    “Large land masses do tend to amplify the temperature variations.”

    Exactly:
    1. http://wattsupwiththat.files.wordpress.com/2010/08/vaughn_lod_amo_sc.png
    2. http://wattsupwiththat.files.wordpress.com/2010/09/scl_northpacificsst.png
    [where SCL' = rate of change of solar cycle length = solar cycle deceleration]

    It’s a simple function of north-south terrestrial asymmetry.

    …but the GLOBAL waves of interannual spatiotemporal chaos are confusing the h*ck out of people, preventing them from seeing the forest for the trees.

    The Atlantic basin is smaller so it can respond with greater amplitude faster (…confusing some into believing it’s somehow a “driver” since it “leads” in their misperceptions).

    -
    Dan says (June 30, 2011 at 11:54 pm)
    “[...] this ‘work’ and the similar icacap effort [...]“

    Absolutely not “similar”. At sharp odds, rather.

    Bob realizes that the “skeptic PDO narrative” is based on severe misconceptions and so has torpedoed it mercilessly (as a doctor would lance a cancer from a patient).

    Dan, you are seeing uniformity where none exists. Please take a closer look, with an eye for factionalization.

    Best Regards.

  38. Tim Clark says:

    Geoff Sharp
    Do you know what’s up with the magnetosphere and the recorders?

    http://137.229.36.30/cgi-bin/magnetometer/magchain.cgi

  39. Bob Tisdale says:

    Brian D says: “I truly believe the atmosphere is the driver of the the PDO/Enso cycles.”

    ENSO is a coupled ocean-atmosphere process. They are dependent on one another. Bill Kessler of NOAA provides a nice description of that dependency:
    http://faculty.washington.edu/kessler/occasionally-asked-questions.html

  40. Bob Tisdale says:

    Tim Clark says: “Bob, Read that again, its illogical.”

    Let’s try again, because the PDO and the North Pacific Residual are inversely related, that means when the PDO is rising the North Pacific Residual is falling. And if the North Pacific Residual is falling, that means one of two things. One: the Global SST anomalies are rising faster than North Pacific SST anomalies. In that case, the North Pacific is suppressing the rise in Global SST anomalies. Or Two: the North Pacific SST anomalies are dropping faster than Global SST anomalies, and if that’s the case, then the original premise is wrong to start with.

  41. Paul Vaughan says:

    Usually I find Judith Curry sickeningly preoccupied with politics, but she is correct in identifying untenable structural assumptions as a severe weakness [ http://judithcurry.com/2011/06/29/critique-of-the-hadsst3-uncertainty-analysis/ ].

    Ninderthana wrote (July 1, 2011 at 9:05 am)
    “[...] Please have a look at my latest posting on my blog.”

    [ http://astroclimateconnection.blogspot.com/2011/07/pdo-signature-of-influence-of-long-term.html ]

    The 18.6 year cycle shows up in the variance, not the mean.

    Ninderthana wrote (July 1, 2011 at 9:05 am)
    “[...] trade winds and surface ocean currents provide about 2/3 of the necessary energy to produce the observed up welling in the oceans. The remaining 1/3 is thought be provided by deep-ocean tidal dissipation [...] powering the up welling of cool deep ocean water.”

    Ninderthana wrote (July 1, 2011 at 7:44 am)
    “[...] long-term variations in the up welling of cool deep ocean water [...] regulated by the lunar tides.”

    This is key at interannual timescales and may account for longer-term interannual phase-reversals (for example as indicated by the Earth orientation record), but this does NOT account for Figure 10 here:

    Carvalho, L.M.V.; Tsonis, A.A.; Jones, C.; Rocha, H.R.; & Polito, P.S. (2007). Anti-persistence in the global temperature anomaly field. Nonlinear Processes in Geophysics 14, 723-733.
    http://www.icess.ucsb.edu/gem/papers/npg-14-723-2007.pdf

    “dallas” nailed that one above:

    dallas wrote (July 1, 2011 at 6:05 am)
    “Large land masses do tend to amplify the temperature variations.”

    It’s a simple function of north-south terrestrial asymmetry. Pole-equator contrast connects the dots. The movements of the whole being vary when a creature with bilateral symmetry limps on one side.

    Best Regards.

  42. Bob Tisdale says:

    Ninderthana says: “Please have a look at my latest posting on my blog.
    http://astroclimateconnection.blogspot.com/”

    Thanks for the link, but your post expresses an opinion. It does not address the request I made in my original reply to you as it relates to the topics of ENSO and the PDO.

    The other links in your July 1, 2011 at 9:05 am comment do not refer to the topics of my post, which are ENSO and the PDO.

    Regards.

  43. Paul Vaughan says:

    I would like to see Ninderthana, Erl Happ, Tomas Milanovic, or whoever attempt (either now or in the future) to prove incorrect Bob’s assertion that PDO is an aftereffect of ENSO. It could be a fascinating exchange if that debate ever goes beyond what we’ve seen to date, which is usually lively ignition followed by pre-resolution fade.

  44. jorgekafkazar says:

    Brian D says: “I truly believe the atmosphere is the driver of the the PDO/Enso cycles…”

    I believe that is essentially correct for ENSO. The bulge in the western pacific has to be wind driven, unless tidal forces somehow have cumulative, longer than diurnal effects. The ocean plays a major part, obviously, since it is the pendulum. The initial swing is the tradewind-driven bulge. Everything else is secondary, with the sun determining the temperature amplitude. LOD probably follows the bulge.

    Bob T. says: “The intent of the smoothing used in Figure 7 was to illustrate the similarities and differences on decadal time spans.”

    That it does. The first order relationships are lost, but second order effects pass the filter. Do the latter have any bearing on the stepwise changes in SST’s?

    Pamela Gray says: “The oceans are the elephant…in the room and AGW’rs…search in vain through the… steaming… evidence for tiny little heat units of anthropogenic far infrared.”

    If they create their own evidence, they can stop searching.

  45. Paul Vaughan says:

    jorgekafkazar wrote (July 1, 2011 at 4:02 pm)
    “The initial swing is the tradewind-driven bulge. Everything else is secondary, with the sun determining the temperature amplitude. LOD probably follows the bulge.”

    Unsustainable spatial patterns collapse. We’re not dealing with unbounded phenomena. Sun & moon constrain the variance. You’re correct that Earth orientation parameters (EOP) reflect the variations rather than drive them.

    Lunisolar frequencies are stationary. It’s solar frequency that’s nonstationary. The effect of changing solar frequency is generalizable even with incomplete knowledge of Earth’s internal cycles (which include stationary lunisolar cycles according to some definitions).

    The mainstream has been slow to catch on to the generalizability. LeMouel, Blanter, Shnirman, & Courtillot’s seminal 2010 observation & implicaitons still haven’t been publicly acknowledged.

    Due to the generalizability, we can get a handle on multidecadal variations without having to wait for the final word on interannual spatiotemporal variability.

    If nonalarmists aren’t first out of the gate embracing the results, alarmists will have the opportunity to spin the observations as irrefutable proof of anthropogenic global warming. (The latter CAN be done using existing EOP records, if only alarmists would take the time to listen carefully to what nature is saying rather than remaining absorbed by computer fantasies.)

    I look forward to working with whatever parties are willing to be sensible.

    Sincerely.

  46. Ninderthana says:

    Bob,

    As I said in an earlier post, I greatly respect your research efforts and your scientific integrity, so I will not embarrass you in public.

  47. Bob asserts:

    This inverse relationship between the PDO and the SST anomaly data of the North Pacific directly contradicts the assumption that a positive (warm) PDO is responsible a rise in global temperatures or that a negative (cold) PDO is somehow responsible for a drop in global temperatures.

    Everything else that you present here — PDO is not SST, PDO is an integration of El Niño / La Niña dominant periods, etc. — can be and doubtless are true, but your statement above can still be and probably is misleading. I say this for at least two reasons:

    First, if we grant that “PDO” is simply a shorthand for an integration of El Niño effects, the question remains open as to what causes the periodicity of Niño/Niña dominance. Whatever it is — or whatever complex combination of effects it is — clearly has a substantial effect on global atmospheric surface temperatures, as well as on much-despised “weather”. Yes, you are quite right that the PDO can’t, as you say, be a direct cause of anything. But it can be [part of] a pointer to whatever is the underlying cause — and as I read it, that’s really all Akasofu and IceCap and the rest are asserting. Obviously, whatever is giving rise to the PDO phenomenon, it’s not CO2.

    Second, heat distribution “patterns” in the ocean can have an effect on global temperatures in non-obvious ways, by affecting e.g. the upper atmosphere wind tracks, the speed and distribution of Hadley circulation, cloud formation at high latitudes, strength of the trade winds, and many other (poorly understood but chaotically related) atmospheric phenomena.

