Guest post by Erl Happ
The Southern Oscillation Index is a reference point for the strength of the Trade winds. It represents the difference in atmospheric pressure between Tahiti and Darwin. In figure 1 the SOI is the red line with its values on the right axis. A negative SOI reflects slack trade winds and a warming ocean. A positive index relates to a cooling globe. Note that the right axis in figure 1 is inverted.
How is it that change in surface atmospheric pressure is so closely associated with a change in the temperature of the tropical ocean? This is the major unsolved riddle in climate science. If temperature is so obviously associated with pressure on an inter-annual basis why not in the long-term? In this article I show that pressure and temperature are intimately related on all time scales. In other words, ENSO is not an ‘internal oscillation of the climate system‘ that can be considered to be climate neutral. ENSO is climate change in action. You can’t rule it out. You must rule it in. Once you do so, the IPCC assertion that the recent increase in surface temperature is more than likely due to the works of man is not just ‘in doubt’, it is insupportable.
If the IPPC can’t explain ENSO it can not explain climate change. It is not in a position to predict surface temperature. Its efforts to quantify the rise in temperature must be seen to be nothing more than wild imaginings. Its prescriptions for ‘saving the planet’ must be viewed as ridiculous.
Surface pressure data: http://www.longpaddock.qld.gov.au/seasonalclimateoutlook/southernoscillationindex/soidatafiles/index.php. Monthly temperature data: http://www.esrl.noaa.gov/psd/cgi-bin/data/timeseries/timeseries1.pl
Temperature change is linked to change in surface atmospheric pressure
Figure 1 Left axis Temperature in °C. Right axis three month moving average of the monthly southern Oscillation Index
The Southern Oscillation Index leads surface temperature on the upswing and also on the downswing. Some factor associated with change in surface pressure is plainly responsible for temperature change.
How and why does atmospheric pressure change?
The evolution of surface pressure throughout the globe depends upon the activity of the coupled circulation of the stratosphere and the troposphere in Antarctica and in the Arctic. These circulations have become more aggressive over time resulting in a loss of atmospheric mass in high latitudes and gain at low latitudes. The gain at low latitudes reflects the seasonal pattern of increased intensity in the respective polar circulations. The stratosphere and the troposphere couple most intensely in February in the Arctic and in June through to September in the Antarctic. The pattern of enhanced activity at particular times of the year is reflected in the timing of the increase in sea surface pressure in equatorial latitudes, as seen in figure 2.
Figure 2 Gain in average monthly sea level pressure between the decade 1948-1957 and the decade 2001-2010. hPa
The coupled circulation in the southern hemisphere produces a deep zone of low pressure on the margins of Antarctica that encircles the entire globe as is clearly evident in figures 3 and 4. In previous posts I have documented the change in high latitude pressure since 1948 and the associated change in wind strength, sea surface temperature and by inference, since the atmosphere is warmed by the descent of ozone into the troposphere, a change in cloud cover.
Figure 3 Mean sea level pressure January
The pressure deficit on margins of Antarctica is deepest in July (winter).
Figure 4 Mean sea level pressure July
It is of interest therefore to look at the evolution of the pressure relationship between Tahiti and Darwin (that is the essence of the SOI) over time.
Bear in mind that as atmospheric mass moves from high latitudes to the equator atmospheric pressure increases at Darwin more than it does at Tahiti and the trade winds slacken. The increase in pressure at Darwin is well correlated with the increase in atmospheric pressure in equatorial latitudes globally. The plunge is atmospheric pressure at high latitudes that enables the increase in pressure at the equator is associated with cloud loss and increased sea surface temperature in mid and low latitudes. The most abbreviated explanation of mechanism behind the loss of cloud can be found here: http://wattsupwiththat.com/2011/08/20/the-character-of-climate-change-part-3/
Figure 5 Thirty day moving average of the difference in daily sea level pressure between Tahiti and Darwin hPa.
The excess of pressure in Tahiti with respect to Darwin over the period 1999-2011 is shown in figure 5. The differential plainly evolves over time and an indication of the direction of change is given by the fitted polynomial curve.
Secondly, we can see that the pressure differential exhibits a pattern of seasonal variation. In general the pressure differential is high at the turn of the year and low in mid year.
The pattern of the average daily differential for the entire period for which daily data is available (1992 -2011) is shown in figure 6.
Figure 6 Average daily sea level pressure differential between Tahiti and Darwin over period 1992-2011. hPa
We observe that the pressure differential between Tahiti and Darwin:
• Reflects strong variability even when averaged over a period of twenty years.
• Is greatest between late December and the end of February (strong Trade winds)
• Is least between April and September (weak Trade winds).
