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CO2 absorbs around the 15 microns wavelenght or wavenumber 650, and radiates in the same but also a somewhat wider range.

However, the top layer of the oceans seem to also convert that spectrum range. According to a paper I found there is some increased absorbance of infrared in water around the 650 wave number.


Can it in a substantial way contribute to a conversion of that spectrum range to other spectra?

Added text for asked clarification.

We know co2 radiation is somewhat wider than absorption. I am asking if that is the same in the first few microns depth in water (few molecules of the top layer). Absorption of infrared in water does the same? And the total (combined with co2) is substantial enough to explain the missing gap around 15 microns wavelenght in the outgoing radiation of the earth?

  • 1
    $\begingroup$ I guess it is unclear what you mean with "conversion of one spectrum to another"? A spectrum is the whole energy distribution over a wavelength range. It cannot be converted. Individual wavelengths can be absorbed or emitted. There are coherent scattering processes that allow a photon to change its energy upon absorption&re-emission. Please take this vocabulary into account and consider improving your question this way, so that we can understand your question. $\endgroup$ Mar 3 at 13:05
  • $\begingroup$ Thank you for your feedback. Adjusted the title by adding the word "range", gladly within max letter limit. Any more changes needed to match the question wise self explanatory visual? $\endgroup$
    – MP1
    Mar 5 at 1:03
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    $\begingroup$ Sorry, I still have no idea of what you are asking. Sometimes it would help to rephrase the entire question, instead of changing just one word. $\endgroup$ Mar 5 at 11:09
  • $\begingroup$ There is something like «spectral range», then related to the frequency scale (here: expressed in wavenumbers). The upper spectrum likely is a recording a transmission IR spectrum of a thin film of water, maybe liquid water, maybe solid water / ice. The lower blue spectrum is similar to the air mass spectrum used e.g. to test solar cells. It deviates from the black body spectra (dashed lines) because some of sun's light is absorbed before it reaches earth's sea level by humidity / water vapour, gases, aerosols, etc. $\endgroup$
    – Buttonwood
    Mar 6 at 15:14
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    $\begingroup$ I find the phrasing of this question confusing too. Are you just asking whether water vapour as well as CO2 contributes to the observed OLR spectrum in the wavenumber 650 region, given that plots like the bottom one tend to only label it "CO2" in that region? In other words, does the presence of water vapour make it look different ("converts it") from how it would look if the water vapour were absent? $\endgroup$
    – Deditos
    Mar 7 at 12:01

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