    So, while I appreciate your valuable research and the contribution you are making in these posts to understanding climate-related phenomena, I can’t fully agree with your conclusion.

  48. Ninderthana says:

    Paul,

    I need some clarification here.

    A. You said: “The 18.6 year cycle shows up in the variance, not the mean.”

    Are you saying that the 18.6 year lunar tidal cycle modulates the variation of climate signal rather than affects it long-term mean? I am genuinely asking a question here, as I am not quiet sure what you are implying.

    B. You said: “Lunisolar frequencies are stationary. It’s solar frequency that’s nonstationary.”

    This is certainly not true if patterns in the Luni-Solar tides are indirectly linked with the
    factors that control long-term variations in solar activity. In this case you cannot separate
    the two phenomenon as one one would reinforce the other e.g. Gleissberg and deVrier
    cycles. It would be crazy to call one stationary and the other non-stationary. At the barest minimum, you need to clarify the timescales over which you are making this assertion. I do not believe that it is true on multi-decadal time scales.

    C. You quote: Carvalho, L.M.V.; Tsonis, A.A.; Jones, C.; Rocha, H.R.; & Polito, P.S. (2007). Anti-persistence in the global temperature anomaly field. Nonlinear Processes in Geophysics 14, 723-733. http://www.icess.ucsb.edu/gem/papers/npg-14-723-2007.pdf

    However, this paper only finds non-persistence variations up to 7 years and says nothing about inter-decadal variations, which is the topic here.

    D. You said: “I would like to see Ninderthana, Erl Happ, Tomas Milanovic, or whoever attempt (either now or in the future) to prove incorrect Bob’s assertion that PDO is an aftereffect of ENSO.”

    PHYSICS dictates that you cannot have A driving B if changes in B occur before A [ignoring the obvious exceptions due to Relativity and high speeds]

    If you are claiming to support Bob’s assertion that the PDO is an after effect of the ENSO then
    you are violating this basic scientific principle.

    Both of you know that it is possible to measure the intensity, as well a relative frequency, of El Nino/La Nina events. I am absolutely certain that you are not willing to defend the notion that ALL El Nino/La Nina events have the same intensity.

    My investigations of El Ninos from 1525 to the present show that the mean intensity of El Nino events continuously increase in magnitude while the PDO is in its positive phase, and continuously decrease in magnitude while the PDO is in its negative phase.

    Here is the temporal sequence [note that the PDO changes from + to -, and vice versa, typically take place over periods of time that Over the next 30 years the El Ninos responds to this change in the PDO by continuously increasing in intensity –> PDO changes from positive to negative –> Over the next 30 years the El Ninos responds to this change in the PDO by continuously decreasing in intensity.

    Unless you are suggesting that causality is reversed, then I do not believe that you have a leg to stand on.

    The reason, I cannot go further into discussions on this topic is that fact that I am in the process of writing a number of peer-reviewed papers on climate. Claire Periguad’s group is also investigating the same phenomenon. However, she has the advantage of being in a collaboration that includes half a dozen scientists, dozens of post-grad/grad students and
    that has $ 100,000′s in research funding to complete her two year research program. I have a bung Italian oil heater (in an Australian Winter) and a couple of cans of bake-beans.

    So you will have to excuse me while I get back to Summer time maximum temperatures in Melbourne between 1856 and 2011.

  49. Ninderthana says:

    The following critical paragraph was garbled by the blogosphere.. Here is the corrected version.

    Here is the temporal sequence [note that the PDO changes from + to -, and vice versa, typically take place over periods of time that are less than 5 years]

    “The PDO changes from negative to positive –> Over the next 30 years the El Ninos responds to this change in the PDO by continuously increasing in intensity –> PDO changes from positive to negative –> Over the next 30 years the El Ninos responds to this change in the PDO by continuously decreasing in intensity.”

  50. Geoff Sharp says:

    Tim Clark says:
    July 1, 2011 at 12:38 pm

    Geoff Sharp
    Do you know what’s up with the magnetosphere and the recorders?

    Hi Tim, I am not up with the land based recordings so am unsure if there is any earthly component in the rise and fall around the 1st of July. But watching the meager sunspot activity recently it has shown a rise and fall that does match the magnetometer results. June is looking to be another low month of solar activity, the LSC results should be available today.

  51. Paul Vaughan says:

    Ninderthana, EOP are the arbiters of terrestrial climate disputes. Please see the following:

    1. http://wattsupwiththat.com/2011/04/10/solar-terrestrial-lunisolar-components-of-rate-of-change-of-length-of-day/

    2. http://wattsupwiththat.com/2010/12/23/confirmation-of-solar-forcing-of-the-semi-annual-variation-of-length-of-day/

    Based on your comments, I don’t believe you’ve understood the implications of Figure 10 here:

    Carvalho, L.M.V.; Tsonis, A.A.; Jones, C.; Rocha, H.R.; & Polito, P.S. (2007). Anti-persistence in the global temperature anomaly field. Nonlinear Processes in Geophysics 14, 723-733.
    http://www.icess.ucsb.edu/gem/papers/npg-14-723-2007.pdf

    Ninderthana wrote (July 1, 2011 at 7:40 pm) “If you are claiming to support Bob’s assertion that the PDO is an after effect of the ENSO then you are violating this basic scientific principle.”

    Although Bob has my FULL support on slicing & dicing PDO misconceptions, nowhere have I suggested that I support Bob on this one; on the contrary, I am keen to see solid challenges. Any solid contributions you can make will be appreciated. I always hope Tomas Milanovic will comment.

    Ninderthana wrote (July 1, 2011 at 7:40 pm) “Claire Periguad’s group is also investigating the same phenomenon. However, she has the advantage of being in a collaboration that includes half a dozen scientists, dozens of post-grad/grad students and that has $ 100,000′s in research funding to complete her two year research program.”

    I’ll give her credit for generating enthusiasm about the findings of others, but so far she hasn’t produced any seminal observations, so far as I’m aware. I suppose one could suggest that she’s keeping original insights under wraps and only communicating publicly about the findings of others.

    I am, however, enthusiastic to see the results of Richard Gross’ (one of Claire Perigaud’s NASA mentors) current work on Antarctic ice mass. Sound familiar? Gross appears to be learning from what the Russians have known for some time (e.g. Sidorenkov 2003 & 2005). When you have a chance, be sure to compare decadal -NPI with Sidorenkov. The early 20th century extremes coincide with currently-unmodeled aspects of nutation in obliquity & longitude, the Chandler wobble phase reversal, a zero-crossing in the lunisolar harmonic spectrum, seminal observations of Kevin Trenberth on SOI evolution, major shifts in atmospheric pressure climatologies, and qualitative shifts in terrestrial cross-recurrence eloquently illustrated by Zolotova & Ponyavin.

    Ninderthana wrote (July 1, 2011 at 7:40 pm) “PHYSICS dictates that you cannot have A driving B if changes in B occur before A”

    Please see the writings of Tomas Milanovic at Dr. Judith Curry’s blog Climate Etc. We need to be thinking in at least 6 dimensions, at least 3 of which need to be spatial (really 12 dimensions with 9 spatial, but autocorrelation usually makes it sensible to whittle this down on the Pareto Principle). Spatial anti-phase should not be mistaken for a temporal lead or lag. Complex numbers & adjacent spatiotemporal derivatives greatly simplify data exploration.

    Thanks sincerely for contributing to the discussion!

    Best Regards.

  52. Bob Tisdale says:

    Geoff Sharp: Your July 1, 2011 at 2:08 am comment above appears to be the same one you left at the cross post at my blog.
    http://bobtisdale.wordpress.com/2011/06/30/yet-even-more-discussions-about-the-pacific-decadal-oscillation-pdo/#comment-2105
    So I’ll repeat the reply I made to you at my blog, but I’ll edit it so it fits here

    I attempted to ignore your July 1, 2011 at 2:08 am comment because you established yourself as someone with zero credibility on the Easterbrook thread at WUWT, starting with your comment that the Antarctic has not warmed in 50 years. For a refresher, start at this comment and read our exchange through the rest of the thread:
    http://wattsupwiththat.com/2011/06/17/easterbrook-on-the-potential-demise-of-sunspots/#comment-684763
    When I confronted you with data that contradicted your bogus statement, you attempted to claim that the short-term Antarctic surface stations were the cause of the rise and linked the longer-term surface stations as evidence that the Antarctic had not warmed in 50 years. Then when I plotted that data and showed you that the trends were significantly positive, you attempted to misdirect the readers with additional nonsensical claims.

    But since you insist on cluttering this thread with more of your baseless claims, let’s take a look at what you’ve written.

    Geoff Sharp says: “The PDO is a valuable tool that is a derived value.”

