Wednesday, December 2, 2009
The aim of the session is to describe all aspects of the
large-amplitude wave phenomenon in the ocean as the freak,
rogue and storm waves: dynamical and statistical theories,
observations and modelling, numerical simulations in the framework of approximate theories as well as full nonlinear equations. Special attention will be paid to the description of the wave breaking process, and also large-amplitude wave interaction with coastal structures. The rogue wave phenomenon in the oceanic waves of any physical nature will be discussed also.
Wednesday, October 28, 2009
"I've been a Maya Lin fan since he was awarded the Vietnam memorial a few decades ago. Her current works intersect with our mission as she's taking on the subject of waves.
Check her work out. It's 3 - 5' in Michigan... on land. Next installation will be at Storm King."
Monday, October 5, 2009
Huntington Beach: The Blessing of the Waves is an annual celebration that includes officials from various religions.
Sunday, August 16, 2009
Laird's Scariest Wave in Wired
The most commonly asked question I get is, what was the scariest wave I ever took? I used to get rescued probably three or four times a week when I was a kid, before I was five or six years old. I was known to be lost at sea, out in the ocean. The lifeguard used to come to my mom's house and say "Laird's out in the rip again." She'd be like "No he's not, he's in his room napping." And they'd be like "No, he's out in the rip again." They'd get sick of rescuing me, so they finally said, "Hey Laird, we gotta fix that." My point is I've had a lot of extremely scary moments growing up as a young kid and young person.
There's been a ton between then and now, but the most recent was one of the scariest things that's ever happened to me and hopefully ever will. It was two years ago, on December 3. A friend and I were out in surf that was over 100 feet—well over a 100 feet—and I had dived off on a wave that might as well have been 100 or 200. I don't know—at that point I didn't have my tape measure—but it demanded every bit of my experience and strength. I came up to the back of it, and my friend who was on the back of the wave grabbed me with the jet ski.
We proceeded to try to run away from the next wave and got run down from behind by one of the biggest waves that I have ever seen. It was definitely the biggest wave to ever run me down from behind.
We were dragged an incredible distance underwater, anywhere from a third to a half a mile, I would say. I came up from a depth that I haven't been down at on a wave before, and just got a breath and got hit by another one. I saw my friend and we got pushed in by probably four more, each one smaller. Finally we were pushed all the way to the inside.
My friend was severely cut and needed a tourniquet. All I had was a wet suit so I used my wetsuit to tourniquet his leg. And then I made a decision: If I didn't swim for the jet ski that was about a quarter to half mile from us, he was going to die and I wasn't going to be able to do anything about it. I had to make a decision to leave him and swim to a jet ski and get back. It's a close friend of mine. We both have daughters the same age and are best friends.
I got there and the jet ski was running. Had it not been running, I don't know what would have happened. He might have bled out or whatever. But because it ran, I was like, "OK, saved by the ski!" You know?
I think that the fear of his death probably scared me worse than anything I've ever had happen to myself because obviously, when it's happening to you, you're not thinking about how bad it is, you're just dealing with it. When it's happening to somebody else—especially someone that you care about—that's a lot worse. So the fact that he was good and I didn't have to explain... that he made it, and I didn't have to tell his family why he didn't come home that day, that was a great thing. The dead aren't worried about dying, it's only the people alive, left here thinking about it, who are. It's a lot harder on them than it is on the people who have died.
Tuesday, August 11, 2009
"Riding waves is a very soulful activity, a perfect interaction, a cleansing experience that never loses its lustre. Remembering my first rides, watching my eight-year-old gliding across blue walls, riding a few this morning, it's like a thread running through my life." - quote from Wayne Bartholomew appearing in this Surfers Path article.
Scientists Track Down Source of Earth’s Hum
You can’t hear it, but the Earth is constantly humming. And some parts of the world sing louder than others.
After discovering the mysterious low-frequency buzz in 1998, scientists figured out that the Earth’s hum is caused not by earthquakes or atmospheric turbulence, but by ocean waves colliding with the seafloor. Now, researchers have pinpointed the source of the Earth’s “background noise,” and it looks like it’s coming primarily from the Pacific coast of North America.
When two waves of opposite direction but similar frequency collide, they create a special kind of pressure wave that carries energy to the ocean bottom. As these waves pound against the sea floor, they generate a constant vibration with a frequency of about 10 millihertz, much too low for humans to hear but easily detectable with seismometers. By comparing the intensity of the hum with the height of waves around the world, scientists can track where the buzz is coming from.
Previous studies suggested that waves from both shallow continental shelves and the deep ocean contribute to the Earth’s hum, but new data indicates otherwise. Based on measurements from a seismic observatory called the USArray EarthScope, most of the hum appears to originate from the Pacific coast of North America, with a smaller contribution from the west coast of Europe. Waves from the deep ocean don’t seem to make much hum at all.
The data for this study, published Thursday in Geophysical Research Letters, was gathered from November 2006 to June 2007, so humming patterns might be different during the summer months.
Simulations point to changes in water depth and currents as increasing likelihood of rogue waves
SAN FRANCISCO, Aug. 5, 2009 – Stories of ships mysteriously sent to watery graves by sudden, giant waves have long puzzled scientists and sailors. New research by San Francisco State professor Tim Janssen suggests that changes in water depth and currents, which are common in coastal areas, may significantly increase the likelihood of these extreme waves.
Published in the Journal of Physical Oceanography, Janssen's wave model simulations show that focusing of waves by shoals and currents could increase the likelihood of a freak wave by as much as 10 times. Although scientists cannot predict the occurrence of individual extreme waves, Janssen's findings help pinpoint conditions and locations favorable for giant waves.
Extreme waves, also known as "freak" or "rogue" waves, measure roughly three times the size of the average wave height of a given sea state. Recorded monster waves have exceeded 60-feet -- the approximate size of a six-story building. Janssen's research suggests that in areas where wave energy is focused, the probability of freak-waves is much greater than previously believed.
Wave focal zones are particularly common in coastal areas where water depth variations and strong currents can result in dramatic focusing of wave energy. Such effects are particularly well known around river mouths and coastal inlets, restricting accessibility for shipping due to large, breaking waves near the inlet, or resulting in erosion issues at nearby beaches. Extreme examples of wave focusing over coastal topography include world-class surf spots, such as Mavericks and Cortez Banks in California. The identification of freak wave hot spots is also important for shipping and navigation in coastal areas, and the design of offshore structures.
"In a normal wave field, on average, roughly three waves in every 10,000 are extreme waves," Janssen said. "In a focal zone, this number could increase to about three in every 1,000 waves. In a focal zone, the average wave height is already increased due to the focusing of energy so that an extreme wave in such a high energy area can potentially be very energetic and dangerous."
Janssen's wave simulations estimated the evolution of waves in open oceans, waves interacting with an opposing current, and waves traveling over a topographical feature such as a reef. The simulations show that freely developing waves maintain normal statistical properties with a small likelihood of extremes. But when the waves are focused by variations in water depth or currents, the rapid increase in energy drives wave interactions that enhance the likelihood of extreme waves.
"We found that if the focusing is sufficiently strong and abrupt, wave interactions create conditions favorable to extreme waves," Janssen said. "When we gradually increase the focal strength, initially wave interactions are weak and statistics remain normal. However, when increasing the focal strength beyond a certain threshold, suddenly wave interactions are enhanced and freak waves are much more likely than normal. It appears that wherever waves undergo a rapid transformation, freak waves can be much more likely than we would otherwise expect."