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New research from the University of Melbourne has deepened our understanding of where waves originate, how they decay and just how far they can travel across oceans.
The work improves the reliability and quality of wave forecasts used by the Bureau of Meteorology as well as industries such as shipping and urban design.
The innovative method tracked ocean swell across the Pacific using more than 300 GPS-enabled buoys. It heralds a shift towards data-driven models, which could revolutionise the way waves and weather are predicted.
WAVING FROM A DISTANCE
Professor Ian Young is an expert in ocean physics and wind-generated waves and the lead author of the study.
He says most waves originate near the polar regions, particularly near Antarctica where intense ocean storms can rotate all the way around the Earth without hitting land.
“Once they’re generated, those waves propagate off across the oceans,” says Ian.
“Just like if you throw a pebble in a pond, then the waves radiate away from that pebble.”
Waves that have propagated from where they originated are called swell.
Some of these waves can travel across oceans for 17 days, reaching shores up to 12,000 kilometres away.
FEELING SWELL
Understanding how waves travel can help us plan for future climate change and sea-level rise.
Waves are getting larger as a result of more intense and frequent storms, especially in the Southern Ocean. This can impact coastal erosion and put coastal infrastructure at risk.
The ocean already plays an important role in mitigating climate change because carbon dioxide from the atmosphere is sequestered in the deep ocean.
“If you’ve got waves breaking on the surface of the ocean, they’re much more efficient at actually taking carbon dioxide and pushing it down into the ocean,” says Ian.
Better prediction models can help us understand the complex ways the ocean influences and is shaped by our changing climate.
OH BUOY
While weather prediction has improved drastically over the past 15 years, Ian says swell propagation models are lagging.
Previously, physicists have used data from satellites taking aerial images of the ocean as they pass overhead.
The new study used data from an array of low-cost GPS-enabled buoys floating freely in the Pacific Ocean.
The buoys report their position in three-dimensional space and the direction they’re travelling in. This data allowed the team to visualise how waves were moving across the ocean.
Ian says the buoys have opened up new possibilities.
“It’s the first time we’ve ever been able to get that sort of data and to understand some of these really quite interesting elements of wave physics,” he says.
WAVE HELLO TO ARTIFICIAL INTELLIGENCE
These floating buoys are contributing to rapid change in the field of wave prediction.
“Ocean science is moving from a time when we complained that we didn’t have enough data to a period where we’re swamped with the data,” says Ian.
Weather predictions are currently made based on complex physics modelling, but researchers are looking to artificial intelligence to turn the influx of information into data-driven models.
Ian is optimistic about what can be achieved in an area of research he describes as “difficult”.
“[The AI models] take only a fraction of the time to run … and produce very, very good results,” he says.
While AI is not as good as traditional models yet, we can expect big changes over the next few years in the way that waves are predicted.
