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
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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.
Does ENSO drive global temperatures in any appreciable way?
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.
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.
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.
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/
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.
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
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.
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.
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?
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).
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.
Geoff Sharp
Do you know what’s up with the magnetosphere and the recorders?
http://137.229.36.30/cgi-bin/magnetometer/magchain.cgi
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
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.
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.
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.
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.
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.
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.
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.
Bob asserts:
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.
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.
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.”