does the color of the water effect its evaporation?



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    The color of the surface of water partly depends on what it’s reflecting. On a clear day at noon, it will look brightest, and at night, darkest. The color of surface of the water, then, partly has to do with whether the sun is shining hard, not really any inherent color of the water. Stormy water with turbulance and whitecaps isn’t evaporating much anyhow, but sunlight (if any) on the froth would tend to reduce evaporation.

    (Frozen water is quite different. Pure white ice or snow reflects far much more than dirty ice or snow, which absorbs energy, melts the frozen water, and allows evaporation. This is a concerns with pollution in frozen areas.)

    The color of liquid, shallow water that is clear of plants, suspended particles and bubbles has much to do with the ground underneath it. As an extreme example, think of photos of tropical shores, where boats and swimmers appear to be floating in air!

    So unpolluted, shallow, still, clear water highly affects the rate evaporation, because the water effectively “bows out”, and the reflectance becomes that of the ground underneath! White ground will tend to bounce the light (and hence the radiation) right back to the surface, and into the air. Dark soil tends to covert the light to heat, which will then warm the water. If the water is shallow enough, the temperature could be substantially raised.

    In deeper water eventually the small amounts of suspended life forms, particles, etc., catch up with sun’s illumination, and it’s either radiated back into the air, or coverted to heat. The heat contributes to evaporation, but nothing like it does in shallow water.

    If the water itself is colored, say by pollutants, or algae, or natural dirt in suspension, then the water temperature will be similarly affected, only this time by interactions before the light hits the ground. But it’s quite different if the sunlight hits algae or kelp — because that’s what it grows with! Only a portion of the energy of light hitting algae is returned. So the green of algae has an entirely different affect than the green of a pollutant or some other non-living thing!

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