I have no idea about absorption in water, but most of the energy in sunlight is in the visible spectrum, which is why both plants and our eyes are adapted to use it. Unless I am completely confusing things. So infrared absorption should not be the important factor.
Oren, part of me wants to thank you and another part doesn't. Your post sent me to read up on this and my brain hurts.
So far I have gathered that:-
- just about all the heat absorption in the oceans is through visible light,
- nearly all the infrared radiation is absorbed in the first few
micrometers of the ocean where the thermal skin layer (TSL) exists.
- so IR radiation does not directly heat the upper few meters of the ocean.
BUT
- due to AGW there is an increase in incoming longwave radiation from clouds,
- this in turn causes additional energy from the absorption of increasing IR radiation into the TSL,
- more of the surface to air heat loss is from the TSL.
- Thus, more heat beneath the TSL is retained leading to the increase in upper ocean heat content.
See link below.
Just think - a few micrometers of surface ocean water heated by increasing infrared radiation the only reason oceans can keep their increased heat. But heating of the ocean itself is nearly all from visible light and the shorter the wavelength the more effective it is. I read somewhere that while at the tropics in clear water enough energy for photosynthesis can reach as deep as 80 metres, in polar water its more like 10 metres.
Postings above are saying that +ve SST anomalies in the Chukchi/Bering are reaching depths to 100 metres. Something else is going on to get the heat to that depth.
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https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1002/2017JC013351The Response of the Ocean Thermal Skin Layer to Variations in
Incident Infrared RadiationAbstract Ocean warming trends are observed and coincide with the increase in concentrations of greenhouse gases in the atmosphere resulting from human activities. At the ocean surface, most of the incoming infrared (IR) radiation is absorbed within the top micrometers of the ocean’s surface where the thermal skin layer (TSL) exists. Thus, the incident IR radiation does not directly heat the upper few meters of the ocean. This paper investigates the physical mechanism between the absorption of IR radiation and its effect on heat transfer at the air-sea boundary. The hypothesis is that given the heat lost through the air-sea interface is controlled by the TSL, the TSL adjusts in response to variations in incident IR radiation to maintain the surface heat loss. This modulates the flow of heat from below and hence controls upper ocean heat content. This hypothesis is tested using the increase in incoming longwave radiation from clouds and analyzing vertical temperature profiles in the TSL retrieved from sea-surface emission spectra. The additional energy from the absorption of increasing IR radiation adjusts the curvature of the TSL such that the upward conduction of heat from the bulk of the ocean into the TSL is reduced. The additional energy absorbed within the TSL supports more of the surface heat loss. Thus, more heat beneath the TSL is retained leading to the observed increase in upper ocean heat content.