Talk:Infrared window

Underestimate?

"...can stay in the atmosphere for over fifty thousand years, a figure which may be an underestimate given the absence of natural sources of these gases."

Does it follow that a lack of natural sources could lead to an underestimate of the duration? Leonard G. 04:28, 23 Mar 2005 (UTC)

Civiltongue (talk) 17:38, 12 July 2010 (UTC)==Too narrow a definition== The atmospheric window goes to much longer wavelengths than infrared. Radio and radar waves below Ku-band frequencies, and also Ka band (around 35 GHz) and W band (around 94 GHz) are also widely used atmospheric windows. -Amatulic 00:04, 2 March 2007 (UTC)

I believe that's covered in the Radio window article! (Or is it the Astronomical window or Optical window article?) Ewlyahoocom 17:18, 2 March 2007 (UTC)

You're right, thanks. This article could use a paragraph describing the other atmospheric windows, rather than a list of "see also" links. In my line of work, "atmospheric window" and "radio window" are interchangeable terms. -Amatulic 18:06, 2 March 2007 (UTC)

Should they be merged? Ewlyahoocom 17:29, 3 March 2007 (UTC)

I think so Sagittarian Milky Way 03:50, 13 June 2007 (UTC)

"The atmospheric window refers to those parts of the electromagnetic spectrum that are, with the earth's atmosphere in its natural state, not absorbed at all. The atmospheric window lies approximately at wavelengths of infrared radiation between 8 and 14 micrometres." The first sentence and the name of the article are general, covering visible, IR and RF, but the second sentence and the body of the article are specifically IR. Seems to me, either the first sentence and the name of the article should be changed, or the second sentence and the rest of the article. I'm inclined to think the article is a nice one about the IR window, and we don't need a general article, so the name should change, but perhaps some will come to the opposite conclusion. Jim.henderson (talk) 06:03, 4 March 2008 (UTC)

"This article focuses on the global-warming aspects of the IR window ("... that lets some infrared radiation from the cloud tops and land-sea surface pass directly to space without intermediate absorption and re-emission ...") and ignores other significant aspects, such as IR astronomy, spectrometry, surveillance, communication, remote sensing, multispectral scanning, meteorology, etc. Also, absorption is not the only window characteristic of interest; scattering and re-emission (i.e., the "darkness" of the window where there are no sources) is important. I hope someone knowledgeable (not me, unfortunately) can incorporate these ideas. Civiltongue (talk) 17:38, 12 July 2010 (UTC)

The infrared atmospheric window's importance for the atmospheric energy transport processes was probably first recognised by George Simpson in 1928. In his 1928 article he speculated about its relevance for a possible future ice age. He did not mention global warming as a potential consequence of anthropogenic CO₂ emissions.Chjoaygame (talk) 22:14, 13 July 2010 (UTC)

Proposed Merger

I think a merged article would be better overall - there's a common concept and 3 specific windows. I'll try to do something about the lack of refs, and (FWIW) I suspect that many (at least introductory) sources discuss all windows at the same time - which makes sense when thinking about energy balances etc. ChrisHodgesUK (talk) 20:08, 20 August 2008 (UTC)

calculations on the infrared atmospheric window

From the introduction to this page, an unnamed editor deleted the references to Miskolczi and Mlynczak, apparently on the grounds that they were only minor contributors, implying that there are more significant contributors. It seems that that editor knows of others who have explicitly calculated the infrared atmospheric window radiation with a line by line code. Please would he or she tell us who they are and what they calculated, with references.Chjoaygame (talk) 14:19, 17 October 2009 (UTC)

Reminder: I am seeking to know the better sources implied by the unamed editor who deleted the references to Miskolczi and Mlynczak, apparently on the grounds that they were only minor contributors.Chjoaygame (talk) 08:37, 21 October 2009 (UTC)

Another reminder: I am seeking to know the better sources implied by the unamed editor who deleted the references to Miskolczi and Mlynczak, apparently on the grounds that they were only minor contributors.Chjoaygame (talk) 02:02, 9 January 2010 (UTC)

Proposed deletion of Kinetics of the infrared atmospheric window

This section is a load of pseudo science at best, and mumbo jumbo at worst. It is without any references and should be deleted. Do I have any supporters for this? A B McDonald (talk) —Preceding undated comment added 14:29, 22 June 2012 (UTC)

I am here defending the section which I wrote. You are judging it to be pseudo-science, but I think that judgment is mistaken. You do not actually offer any reason why you call it pseudo-science or mumbo-jumbo. You just throw the labels.