    You must not have read my post, or you elected to ignore what I presented.

    Geoff Sharp says: “The pacific temperatures north of 20N are not important… “

    Once again, reality offers a different picture, Geoff. The North Pacific north of 20N represents about 15% of the surface area of the global oceans. They, therefore, are a significant part of global surface temperatures. The North Pacific SST anomalies have a higher trend than the Global oceans since 1900. The North Pacific SST anomalies also have a stronger multidecadal variation than the Global Oceans, which illustrates that they contributed to the decline in global surface temperatures from the 1940s to the 1970s and to the rises in global temperatures during the early and latter parts of the 20th Century.
    http://i56.tinypic.com/rvvarq.jpg

    One might conclude from that that the SST anomalies of the North Pacific north of 20N play an important role in the rise in global temperatures, and that contradicts your erroneous claim.

    Geoff Sharp says: “….when the north is cooler it allows the equatorial regions to warm.”

    It does? The data appears to contradict you on this one, too, Geoff. Please use the following graph to document your statement:
    http://i53.tinypic.com/efp448.jpg

    Geoff Sharp says: “The PDO trend quite clearly follows the world temperature trend…

    The linear trend of the PDO data is flat, slightly negative, Geoff, while the Global SST anomalies have a positive trend.
    http://i56.tinypic.com/25smooi.jpg

    But that part of your sentence could be interpreted other ways. Are you now claiming that a rise on Global temperatures dictates the sign of the PDO, or is it vice versa? Regardless, when you decide, please document through what mechanism or process global temperatures would drive the sign of the PDO or through what mechanism or process the PDO would drive global temperatures.

    Geoff Sharp says: “…and by adding solar variation all temperature measurement movements can be explained by natural variation.”

    You made similar statements on the Easterbrook thread, and when I asked you to confirm the claim with data, you advised me that the datasets could not be plotted together and that I would have to imagine the relationship. Sorry. It doesn’t work that way, Geoff.

    And as discussed and linked for you on the Easterbrook thread, I’ve prepared posts that have shown that natural variables can account for 85% of the global warming for the latitudes of 60S to 60N since 1982. And what did you do? You attempted to downplay those findings by erroneously claiming that those latitudes represent only 40% of the surface of the globe, when in fact those latitudes make up 88% of the global surface area. Do you recall your nonsensical statement? Here’s a link to your comment:
    http://wattsupwiththat.com/2011/06/17/easterbrook-on-the-potential-demise-of-sunspots/#comment-684763

    Geoff Sharp says: “Positive PDO correlate with higher incidence of El Nino and vice versa. There is insignificant evidence to say what drives what…

    I’m beginning to believe that you failed to read my post, because I provided quotes from and links to three papers that indicated that ENSO leads the PDO. But if you have read my post, then YOU elect to ignore the evidence. That’s telling in and of itself.

    Geoff Sharp says: “…but I am with Erl Happ when it comes to the ENSO driver. The strength and direction of the Trades is the initiator of the ENSO cycle which is driven by changes in atmospheric pressure. What drives the changes in atmospheric pressure will be the key to understanding the most important oceanic region.”

    This is the closest your comment has come to reality. The strength and direction of the trade winds and the surface temperature of the topical Pacific are closely coupled. The east-to-west SST gradient does not exist without the trade winds and the trade winds don’t exist without the temperature gradient. And of course, El Nino events are thought to be initiated by a relaxation in the strengths of the trade winds. And all of that is basic ENSO:
    http://bobtisdale.wordpress.com/2010/08/08/an-introduction-to-enso-amo-and-pdo-%e2%80%93-part-1/

    Geoff, you’ve once again illustrated for all who read this thread that your claims have little-to-no basis in reality. You, not me, undermine your credibility. You can respond to part or all of this, but I won’t feel obligated to reply to you. In the future, though, rest assured that if you want to attempt to contradict what I’ve written in a post, I will be happy to illustrate the errors in your comments and to link all of the erroneous claims you have made in our past exchanges.

    Good-bye, Geoff.

  53. Geoff Sharp says:

    Bob Tisdale says:
    July 2, 2011 at 4:37 am

    You get so worked up Bob. You have a theory on the PDO that needs to be tested, but there is no need to take it so personal. Instead of playing the ad hominen card try to look through the red mist and acknowledge that science is a method of testing hypothesis where is this case I think you do not have a strong argument.

    The PDO is a standard measurement, and despite your intentions it will not go away. Your repeated attempts to discredit this long time record by trying to isolate the northern pacific SST’s is a side show with little relevance to this derived value that is so important to understanding world climate. Until you can come up with an ENSO driver that in your book produces the PDO, you will always be on shaky ground.

    Chill out a little….

  54. Bob Tisdale says:

    Ninderthana says: “As I said in an earlier post, I greatly respect your research efforts and your scientific integrity, so I will not embarrass you in public.”

    Please feel free to disprove anything I’ve written or presented in this post. I always look forward to learning something new on this topic.

  55. Bob Tisdale says:

    Craig Goodrich says: “Everything else that you present here — PDO is not SST, PDO is an integration of El Niño / La Niña dominant periods, etc. — can be and doubtless are true, but your statement above can still be and probably is misleading.”

    I will agree. I should replace the “a rise in global temperatures” with “THE rise in global temperatures”, and replace the “a drop in global temperatures” with “THE drop in global temperatures”. That’s really the point of all of this.

    The paragraph would read in full:
    This inverse relationship between the PDO and the SST anomaly data of the North Pacific directly contradicts the assumption that a positive (warm) PDO is responsible the rise in global temperatures or that a negative (cold) PDO is somehow responsible for the drop in global temperatures.

    I’ll change the language on the cross post at my blog. Thanks.

  56. Dave Springer says:

    Ninderthana says:
    July 1, 2011 at 7:27 am

    “You might want to look at figure 8 on page 15 of my paper. It shows that whenever there is a significant deviation of the Earth’ s rotation rate (as measured by the Length-Of-Day LOD) away from its long-term trend, the PDO is positive. What is not immediately apparent from this graph is the fact that the changes in LOD (i.e. the Earth’s rotation rate) occur seven years earlier than the changes in the PDO.”

    There is a chicken-egg paradox that remains controversial. The controversy is whether weather drives rotation rate changes or rotation rate change drives the weather. Either way there is strong correlation between changing winds and changing rotation rate. Winds are definitely a big factor in SST oscillations. More wind makes SST go down and less wind makes it rise. That however is not a theory of SST oscillations it merely pushes the problem out to needing a theory for oscillation in wind patterns.

    You do however make a good point and heretofore I was unaware of a connection between earth rotation rate and wind patterns. Rotation rate changes are so small I thought it could be ignored for all practical matters. I’m still not convinced it shouldn’t be ignored.

  57. Dave Springer says:

    edwardt says:
    July 1, 2011 at 7:26 am

    “Does ENSO drive global temperatures in any appreciable way?”

    Evidently. There’s huge spike in global average temperature as measured by satellites that occured when the 1998 “mother of all El Ninos” was happening. SST rises when average wind speed falls. Less evaporation is happening and less mixing with colder deeper water. The end result is the surface layer gets warmer and since the atmosphere is heated by the ocean the atmosphere gets warmer too.

  58. Paul Vaughan says:

    Bob, a clarification request:

    When you constructed “ADO” here [ http://i51.tinypic.com/17901t.jpg ], did you use North Atlantic residuals (as per your regional minus global definition of residuals)?

    It might be constructive to comparatively illustrate the exact Atlantic, Indian, South Pacific, whole Pacific, & Southern Ocean analogies to this [ http://i52.tinypic.com/1zo8686.jpg ] at some point in time.

  59. Paul Vaughan says:

    @Geoff Sharp (July 2, 2011 at 6:28 am)

    Geoff, Bob isn’t trying to “discredit” PDO; rather he’s suggesting that it be INTERPRETED CORRECTLY. Perhaps 99 out of 100 commenting at WUWT appear to misinterpret PDO. Most apply a COLLOQUIAL definition of PDO, which is basically NHT (northern hemisphere temperature). I would suggest calling this colloquial construct PMO (analogous to AMO) to improve mutual understanding, but I’ll agree that the mislabeling & misinterpretations aren’t going away anytime soon since most here are more interested in bitterly partisan politics than the nuances of climate & data interpretation. Most just lazily grab the colloquial “PDO” handle and throw it around in ignorant misapplication. My interpretation of Bob’s ongoing PDO campaign: Say what you mean and mean what you say. When you mean North Pacific SST, say “North Pacific SST”, NOT “PDO”. Both have a place in the climate discussion, but let’s not get their names mixed up. North Pacific SST is a PURELY DIRECT & ABSOLUTELY SIMPLE input to both NHT & global T. Can the same be said of PDO? Certainly not, which means the standard “skeptic PDO narrative” is EASILY shot down by novice alarmists. Quite a humorous display of self-sabotage.

