West Coast

CA - The effects of onshore and offshore wind on wave shape

Scientists at Scripps Institution of Oceanography in San Diego, California, concluded that offshore wind promotes the creation of barreling waves.

A study published in the Journal of Fluid Mechanics confirms the empirical notion that winds blowing from land to ocean help develop perfect-breaking tubular waves.

Falk Feddersen and his team analyzed the patterns and breaking behavior of waves at the Surf Ranch in Lemoore, Central California.

The wave pool facility allowed researchers to record the movement of identical waves in a controlled environment where the only variable changing is wind.

The research team mounted cameras, flew drones, and installed light detection and ranging (LIDAR) technology to monitor the breaking of the waves with different wind speeds and directions.

Spilling vs. Plunging Waves

The impact of wind on the way waves break has not been studied much.

This is because it is hard to separate environmental factors such as tides, the depth of the water, and random and directional waves from the effect of the wind.

"Surfers know that when the wind is offshore, the surf is generally better than onshore," underlined coastal physical oceanographer at Scripps, Falk Feddersen.

"Although this is common surfing wisdom, it has not been something that has been scientifically studied."

So, while offshore winds tend to smoothen out wave faces and encourage a cavern-like structure perfect for surfers, onshore winds contribute to creating the so-called spilling waves.

In a spilling wave, whitewater cascades down the wave face, resulting in lower levels of turbulence generation.

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