April 25, 2019
University of Melbourne
Extreme ocean winds and wave
heights are increasing around the globe, with the largest rise occurring in the
Southern Ocean, University of Melbourne research shows.
Global trends in extreme (90th
percentile) wind speed over the period 1985-2018. Areas in red indicate
increasing values, whereas blue indicates decreases.
Credit: Professor Ian Young
[IMAGE]
Extreme ocean winds and wave
heights are increasing around the globe, with the largest rise occurring in the
Southern Ocean, University of Melbourne research shows.
Researchers Ian Young and
Agustinus Ribal, from the University's Department of Infrastructure
Engineering, analysed wind speed and wave height measurements taken from 31
different satellites between 1985-2018, consisting of approximately 4 billion
observations.
The measurements were compared
with more than 80 ocean buoys deployed worldwide, making it the largest and
most detailed dataset of its type ever compiled.
The researchers found that
extreme winds in the Southern Ocean have increased by 1.5 metres per second, or
8 per cent, over the past 30 years. Extreme waves have increased by 30
centimetres, or 5 per cent, over the same period.
As the world's oceans become
stormier, Professor Young warns this has flow on effects for rising sea levels
and infrastructure.
"Although increases of 5
and 8 per cent might not seem like much, if sustained into the future such
changes to our climate will have major impacts," Professor Young said.
"Flooding events are
caused by storm surge and associated breaking waves. The increased sea level
makes these events more serious and more frequent.
"Increases in wave
height, and changes in other properties such as wave direction, will further
increase the probability of coastal flooding."
Professor Young said
understanding changes in the Southern Ocean are important, as this is the
origin for the swell that dominates the wave climate of the South Pacific,
South Atlantic and Indian Oceans.
"Swells from the Southern
Ocean determine the stability of beaches for much of the Southern Hemisphere,
Professor Young said.
"These changes have
impacts that are felt all over the world. Storm waves can increase coastal
erosion, putting costal settlements and infrastructure at risk."
International teams are now
working to develop the next generation of global climate models to project
changes in winds and waves over the next 100 years.
"We need a better
understanding of how much of this change is due to long-term climate change,
and how much is due to multi-decadal fluctuations, or cycles," Professor
Young said.
Story Source:
Materials provided by University of Melbourne. Note:
Content may be edited for style and length.
Journal Reference:
Ian R. Young, Agustinus
Ribal. Multiplatform evaluation of global trends in wind speed and wave
height. Science, 2019; eaav9527 DOI: 10.1126/science.aav9527
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