Effects of water colour and depth

The water column acts to attenuate light by features which absorb and scatter light. This affects the ability of remote sensing systems to 'see' what is in or under the water column. Absorption per unit depth is greatest for red light and least at blue wavelengths, hence the 'blue' appearance of the image at 5m on the left. Scattering is controlled by particles in the water and the water itself. Suspended sediment will scatter red light more than other wavelengths, as shown in the image on the right.

Colour spectrum at 5m depth in clear water	Colour spectrum at 5m depth in turbid water