  60. Paul Vaughan says:

    Dave Springer wrote (July 2, 2011 at 6:59 am)
    “There is a chicken-egg paradox that remains controversial. The controversy is whether weather drives rotation rate changes or rotation rate change drives the weather. Either way there is strong correlation between changing winds and changing rotation rate. Winds are definitely a big factor in SST oscillations. [...] heretofore I was unaware of a connection between earth rotation rate and wind patterns. Rotation rate changes are so small I thought it could be ignored for all practical matters. I’m still not convinced it shouldn’t be ignored.”

    There’s no controversy here Dave. It has been known for decades that pole-equator contrasts induced by the seasons drive the westerlies and hence atmospheric angular momentum and changes in length of day. If your objective is to know what time it is, go ahead and ignore the changes, but if your objective is to understand terrestrial climate, see the following:

    a) Exposition of p. 433 [pdf p.10]:

    Sidorenkov, N.S. (2005). Physics of the Earth’s rotation instabilities. Astronomical and Astrophysical Transactions 24(5), 425-439.
    http://images.astronet.ru/pubd/2008/09/28/0001230882/425-439.pdf

    (When you have more time, the whole paper deserves careful reading.)

    b) Figures 8, 11, 13, & 15 – (study them comparatively very carefully to “spot the differences” between pictures & hemispheres, consulting the associated text if something is unclear):

    Leroux, Marcel (1993). The Mobile Polar High: a new concept explaining present mechanisms of meridional air-mass and energy exchanges and global propagation of palaeoclimatic changes. Global and Planetary Change 7, 69-93.
    http://ddata.over-blog.com/xxxyyy/2/32/25/79/Leroux-Global-and-Planetary-Change-1993.pdf

    Please take however much time is necessary to understand. The discussion cannot advance until people make the effort to understand the basics.

  61. Bob Tisdale says:

    Paul Vaughan says: “When you constructed “ADO” here [ http://i51.tinypic.com/17901t.jpg ], did you use North Atlantic residuals (as per your regional minus global definition of residuals)?”

    No. The dataset identified “1st PC of North Atlantic SST Anomalies” has only been detrended. That is, the SST anomalies for each 5 deg X 5 deg are detrended. The KNMI Climate Explorer doesn’t have the option for the residuals in each grid like the PDO.

  62. Bob Tisdale says:

    Geoff Sharp says: “You have a theory on the PDO that needs to be tested…”

    It’s not a theory, Geoff. The following are facts:
    1. The PDO does not represent the SST anomalies of the North Pacific.
    2. The PDO is inversely related to the SST anomaly residuals of the North Pacific, where the residuals are calculated by subtracting Global SST anomalies from the North Pacific SST anomalies.
    3. The PDO is standardized, and because of the standardization, the PDO exaggerates the variability of the North Pacific Residuals by a factor of more than 5.5.

    Geoff Sharp says: “The PDO is a standard measurement, and despite your intentions it will not go away.”

    I have no intentions of making it “go away”. These posts about the PDO are intended only to illustrate what the PDO is and what it is not. I am trying to make the misuse of the PDO go away.

    Geoff Sharp says: “Your repeated attempts to discredit this long time record by trying to isolate the northern pacific SST’s is a side show with little relevance to this derived value that is so important to understanding world climate.”

    I’m not attempting to discredit the PDO. And the only reason you believe the PDO is “so important to [the] understanding world climate” is because of your misunderstandings about the PDO.

    There is no process through which the PDO can be responsible for the rise and fall in global surface temperatures on multidecadal timescales. On the Easterbrook thread, almost 2 weeks ago, I asked you: through what process does the PDO cause global temperatures to rise and fall?
    http://wattsupwiththat.com/2011/06/17/easterbrook-on-the-potential-demise-of-sunspots/#comment-684853
    You still have not answered.

    Geoff Sharp says: “Until you can come up with an ENSO driver that in your book produces the PDO, you will always be on shaky ground.”

    If you had read my post, you would not have written that sentence. I’ve explained the process through which ENSO creates the PDO pattern, and I have explained that the periodic difference between the PDO and an ENSO proxy such as NINO3.4 SST anomalies is caused by variations in Sea Level Pressure–that the changes in Sea Level Pressure impact how the SST anomalies of the North Pacific respond to ENSO.

  63. Pamela Gray says:

    Geoff, I get what Bob is saying after two glasses of very bad red wine cut with sherry in my attempt to improve it (see thread on wining). Surely you can see that further argument really makes you look sillier than I feel at the moment.

  64. Geoff Sharp says:

    Bob Tisdale says:
    July 2, 2011 at 1:53 pm

    Geoff Sharp says: “You have a theory on the PDO that needs to be tested…”
    —————————-
    It’s not a theory, Geoff. The following are facts:
    1. The PDO does not represent the SST anomalies of the North Pacific.
    2. The PDO is inversely related to the SST anomaly residuals of the North Pacific, where the residuals are calculated by subtracting Global SST anomalies from the North Pacific SST anomalies.
    3. The PDO is standardized, and because of the standardization, the PDO exaggerates the variability of the North Pacific Residuals by a factor of more than 5.5.

    Ok, this is where the problem lies, point one in particular. The PDO represents spatial pattern changes in the Nth Pacific. In your long winded article you have not fully described the process involved in determining the PDO values. Please describe the exact process that JISAO use to calculate the PDO values.

  65. Bob Tisdale says:

    Geoff Sharp says: “Please describe the exact process that JISAO use to calculate the PDO values.”

    The exact description, per an email from Nate Mantua:

    The full method for computing the PDO index came from Zhang, Y., J.M. Wallace, D.S. Battisti, 1997: ENSO-like interdecadal variability: 1900-93. J. Climate, 10, 1004-1020.

    “They labeled this same time series “the NP index” (see their figs 5 and 6). The steps are listed below, and files described below can be found at: ftp://ftp.atmos.washington.edu/mantua/pdofiles/

    “Data used:
    * monthly 5×5 Hadley Center SST 1900-93

    “Method:

    1. create monthly anomaly fields for all grid points

    2. create a monthly mean global SST anomaly time series for all months, 1900-93, using gridpoints specified in file grid.temp.glob_ocean.977

    3. create a “residual SST anomaly” field for the North Pacific by subtracting out the global mean anomaly from each North Pacific grid point in file grid.N_Pac_SST.resi.172 (20N-65N, only in Pacific Basin) for all months and locations

    np_resi(mo,loc)= np_ssta(mo,loc) – global_mean(mo)

    4. compute the EOFs of the North Pacific residual SST anomaly fields, and ignore all missing data point (set them to zeros)

    5. the PDO index is the leading PC from the above analysis

    6. for PDO index values post 1993, project observed ‘North Pacific residual SST anomalies’ onto the leading eigenvector (what we call the ‘PDO pattern’ of ssts) from the EOF analysis done in step 4. We now do this with the Reynold’s and Smith Optimally Interpolated SST (version 2) data.”

  66. Paul Vaughan says:

    Geoff, here’s the long-sought recipe for showing EXACTLY how PDO relates to NHT & global T…

    1. Start with PDO.
    2. Reverse-calculate back to North Pacific SST.
    3. Correlate North Pacific SST with NHT & global T.

    (I realize some want it to be more complicated.)

  67. Geoff Sharp says:

    Bob Tisdale says:
    July 2, 2011 at 6:15 pm

    Points 4 & 5 are unclear. How is a negative PDO figure obtained when the majority of the Nth Pacific SST’s are warmer? Is there a factor applied or is the subtraction of the global mean SST’s producing the neg value?

  68. Paul Vaughan says:

    @Bob Tisdale (July 2, 2011 at 6:15 pm — where Bob goes through PDO calculation steps)

    Bob, varimax rotation often makes interpretation far more intuitive. Have you ever come across a varimax-rotated version of PDO & NPGO in the literature? And does KNMI Climate Explorer facilitate rotation?

    Geoff, consistent with some of Erl Happ’s ideas, you might find Figure 3 & Table 3 (based on varimax rotation) valuable here:

    Trenberth, K.E.; Stepaniak, D.P.; & Smith, L. (2005). Interannual variability of patterns of atmospheric mass distribution. Journal of Climate 18, 2812-2825.
    http://www.cgd.ucar.edu/cas/Trenberth/trenberth.papers/massEteleconnJC.pdf

    Note the prominence of NPI (an index of North Pacific Sea Level Pressure).

    Here’s a graph to assist with translation:
    http://wattsupwiththat.files.wordpress.com/2011/05/vaughn_npp_image2.png
    ( D – T = -SOI )

    (Things get a whole lot more insightful when broken down by season.)