The section is an attempt to summarize and set out in general terms the meaning of the inhomogeneity of the atmosphere for radiative transfer of heat.

Heat is generally being transported by radiation, from the land-sea body and from the atmosphere itself, to outer space, as set out in detail in for example Goody and Yung 1989. Water vapour is more concentrated in the lower atmosphere and this makes the atmosphere significantly inhomogeneous from the viewpoint of thermal radiation. The 'atmospheric window' refers to the whole-atmosphere process while the 'spectral window' refers to molecular aspects of it. The molecular aspects are in a sense isotropic at each point of space, in the sense that the molecules considered separately do not take regard of the direction of transfer of heat. The whole-atmosphere process involves heat transfer, mostly from lower altitudes, to higher altitudes and to space, and in that sense is not to be described as 'isotropic', and is importantly inhomogeneous. An account of the window solely as a molecular phenomenon would inappropriately omit the fact that for vertical rays from the land-sea body to space, the optical thickness is very much less than that for oblique rays; that is why the term 'isotropic' does not adequately describe the whole-atmosphere process.

If you think my summary and setting out is unclear or mistaken in some particular way I urge you to clarify it or put it right. But I think it mistaken and unjustified simply to delete expression of the general idea of the section.Chjoaygame (talk) 00:15, 24 June 2012 (UTC)

I agree with A B McDonald, I myself came to the talk page specifically to suggest deleting that section. While I wouldn't call it "pseudo science", it is thoroughly incoherent. The point of the section seems to be that one should not misuse the Beer-Lambert law. It really has nothing to do with the topic of this article. I will go ahead and delete it; if the author of that section wishes to restore it, I suggest that s/he re-write it in a way that makes sense to others first. 18.95.6.93 (talk) 06:03, 30 October 2013 (UTC)

I deleted it, but I do want to apologize for the harshness of the language I used to express my opinion of that section. 18.95.6.93 (talk) 06:11, 30 October 2013 (UTC)

I agree that some of the point of the section was that one shouldn't misuse the Beer-Lambert law. But more precisely, the point of the section was that though the Beer-Lambert law is very relevant here, its application is not simple. This is because the atmosphere is not homogeneous, and because we are interested in transfer of energy as heat, which is not monochromatic. The Beer-Lambert law is simple only for a homogeneous body and a monochromatic ray. Consequently, there is a difference between the 'spectral window' and the 'atmospheric window'. It is not right to say that the section "has nothing to do with the topic of this article." Whether the section is thoroughly incoherent or not I wouldn't say; it seems it is not very clear to some readers, I have to agree to that. I do not at present feel like spending time re-writing the section, especially since it was called pseudo-science and mumbo-jumbo, and is now called thoroughly incoherent, even with the due apology. Maybe some other time. It would be polite of you to bother to sign in with your regular user name.Chjoaygame (talk) 06:46, 30 October 2013 (UTC)

I agree that this section is a complete jumble and I intend to edit it tomorrow to clear things up. The definition of the atmospheric window is the part of the spectrum that is transparent to IR so that emission from the surface directly reaches space without being absorbed. Generally speaking the effect of clouds is not considered or very high humidity. I refer you to the American Meterological Society definition:

Atmospheric Window A range of wavelengths over which there is relatively little absorption of radiation by atmospheric gases.

The major windows are the visible window, from ∼0.3 to ∼0.9 μm; the infrared window, from ∼8 to ∼13 μm; and the microwave window, at wavelengths longer than ∼1 mm. The infrared window loses much of its transparency under very humid conditions due to continuum absorption by water vapor, and can become completely opaque when clouds are present. Joshua Halpern (talk) 04:32, 13 April 2020 (UTC)

References

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