• Shows a pattern of enhancement in February- March and also in September- October that plainly relates to the pattern of pressure increase in near equatorial latitudes evident in figure 2. The shift in the atmosphere away from Antarctica tends to enhance the pressure differential driving the trade winds all year, but in particular in September and October. So far as the Arctic is concerned the pressure loss is centered on February and March.
Why do the trades tend to fail in mid year?
Figure 7 Sea level pressure hPa. Seasonal pattern in Tahiti and Darwin.
The erosion of the pressure differential in southern winter relates to the establishment of a high pressure zone over the Australian continent. Compare figures 3 and 4 noting the difference in atmospheric pressure over Australia in summer and winter.
Change in the pressure differential (and the trade winds) over time.
In figures 8-11 the evolution of the pressure differential between 1997 and 2000 is compared with its evolution between the years 2009-2011.
Figure 8 Daily pressure differential. Tahiti less Darwin. hPa
The first and largest El Nino of solar cycle 23 began in early 1997. The first El Nino in Cycle 24 started in late 2009. The pattern of the differential is shown in figure 8. Plainly, the reduction in the pressure differential was more extreme in 1997 than in 2009.
Figure 9 Daily pressure differential. Tahiti less Darwin. hPa
The reduced differential persisted till March in 2010 and May in 1998. The last half of the year saw a strong recovery.
Figure 10 Daily pressure differential. Tahiti less Darwin. hPa
In 1999 and 2011 we see a strong pressure differential (La Nina) in the early part of the year, and in the case of 1999 this enhanced differential persisted through to the end of the year. The differential in early 2011 was much stronger than it had been in 1999.
It is noticeable that week to week variability is enhanced in 2011. I suggest that this relates to increased plasma density in an atmosphere due to reduced ionizing short wave radiation in solar cycle 24 by comparison with 23. Under these circumstances El Nino and La Nina produce a relatively ‘wild ride’.
We note the extension of La Nina into a second year.
Figure 11 Daily pressure differential. Tahiti less Darwin. hPa
2000 was a La Nina year coinciding with solar maximum. A coincidence of La Nina with solar maximum is more usual than not. On that basis one expects the current La Nina to continue into 2012. However, given the relative deficiency in short wave ionizing radiation in cycle 24 with respect to cycle 23 this time around might be different. The likely lack of a well-defined peak in cycle 24 will make a difference. If the cycle goes in fits and starts, so to will the ENSO experience.
Is the climate swinging towards El Nino as it warms?
It is a favorite meme of those who suggest that the globe is warming ‘due to change in trace gas composition’ that the climate is likely to progress towards a more of less permanent El Nino existence. Does recent history support this assetion? Is a warming globe associated with increased incidence of El Nino?
Figure 12 Average daily pressure differential Tahiti less Darwin hPa
In the six year period 1992-1997 the average daily pressure differential reveals an El Nino bias in relation to average for the entire period 1992-2011. In this period the globe warmed, but the degree of warming was subdued by the eruption of Pinatub0 in 1991.
Figure 12 Average daily pressure differential Tahiti less Darwin hPa
A cooling bias is evident over the last seven years from 2005 through to 2011.
Figure 13 Average daily pressure differential. Tahiti less Darwin. hPa
Plainly there has been a progression away from an El Nino towards a La Nina state over the twenty years since 1992. In the period to 1998 the globe plainly warmed. In the period since 1998 warming seems to have ceased. There have been a suggestion that some heat that ‘should be there’ has gone missing. Can this be read as an admission that warming has either slowed down or has actually ceased?
Conclusion:
ENSO is not climate neutral. ENSO is the reality of climate change in action. The progression towards cooling that is evident in the increasing pressure differential between Tahiti and Darwin shows no sign of abating. The ENSO state changes not only on an inter-annual time scale but on very much longer time scales. ENSO is plainly not ‘climate neutral’.
If we look back at figure 1 we will see that the Southern Oscillation Index leads the change in tropical sea surface temperature on the upswing and the downswing. The SOI is more positive (cooling) in 2011 than it has been at any time over the last sixty years.
Until the IPPC can properly account for ENSO cycles they can not attribute climate change to ‘change in trace gas composition due to the works of man’. We see an excellent correlation between surface pressure and surface temperature and no correlation at all between trace gas concentration and surface temperature.
Where is Science?
Well, bugger AGW! Let’s get real here. What does all this mean in terms of wine production, Earl?
JPM,
A few more bits of data need to fall into place before I could consider my hypotheses clearly demonstrated but your suggestion is appreciated.
Very interesting read, thank you.
I agree with cal
September 23, 2011 at 2:36 am
who says that the the ideal gas law PV = RT explains how temperature and pressure of the atmosphere vary.
There is no room for a theory considering the radiative effects of CO2, a trace gas. The AGW theory.