  69. M.A.Vukcevic says:

    I find Mr. Tisdale’s graphs and reasoning inspiring and a good solid base for understanding oceans’ role as the dominant factor in natural climate change.
    North Pacific has Kuroshio Current
    http://www.vukcevic.talktalk.net/Kuroshio.jpg
    North Atlantic has Gulf Stream
    http://oceancurrents.rsmas.miami.edu/atlantic/spaghetti-speed/gulf-stream.jpg
    Study of the branching of these two currents has produced two apparently totally independent climate drivers, as expressed in PDO and AMO indices:
    http://www.vukcevic.talktalk.net/A&P.htm
    Of course correlation does not imply causation, but all required elements for the equation are there. May I add that I do not see a ‘direct’ solar link, particularly not in the North Pacific.

  70. Geoff Sharp says:

    Bob Tisdale says:
    July 2, 2011 at 4:37 am

    When I confronted you with data that contradicted your bogus statement, you attempted to claim that the short-term Antarctic surface stations were the cause of the rise and linked the longer-term surface stations as evidence that the Antarctic had not warmed in 50 years. Then when I plotted that data and showed you that the trends were significantly positive, you attempted to misdirect the readers with additional nonsensical claims.

    I suggested the short term stations would skew the figures more. At the end of the day the long term station data rises about .5 C over 60 years, that’s pretty flat to me.

    Once again, reality offers a different picture, Geoff. The North Pacific north of 20N represents about 15% of the surface area of the global oceans. They, therefore, are a significant part of global surface temperatures. The North Pacific SST anomalies have a higher trend than the Global oceans since 1900. The North Pacific SST anomalies also have a stronger multidecadal variation than the Global Oceans, which illustrates that they contributed to the decline in global surface temperatures from the 1940s to the 1970s and to the rises in global temperatures during the early and latter parts of the 20th Century.
    http://i56.tinypic.com/rvvarq.jpg

    You are twisting my meaning to enable some sort of point scoring. I am saying it doesnt matter what sign of the Nth Pacific SST’s are used, I am not saying that part of the ocean is not important.

    Geoff Sharp says: “The PDO trend quite clearly follows the world temperature trend…
    ———
    The linear trend of the PDO data is flat, slightly negative, Geoff, while the Global SST anomalies have a positive trend.
    http://i56.tinypic.com/25smooi.jpg

    Once again you are not listening. The modulation of the PDO follows the same modulation of the World temps. When solar is added the picture becomes clear to us who understand the mechanics. Solar influence on the jetstream, cloud cover etc are not easy to plot, unless you have a suggestion?

    Geoff Sharp says: “Positive PDO correlate with higher incidence of El Nino and vice versa. There is insignificant evidence to say what drives what…
    —————–

    I’m beginning to believe that you failed to read my post, because I provided quotes from and links to three papers that indicated that ENSO leads the PDO. But if you have read my post, then YOU elect to ignore the evidence. That’s telling in and of itself.

    Your evidence is weak, one stating that PDO leads ENSO during the summer. You and others may well be right but you are missing the point, whether the PDO drives the ENSO or the reverse is not of importance to this discussion, The importance of the PDO measure and its ability to predict future climate is the issue.

    What is becoming increasing obvious is your incorrect statement that is often repeated “. The PDO does not represent the SST anomalies of the North Pacific.” It clearly does represent the SST anomalies but using the reverse sign. You wording is misleading and should be amended. The Nth Pacific SST’s are used as a flag to show the reverse is happening at the equator, your own graphs shows that?

    The PDO is standardized, and because of the standardization, the PDO exaggerates the variability of the North Pacific Residuals by a factor of more than 5.5.

    You might need to expand on this point. When comparing apples with oranges you cannot expect the modulation to follow the same highs and lows. Rescale the ENSO data on your Figure 7 so that the high and low points match the PDO, then we might see a comparison.

    The PDO continues to be a valid tool which is made from Nth Pacific SST’s that reflect the pacific basin and tie in very closely with ENSO. So far you have provided no evidence to discredit the PDO and it remains a valuable tool that shows us the overall modulation of ENSO. If your only point was to show the the Nth Pacific SST’s are in reverse to the PDO you have gone about it in a strange fashion.

  71. phlogiston says:

    Bob,

    Very helpful post, as always, thanks. You resist the use of the term “spatio-temporal pattern” when its utility here is very compelling, preferring to discuss spatial and temporal pattern separately.

    Why? Are you afraid to let in the “chaos cat” through the back door?

  72. Bob Tisdale says:

    Geoff Sharp says: “Points 4 & 5 are unclear. ”

    I assume you’re referring to steps 4 and 5 of the description of how the PDO is calculated that I provided for you in my July 2, 2011 at 6:15 pm comment.

    EOF stands for empirical orthogonal function and PC stands for Principal Component. I provided an overview of this in the Introduction to the PDO post that was linked numerous times in the post:
    http://bobtisdale.wordpress.com/2010/09/03/an-introduction-to-enso-amo-and-pdo-part-3/
    Refer to discussion under the heading of HOW DO RESEARCHERS DETERMINE WHICH PATTERN REPRESENTS THE PDO? It reads:

    Researchers use a method of statistical analysis called empirical orthogonal function (EOF) analysis to determine the pattern that represents the PDO. Wikipedia describes EOF analysis as “a decomposition of a signal or data set in terms of orthogonal basis functions which are determined from the data. It is the same as performing a principal components analysis on the data, except that the EOF method finds both time series and spatial patterns.” Further discussions of this are well beyond the scope of this post. But I did ask someone on a recent thread at WattsUpWithThat if he could simplify the description of Principle Component Analysis (PCA) and EOF analysis for readers without science backgrounds. And while the description is complex, for those who are interested, it is worth reading. Here’s a link:
    http://wattsupwiththat.com/2010/08/19/tisdale-on-liu-and-currys-accelerated-warming-paper/#comment-464129

    You asked, “How is a negative PDO figure obtained when the majority of the Nth Pacific SST’s are warmer? Is there a factor applied or is the subtraction of the global mean SST’s producing the neg value?”

    There is no inverting factor listed in the description of their calculation.

  73. Bob Tisdale says:

    Paul Vaughan says: “Bob, varimax rotation often makes interpretation far more intuitive. Have you ever come across a varimax-rotated version of PDO & NPGO in the literature? And does KNMI Climate Explorer facilitate rotation?”

    I’ve never seen varimax-rotated versions of the PDO & NPGO. And I do not believe the KNMI Climate Explorer facilitates rotation.

  74. Paul Vaughan says:
    July 2, 2011 at 10:35 am
    Dave Springer wrote (July 2, 2011 at 6:59 am)
    “There is a chicken-egg paradox that remains controversial. The controversy is whether weather drives rotation rate changes or rotation rate change drives the weather. Either way there is strong correlation between changing winds and changing rotation rate. Winds are definitely a big factor in SST oscillations. [...] heretofore I was unaware of a connection between earth rotation rate and wind patterns. Rotation rate changes are so small I thought it could be ignored for all practical matters. I’m still not convinced it shouldn’t be ignored.”

    There’s no controversy here Dave. It has been known for decades that pole-equator contrasts induced by the seasons drive the westerlies and hence atmospheric angular momentum and changes in length of day. If your objective is to know what time it is, go ahead and ignore the changes, but if your objective is to understand terrestrial climate, see the following:
    Leroux, Marcel (1993). The Mobile Polar High: a new concept explaining present mechanisms of meridional air-mass and energy exchanges and global propagation of palaeoclimatic changes. Global and Planetary Change 7, 69-93.
    http://ddata.over-blog.com/xxxyyy/2/32/25/79/Leroux-Global-and-Planetary-Change-1993.pdf

    Please take however much time is necessary to understand. The discussion cannot advance until people make the effort to understand the basics.

    My reply; If you read the paper by Leroux he has found and well defined the actions of the air masses, that make up a typical lunar declinational tidal bulge. The Mobile Polar Highs are the polar component of the resultant tidal bulges and the equatorial air masses he thought were pushed by the polar highs are actually pulled off of the meteorological equator or “ITCZ”. The slow and fast phases he eludes to are the result of the 18.6 year variation of the declinational angle at culmination with reference to the equator.

    Reading his paper and substituting Lunar tidal bulge (LTB) for MPH, he very accurately describes the whole range of topographical effects of the orthographic forcing of the global circulation projected on the various topographical features. Rossby saw the zonal flows and jet streams as the feature of primary interest, where Leroux saw the pulses of turbulent meridional flow aspects of the Lunar tidal effects on the atmospheric circulation.

    Neither of them looked at the orbital dynamics of the Moon and its close ties to the patterns seen on the surface, and still the mainstream is ignorant of the patterns and timing of the global circulation, that can be forecast from including the reference point of the lunar declinational tidal effects. For over 20 years now no one has made the connection between these studied and accepted dynamics, to the real driver the Moon.

