Ensemble of eddies

No this is not about a music band, in which all musicians are named Eddie… It is about art and water eddies! You may have come across them if you’ve been canoeing – they are the little whirlpools that form while you paddle through the water (more about them later).

I studied water eddies and the way they form during my studies (MSc in Hydrology), but knowing their dynamics never really made me like them. I’ve recently changed my mind – they’re pretty cool! – since I was given the chance to explore them artistically.

A little while back, Hannah Cloke (my PhD supervisor) asked me whether I could draw her a water eddy. Above is the final result, a triptych of water eddies.

A bit about the artistic process

I had to look at many photos of water eddies before I was inspired to start drawing. If you search on the internet, a lot of photos of water eddies include the landscape that surrounds them – for example a river and its green river banks. Instead, I decided to zoom in onto the water eddy, to make it the centre of attention. Rather than going for a very realistic painting of an eddy, I decided to follow a more abstract approach and let the movement of the brush guide the evolution of the drawing on the page.

This is how I started a little study of water eddies… I first used dry pastels to make the circular patterns in the centre of the page, and then passed over the lines with a brush full of water to dilute the pastel and give a fluidity to the lines. After more than an hour trying out several different pastel strokes, pastel colours and brush types, I was surrounded by a sea of water eddies and done!

The water eddies I had created were all different, each conveying its own emotion and I couldn’t choose a single water eddy for Hannah. So I went for my three favourite, the final tryptich, which I called: Ensemble of eddies.

Ensemble of eddies in Hannah Cloke’s office

Because this is a Science & Art blog, I have to talk a bit about the science behind the formation of water eddies. So, what are water eddies?

What are water eddies?

Water eddies are circular currents of water created behind an obstacle, such as your paddle or a rock. Eddies flow upstream, opposite to the direction of the main flow – water flowing down the river.

But water eddies aren’t only found in rivers. They are also common in the ocean, where they can be centimeters to hundreds of kilometers large! While the smaller oceanic eddies usually last for a few seconds, larger eddies can last for a months or even years. These are known as mesoscale eddies (mesoscale is the intermediate scale between those of weather systems and of microclimates, on which storms occur). There are two types of mesoscale eddies:

  • Static eddies: they are caused by flow around an obstacle (which we already talked about).
  • Transient eddies: they can be caused by and found in major ocean currents, such as the Gulf Stream. And in the atmosphere, the same mechanism is responsible for shaping cyclones and anticyclones.

Oceanic eddies have an important role in moving heat from the tropics to the poles, affecting the climate worldwide. And there is the link with weather forecasting and my PhD research!

Before you go, have a look at this beautiful NASA video of ocean currents (and eddies) around the world from June 2005 to December 2007!

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