Stupid as it sounds, one of my favourite wave watching spots in Bergen is a busy bridge with a view onto another busy bridge. But the bridge goes across a very narrow opening which connects Storelungegårdsvannet, which you see in the pictures, with a fjord and ultimately the open ocean. As the opening is a lot narrower than both the fjord and the lake at the fjord’s head, there are pretty much always strong tidal currents going one way or the other, sometimes leading to a substantial difference in sea surface height on either side of the bridge. I found that quite scary the first couple of times I had to paddle through!
But what I found most fascinating today is how many different colors you see on the water, and how they are all explained by different physical processes.
If we look at the bottom end of the picture above, we see that we can look fairly well into the water and see the sandy/rocky bottom with some algae growing on it. You can look into the water so well because several things came together at the time when I took the picture:
- There weren’t a lot of waves to disrupt the view
- I’m looking into the water at quite a steep angle, so even though the light going in and out of the water is refracted at the interface, the angle is too steep for total reflection to happen
- This lower area of the image is reflecting the dark underside of the bridge rather than the bright sky, making it easier to see the muted colors in the water because there isn’t too much interference with bright colors from elsewhere
Moving on a little up in the picture above: Here we see the reflection of the sky (see the clouds reaching down the slopes of the mountain? (If you don’t see what I mean, check out the image at the top of this post where you can see it both reflected and “for real”)
We see the reflection here because the angle is a lot shallower and we don’t have the bridge’s shade making it possible to look inside.
Notice how the bridge’s reflection doesn’t have a sharp edge but shows up all the turbulence in the water? You can also notice more turbulence on the right side slightly above the middle of the image.
And then there is this grey stripe going all across the reflection of the mountain and houses. That’s where a little breeze is going over the surface, creating ripples. Since the surface is rougher now, we get a lot of bright sky reflected towards us.
Below another image, where you see both sides of the bridge’s reflection. Isn’t it fascinating how turbulence is distorting the reflection? And there is a lot more turbulence on the left than on the right at the bottom end of the bridge’s reflection, where you can still make out the railing of the bridge in the reflection…
In the uppermost image, you also see that it becomes more and more difficult to see the bottom as water depth increases – the water seems to be getting greener and greener, darker and darker.
What else did you spot that I didn’t mention? And do you think you’ll look at Storelungeren the same way as before next time you cross that bridge? ;-)