Solar activity levels vs surface temperature variation

Posted: October 26, 2015 by tallbloke in climate
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I posted the short comment below in reply to a blog post by Richard Telford

The first thing to do before making any stats tests is to consider how the physical mechanism may work. If the relatively high solar activity of the C20th did have an effect on temperature then it was by warming the oceans. Water has a high heat capacity, so Ocean Heat Content (OHC) (and thence SST) wouldn’t be expected to react instantaneously to solar variation. So we need to low pass filter or integrate solar data to mimic the thermal inertia of the oceans.

Sunspot number (SSN) is a good proxy for total solar irradiance (TSI). Over the period of record since 1749, the average sunspot number is 40. This is also the number found when averaging the SSN over a period where SST didn’t vary much. Integrating SSN as a cumulative total departing from this ‘equilibrium’ value generates a curve which shows a slight fall from 1880 to 1934, and then a rise to 2003. When combined with a suitably phased ~60 year sinusoid representing the Atlantic multidecadal oscillation (AMO), something close to the 5 year smoothed surface temperature record is obtained.

I took this idea a little further with by combining AMO, integrated SSN, SOI and LnCO2 (at a suitable value), producing a match between model and HADSST with an R^2 of ~0.8 for MONTHLY values since 1875 and R^2=~0.9. for more accurate data since 1960

Simple model combining solar integral as OHC proxy, detrended AMO, SOI and a nominal value for LnCO2 equivalent to around 0.6C for a doubling from 270 to 540 ppm. The projection to 2050 reuses an earlier section of the AMO and a solar integral based on the output of our 4-orbit model.

I can make the spreadsheet available to interested parties.

One of the many problems with discerning the solar effect on surface temperature is that the solar derived energy building up in the Pacific Warm Pool (PWP) between El Nino events is hidden from surface temperature datasets. Big El Nino’s tend to occur at solar minimum, and so are in anticorrelation to the solar signal on SST. This flattens the apparent magnitude of the solar effect.

There are on average three el nino events per solar cycle, so by smoothing the temperature data at 40 months, and detrending the temperature data to match the unintegrated solar data, a better solar-surface temperature correlation appears, though of small magnitude and varying phase due to the ENSO effect outlined above.

Simple correlation between solar activity and surface temperature using detrended temperature smoothed at 40 months – near the ENSO period.

  1. ivan says:

    Are we allowed to say ‘it’s the sun wot does it’? 🙂

  2. Thanks, very interesting. Could you send me the spreadsheet

  3. tallbloke says:

    Willdo later, it’s on another hard drive.

  4. My question is when the sun is in a prolonged severe minimum period what will be the response of El Nino/La Nina when this state of the sun is present?

    I think it will be different in contrast to when the sun is in a rhythmic so called 11 year sunspot cycle.

    Although solar activity has been very low overall post 2005 ,it is still not in a severe prolonged solar minimum period but still behaving closer to the so called rhythmic solar cycle.

    I want to know what happens if Maunder Minimum conditions start to be approached?

    The data for ENSO back then is very uncertain.

    One thought I have is maybe a weak El NINO tendency at this time would take place, superimposed upon an overall global lowering of sea surface temperatures in conjunction with the weak El NINO displaced around maybe 3 degrees south of the equator rather then along the equator.

    Any thoughts?

  5. Paul Vaughan says:

    …and AMO’s a sun-shaped spatial pattern:

    Total heat relates to sunspot integral, but of course poleward flows of heat intersecting the northern hemisphere’s asymmetrical ocean-ice margin are paced by spatiotemporal gradients.

    TSI doesn’t vary in the polar night. It’s zero whether solar min or max.

    Poleward advection intensity pulses with the solar-cycling equator-pole gradient. Temporally orthogonal freshwater exports from the arctic clarify the consequence of polar asymmetry (the arctic dipole & trans-polar drift).

    Lukes love AMO because it’s a big spatial distortion that obscures the sunspot integral.
    They of course love ENSO for the same reason.

  6. Paul Vaughan says:

    Btw the papers on the arctic dipole and transpolar drift need to be updated in light of the semi-annual solar-terrestrial weave in LOD & AAM.

    They found that EOF2 of northern pressure explains 13% of the variance but they didn’t dig down to the root of that.

    Equator-pole gradients are the kinetic root and geography’s the root of the asymmetric potential.

    It’s a lot simpler than people think and they’re not cluing in because they’re locked into a counterproductive mindset that’s opposed to looking from a vastly superior perspective.

    The implicit assumption of uniformity in conventional narratives can be firmly dismissed as totally & completely divorced from reality. (I recommend not letting them get that ignorant/deceptive wool over your eyes by evading clear explicit statement of their hidden false assumptions.)

    Technically you don’t even need to keep track of the (detailed allocation of) potential. Knowing that it extists and that it’s harshly physically asymmetric is enough to prove the role of frequency shift whether at Milankovitch or Schwabe timescale.

    The proofs are done and what’s missing at this point is willingness &/or ability to understand and acknowledge.

  7. Paul Vaughan says:

    SDP there may be some misunderstanding at play but assuming there isn’t for the sake of exploratory communication, why do you think equatorial winds will stop being easterly and midlatitude winds westerly during a prolonged solar minimum?

  8. tallbloke says:

    Paul V: The proofs are done and what’s missing at this point is willingness &/or ability to understand and acknowledge.

    The other thing that’s missing is a good summary of the proofs written in layman language. We should find the time to work on that together after Paris.

  9. What I was saying is not that the equatorial winds would stop being easterly or the mid latitude winds would stop being westerly during a prolonged solar minimum but rather during a prolonged solar minimum due to UV light emission changes the distribution of ozone in the atmosphere in a vertical and horizontal sense would be such that it would promote the polar vortex to become less intense but more expansive at the same time.