    Now the current political agenda has every one focused on demonic CO2, and still no one can look up and see the moon for what it does, The big lie that was told, “the moon has no effect on the weather” repeatably to switch the focus of funding from cyclic studies to Numerical models, has been as complete as they are now trying to do with CO2 based climate models. For the same reason you cannot tax the moon, and models are cleaner and safer than doing research outside.

    The answer is still the same the solar/lunar connection to the global circulation is most of the natural variability, most of the rest is the modulation of the SSN/solar CME/ flare activity as a result of the electromagnetic influences of the outer planets acting on the sun and inner planets movement about the SSB. Many times the answers have been found but not referenced to the drivers causing the effects, so are still not understood as to total effects to the point of being able to predict weather or climate. It is only through finding the drivers and patterns of their influences will we be able to forecast more that 10 days out into the future.

  75. Bob Tisdale says:

    phlogiston says: “You resist the use of the term ‘spatio-temporal pattern’ when its utility here is very compelling, preferring to discuss spatial and temporal pattern separately.”

    The intent of the post is to clarify the PDO. Based on a recent discussion with another blogger, I found the multiple meanings of the word pattern, without specifying whether the pattern was spatial or temporal, was causing confusion. I was discussing spatial patterns and the other blogger thought I was referring to temporal patterns. That’s the only reason the subject was raised in this post.

  76. Geoff Sharp says:

    Bob Tisdale says:
    July 3, 2011 at 2:36 am

    You asked, “How is a negative PDO figure obtained when the majority of the Nth Pacific SST’s are warmer? Is there a factor applied or is the subtraction of the global mean SST’s producing the neg value?”
    ————————-
    There is no inverting factor listed in the description of their calculation.

    Your graphs show that the PDO values are very close to inverted Nth Pacific SST’s, but you have not answered my question. Do you have a thorough understanding of how the PDO values are calculated?

    btw.. you may need to read back as my comments quite often end up in the sinbin. (the landsch*** connection)

  77. Bob Tisdale says:

    Geoff Sharp: With respect to your July 3, 2011 at 1:43 am comment, which is a response in part to my comment of July 2, 2011 at 4:37 am. In my comment, I suggest that you: start at this comment and read our exchange through the rest of the thread:
    http://wattsupwiththat.com/2011/06/17/easterbrook-on-the-potential-demise-of-sunspots/#comment-684763

    If you had refreshed your memory by reading that thread, you would not be now making statements that contradict what you’d written about a week ago. I have no plans to go through them point by point to show that your current claims do not reflect the reality of what you wrote a week ago.

    You continue to attempt to dispute my findings with unfounded statements, when in reality you have acknowledged that you do not understand how the PDO is calculated and, therefore, don’t understand what it represents.

    If you can disprove anything that I’ve written in this post or on this thread, using data instead of baseless claims, I will respond to it. Other than that…

    Good-bye, Geoff. I attempted to ignore you earlier. I will try again.

  78. Geoff Sharp says:

    Bob Tisdale says:
    July 3, 2011 at 6:47 am

    good-bye, Geoff. I attempted to ignore you earlier. I will try again.

    A very weak answer Bob. If this is too much for you then I can sympathize, but you have not answered my questions. You have castigated Easterbrook for using an “outdated” PDO scale and then tried to denigrate the PDO as a tool not worthy of substance but put up no reasonable evidence. You have shown no real understanding of how the PDO values are calculated, this should be a mandatory requirement for someone challenging its credibility.

    Lets cut thru the crap….I have offered you a challenge on your Figure 7. Lets see the result?

  79. Bob Tisdale says:

    Geoff Sharp: Here’s one last graph for you to consider. I had the KNMI Climate Explorer perform Principal Component analyses of three regions in the Pacific: the North Pacific north of 20N (20N-65N, 100E-100W), the Eastern Tropical Pacific (20S-20N, 180-90W), and NINO3.4 region (5S-5N, 170W-120W). All datasets are detrended. None of the data is standardized. And I’m illustrating the 1st Principal Component for those three regions in the following graph. The variability of the 1st PC North Pacific north of 20N is not in the same ballpark as the Eastern Tropical Pacific and it’s not in the same league as the variability of 1st PC of the NINO3.4 region:
    http://i54.tinypic.com/x6cxvo.jpg

  80. Geoff Sharp says:

    Bob Tisdale says:
    July 3, 2011 at 8:33 am

    Lets cut thru the crap….I have offered you a challenge on your Figure 7. Lets see the result?

  81. Bob Tisdale says:

    Geoff Sharp: Your replies are beyond laughable. You asked me how the PDO was calculated. I provided you with an answer, quoting an email I received from the keeper of the PDO data, Nate Mantua. You advised me that you didn’t understand it and you asked a couple of questions. I linked simpler discussions of how the PDO was calculated and replied to your questions.

    And after all of that, now you have the audacity to write, “Your graphs show that the PDO values are very close to inverted Nth Pacific SST’s, but you have not answered my question. Do you have a thorough understanding of how the PDO values are calculated?”

    Later you replied, “Lets cut thru the crap….I have offered you a challenge on your Figure 7. Lets see the result?”

    Correction, in your earlier comment you made the request, “Rescale the ENSO data on your Figure 7 so that the high and low points match the PDO, then we might see a comparison.” I elected to ignore your request. Now you call it a challenge. Your challenge is based on your failure to grasp the subject at hand, which I’m sure Pamela Grey continues to find entertaining.

    I believe in the post above I have repeatedly addressed the fact that the PDO does not represent the SST anomalies of the North Pacific, while the NINO3.4 SST anomalies do represent the SST anomalies of the NINO3.4 region. You even mentioned that the comparison is apples and oranges. Scaling them does not eliminate the fact that they’re still apples and oranges.

  82. M.A.Vukcevic says:

    Tisdale & Sharp
    I have no idea how PDO and ENSO indicies are calculated, but when normalised to the same scale there is a high degree of correlation year in year out.
    http://www.vukcevic.talktalk.net/P&E.htm

  83. Geoff Sharp says:

    M.A.Vukcevic says:
    July 3, 2011 at 2:18 pm

    Thanks Vuk, you have saved me the trouble and eloquently put this argument to rest. Enough said I think.

  84. Bob Tisdale says:

    M.A.Vukcevic says: “I have no idea how PDO and ENSO indicies are calculated, but when normalised to the same scale there is a high degree of correlation year in year out.”

    Agreed, and that’s been well known for years, but that’s not the topic of this conversation.

  85. Geoff Sharp says:

    Bob Tisdale says:
    July 3, 2011 at 7:27 pm

    Agreed, and that’s been well known for years, but that’s not the topic of this conversation.

    You just do not know when to lie down. Some excerpts from your article and discussions proves otherwise.

    The PDO data is standardized. This could greatly exaggerate the magnitude of its variations. Could the standardization also inflate its perceived importance?

    I had also wanted to include the errors in the SkepticalScience post It’s Pacific Decadal Oscillation . The SkepticalScience post was obviously written by someone who never plotted the Sea Surface Temperature anomalies of the North Pacific, who misunderstands how the PDO is calculated and what it represents, and who misunderstands or elects to misrepresent climate oscillations.

    One might conclude the PDO data exaggerates the actual multidecadal variations in North Pacific SST anomalies.

    Now I do realize that IceCap has not stated that the positive PDO is responsible for the more frequent, stronger and longer El Niño events and vice versa, but they implied it.

    Figure 7 is a time-series graph that compares the PDO and NINO3.4 SST anomalies (a commonly used proxy for the frequency and magnitude of El Niño and La Niña events). Both datasets have been smoothed with a 121-month filter. Keep in mind that the NINO3.4 SST anomalies represent exactly that, the SST anomalies of an area of the tropical Pacific called the NINO3.4 region, which is bordered by the coordinates of 5S-5N, 170W-120W, while the PDO does not represent the SST anomalies of the North Pacific. The PDO is a statistically manufactured dataset. As illustrated, the multidecadal variations in the PDO and the NINO3.4 SST anomalies are different.

    Third, if the PDO and an ENSO proxy can run out of synch occasionally, then the PDO is truly not a reasonable proxy for ENSO tendencies. You’re better off using an ENSO proxy.

    DOES THE PDO DATA EXAGGERATE ITS RELATIVE SIGNIFICANCE?

    Figure 9 compares the Pacific Decadal Oscillation (PDO) data and NINO3.4 SST anomalies. The scales are similar and that might lead one who is unaware of the differences between the two datasets to believe the two “signals” are similar in magnitude. That’s wrong for a number of reasons. First, the NINO3.4 SST anomalies represent the SST anomalies of an area in the equatorial Pacific, but the PDO data does not represent the SST anomalies of the North Pacific. The PDO data is a statistically manufactured dataset that represents an abstract form of the SST data there. Second, the NINO3.4 SST anomalies are presented in Deg C. The PDO data is not. The PDO data has been standardized.

