Is there robust evidence of solar variability in palaeoclimate proxy data?

This is my EGU 2015 poster which I am presenting this evening. Poster B25 if any readers are at EGU and want to see it nailed to the board.

With my coauthors Kira Rehfeld and Scott St George, I have done a systematic review of high-resolution proxy data to detect possible solar-signals. It is an attempt to avoid the publication bias and methodological problems in the existing literature on solar-palaeoproxy relationships. A manuscript in in preparation.

There is no prize for finding any typos.

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About richard telford

Ecologist with interests in quantitative methods and palaeoenvironments
This entry was posted in solar variability. Bookmark the permalink.

9 Responses to Is there robust evidence of solar variability in palaeoclimate proxy data?

  1. BBD says:

    I hope it goes well RT. I’m sure it will. I have enjoyed reading your search for robust evidence presented by others for solar variability in palaeoclimate proxy data 😉

  2. Jamal Munshi says:

    I was hoping for a prize for finding typos but my hopes were dashed.

  3. Jamal Munshi says:

    really great summary of the relevant issues. thank you.but what do you mean by “robust” evidence. robust with respect to what?

  4. Geoff Sharp says:

    The Gleissberg and DeVries cycles are in fact not cycles at all and should not be expected to repeat on a constant basis. They are the most common gap between overall solar activity and solar grand minima.

    The effects of differing grand minima affect the Gleissberg “cycle” which in fact is just the accumulation of extra Angular Momentum as N/U come to conjunction. The overall solar cycle modulation follows this wave over 172 years (divide by 2 to get the Gleissberg) and is only disrupted by grand minima. This is observed clearly over the 400 year sunspot record.

    The De Vries cycle (208 years) is just the most common gap between grand minima. This occurs because an average of 3 Barycentric Anomalies are presented each 172 years which are separated by 40 years. It is very rare to have 3 strong Anomalies per 172 year cycle, so the average gap between grand minima just happen to be 208 years across the Holocene. The LIA is a good example where a period of strong 172 years cycles that contain higher than average strong Barycentric Anomalies, this phenomenon displays a much smaller gap than 208 years over this period. An example of a weaker Barycentric Anomaly is SC20 at 1970, which is not strong enough to cause a grand minimum but still greatly affects the cycle. This type of smaller slowdown is not seen in the solar proxy record due to the sample resolution, but this relationship is very accurately seen in the 400 year sunspot record with all Barycentric Anomalies occurring with solar slowdowns. This cannot be just a coincidence?

    McCracken, Beer and Steinhilber are in full agreement.

    • For the sake of my work, the origin and nature of the purported solar cycles are not important. All that matters is whether the spectral power apparent in the TSI reconstruction can be detected in proxies.

      • Geoff Sharp says:

        On the contary, your talk is questioning the validity of the Gleisberg and DeVrie ‘cycles’ because they dont hold up so well went you carve up the Holocene solar proxy record. As shown once you understand the driver that result is totally expected…your results are flawed.

      • I think I should know what my presentation was about! I am only interested in the proxy-representation of solar-driven climatic variability. What drives the solar variability is entirely irrelevant to my presentation.

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