Shouldn’t these discussions which significantly focus on pressure and velocity suggest that enthalpy is what we should really be measuring for measuring “climate” changes vice being so focused on temperature?
Philip Bradley says:
September 23, 2011 at 1:14 am
Energy is added to a gas when you compress it. (work = force x distance and all that.) If the container is poorly insulated, then more thermal energy is released from the warmed gas than would be had it not been compressed.
Of course, the energy added to the gas had to be released by whatever drives the compressor. In that sense your statement is ambiguous.
BTW, you seem to have misterminated a <i> and triggered a WordPress bug that leaves italics on to the end of the post. The proper termination is </i>.
Tim Folkerts
I am no expert, but measuring over a year seems right considering the axis of the earth is not perpendicular to the plane, and that land-mass is not evenly distributed around the planet.
More evidence to present to the IPCC.
But, will they accept it? No!
Impudent Pack of Condescending Clowns.
Your first graph clearly shows a correlation. However, there is also a clear trend of the SST upward IN ADDITION to the correlation to the pressure data.
Put another way, there is no long-term trend in the pressure data, but there is a long-term upward trend in the SST data. Thus it appears your approach shows what drives short term (monthly or annual) variations, but it does NOT show what drives long-term (decadal) changes. The long-term changes would need some OTHER explanation (like changes in the sun or changes in GHGs).
@ur momisugly Eternal Optimist
Certainly a year is a reasonable period to choose; my point was more that Jan-Dec (summer-summer in the southern hemisphere) period is artificial. It would make just as much sense to fit the data from JUL-JUN (winter-winter). The fit as shown is a handy guide for the eye, but making any inferences from such an artificial fit seems to be asking too much from such a fit.
And again, a sinusoidal fit makes more sense, because then the fit would repeat smoothly, rather than having a discontinuous cusp at the end of every year.
RE: Erl Happ: (September 22, 2011)
“If the [IPCC] can’t explain ENSO it can not explain climate change.”
I believe that the IPCC was founded on the general proposition that human behavior, especially that in modern western civilization, was adversely affecting the climate, thus the governments of the world must get together and control this adverse human behavior worldwide before our environment is damaged beyond amendment.
If, as many now believe, the climate is largely beyond our control, then perhaps it should be replaced or augmented by an organization dedicated to dealing with the international aspects of human adaptation to gross climate changes.
There seem to be increasing indications that our knowledge of climate science is much less mature than we had believed in the past.
Not sure this proves anything. Of course Pressure and Temperature are linked inherently everywhere in our atmosphere. It’s basic high school chemistry – look up Boyle’s and Charles law and the ideal gas law PV=nRT.
Where is the science?
In your basic high school text book.
Mods, I lost a comment to the nether worlds!
[REPLY: I didn’t find anything in Spam. If it did not appear, resubmit. -REP, mod]
It all reminds me of the parable of the blind man trying to discern an elephant by touch.
We have been examining the tail of this beast, for some time, and we are still cannot identify the fundamental animal. Frustrating as hell.
Btw: Add to this enigma, Cern’s neutrino faster than light speed results and one has to be amazed, by our apparent ignorance (see tips and notes) GK
Jeremy says:
September 23, 2011 at 6:49 am
Not sure this proves anything. Of course Pressure and Temperature are linked inherently everywhere in our atmosphere. It’s basic high school chemistry – look up Boyle’s and Charles law and the ideal gas law PV=nRT.
Where is the science?
In your basic high school text book.
================================================
I wish I’d remember to refresh the page before I post. But, yes, it seems it might be appropriate to apply some gas laws. But, Jeremy, it’s been done before and, wow, you wouldn’t believe how many people oppose that type of application of such science laws.
Mods…… italics seem to be stuck on!!!!
I now have a kink in my neck from reading italics. Someone forgot to “unitalic”.
[REPLY: It’s fixed! It’s fixed! -REP, mod]
nice work, Erl.
nice comment by Roy, too.
i submit that a ‘cloud’ need not be visible as condensed vapor, too – a volume of water vapor which is invisible is as effective an ir blocker/absorber as a visible cloud.
Gentlemen,
Thanks for your comments. It seems that you miss the thrust of the exposition. It is encapsulated in the last graph (figure 13) where we see the average differential for six then seven and another seven years that brings us up to the present time. That data shows that the excess of surface pressure (Tahiti less Darwin) has been increasing over the entire period. In other words the trade winds have been strengthening throughout.
What this means is that, in the earliest years the climate regime was strongly El Nino dominant (weak Trades) and it has become less El Nino dominant over time. Since 2007 we have been in a La Nina state most of the time.