    But the PDO cannot be used to explain epochs of global warming or cooling because the PDO does not represent a process through which the North Pacific could raise or lower global temperatures.

    This post also illustrated how the PDO data is inversely related to North Pacific SST anomalies and how the PDO data greatly exaggerates the actual variations in the Sea Surface Temperatures of the North Pacific.

    (your attack on Easterbrook) Arguments about anthropogenic global warming cannot be won by misrepresenting the PDO,

    My views about the PDO are based on data. Dr. Easterbrooks views on the PDO are based on his misunderstandings, as are yours.

    Last, have you noticed that Easterbrook never responded to my comments about his post at WUWT? It’s been about a week. You on the other hand, based on you unwillingness to accept what is presented by data, will argue, apparently for the sake of highlighting your own failings.

    The failure of your article is your assumption that the Nth Pacific SST’s are the PDO. The PDO uses the area north of 20deg in the Pacific as a component of the overall Pacific basin, look at it as a proxy record if your like, or perhaps a bi product of a larger system or dare I say perhaps a driver of what occurs in the central Pacific. Whoever came up with the spatial mechanisms for calculating the PDO should be applauded as it has stood the test of time and meshes beautifully with the ENSO record.

  86. Geoff Sharp says:

    M.A.Vukcevic says:
    July 3, 2011 at 2:18 pm

    Tisdale & Sharp
    I have no idea how PDO and ENSO indicies are calculated, but when normalised to the same scale there is a high degree of correlation year in year out.
    http://www.vukcevic.talktalk.net/P&E.htm

    Vuk, of special interest relating to your graph. Nearly all La Nina’s are preceded by a cool PDO (warm water near Asia). This is in direct contrast to Bob’s and the Newman et al 2003 position. But if we look at the El Nino position they tend to lead the PDO. You will notice the reference in the article refers to an ENSO/PDO relationship when comparing what comes first. Perhaps the La Nina/PDO comparison is of special interest. La Nina cannot start until the Walker Circulation pump is in action. The pump cannot start unless there is warm water around Asia and your graph supports this assumption.

    Bob asks the question how can the PDO affect world temperatures. Your graph shows exactly how this can happen.

  87. Bob Tisdale says:

    Geoff Sharp says: “You just do not know when to lie down. Some excerpts from your article and discussions proves otherwise.”

    The only reasons you would believe my discussions prove otherwise is because you don’t understand what you quoted, or you and I are having two different discussions. I’m attempting to illustrate for you that the magnitude of the variations in the SST anomalies and in the 1st Principal Components of the SST anomalies of the NINO3.4 region are far greater than those of the North Pacific. What are you arguing about?

    Geoff Sharp says: “Whoever came up with the spatial mechanisms for calculating the PDO should be applauded as it has stood the test of time and meshes beautifully with the ENSO record.”

    A major difference between the PDO and ENSO is the magnitude of their variations, which is one of the points of my post that you continue to fail to accept. This can be seen in the graph that you dismissed, which compared the 1st Principal Components of the detrended SST anomalies for the North Pacific, and the eastern Tropical Pacific, and the NINO3.4 region. The variations in the 1st PC of the NINO3.4 region are 5.5 times greater than those of the North Pacific.
    http://i54.tinypic.com/x6cxvo.jpg

    We can smooth the1st PC of the NINO3.4 region and the 1st PC of the North Pacific datasets and create a graph that was similar to Figure 7 in the post. The relationship continues. The multidecadal variations in ENSO dwarf those of the PDO.
    http://i55.tinypic.com/aakjsn.jpg

    The same relationship holds true if we switch back to SST anomalies. The variations in NINO3.4 SST anomalies dwarf the detrended North Pacific SST anomalies and the North Pacific residuals, where the North Pacific Residuals are calculated as North Pacific SST anomalies minus Global SST anomalies.
    http://i53.tinypic.com/205tauu.jpg

  88. Bob Tisdale says:

    Geoff Sharp: Let’s wrap this up. I have provided papers that show the PDO lags ENSO. I have illustrated that the PDO is inversely related to the SST anomalies of the North Pacific. I have illustrated that the PDO exaggerates the variations in the North Pacific SST anomalies because the PDO is standardized. Further to that, in my July 4, 2011 at 1:32 am comment, I have illustrated that the variations in the 1st Principal Component of the NINO3.4 region are more than five times greater than the 1st Principal Component of the North Pacific, and I have illustrated that the variations in NINO3.4 SST anomalies dwarf the variations in the SST anomalies of the North Pacific.

    And on this thread and in the thread of the Easterbrook post, I asked you a very basic question, which you have failed to respond to on both occasions. That question is, through what process does the PDO cause global temperatures to rise and fall? If you cannot answer that question and document the basis for your belief with data, there is no reason to continue this discussion.

  89. Geoff Sharp says:

    I think you need to read back Bob, Vuk’s graph and my response to it blow every weak point you have tried to raise in this article as well as answering your last question with basic accepted ENSO knowledge. I believe you have sided with the AGW crew and continue to argue along their predictable lines and references.

    I don’t need to have discussions with you but I will continue to appose your AGW views when presented. Let’s see if your man enough to approve my comments on your blog?

  90. Bob Tisdale says:

    Geoff Sharp: Regarding your latest conjecture on how climate and ENSO works that you expressed in your July 4, 2011 at 12:59 am comment, it is based on your assumptions and therefore riddled with errors. When you have a hypothesis, always check the satellite-era SST data first, because that’s the epoch with the most spatially complete source data. First, the SST anomalies of the Western and Central Pacific (Kuroshio-Oyashio Extension or KOE) are not the PDO. They are a component of the PDO. Second, the NINO3.4 SST anomalies precede KOE SST anomalies most often during the transition from El Niño to La Niña.
    http://i52.tinypic.com/28jcsv4.jpg

    FYI, I discussed the ENSO-caused variations in the KOE SST anomalies and their impact on Global Surface Temperatures in the following post:
    http://bobtisdale.wordpress.com/2010/12/08/the-enso-related-variations-in-kuroshio-oyashio-extension-koe-sst-anomalies-and-their-impact-on-northern-hemisphere-temperatures/

    Second, by your own description, you confirmed what I have said and illustrated in my post. When the PDO is negative, the SST anomalies of the KOE are positive, and since this has a greater impact on North Pacific SST anomalies than the cooling in the east, the North Pacific SST anomalies will rise.

    Your attempts to disprove my post have once again failed.

  91. Bob Tisdale says:

    Geoff Sharp says (July 4, 2011 at 2:23 am ): “I think you need to read back Bob, Vuk’s graph and my response to it blow every weak point you have tried to raise in this article as well as answering your last question with basic accepted ENSO knowledge.”

    Whose “basic accepted ENSO knowledge”? Yours? You have demonstrated little “basic accepted…knowledge” on even the simplest subjects. You have expressed no knowledge of ENSO. Also, I have addressed the failings in your response to M.A.Vukcevic’s graph.

    You continued, “I believe you have sided with the AGW crew and continue to argue along their predictable lines and references,” and you closed with, “I don’t need to have discussions with you but I will continue to appose your AGW views when presented.”

    I do not present AGW views. If I did, Anthony Watts would not continue to cross post me here at WUWT. Your failure to understand the difference between my arguments and those of AGW proponents, your failure to recall my history of posts that undermine the AGW hypothesis, and your need to attempt to claim that I have AGW views broadcast the weaknesses of your arguments. Your comments really are laughable, Geoff.

    You concluded, “Let’s see if your man enough to approve my comments on your blog?”

    Why would I approve the comments of a troll? You have no understanding of the topics being discussed. Your arguments are not based on data, and when confronted with data, you attempt to spin, fabricate, misdirect, and redirect.

    Geoff, I’ve taken the time to go back and review some of the points you attempted to make earlier on this thread.

    Geoff Sharp says (July 3, 2011 at 1:43 am): “Your evidence is weak, one stating that PDO leads ENSO during the summer.”

    You took the discussion out of context. Newman et al wrote in full, “Summer PDO appears to lead ENSO the following winter, but this could be an artifact of the strong persistence of ENSO from summer to winter (r = 0.8), combined with ENSO forcing of the PDO in both summer and winter. Note also that for intervals less than 1yr the lag autocorrelation of the PDO is low when the lag autocorrelation of ENSO (not shown) is also low, through the so-called spring persistence barrier (Torrence and Webster 1998).”

