Happy World Water Day
In honor of World Water Day, let’s take a look at something near (very near) and dear to us: waves. Not all waves have the same characteristics and they can often seem to have particular personalities. If you’re going to spend a lot of time with waves, it’s a good idea to get to know them.
Waves travel in groups. Every seventh wave is higher.
When a wave breaks, the water surface speed at its crest approaches its travel speed.
Waves begin to “feel the bottom.” They slow down and get higher and steeper when the depth is less than one-quarter of their length.
Wave steepness (height/wavelength) is limited by breaking, so the highest waves have the longest wavelengths and the highest speeds.
The fastest-moving and “tightest” lows produce the highest waves.
All numerical models fail to predict the very highest waves in intense storms.
When a wave 1.3m high breaks on the shore it releases the equivalent of about 16.5 megawatts of power per kilometer of shore¬line.
Most wind-driven waves start as deep-water waves, where the depth of the water is more than half their wavelength.
Waves in the ocean consist of different wave-trains of varying wave height and length, each wave-train moving at its own speed.
When the wave in front of the train moves into still water, some of its energy is transferred to the water molecules in the undisturbed water, which starts their orbital motion.
In this way the leading wave is perpetually losing its energy and dispersing, and it is replaced by the next wave, which undergoes the same process.
The water molecules continue their motion after the train has passed and a new wave is created at the end of the train.
A “rogue wave” is an unexpected one – often the result of the superposition of two wave trains travelling in different directions.
Waves break on the shore when the water depth below them is about 1.3 times the wave height; a 6m wave, for example, breaks in 8m of water.
The pressure at the deepest point in the ocean is the equivalent of one person trying to support 50 jumbo jets.
The top ten feet of the ocean hold as much heat as the entire atmosphere.
The Pacific Ocean, the world’s largest water body, occupies a third of the Earth’s surface.
Waves by Manfred