Comments on: Solar Proxies

By: rjtomes

rjtomes — Sat, 13 Feb 2010 22:04:44 +0000

There is a new calibration of C14 for the last 50,000 years. See http://www.radiocarbon.org/IntCal09.htm

I have made a graph of the last 2000 years C14 variation and it shows a huge increase in the last century or so. See http://ray.tomes.biz/b2/index.php/a/2010/02/13/p177 for graphs.

By: Bob KC

Bob KC — Tue, 27 Nov 2007 16:28:34 +0000

re #125 Here's a link to the paper .

By: Steve McIntyre

Steve McIntyre — Tue, 27 Nov 2007 14:41:21 +0000

Dr Usoskin, thanks for drawing this to our attention. I will probably post up a thread for discussion after I’ve had a chance to read it.

By: Ilya Usoskin

Ilya Usoskin — Tue, 27 Nov 2007 14:12:16 +0000

As concerning the long-standing discussion between our team and Muscheler et al. (see the section “Muscheler Criticisms” above), there is a recent paper by McCracken & Beer, Long-term changes in the cosmic ray intensity at Earth, 1428-2005 (JGR, 112, A10101, 2007), where the authors show that the previous use of the Forbush’s record of ground based Cheltenham ionization chamber was applied incorrectly. This record was the basis for Mucheler’s normalization. This implies that our earlier contra-critics was absolutely correct. Note that a recent reconstruction by Muscheler et al. (QSR, 2007) is quite close, in the overall level, to our reconstruction.

By: Francois Ouellette

Francois Ouellette — Mon, 26 Nov 2007 21:29:33 +0000

For those intersted in the role of the Sun on the climate, and how reconstructions can be used to assess it, there is an interesting paper just out in JGR by Nicola Scafetta and B J West. The paper is available here. This is a continuation of their previous work. Basically they use a phenomenological approach. So instead of taking the reconstructed TSI values, plug them into a model, and find that indeed the Sun has only a minor influence (like Ammann et al. did in their PNAS paper of March 6, 2007 | vol. 104 | no. 10 | 3713-3718 ), they make no prior assumption on the total Solar forcing. They just assume, mostly rightly, that the Sun was the main driver of climate variability. Then from the solar reconstruction and the temperature reconstruction, they deduce which model of solar forcing best matches the two together. They have a nice discussion in the introduction about the pitfalls of the usual method. For the record, even though they use both Mann03 and Moberg05 reconstructions, they refer to MM05 and the Wegman report as pointing to the flaws of Mann03. This is all to show that temperature reconstructions do play an important role in understanding the human role on climate.

By: Bruce

Bruce — Tue, 13 Nov 2007 19:17:38 +0000

Regardless of these uncertainties,the cosmogenic radionuclide records indicate that the current solar activity is relatively high compared to the period before 1950AD.

However,as the mean value during the last 55yr was reached or exceeded several times during the past 1000yr the current level of solar activity can be regarded as relatively common.

This hardly contradicts: http://www.nature.com/nature/journal/v431/n7012/full/nature02995.html#B1

almost all of the earlier high-activity periods were shorter than the present episode.

Its the duration combined with the higher activity that is rare.

By: John V.

John V. — Tue, 13 Nov 2007 18:31:29 +0000

Link for conversation continued from here:
http://www.climateaudit.org/?p=2335#comment-160442

Muscheler at al 2007:
http://www.eawag.ch/organisation/abteilungen/surf/publikationen/2007_solar_acitivty

By: dscott

dscott — Fri, 09 Nov 2007 20:47:16 +0000

For comparison purposes can you give an example where this methodology is used elsewhere? I would like to see if this methodology has scientific precendent and is acceptable for making the case for an external explanation of climate such as the Orbital Monsoon hypothesis. http://www.soest.hawaii.edu/GG/FACULTY/POPP/Lecture13.ppt

By: Jim Goodridge

Jim Goodridge — Fri, 09 Nov 2007 19:30:39 +0000

The accumulated departure from average is simply the average of all numbers of the time series substracted from each number and then the accumulated sub totals.

By: dscott

dscott — Fri, 09 Nov 2007 18:03:56 +0000

Can anyone comment on the methodology used by Jim Goodridge in this article: http://wattsupwiththat.wordpress.com/2007/11/04/guest-weblog-co2-variation-by-jim-goodridge-former-california-state-climatologist/ I would like your take on the idea he has presented on the Accumulated Departure method of solar irradiance.

If we are to believe that the irradiance and sunspot numbers correlate for the 3 sunspot cycles from 1975 to 2005 them it can be assumed that a correlation for the 1500 to 2005 follows. It is common to think of individual sunspot cycles to be independent events. This was not the case during the Maunder Minimum of sunspot activity from 1650 to 1710 when Earth was in the middle of the Little Ice Age.

The sunspot record needs to be examined in its entirety rather than as individual sunspot cycles. The method to do this is by calculating the accumulated departure from the average of all the sunspot numbers of the entire 500-year index. This reveals the cooling during the Maunder Minimum and the current global warming. The current warming of 15 watts per square meter began in 1935, based on the sunspot record.

If this is a valid statistical methodology, are there any solar scientists willing to co-author a paper with Goodridge so we can have a balanced insight into the extraterrestial nature of earths climate? This would dovetail nicely with Marsh & Svensmarks Cosmic Ray theory affecting cloud cover. http://www.dsri.dk/~hsv/SSR_Paper.pdf#search=%22Cosmic%20Rays%2C%20Clouds%2C%20and%20Climate%20%22 http://www.aip.org/pnu/2000/split/513-2.html http://environment.newscientist.com/channel/earth/climate-change/dn6270