Posts Tagged ‘solar forcing’

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.
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H/T to Chaeremon for flagging up this recent paper from Jiang et al which gets better detail on solar forcing of climate. Paywalled, abstract only, but there is a fugure from Jiang’s earlier 2005 paper covering 1200 years around Iceland.

jiang2005Abstract

Mounting evidence from proxy records suggests that variations in solar activity have played a significant role in triggering past climate changes. However, the mechanisms for sun-climate links remain a topic of debate. Here we present a high-resolution summer sea-surface temperature (SST) record covering the past 9300 yr from a site located at the present-day boundary between polar and Atlantic surface-water masses. The record is age constrained via the identification of 15 independently dated tephra markers from terrestrial archives, circumventing marine reservoir age variability problems. Our results indicate a close link between solar activity and SSTs in the northern North Atlantic during the past 4000 yr; they suggest that the climate system in this area is more susceptible to the influence of solar variations during cool periods with less vigorous ocean circulation. Furthermore, the high-resolution SST record indicates that climate in the North Atlantic regions follows solar activity variations on multidecadal to centennial time scales.

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Repost from Roger Pielke Sr’s weblog. Important this isn’t lost, because it shows a fatal error in Schmidt and Benestad’s paper. A paper still relied on by the IPCC in AR5 to dismiss solar forcing as an important climate variable, five years after Nicola demolished it. Benestad and Schmidt claim they successfully rebutted Scafetta’s exposure of their fatal error, something Scafetta vigorously disproved. We’ll take a look at that part of the controversy later.

Roger Pielke Sr’s original intro:
On July 22 2009 I posted on the new paper on solar forcing by Lean and Rind 2009. In that post, I also referred to the Benestad and Schmidt 2009 paper on solar forcing which has a conclusion at variance to that in the Lean and Rind paper.

After the publication of my post, Nicola Scafetta asked if he could present a comment (as a guest weblog) on the Benestad and Schmidt paper on my website, since it will take several months for his comment to make it through the review process. In the interests of presenting the perspectives on the issue of solar climate forcing, Nicola’s post appears below. I also invite Benestad and Schmidt to write responses to the Scaftta contribution which I would be glad to post on my website.
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