Scientists have become very good at measuring key indicators of climate change such as temperature and sea level rise. However, other important parameters of the global climate system, such as wind strength and wave height, haven’t been given nearly as much attention — until now.
A new study compiled and summarized data from 31 orbiting satellites finding that winds and waves are becoming stronger each year. The year-by-year changes are actually tiny but they still show a clear trend of amplification that might become important in forecasting storms and other extreme weather.
Wind and wave measurements are important for modeling the climate. Both are at the interphase between the atmosphere and ocean, affecting the transfer of energy and matter like carbon. The frustrating part is that it has always been rather tricky to record and analyze historical data on these phenomena.
The problem doesn’t lie in the lack of data itself but rather in reliable measurements across the board. For instance, researchers and the industry have been employing ocean buoys for decades. It’s when you try to compare and normalize their data, which is recorded by different instruments and designs, that you run into trouble.
Ian Young, a professor of marine engineering at the University of Melbourne, and colleagues may have solved the problem by looking to the sky for a solution. In fact, the satellite record, which reliably spans 1985 through 2018, seems like an obvious solution. But shouldn’t the different kinds of instruments aboard satellites be causing the same problems as buoys? Apparently not.
Young and colleagues studied the data collected by altimeters, which can measure both wave height and wind speed, radiometers, which only measure wind speed, and scatterometers, which measure wind speed and direction. After cross-checking the data, the researchers concluded that the satellite records are a reliable source from which you could draw historical trends.
Their results suggest that in the past 30 years global wind speed and wave height have been noticeably getting stronger. These changes were very slight. Wind speeds amplified by only about an inch per second every year south of the equator and about half that in the North Atlantic. Wave height increase wasn’t as uniform as wind speed, but there were large patches were researchers observed an increase of about a tenth of an inch per year. One isolated spot in the North Pacific actually experienced a drop.
Although the changes might look negligible, these trends were much more noticeable in extreme cases. What’s more, these slight up-ticks add up in time to drive global behavior. And, ultimately, any improvements in our understanding of how the climate works are very welcomed.
The findings appeared in the journal Science.