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The Cloud-Climate Feedback Uncertainty


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#1
Black Hole

Posted 31 August 2017 - 07:07 AM

Black Hole

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Most Global Climate Models (GCMs) have had an estimate of temperature increasing 1.5 to 4.5 C with a doubling of CO2, with the primary source of uncertainty being clouds. Some GCMs have a strong positive feedback with clouds while others have a negative feedback.

Some interesting work done recently by a professor of mine and others suggest that at least for the tropics there may be zero feedback, meaning the tropics are insensitive to changes in clouds. Since the tropics cover a large portion of the Earth this would mean that most likely the climate is on the less sensitive end of possibilities. 

Anyway, I thought it was interesting and whenever it is published I will link it here. 


  • Phil and wx_statman like this

BS Atmospheric Science University of Utah May 2015

PhD Candidate Atmospheric Sciences

 

--Emphasis on: Forecasting, Mountain Weather, Numerical Weather Prediction, Data Assimilation

 

Winter 2017/2018

Dec 4: 3.2", 16: 0.9", 20: 2.1", 23: 1.5", 25: 4.6"

Jan 6: 1.5", 20: 10.8", 25: 1.5"

Feb 19: 8.6", 20: 2.4", 23: 7.1", 25: .5"

Mar 4: 13", 15: 1.8", 17: 5.3", 25: 4.2"

April 12: 1", 17: 1.3"

Total: 69.3"

 

 

Winter 2016/17 Snow:
Nov 17: 3.2", 23: 1.6", 28: 9.2" (14)

Dec 1: .5", 16: 2.5", 25: 13" (16)

Jan 2: 5", 3: 2.4", 4: 7.7", 12: 1", 19: 1.2", 21: 13", 23: 6", 24: 1", 25: 3.7", 26: 2.5" (43.5) 

Feb 11: .5", 23: 6.5", 27: 4.5" (13.5)

Mar 5: 5.5" (5.5)

Apr 8: 2", 9: 1.8" (3.8)

May 17: 1" (1)
Total: 96.3"

Lowest Temp: 2F


#2
Phil

Posted 31 August 2017 - 11:07 AM

Phil

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Most Global Climate Models (GCMs) have had an estimate of temperature increasing 1.5 to 4.5 C with a doubling of CO2, with the primary source of uncertainty being clouds. Some GCMs have a strong positive feedback with clouds while others have a negative feedback.

Some interesting work done recently by a professor of mine and others suggest that at least for the tropics there may be zero feedback, meaning the tropics are insensitive to changes in clouds. Since the tropics cover a large portion of the Earth this would mean that most likely the climate is on the less sensitive end of possibilities.

Anyway, I thought it was interesting and whenever it is published I will link it here.


Interesting. Thanks for the share, and I look forward to reading the paper.

One of my interests is in the modeled lapse rate feedback via H^2O loading, and how it could impact ET circulation(s), which could further play on tropical static stability through other conduits.

So far, the slackening of the lapse rate, as modeled, has not manifested in either the radiosonde or satellite data, so I'm skeptical of the positive feedback sign altogether.
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#3
stuffradio

Posted 31 August 2017 - 09:30 PM

stuffradio

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Most Global Climate Models (GCMs) have had an estimate of temperature increasing 1.5 to 4.5 C with a doubling of CO2, with the primary source of uncertainty being clouds. Some GCMs have a strong positive feedback with clouds while others have a negative feedback.

Some interesting work done recently by a professor of mine and others suggest that at least for the tropics there may be zero feedback, meaning the tropics are insensitive to changes in clouds. Since the tropics cover a large portion of the Earth this would mean that most likely the climate is on the less sensitive end of possibilities. 

Anyway, I thought it was interesting and whenever it is published I will link it here. 

There was an article I saw posted recently in the last couple months where they suggested they under estimated the warming, and they were going for an increase of 6-7C increase not 4C.



#4
Black Hole

Posted 01 September 2017 - 02:06 PM

Black Hole

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There was an article I saw posted recently in the last couple months where they suggested they under estimated the warming, and they were going for an increase of 6-7C increase not 4C.

Well, I suppose anything is possible but I have always felt skeptical of these runaway warming forecasts because you just don't see it happening. Sure, our temperature is increasing, but very slowly and slower than most of the GCMs said we would. To that end, although I haven't known why, I expected that the climate was less sensitive and this research seemed to possibly be the answer. 

The guy who did this has a very unique way of thinking and an usual ability to tie different fields and ideas together the way that most cannot which I think is how he came up with the approach that he did.

Anyway, time will tell. 


  • Phil likes this

BS Atmospheric Science University of Utah May 2015

PhD Candidate Atmospheric Sciences

 

--Emphasis on: Forecasting, Mountain Weather, Numerical Weather Prediction, Data Assimilation

 

Winter 2017/2018

Dec 4: 3.2", 16: 0.9", 20: 2.1", 23: 1.5", 25: 4.6"

Jan 6: 1.5", 20: 10.8", 25: 1.5"

Feb 19: 8.6", 20: 2.4", 23: 7.1", 25: .5"

Mar 4: 13", 15: 1.8", 17: 5.3", 25: 4.2"

April 12: 1", 17: 1.3"

Total: 69.3"

 

 

Winter 2016/17 Snow:
Nov 17: 3.2", 23: 1.6", 28: 9.2" (14)

Dec 1: .5", 16: 2.5", 25: 13" (16)

Jan 2: 5", 3: 2.4", 4: 7.7", 12: 1", 19: 1.2", 21: 13", 23: 6", 24: 1", 25: 3.7", 26: 2.5" (43.5) 

Feb 11: .5", 23: 6.5", 27: 4.5" (13.5)

Mar 5: 5.5" (5.5)

Apr 8: 2", 9: 1.8" (3.8)

May 17: 1" (1)
Total: 96.3"

Lowest Temp: 2F