Remote sensing of NO2
3.2.2.3 Vibrational Raman scattering in surface water

Although not strictly a part of the Ring effect, a further phenomenon caused by Raman scattering is of significance in processing retrieval data.

In the atmosphere, rotational Raman scattering of radiation by air molecules is the dominant inelastic scattering process. A similar effect, namely vibrational Raman scattering by water molecules occurs in liquid water such as clear ocean. In water, vibrational Raman scattering has a Δλ of approximately 30..50 nm, that is, the wavelength of incident photons is changed after scattering by this amount.

This phenomenon can also have an effect on the retrieval if a significant number of photons can leave the water and reach the satellite instrument. In fact, the magnitude of the effect can be used to estimate the turbidity of surface water and to derive information on the amount of sediments and biomass contained in the water.

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