Not my picture. A less common view on how the planes are flying.

Could need a bit of extra resolution but perhaps it makes a nice wallpaper then.

Cool shot CoolP.

 

I wonder how much global cooling this produces?

Here's a shot from NASA showing Florida and contrails.

 

RJ

You are mixing up things, those contrails only produce income. :lol:

You are mixing up things, those contrails only produce income. :lol:

 

Thumbs up to that!! :good:

 

RJ

I wonder how much global cooling this produces?

 

It actually heats the earth up by reflecting radiation back down again. There was an article I remember reading that the earth cooled after 9/11 because of the lack of contrails from all the grounded aircraft.

It actually heats the earth up by reflecting radiation back down again. There was an article I remember reading that the earth cooled after 9/11 because of the lack of contrails from all the grounded aircraft.

 

Yeah who knows. From this article it almost sounds like a net cooling effect.

 

"For those three days, the average range between highs and lows at more than 4,000 weather stations across the US was 1 degree C wider than normal. In other words, contrails seemed to raise nighttime temperatures and lower daytimes ones.

 

But the real effect was in daytime highs, which were much higher. That would seem to indicate that, contrary to prevailing thinking, contrails might have a net cooling effect."

 

I tried reading this study on the topic but found myself falling asleep. I thought only the reality TV show "The bachelorette" made me fall asleep. :rolleyes:

 

RJ

It actually heats the earth up by reflecting radiation back down again.

Wouldn't it reflect in both directions then? And if they studied the effect of the grounding, the lack of contrails would have been just one factor. Among the normal weather variations for example.

The radiation comes in as shortwave and radiates back skyward as longwave which reflects back again from high cirrus clouds.

 

Here is a good description on the process of changing radiation and the clouds effect.

 

http://earthobservatory.nasa.gov/Features/Clouds/

 

Among the normal weather variations for example.

 

Nearly every variation in the atmosphere is recorded. It's fairly simple to find the effects within the air mass.

Great pic !

I agree, McCarter. Makes a nice wallpaper.

 

Nearly every variation in the atmosphere is recorded. It's fairly simple to find the effects within the air mass.

Really? 'Fairly simple'. You mean like weather prediction? ^_^ Well, I guess I would agree if only one factor changed and you could measure the direct outcome of it. But you can't isolate much within that thermodynamic box.

 

 

Really? 'Fairly simple'. You mean like weather prediction?

 

No, there is a difference between analysis and prediction.

Mmm. Lets see. How can I help you?

 

Taking the (US) passenger movement of the year 2001 and looking at three days 'off'. We are talking about roughly 5.7 million people not moving by plane. If we would assume that a plane emits more than a contrail at altitude, that it e.g. experiences skin friction, interchanges energy with the surrounding, alters the airflow and, on the scale of 6 million passengers less, most of all does not convert plenty of fuel into forward motion and electricity, what does the first analysis show?

 

Adding to that, as a dominant influence, there's the normal change going on when it for example comes to clear weather or the opposite of it. The NASA folks do offer some detailed docs on the case. http://enso.larc.nas...etal.GRL.08.pdf

 

So that's why I have a hard time believing that anybody was able to isolate and measure the contrail influence within that global box. Besides, the science folks correctly use the words 'may' or 'suggest' and that's on all ends, namely the ones stressing that there's a contrail influence, that there's none or that we, currently, just can't tell. :mellow:

Christian Science Monitor? Hardly a reliable source. And I think contrails and aircraft movement have a negligible effect on Earth's temperature.

Contrails are for screenshots! :lol:

Well your study that you linked concluded what I was explaining.

 

The variations in high cloud cover, including contrails and contrail-induced cirrus clouds, contribute weakly to the changes in the diurnal temperature range, which is governed primarily by lower altitude clouds, winds, and humidity.