Heat waves don’t just strike on land — they can also occur in the ocean. And roughly a third of marine heat waves aren’t detectable at the ocean’s surface, a new study reports. The findings, published in the December Nature Geoscience, suggest that far more of these potentially harmful events might be occurring than previously believed.
Marine heat waves are often identified with satellite observations that measure the temperature of the ocean surface. But these data leave the ocean depths unmonitored.
To literally take a deeper look, statistician Furong Li and colleagues turned to computer simulations of the ocean’s temperature, salinity and currents, among other parameters, created from both satellite and subsurface data stretching back to the early 1990s. Such simulations are a powerful way of studying the ocean on a global scale, says Li, of the Ocean University of China in Qingdao.
The researchers pinpointed ocean heat waves in the simulations by looking for layers of water that remained unusually warm — up to a few degrees Celsius above surrounding levels — for at least five days. Such events can be caused by changes in atmospheric circulation, for instance, or shifts in ocean currents.
2023-12-14 14:30:00
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