A new study looking at data covering a twenty-year period suggests that in extreme weather conditions, wind speeds have increased by 10% and wave heights have grown by nearly 7%.
Credit: iStockPhoto
This model shows areas of the globe where researchers found an increasing trend in wave height. The red regions at high latitudes show the highest increases in wave height.
Credit: Ian Young / ANU
SYDNEY: Global wind speeds and ocean wave heights have been steadily rising over the past two decades, with the biggest increases noticed in extreme weather events, a new study suggests.
In these extreme conditions wind speeds are reported to have increased by 10% and wave heights have grown by nearly 7% over a twenty-year period. These findings can be used as an indicator of climate change and could reveal new information about the energy transfer that takes place between the atmosphere and the Earth’s oceans.
“What this means is that in places where we see extreme storms they are either happening more frequently or becoming more intense,” said Alexander Babanin, a professor of oceanography at Swinburne University of Technology in Melbourne and co-author of the paper in Science.
Wind, waves and climate change
While factors such as temperature and precipitation are popular indicators of climate change, wind speed and wave height also play an important role in gauging climate change because they influence the energy transfer mechanisms between the air and sea.
“If the temperature changes this leads to changes in pressure patterns. This defines the wind, which then affects the waves causing changes in the ocean,” said Babanin. “If waves are growing it mixes the ocean deeper and this affects other factors in atmospheric circulation.”
These trends could also have implications for the engineering of offshore and coastal structures, shipping safety and potential flooding in coastal areas during storms, said lead researcher Ian Young, vice chancellor of the Australian National University in Canberra.
Benefits of an overhead view
Using satellite images and altimeter measurements, researchers were able to determine the monthly averages of wave height and wind speed over a 23-year period from 1985 to 2008.
In the past, attempts to gauge trends in oceanic wind speed and wave height have relied largely on in-situ observations using ships and wave buoys. These methods are restricted to specific areas close to shore or inside shipping lanes and are therefore limited in their geographic scope.
In comparison, satellites are capable of mapping the Earth’s entire ocean surface and can provide uniform coverage on a global scale. They also allow researchers to view the most extreme weather conditions – the stuff that ships deliberately avoid, said Babanin.
