Wagering on Waves - NYTimes.com Jim Thomson is principal oceanographer at the Applied Physics Lab at the University of Washington. He studies ocean surface waves and coastal processes. 28 36.780 degrees north latitude, 123.878 degrees west latitude I sleep well at sea, but only a few hours at a time. I wake up as the ship changes course (rare on this trip) or rolls over a big wave. The motion is both familiar and strange. Every wave is different, and every ship has a particular feel. The waves we feel right now have come from thousands of miles away. They started as ripples on the water's surface on the other side of the Pacific Ocean. Once the ripples form, the wind has more to push on (more drag), and the ripples build. The feedback continues as long as there is wind, but the waves also begin to outrun the wind. Traveling at speeds of up to 30 miles per hour, the long waves travel the fastest, and the rest disperse according to their length and period. A few days later, no longer ripples, these waves are the steady metronome of our northward march. But there are ripples here too, because the wind is blowing. The swell, the ripples, and everything in between make up a whole spectrum of waves for us to observe (and to feel). The spectrum that comes from distant storms and local wind is what makes this interesting: Imagine a concert in Ohio where you hear a bass guitar from California and a piano from Maine. Intermittently, there are collisions in this spectrum, and that's where a wave breaks. That's what we're out here to measure. That's the missing part of modern wave forecasts - forecasts that are used for everything from ship safety to climate modeling. Yesterday we paused our transit north for a few hours and measured some waves. We deployed a couple of Swift buoys and a mini-Waverider buoy. We launched the balloon and fired up the cameras (well, the ones that are working, at least the stabilized system is still having problems). There wasn't much breaking, but a nice swell was rolling through - plenty to measure, and nice conditions to practice getting the buoys back onboard the ship. As we stood on the rail watching the buoys drift away, we took wagers on the wave height. Before there were scientific wave measurements, mariners would estimate wave heights by eye and record the estimates in the ship's log. When modern wave measurements were just starting, scientists tried to find some consistency with the traditional visual method. It turns out the logs corresponded not with the average height of all waves, but rather with the average of the largest one-third of the waves. Rather than change centuries of ship's logs, the term "significant wave height" was introduced and defined as the largest third. The term is now the standard metric for wave measurements. The wagers for significant wave height ran from 1 to 2 meters. I guessed 2, but the buoys came back with 1.8. Call me an optimist.