Why does the heat in the atmosphere mostly go down?

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Discussion Overview

The discussion centers on the mechanisms of heat transfer in the atmosphere, particularly why a significant portion of heat is directed downwards towards the Earth rather than upwards into space. Participants explore concepts related to the greenhouse effect, types of heat transfer (conduction, convection, and radiation), and the implications of these processes on energy distribution within the atmosphere.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested
  • Mathematical reasoning

Main Points Raised

  • Some participants suggest that the infrared radiation emitted by greenhouse gases is equally distributed, with half going up into space and half down to Earth, although this is challenged by others.
  • One participant notes that the atmosphere radiates energy both upwards and downwards, with the downward radiation being absorbed by the Earth's surface.
  • Another participant emphasizes that radiation is the only form of heat transfer that can occur into space, as conduction and convection require matter, which is absent in space.
  • Some argue that while conduction and convection are present, they play a minor role in the overall energy budget of the Earth, with the majority of energy leaving the surface as thermal radiation.
  • One participant introduces the concept of latent heat as a significant factor in energy transfer, accounting for over 17% of total energy leaving the Earth's surface.
  • There are differing views on the specific percentages of energy transfer mechanisms, with one participant providing their own calculations that differ from others' estimates.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the exact mechanisms and percentages of heat transfer in the atmosphere. Multiple competing views and interpretations of the data remain, particularly regarding the roles of conduction, convection, and latent heat in the energy budget.

Contextual Notes

Some participants express uncertainty about the specific contributions of different heat transfer mechanisms and the implications of their calculations. There is also a lack of clarity on how latent heat fits into the overall energy budget, with differing interpretations of its impact.

Who May Find This Useful

This discussion may be of interest to those studying atmospheric science, climate change, or thermodynamics, as well as individuals curious about the complexities of energy transfer in the Earth's atmosphere.

  • #31
F X said:
That can't possibly be correct. It would mean the planet is always heating up, and very fast.
Why do you say that? Did you carefully look at the picture?
 
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  • #32
The IR amount shown leaving (arrows pointing away from planet) is 343.8, the amount pointing towards the planet is 340.3

So "The atmosphere as a whole emits more thermal radiation to the Earth's surface (340 than it does to space (200 W/m^2)" is completely wrong. It's comparing just two parts of the picture, not the whole amounts.

Just think about the claim. It can't even be possible. An extra 140 W/m^2 would cook the planet in a short time. It's self evident.
 
  • #33
klimatos said:
For historical reasons, heat budgets are usually given in units of watts per square meter, averaged over the Earth’s entire surface. One watt is one joule per second. Since the Earth’s surface area is exactly four times its disc area, this gives us an energy income for our global heat budget of 342 watts per square meter—more or less.
It's not clear what you are claiming. It's impossible, just a physical impossibility for each square meter of the planet to have 342 watts per square meter being added all the time. The budget has to balance, the amount of heat in has to equal the amount out or the planet is heating up at every second in time. If you shine 342 watts of energy on a square meter surface you will learn what this actually causes to happen, and fast. Physics tells us it is impossible for that amount of energy to the added to the planet. The world would never have lasted.
 
  • #34
F X said:
The IR amount shown leaving (arrows pointing away from planet) is 343.8, the amount pointing towards the planet is 340.3

So "The atmosphere as a whole emits more thermal radiation to the Earth's surface (340 than it does to space (200 W/m^2)" is completely wrong. It's comparing just two parts of the picture, not the whole amounts.
The atmosphere emits 169.9 W/m2 + 29.9 W/m2 = 199.8 W/m2 towards space, and 340.3 W/m2 towards Earth, exactly as @D H said.

F X said:
Just think about the claim. It can't even be possible. An extra 140 W/m^2 would cook the planet in a short time. It's self evident.
The Earth's surface is emitting 398.2 W/m2...
 
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  • #35
F X said:
The IR amount shown leaving (arrows pointing away from planet) is 343.8, the amount pointing towards the planet is 340.3

So "The atmosphere as a whole emits more thermal radiation to the Earth's surface (340 than it does to space (200 W/m^2)" is completely wrong. It's comparing just two parts of the picture, not the whole amounts.

Just think about the claim. It can't even be possible. An extra 140 W/m^2 would cook the planet in a short time. It's self evident.

redo your maths and directions ... you are not understanding the diagramD
 
  • #36
I do not think we have a complete picture of all the energy paths in and out of the earth.
An example, We know tides are a result of other gravity fields pulling and pushing the oceans around,
yet the tides represent real measurable energy. How far fetched is it to believe, that the processes
responsible for moving tidal energy in, is also capable of moving energy out?
 
  • #37
I have deleted a few problematic posts. I would like to remind everyone that only mainstream science is allowed on PF, and that climate change/AGW is accepted science.

Thread closed.
 
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