Joined: Mar 04, 2005 Posts: 2642 Location: New Zealand
Posted: Mon Jan 23, 2006 11:04 pm Post subject: Solar physicists report paradox: Less sunlight, but temps ri
Solar physicists report paradox: Less sunlight, but temps rise
Quote:
Less sunlight reaching the Earth's surface has not translated into cooler temperatures, according to a team of solar physicists at New Jersey Institute of Technology. The scientists, who monitor the Earth's reflectance by measuring what is known as the moon's earthshine, have observed that the amount of light reflected by Earth -- its albedo -- has increased since 2000. The result has been less sunlight reaching the Earth's surface. "Our findings have significant implications for the study of climate change," said Philip R. Goode, PhD, principal investigator and distinguished professor of physics at NJIT. "The results raise questions about how global temperatures can still rise when the amount of sunlight reaching the surface has decreased."
The just-released update of the 20-year sequence of ISCCP satellite cloud data shows that during the first 15 years of observations, the percent difference between high lying and low-lying clouds remained steady at 7-8 percent. But in the last five years, for some unknown reason, the difference has almost doubled to 13 percent. The ISCCP data is a careful compilation of cloud observations covering the entire Earth from a range of meteorological satellites.
"That increase in the difference signals a relative decrease in the cooling effect of clouds," said Goode. "Thus, the rising reflectance of the Earth has not led to a reversal of global warming from the increase in sunlight being reflected back into space." What has happened is that the low, cooling clouds have decreased during the most recent years, while high, warming clouds have increased even more. Thus, the cloud data also reveal an increase in total cloud amount during 2000-2004. That increase is consistent with the earlier earthshine result of growing reflectance throughout that period.
Joined: Dec 08, 2004 Posts: 921 Location: 145'2"E 37'46"S
Posted: Tue Jan 24, 2006 4:01 am Post subject: Re: Solar physicists report paradox: Less sunlight, but temp
oh just great..
Quote:
Goode noted that the Earth's reflectance depends primarily on cloud properties. Recent ground-based and satellite studies of the albedo have shown a surprisingly significant inter-annual and decadal variability. From about 1985-2000, the Earth steadily received more sunlight, before the recent reversal of the trend from 2000-2004. "This is not the first time such a situation occurred," Goode said.
Ground-based radiometers hint at a similar reversal from the 1960's through the mid-1980's, which some scientists have dubbed global dimming. Thus, it seems there may be a large, unexplained decadal variation in sunlight reaching the Earth, as well as a large effect of clouds re-arranging by altitude.
Joined: Dec 08, 2004 Posts: 921 Location: 145'2"E 37'46"S
Posted: Tue Jan 24, 2006 8:29 am Post subject: Re: Solar physicists report paradox: Less sunlight, but temp
Ah, correct me if i'm wrong, but this adds significantly to the dimming picture, hence my variables quip. If this moderated dimming is cycling over yet to be determined # yrs/decades as article suggests, the math just got harder.
From Aarons site:
Quote:
Global Dimming? ...What's that, you might ask? It's the effect of fossil fuel by-products reflecting back the sun's rays, keeping an underlying warming trend in check and moderating any global warming increase.
The phys.org article says actually the dimming=cooling effect isn't so strong because the clouds (which they measured by earthshine) are, yes, reflecting more incident solar radiation, but they're ALSO holding 'more' reradiated heat in (which is prob related to the more-high-cloud measured).
Joined: Aug 13, 2004 Posts: 1185 Location: Richmond, VA, Pale Blue Dot
Posted: Tue Jan 24, 2006 7:29 pm Post subject: Re: Solar physicists report paradox: Less sunlight, but temp
UIUCstudent01 wrote:
Heh. Sounds like burning those billions of barrels PER DAY are actually doing something, eh?
millions per day... but billions per year would be just as strong. _________________ "If you are a real seeker after truth, it's necessary that at least once in your life you doubt all things as far as possible"-Rene Descartes
"When you have excluded the impossible, whatever remains however improbable must be the truth"-Sherlock Holmes
Joined: Aug 13, 2004 Posts: 1185 Location: Richmond, VA, Pale Blue Dot
Posted: Tue Jan 24, 2006 8:09 pm Post subject: Re: Solar physicists report paradox: Less sunlight, but temp
UIUCstudent01 wrote:
turmoil wrote:
UIUCstudent01 wrote:
Heh. Sounds like burning those billions of barrels PER DAY are actually doing something, eh?
millions per day... but billions per year would be just as strong.
My mistake... blah.. but there's also other sources of CO2 and other gasses that contribute to it...
Very true. Methane, for example, is a much stonger greenhouse gas.
http://en.wikipedia.org/wiki/Global_warming_potential _________________ "If you are a real seeker after truth, it's necessary that at least once in your life you doubt all things as far as possible"-Rene Descartes
"When you have excluded the impossible, whatever remains however improbable must be the truth"-Sherlock Holmes
Posted: Wed Jan 25, 2006 10:11 am Post subject: Re: Solar physicists report paradox: Less sunlight, but temp
Cows release the most methane, its the overfarming of cattle that is doing damage.
I think we have hit peak methane. _________________ ___________________________
WHEN THE BLIND LEAD THE BLIND...GET OUT OF THE WAY!
Using evil to further good makes one evil
Doubt everything but the TRUTH
This posted information is not permissible to be used
by anyone who has ever met a lawyer
Posted: Thu Jan 26, 2006 7:45 pm Post subject: Re: Solar physicists report paradox: Less sunlight, but temp
Oh, I've seen the global dimming program, definately a must watch. Basically, our particulate emmissions are blocking sunlight, masking the full effects of global warming. On Sept. 12, when all the planes in the U.S. were grounded, the temperatures rose (becuase of the lack of contrails). Basically, when we stop emmitting, or emit less particulate emmisions, the temperatures will rise. I'm not sure how this will play out post peak, when we start burning more coal, which have more particulate emissions. But post fossil fuels, I can guess what is likely to occur, temperatures 10-15C hotter. OUCH. Better start heading for Alaska.
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