Regional atmospheric circulation shifts induced by a grand solar minimum
- Nature Geoscience
- Published online 06 May 2012
Large changes in solar ultraviolet radiation can indirectly affect climate1 by inducing atmospheric changes. Specifically, it has been suggested that centennial-scale climate variability during the Holocene epoch was controlled by the Sun2, 3. However, the amplitude of solar forcing is small when compared with the climatic effects and, without reliable data sets, it is unclear which feedback mechanisms could have amplified the forcing. Here we analyse annually laminated sediments of Lake Meerfelder Maar, Germany, to derive variations in wind strength and the rate of 10Be accumulation, a proxy for solar activity, from 3,300 to 2,000 years before present. We find a sharp increase in windiness and cosmogenic 10Be deposition 2,759 ± 39 varve years before present and a reduction in both entities 199 ± 9 annual layers later. We infer that the atmospheric circulation reacted abruptly and in phase with the solar minimum. A shift in atmospheric circulation in response to changes in solar activity is broadly consistent with atmospheric circulation patterns in long-term climate model simulations, and in reanalysis data that assimilate observations from recent solar minima into a climate model. We conclude that changes in atmospheric circulation amplified the solar signal and caused abrupt climate change about 2,800 years ago, coincident with a grand solar minimum.
Sorry, but there is no way the Sun caused climate disruption only 2800 years ago. Climate disruption is bad, and everyone knows that all things bad are caused by humans.ReplyDelete
Just remember this simple rule; if its bad, its caused by humans. If its good, its caused by nature.
Just helping you out.
Generally we reckon it between 30-40% of the forcing, but it isn't going in the right direction.
The authors of this paper were merely introducing their study with a quote from another established paper, Gray, L.J. - "Solar Influences on Climate". The UV -IS- a component of TSI and is considered as a part of it.
The authors do not appear to bring this into any relation with the current climate and TSI and the article is behind a paywall. Gotta love those things.
"Specifically, it has been suggested that centennial-scale climate variability during the Holocene epoch was controlled by the Sun."
Well DUH!!! up until the last century that was CERTAINLY true. We weren't messing with forcings and CO2 wasn't changing a lot... so the next biggest player was it. There is a really REALLY consistent logical error made by denialists.
Just because it is CO2 driving changes right now, doesn't mean that it has to have been CO2 driving changes in the past. The Sun and our orbital configuration are also forcings. Any change is related to the sum of ALL the forcings. So arguments about what is causing any given change cannot be resolved by simply saying it was the sun last time so it must be the sun every time. Any more than the scientists say "It is the CO2 this time so it must have been the CO2 every time" - They don't say that because it is nonsense, nor do you say it is the Sun every time because THAT is nonsense... but that is the basis of the argument being made.
The Solar goes down, the temperature goes up... explain THIS forcing!!! You can't of course, because in your world it CANNOT be the CO2. Which leaves you with either the "it ain't happening" argument or the "big conspiracy" argument. Not really a lot to work with.
Have you ever considered that YOU might be wrong?
1. "Skeptical science" as noted by WUWT is, "unreliable due to (1) deletion, extension and amending of user comments, and (2) undated post-publication revisions of article contents after significant user commenting." I agree, as my own inconvenient comments have been deleted at that site.ReplyDelete
2. You state "The UV -IS- a component of TSI and is considered as a part of it." I'm well aware of that and that's why it is called "Total." However, UV is the most energetic of solar wavelengths and penetrates the oceans up to 300m. It is now well known that solar UV varies up to 20% within and between solar cycles while the TSI remains relatively constant. Solar UV heats the oceans, not IR from GHGs. Many other posts at this site have shown small changes in TSI/UV are amplified via ozone, the atmospheric circulation, and possibly clouds.
3. "Just because it is CO2 driving changes right now, doesn't mean that it has to have been CO2 driving changes in the past" assumes the premise, which is false to minuscule.
4. "The Solar goes down, the temperature goes up... explain THIS forcing!!!"
It is well known the Sun reached a grand solar maximum near the end of the 20th century. There is no doubt a large lag between solar changes and global temperatures due to the huge thermal inertia of the oceans. In addition, Earthshine data from Palle et al show Earth's albedo significantly decreased from 1985-1997, and the PDO 60 year cycle peaked near the end of the 20th century, etc. etc.
5. Don't put words in my mouth. I never said global warming is a "big conspiracy" or "didn't happen." You really ought to read some of my over 1000 posts before jumping to conclusions.
Decreased albedo from 1984-1997, confirming Palle et al Earthshine data:ReplyDelete
So what causes these cyclical links between solar variability and the Nile? The authors suggest that variations in the sun’s ultraviolet energy cause adjustments in a climate pattern called the Northern Annular Mode, which affects climate in the atmosphere of the Northern Hemisphere during the winter. At sea level, this mode becomes the North Atlantic Oscillation, a large-scale seesaw in atmospheric mass that affects how air circulates over the Atlantic Ocean. During periods of high solar activity, the North Atlantic Oscillation’s influence extends to the Indian Ocean. These adjustments may affect the distribution of air temperatures, which subsequently influence air circulation and rainfall at the Nile River’s sources in eastern equatorial Africa. When solar activity is high, conditions are drier, and when it is low, conditions are wetter.