Written by Jason Phipps Morgan on Wednesday, 30 October 2013. Posted in Cruise 2013

29 October 2013, Jason Phipps Morgan


On a ship, one thing you can do as much as you wish is look at waves. But the usual measurements that weathermen use to characterize the surface of the sea don’t do full justice to the many moods and flavors of swell, ripples, glass, whitecaps, Poseidon’s chariots... that often fill a day at sea.

Usually the marine weather report will quantify the likely sizes of waves and wind, both the waveheight of the shorter choppier breaks that are formed by winds nearby, and the swell, the longer rolling waves that sway and vibrate a ship and tell of far off storms, that even let you dead reckon under a cloudy sky if you assume that they point away from a particular stormbelt like the high latitudes to the south.

Size does matter, but waves have many unique flavors and can change throughout a day. Around noon, we had a short rainstorm from a mild tropical depression that has been slowly following us the past few days, giving us grey clouds and rain to protect us from the blue sky. After the rainburst, the sea surface became a mosaic of tiny crinkly ripples forming, mutating, and disappearing above a semi-glassy ~2 meter swell. The swell was big enough to rock the ship as each wave moved at a speed like a running horse, and the tiny crinkles scurrying over the moving swell seemed almost alive. So different from the similar sized swell with choppy whitecaps that had preceded the squall.

About the Author

Jason Phipps Morgan

Jason Phipps Morgan

Professor of Geophysics

Royal Holloway University London

Leave a comment

Please login to leave a comment.