Shedding some light on the water
The drive from the family farm back to the airport is always bittersweet; it’s also quite beautiful.
Last Sunday, as we crossed one of the bridges that takes us onto the Island of Montreal, Mom commented on how lovely the water looked; I added that it looked cold. That got us talking about the colour of the water. I’m sure you’ve noticed that the same body of water can look very different from one season to another but also from one day to another. The colour you see depends on two things: the concentration and nature of the organic and inorganic particles in the water and the reflection of light at the surface of the water. Let’s start with basics of colour: Colour is what you see when light isn’t absorbed by an object. In other words, it’s the result of the wavelength of light that is reflected from an object; in this case, the water. The atmosphere, for example, absorbs all the colours except blue which is scattered by the nitrogen atoms that are predominant in our air. The light, and therefore the colour reflected that our eyes see, is more a function of light absorbance and scattering by the objects reflecting light.
Now if the water has a high concentration of particulate matter, the water colour can take on a green or murky look. Pure water is very blue. The second factor in determining the colour of water in a lake of river is, believe it or not, cloud cover. Water reflects what is happening in the sky. Fall clouds – the low, heavy dark clouds – block out the light and cast the water in shades of silver, greys, and mauves.
Sunning Stunning Asperitas clouds - formerly known as Undulatus asperatus. This cloud formation was first proposed as a type of cloud in 2009 by Gavin Pretor-Pinney of the Cloud Appreciation Society. (Contributed)