    You continued, “What is becoming increasing obvious is your incorrect statement that is often repeated ‘. The PDO does not represent the SST anomalies of the North Pacific.’ It clearly does represent the SST anomalies but using the reverse sign. You wording is misleading and should be amended. The Nth Pacific SST’s are used as a flag to show the reverse is happening at the equator, your own graphs shows that?”

    My wording is not misleading, Geoff. My statement, the PDO does not represent the SST anomalies of the North Pacific, does not conflict with my other statements that the PDO is inversely related to the North Pacific SST anomalies, or inversely to the detrended North Pacific SST anomalies, or inversely related to the North Pacific Residuals.

    You continued, “The PDO continues to be a valid tool which is made from Nth Pacific SST’s that reflect the pacific basin…”

    Incorrect. The PDO is the product of a Principal Component analysis of the North Pacific north of 20N, and only that area. It represents nothing else in the Pacific basin.

    Geoff Sharp says (July 3, 2011 at 7:32 am ): “You have castigated Easterbrook for using an ‘outdated’ PDO scale…”

    This is a blatant fabrication, Geoff. I clearly stated in my Easterbrook post, “Arguments about anthropogenic global warming cannot be won by misrepresenting the PDO, or by using outdated TSI data, or by creating unusual global temperature anomaly graphs that are obviously wrong to anyone familiar with the instrument temperature record.” Outdated referred to TSI data, not the PDO data.

    You continued, “…and then tried to denigrate the PDO as a tool not worthy of substance but put up no reasonable evidence.”

    I have discussed why the PDO is a useful tool in the post, Geoff, so that statement clearly misrepresents my record. And the reason you do not find the evidence to be reasonable is because you either do not understand what is presented or you simply elect not accept it due to your tunnel vision.

    You continued, “You have shown no real understanding of how the PDO values are calculated, this should be a mandatory requirement for someone challenging its credibility.”

    This is another falsehood on your part, Geoff. I have provided you with the description of the method JISAO uses to calculate the PDO. You acknowledged that you didn’t understand parts of it. Additionally, using the KNMI Climate Explorer, I have replicated the PDO in standardized and in un-standardized forms. The record on this thread clearly indicates that you purposely ignored those graphs.

    Your false claim that I have AGW views has reduced your arguments to the nonsense level, and I no longer have the need to respond to you on this or any other thread.

    Good-bye, Geoff.

    REPLY: Geoff, take that as a “thread closed” to further discussion on this matter. I’m rather disappointed in the way you’ve been behaving. So at this point, just walk away and stick to the solar cycle issues – Anthony

  92. Paul Vaughan says:

    Geoff Sharp wrote (July 3, 2011 at 9:16 pm) “Whoever came up with the spatial mechanisms for calculating the PDO should be applauded as it has stood the test of time and meshes beautifully with the ENSO record.”

    Geoff, here you are making it crystal clear that you don’t understand how factor analysis (e.g. PCA, EOF, SSA) calculations work. The PDO as defined COULD NOT POSSIBLY AVOID looking like ENSO — and this is an INCREDIBLY trivial point for anyone who understands factor analysis.

    I recommend Johnson & Wichern’s textbook on applied multivariate statistical analysis as a starting point. As a prerequisite for reading that textbook one needs a solid understanding of advanced regression analysis.


    Richard Holle, Thanks for your comments.

  93. Paul Vaughan says:

    Stream of thought of reader ALMOST getting what Bob is saying:

    “NHT is a function of North Pacific SST.
    PDO is a function of North Pacific SST.

    Could North Pacific SST be the long-sought intermediary between PDO and NHT???…

    Global T is a function of North Pacific SST.
    PDO is a function of North Pacific SST.

    Could North Pacific SST be the long-sought intermediary between PDO and global T???…

    Naaaawwww! That CAN’T (!) be right.”

    -
    Easier to bury heads in sand than face disconcerting affirmatives.

  94. Bob Tisdale says:

    M A Vukcevic: Sorry it took so long for me to take a better look at the graph you presented. My earlier reply was simply a response to what you’d written and not the graph.

    You wrote, “I have no idea how PDO and ENSO indicies are calculated, but when normalised to the same scale there is a high degree of correlation year in year out.
    http://www.vukcevic.talktalk.net/P&E.htm

    You’ve presented two obscure datasets.

    Your PDO data is based on ERSST.v3b data:
    ftp://eclipse.ncdc.noaa.gov/pub/ersstv3b/pdo/pdo.1854.latest.situ.v3b.ts
    There are some differences between it and the more widely referred to JISAO version of the PDO data.

    And your ENSO Index link includes data for the Global-SST ENSO index:
    http://jisao.washington.edu/datasets/globalsstenso/globalsstenso18002010

    The parent page is here:
    http://jisao.washington.edu/data/globalsstenso/

    The Global-SST ENSO index is calculated as the average SST anomaly equatorward of 20-degrees latitude (north and south) minus the average SST poleward of 20-degrees. That’s really obscure. Our discussion here has been about the commonly used NINO3.4 SST anomalies for an ENSO proxy, and I’m afraid the two obscure indices you use have led to some strange theories by another blogger.

  95. M.A.Vukcevic says:

    Mr. Tisdale
    When I posted the graph,
    http://www.vukcevic.talktalk.net/P&E.htm
    I only briefly scanned trough the posts, not realising intensity of the exchange .
    I do not understand in depth the physical background of either the ENSO or PDO. I just look into available data from respectable institutions, in this case NOAA and University of Washington, assuming that data are authentic and in a legitimate use by the climate science. My only interest is in good correlation of the above data with my privately assembled datasets referring to non-climatic processes of the North and Equatorial Pacific.
    BTW. Dr J. Curry suggested elsewhere that both the PDO and ENSO data prior 1950’s are partly reconstructions and as such may not be absolute.
    Note: I am limiting my posting to no more than 1-2 / day on average.

  96. Bob Tisdale says:

    M.A.Vukcevic: I agree with Judith Curry. Everyone has to be wary of the early years of any SST-based dataset–actually any surface temperature dataset–due to the poor spatial coverage.

    But I thank you for reintroducing me to that curious Global-SST ENSO index. It appears to have been first developed in the early 1990s, and with how it’s created, I’m still trying to determine why the researchers thought it might have been a worthwhile ENSO Index. I’m thinking of writing a post about it.

    Regards

  97. Paul Vaughan says:

    M.A.Vukcevic wrote (July 4, 2011 at 10:22 am) “Dr J. Curry suggested elsewhere that both the PDO and ENSO data prior 1950’s are partly reconstructions and as such may not be absolute.”

    Huge topic. Properly interpreting some aspects of the early PDO record could involve truly monumental diagnostics exercises.

    In many of the indices we discuss there are strong early-record seasonal peculiarities that precisely match strong excursions in the Earth Orientation Parameter (EOP) records. The Climate & EOP communities haven’t made a satisfying effort to integrate knowledge across disciplines. A lot of the work that needs to be done is incredibly tedious, but there is the potential to answer some very interesting questions.

    Bob Tisdale wrote (July 4, 2011 at 9:25 am) “[...] Global-SST ENSO index is calculated as the average SST anomaly equatorward of 20-degrees latitude (north and south) minus the average SST poleward of 20-degrees.”

    Bob Tisdale added (July 4, 2011 at 4:03 pm) “[...] thinking of writing a post about it.”

    Sounds worthwhile and quite interesting.

  98. Brian D says:

    Yes, I read that, Bob. They still don’t know what comes first. Its the chicken and egg scenario as they stated between trade winds and ocean temps. Is there a coupling? Sure but the chicken is the air pressure IMO. Not looking for a squabble. If they don’t know for sure, then its moot to argue about it. My gut tells me weather (high pressure position and strength).

  99. Bob Tisdale says:

    Brian D says: “Yes, I read that, Bob. They still don’t know what comes first. Its the chicken and egg scenario as they stated between trade winds and ocean temps. Is there a coupling? Sure but the chicken is the air pressure IMO. Not looking for a squabble.”

    I’m not squabbling, just discussing. I’m also not disagreeing with you completely.

    As Bill Kessler described, the pressure difference would not exist without the Sea Surface Temperature difference, so under “normal” conditions, how could sea level pressure be the chicken? On the other hand, the SST difference wouldn’t exist without the sea level pressure difference.

    A relaxation of the trade winds intitiates the El Nino, so in that regard, the chicken would be sea level pressure? But on the other hand, the La Nina phase (after an El Nino) is said to start with the formation of a Rossby wave at approximately 10N in the eastern tropical Pacific (It carries the leftover warm water back to the western Pacific). And the Rossby wave is a coupled phenomenon.

    And of course, those explanations pertained to typical events. If memory serves me well, much of the uncertainty in Kessler’s discussion had to do with the fact that different factors can initiate ENSO events, so we’re back at square one.

    Regards

Comments are closed.