ENSO is supposed to be climate neutral. If you think it climate neutral I ask you, over what period might it be considered climate neutral. Over the last twenty years it has been heading one way and is likely to keep going in that direction for a while yet. Was it even more El Nino dominant prior to 1992? When will it reach its peak in terms of the La Nina tendency that is now well established?
We are plainly dealing with a very long cycle here. A cycle where the trade winds and the westerlies strengthen for perhaps 60 years and then weaken for another sixty years.
Now, if you can see that this is the case, ask yourself why the pressure relativities that lie behind the change in wind speed change as they do. Is this change consistent with the idea of a climate system that oscillates about a mean state within the space of a decade? Plainly not.
In other words ENSO changes surface temperature over sixty year time scales. Before we can attribute the temperature change that plainly worries some people to any particular factor we have to establish what the ENSO factor is contributing.
Going back to figure 1. When I set that up I should have acknowledged a strong elevation of the SOI curve above the SST curve at the beginning to recognize the El Nino bias at that time. The curves should be fitted to match in 1997 when the Earth stopped warming. That is the pivot point. To recognize a state of El Nino dominance the red line should be well above the blue at the start. After 1997 the red line slips below the blue line. But if ENSO is the only factor changing temperature the blue line should follow it down. If there is some other factor driving temperature upwards the two will never meet. But my gut feeling says that they will. I know what is driving the shift in the atmosphere that changes the pressure relativities and therefore the winds. I know that as the westerlies increase in strength so do the trades and the ocean warms in a lock step fashion with the increase in the winds.I know what cause the winds to blow harder and the clouds to disappear. The mechanism is in the coupled circulation of the stratosphere and the troposphere at the poles.
“The Southern Oscillation Index is a reference point for the strength of the Trade winds. It represents the difference in atmospheric pressure between Tahiti and Darwin.”
Indeed that’s how it was defined and Leroux demonstrated why it is an aberration.eom.
Earl,
Good analysis and a very important point – ENSO change IS climate change. It’s not climate neutral and it’s not noise.
http://www1.ncdc.noaa.gov/pub/data/cmb/teleconnections/eln-f-pg.gif
http://www1.ncdc.noaa.gov/pub/data/cmb/teleconnections/lan-f-pg.gif
Ok, trying again…..
Erl, you are skirting on a very contentious issue by even daring to mention atmospheric pressure. You may not be aware of the history. A about a year & 1/2 ago a frequent contributor (Steve Goddard, who has gone on to run his own blog……http://www.real-science.com/) presented the thought of applying the Ideal Gas Law to the climate issue. http://wattsupwiththat.com/2010/05/06/hyperventilating-on-venus/ and http://wattsupwiththat.com/2010/05/08/venus-envy/ .
As you can see, the idea was quite controversial, and was met with much resistance from alarmist and skeptic alike. That said, Steve’s writing and response style is more provocative and elicits emotive responses rather than intellectual exploration.
The law, PV=nRT, is apparently not very palatable to many that have considered the CAGW hypothesis. Now, I’m not familiar with all of the intricacies of atmospheric pressure. But, what I do know is that science laws don’t selectively apply. They always work or they are not laws. The laws of motion don’t cease to exist because we aren’t considering them, neither do the laws of energy transfer. Some, from conversations in the past, seem to think the Ideal Gas Law only applies when we consider the question.
Perhaps its time for a more level-headed discussion regarding how the Ideal Gas Law applies to the earth’s temps.
James
T = pV/nR = pv/Rspec = p/ρRspec
That means that if pressure and volumen (or density) are given, the temperature is defined and depends only on these two. You can only change the temperature if you change the p/ρ ratio, assuming any change in specific gas constant is insignificant.
“ENSO is supposed to be climate neutral. ” Given a long enough period of time it is. That is why this climate science debate is so frustrating. There are natural frequencies in any dynamic system. 9.5 years and 15.3 years would seem to be the most applicable, but there are 40, 65 and 96 years cycles that should be considered in 100 years forecasts of climate change. Now that the bar for a trend is set at greater than 17 years, it is more of a challenge. Before, 14.7 years was a reasonable minimum period for a trend.
James Sexton says: September 23, 2011 at 7:55 am
The atmospheric pressure on Venus is greater than 9,000 kPa. At those pressures, we would expect Venus to be very hot. Much, much hotter than Death Valley.
Sorry James, not going to buy it. It is once compressed and just as the heat is dissipated from a high pressure cells where the air is being compressed as it descends via the usual means i.e. long wave radiation, so too would the heat of compression be dissipated from Venus. When its gone its gone unless the atmosphere is compressed again.
I believe Venus is actually a bit closer to the fire. Would that not make it warmer?
James and Edim
Let’s ground this discussion by clearly establishing what I refer to when I speak in terms of change in atmospheric pressure. See here:http://wattsupwiththat.com/2011/01/12/earths-changing-atmosphere/