Thread Rating:
  • 0 Vote(s) - 0 Average
  • 1
  • 2
  • 3
  • 4
  • 5
Ocean Heat Content and backradiation
#1
There is a discussion on Ocean Heat Content over at WUWT where I asked a question and received an interesting answer.

Quote:Richard111 says:
May 13, 2011 at 9:30 am

Can anyone explain the physics of how greenhouse gases warm the oceans by backradiation?
This has been talked about for so long there should be reams of papers available on the web that explain this phenomenon so a layman like myself can understand how it works.

Just one link will do for starters please.

Quote:Stephen Wilde says:
May 13, 2011 at 10:04 am

“Can anyone explain the physics of how greenhouse gases warm the oceans by backradiation?”

It can’t, but one scientist tried to set up a theory involving the ocean skin. However I think I have explained why that theory doesn’t fly.
The subject was canvassed in some detail here:

http://climaterealists.com/index.php?id=4245

Since then I have come to the conclusion that the net effect of DLR on the ocean surface as regards the rate of energy flow from ocean to air is zero rather than net warming or net cooling.

The reason being that the increased evaporation from more DLR is a self limiting process. When the DLR has been used up the increase in the rate of evaporation stops.

You might also like to consider this:

http://en.wikipedia.org/wiki/Enthalpy_of_vaporization

“the molecules in liquid water are held together by relatively strong hydrogen bonds, and its enthalpy of vaporization, 40.65 kJ/mol, is more than five times the energy required to heat the same quantity of water from 0 °C to 100 °C (cp = 75.3 J K−1 mol−1). ”

In other words the process of evaporation removes from the local environment (in the form of latent heat) five times the amount of energy required to induce that evaporation.

In the face of that energy imbalance the extra DLR has no opportunity to heat up anything other than the specific molecules that then evaporate earlier than they otherwise would have done.

The reason for the size of that imbalance is atmospheric pressure and the relative densities of air and water but that is for another day. Just note that water boils at a lower temperature at the top of Everest.

The Wikipedia entry was a revelation to me. This is a real nail in the AGW coffin. Anyway, I had a read of the following page;

Greenhouse Gases Can Cause Cooling !

and pulled out this quote.

Quote:That brings us back to that infrared radiation which reaches the ocean surfaces either directly from the sun or alternatively from what is known as downwelling infrared from the gas molecules in the air. That downwelling happens constantly even at night and worldwide and it has been theorised by global warming proponents that extra downwelling infrared from more greenhouse gases is at the heart of the proposed climate effect from human sources of CO2.

However the effect of downwelling infrared is always to use up all the infrared in increasing the temperature of the ocean surface molecules whilst leaving nothing in reserve to provide the extra energy required (the latent heat of evaporation) when the change of state occurs from water to vapour. That extra energy requirement is taken from the medium (water or air) in which it is most readily available. If the water is warmer then most will come from the water. If the air is warmer then most will come from the air. However over the Earth as a whole the water is nearly always warmer than the air (due to solar input) so inevitably the average global energy flow is from oceans to air via that latent heat of evaporation in the air and the energy needed is taken from the water. This leads to a thin (1mm deep) layer of cooler water over the oceans worldwide and below the evaporative region that is some 0.3C cooler than the ocean bulk below.

Much more to read there. Note the update comment at the end.

My conclusion is that only direct sunshine can heat the oceans. Infrared radiation from any source will not heat the oceans. This means that the global energy budget is also suspect since some 40% of incoming radiation from the sun is in the IR region.
Environmentalism is based on lies and the lies reflect an agenda that regards humanity as the enemy of the Earth. - Alan Caruba
Reply
#2
"Much more to read there. Note the update comment at the end.

My conclusion is that only direct sunshine can heat the oceans. Infrared radiation from any source will not heat the oceans. This means that the global energy budget is also suspect since some 40% of incoming radiation from the sun is in the IR region."

You are right, liquid water is completely opaque to IR. Back radiation CANNOT heat the oceans. Ocean heat energy has to come from visible light penetrating the first 100m or so.
Reply


Possibly Related Threads...
Thread Author Replies Views Last Post
  The Myth of Backradiation Sunsettommy 69 100,221 11-21-2010, 11:18 AM
Last Post: h-j-m



Users browsing this thread: 1 Guest(s)