    If the polar vortex were to become more expansive in response to a prolonged solar minimum period of time this would then push all of the climatic zones such as the ITCZ further south, causing the latitudes of the extension of westerly winds to sink further south along with the equatorial easterlies.

    In other words all climate zones in the N.H would shift toward the equator similar to the effects associated with a -AO versus a +AO. The negative AO pushing the storm track and atmospheric circulation away from the higher latitudes towards lower latitudes.

  10. jdmcl says:

    Please put some figures on this; IIRC the variation in solar radiation is tiny. Further, I doubt very much that the solar radiation is more important than the insolation, i.e. the amount of radiation that reaches the Earth’s surface. Also (a) smoothed data loses important nuances (e.g. the impact of volcanic eruptions on the temperature record) and (b) how do you account for the divergence after 1997?

  11. tallbloke says:

    jdmcl: Please put some figures on this; IIRC the variation in solar radiation is tiny.

    Hi jdmcl, a reasonable question, thank you. I have put figures on this, they are in the spreadsheet. The thing to realise about this, is that although the variation in solar is tiny, the variation in Earth’s surface temperature over the last 130 years is pretty tiny too. Solar output increased maybe 0.05-0.1% over the C20th, while sea surface temperature increased from ~287K to ~287.7K, which is a 0.25% increase.

    ” I doubt very much that the solar radiation is more important than the insolation, i.e. the amount of radiation that reaches the Earth’s surface.”

    Surface insolation is obviously related to total solar irradiation, but you’re right, the amount of cloud cover is crucial. The ISCCP data shows a reduction in low cloud cover of around 0.4% between 1980 and 1997, which represents an amplification of the irradiance variation. Prof. Nir Shaviv, in his paper on using the oceans as a calorimeter, found an amplification of the solar variation in the thermal expansion and contraction of the ocean on the decadal timescale.

    ” Also (a) smoothed data loses important nuances (e.g. the impact of volcanic eruptions on the temperature record)”

    All the data used in the model above is monthly data, including the solar integral. In the second plot, the temperature data has to be smoothed to iron out the ENSO effects to reveal the Solar-Terrestrial link. The IPCC exaggerates the effect of volcanos on the temperature record as they need a strong negative forcing to counterbalance the exaggerated CO2 forcing they hypothesise. This sort of works for the record over the last 40 years, but their model fails further back in time. In contrast, the solar integration method used here matches proxy temperature data going back a thousand years and more.

    “and (b) how do you account for the divergence after 1997?”

    I think you’re referring to the second plot above. The 1997 ‘super El Nino’ heavily affects the surface temperature record for a number of years following the solar minimum in 1996, because it’s followed by a La Nina near the top of solar cycle 23. The same disruption occurs around 1940 at the peak of the Atlantic multidecadal Oscillation and in 1880, again near the peak of the AMO, when there were also ‘super El Nino events’.

  12. I think based on normal average solar minimums this is what is needed to have a change in solar activity translate to a change in the climate that can be correlated to a better degree. In the normal 11 year sunspot cycle I do not doubt a solar/climate connection but it is obscured by too many counter forces and by solar conditions not staying in a particular state of activity for a long enough duration of time, or be low enough in degree of magnitude change. The criteria I list for solar activity
    to have a more noted impact on the climate is below normal solar minimum activity conditions both in duration of time and degree of magnitude change.

    This criteria I am quite sure has been met or exceeded during the recent Maunder Solar Minimum occurrence from 1640-1705 AD.


    Solar Flux avg. sub 90

    Solar Wind avg. sub 350 km/sec

    AP index avg. sub 5.0

    Cosmic ray counts north of 6500 counts per minute

    Total Solar Irradiance off .15% or more

    EUV light average 0-105 nm sub 100 units (or off 100% or more) and longer UV light emissions around 300 nm off by several percent.

    IMF around 4.0 nt or lower.

    The above solar parameter averages following several years of sub solar activity in general which commenced in year 2005. The key is duration of time because although sunspot activity can diminish it takes a much longer time for coronal holes to dissipate which can keep the solar wind elevated which was the case during the recent solar lull of 2008-2010 ,which in turn keep solar climatic effects more at bay. Duration of time therefore being key.

    The decline in temperatures should begin to start to take place within six months after the ending of the maximum of solar cycle 24,if sub- solar conditions have been in place for 10 years + which we have now had. Again the solar wind will be needed to get to an average of below 350km/sec. which takes time because not only do the sunspots have to dissipate but also the coronal holes. In other words a long period of very low sunspots will be need to accomplish this. It will be a gradual wind down..

  13. Paul Vaughan says:

    The channels to a broader audience are so clogged with incorrect information that they are for all practical purposes literally impenetrable.

    The prudent objective for responsible luminaries may be ensuring awareness survives in refuges during an era of extremely strict, grotesquely unjust suppression.

    The pendulum is swinging decisively hard in the wrong direction.
    Can genius messaging crafted at great expense correct this?

    Even if so, it isn’t sufficiently efficient — and therefore it isn’t a sensible strategy — being such a try-hard.

    An efficient, aesthetic path will arise naturally when the time is ripe.

  14. Paul Vaughan says:

    OB they could decisively crush with no-contest aggression the notion they’re on a “fishing expedition” if they actually understood this:

    …but unfortunately I see no evidence whatsoever that they’ve managed to do the simple homework
    …which involves one step: subtract one column of numbers from another in a spreadsheet.

    Not very inspiring unfortunately.
    Very disappointing actually if that’s the best they can do.
    Obama will be pleased with them. They’re serving him as perfectly as any opposition could by being so stupidly ignorant of something so wrong and so incredibly simple. I could teach a 3-year-old to do the calculation in a few seconds …and this is the US Senate. *ing ridiculous