A paper published in Geophysical Research Letters finds another means by which climate models dismiss the role of the Sun in climate change. The paper notes that climate models consider total solar irradiance [TSI], but ignore the large shifts in wavelength distributions during solar cycles. The most energetic wavelengths from the Sun in the UV can vary up to 100% over solar cycles, and have significant effects on climate via stratospheric ozone.
According to the authors, "These findings need to be incorporated into Earth-climate [models] since the solar forcing induced by these differential trends are inherently different from the relatively flat spectral contributions employed in the IPCC assessments."
The authors find periods of low solar activity increase high-energy UV wavelengths, which would increase stratospheric ozone production. This has an inverse effect upon global temperatures, thus acting as a solar amplification mechanism.
|Figure from another paper showing the inverse relationship between ozone and global temperatures|
Time series of annual data of: Land air T anomalies (thin line with dots); CO2 anomalies (squares); Arosa total ozone (dash-dotted line with diamonds) for period 1900–2010. The values of CO2 anomalies are rescaled by the formula: CO2=(measured−mean)/100. The thick continuous curves are smoothed values(11-year and 22-year running averages) of total O3 and land air T.
Jerald W. Harder, Juan M. Fontenla, Peter Pilewskie, Erik C. Richard, Thomas N. Woods
The Spectral Irradiance Monitor (SIM) on-board the Solar Radiation and Climate Experiment (SORCE) satellite provides the first multi-year continuous measurements of solar spectral irradiance (SSI) variability from 200–2400 nm, accounting for about 97% of the total solar irradiance (TSI). In addition to irradiance modulation from active region passage, the SSI values for wavelengths with a brightness temperature greater than 5770 K show a brightening with decreasing solar activity, whereas those with lower brightness temperatures show a dimming. These results demonstrate that different parts of the solar atmosphere contribute differently to the TSI with the behavior in the deep photospheric layers giving an opposing and nearly compensating trend to that in the upper photospheric and lower chromospheric layers. These findings need to be incorporated into Earth-climate assessments since the solar forcing induced by these differential trends are inherently different from the relatively flat spectral contributions employed in the IPCC assessments.
This is getting very close to my old suggestions;ReplyDelete
I’ve been proposing for some years that an active sun reduces ozone higher up and that the reduction higher up is more dominant than the previously observed increases lower down when the sun is active so that overall, ozone above the tropopause decreases when the sun is active.
The reduction higher up being most dominant towards the poles.
That gives the necessary reverse sign effect on ozone above the tropopause from solar influences that I said was necessary to produce more zonal jets when the sun is more active as per observations.
It will be interesting to see how this develops.
"The authors find periods of low solar activity increase high-energy UV wavelengths, which would increase stratospheric ozone production. This has an inverse effect upon global temperatures, thus acting as a solar amplification mechanism."ReplyDelete
Low solar activity leads to more ozone and a warmer stratosphere especially towards the poles which causes AO and AAO to go more negative leading to more meridional jets, more global cloudiness and less solar energy into the oceans for a cooling climate system.
The opposite when the sun is more active.
As per my New Climate Model.
From this thread on another solar amplification mechanism:ReplyDelete
Alec Rawls says:
December 26, 2013 at 11:21 am
Nice summary of the various proposed possible mechanisms of solar amplification. Contrast with the IPCC, which in the Second Order Draft of AR5 acknowledged the extensive historic and paleo evidence that SOME mechanism of solar amplification seems to be at work, then only mentioned one of the possible mechanisms (page 7-43, lines 1-5):
Many empirical relationships have been reported between GCR or cosmogenic isotope archives and some aspects of the climate system (e.g., Bond et al., 2001; Dengel et al., 2009; Ram and Stolz, 1999). The forcing from changes in total solar irradiance alone does not seem to account for these observations, implying the existence of an amplifying mechanism such as the hypothesized GCR-cloud link.
They found the evidence for the GCR-cloud mechanism unconvincing and used this as their excuse for leaving it out of their models. Nowhere else in the report are any of the other possible mechanisms of amplification considered, with the result that this acknowledged evidence is never taken into account.
The only change in the final report was to edit out the SOD’s acknowledgment that the empirical evidence points to SOME mechanism of solar amplification being at work. I’ve got a post on this subject on the back burner. Will try to get to it soon.