Swiss authored paper reconstructs solar variability

Posted: May 10, 2011 by tchannon in solar system dynamics

WUWT has an article about a recent paper published in Astronomy & Astrophysics

“A new approach to long-term reconstruction of the solar irradiance leads to large historical solar forcing
A. I”. Shapiro1, W. Schmutz1, E. Rozanov1,2, M. Schoell1,3, M. Haberreiter1, A. V. Shapiro1,2, and S. Nyeki1″

PDF of the paper

The PDF has an online material section where Fig 5 is about solar spectral change at extreme short wavelengths.

Solar spectral modelling

The implication is solar TSI has varied more than popularly supposed within the formal science community.

Note: I am Tim Channon and I am helping out Tallbloke with blog moderation

Comments
  1. vukcevic says:

    Problem is that they use 10Be records from the Greenland Ice core Project.
    My reservations are mention here and elsewhere before, but in case you missed it here is the link: http://www.vukcevic.talktalk.net/CET&10Be.htm

  2. tallbloke says:

    Tim is being overly modest. I have asked him for assistance to run the blog while I’m going through a particularly busy period and hopefully beyond then too. This is his first post and he has full site admin status. I want to shout a big THANKYOU to Tim for stepping up to help.

    Now, regarding this paper. I don’t know the ins and outs of Vuk’s concerns about the Be10 record from Greenland, but I’m pretty sure the authors will be aware of them too. Their work is also corroborated by Nir Shaviv’s finding that the variation in the solar signal is amplified by terrestrial mechanisms by seven to ten times

    http://sciencebits.com/calorimeter

  3. Tim Channon says:

    Vuk, I agree, so what would happen if they used an Antarctic ice core, what were their reasons for choosing one over the other?

    You have done a lot more than I have.

    On digging, is this what you need, seems to be the data for the paper copy you are using.
    ftp://ftp.ncdc.noaa.gov/pub/data/paleo/icecore/greenland/summit/ngrip/ngrip-10be.txt

    Caution, once again is trip you up, doesn’t bother marking missing data. (caught me, index didn’t match, huh?)

    After sort that out I produced an annual ssn from month 1749 and plotted together. They do not match.
    Flux doesn’t match. Raw doesn’t match either.

    This needs more investigation.

  4. Roger Andrews says:

    Tallbloke:

    Shaviv’s estimate of seven to ten times amplification was based on IPCC data that showed a TSI increase of only about 1 w/m2 since the Maunder Minimum. However, Shapiro et al. show an increase of 7 w/m2 since the Maunder. Allowing for geometric and albedo effects this would translate into an effective forcing of about 1.2 w/m2, and factoring this forcing with the IPCC’s 3C climate sensitivity gives us 1C of warming, which is roughly what we we got. So maybe we don’t need to amplify the solar signal after all. And wouldn’t that be nice 🙂

  5. tallbloke says:

    Hi Roger,
    Lean and Schatten also got bigger variation in their earlier efforts, before her curve got squashed by Svalgaard and the Stanford AGW monolith. Given the uncertainty over TSI measurement in the modern era, it’s an open question IMO. Shaviv has worked along with people from the ACRIM team, who maintain that the adjustments made to TSI data by Svalgaard’s pal Claus Frohlich are invalid.

    Given that we still haven’t had any explanation as to why the TIMS data shows a lower TSI than previousl satellite bourne instruments, I’m keeping a skeptical and open mind on all of it.

  6. vukcevic says:

    Tim
    I was given data file produced by NASA’s McCracken http://adsabs.harvard.edu/abs/2007AdSpR..40.1070M
    for my personal use, I can use data for graphs, but I am not authorised to pass the actual data file to others.
    Svalgaard expressed surprise that I manage to get it, since he has no access to it.

  7. Tim Channon says:

    Quite a few people seem to cite and use McCracken.

  8. Roger Andrews says:

    Hi Tallbloke:

    I’m not quite as skeptical as you. After doing some work on the Shapiro et al. reconstruction I’ve decided I like it, and here’s why.

    First, with Shapiro TSI we can explain the numerous solar-temperature correlations we see with only about a twofold amplification of solar forcings, which is a lot more easily explained than the +/- ten times amplification we’ve been assuming up to now.

    Second, I can fit the ICOADS SST series to Shapiro TSI all the way from 1850 though at least 1980 (R=0.92 with an 11-year delay in SST response). I couldn’t fit Lean or any other reconstruction before 1910 because the shapes were wrong. In other words, Shapiro fits observations better as well.

    So my provisional null hypothesis is that the Shapiro reconstruction is, if not right, then at least closer to reality than the other TSI reconstructions.

    And if Shapiro is right then the IPCC’s climate models underestimate solar forcing since 1900 by a factor of about six, and factoring solar forcing up by this amount makes it about equal to anthropogenic forcing over this period. So it would be back to the drawing board with the models, and with AGW theory too.

    Obviously the implications of Shapiro et al. are significant. I think we need to discuss it some more.