NASA spots Florida’s ocean waters changing color
Most people naturally focus on the freezing temperatures and mountains of snow outside their door when a winter storm hits. But freezing weather can often have dramatic effects offshore, even in typically tropical regions. As NASA pointed out today, a surge of arctic air recently transformed the deep azure waters of the Gulf of Mexico into an incredibly brilliant mix of blues and greens.
The rapid brightening off the west coast of Florida occurred in late January and early February amid two massive winter storms named Fern and Gianna. The weather systems were so large that they even dropped temperatures below freezing in some parts of the state. Earlier cold snaps caused iguanas to fall from trees, and the ocean also saw a rarely seen change. On February 3, the Moderate Resolution Imaging Spectroradiometer (MODIS) tool aboard NASA’s Terra satellite spotted the rare water change in orbit over the western Florida panhandle. The waters had turned pale blue from churned up calcium carbonate mud composed mostly of the remains of marine organisms.
But what caused all that mud to swirl in the first place? According to NASA, this was all due to this historic cold air event. As ocean temperatures dropped and winds strengthened, colder, shallow waters became denser and flowed offshore with the tides. Although such circumstances are primarily seen during hurricanes, they can also occur during winter storms.
Additional images acquired by Landsat 9’s Operational Land Imager (OLI) reveal an even more detailed look at the process. Winter interactions clearly produced “hammerhead” eddies near the slope of the western Florida shelf. This happens when narrower, denser, colder water draws sediment into the slower-flowing Gulf of Mexico. Fluid physics then creates undulating, counter-rotating vortices – the same dynamics seen in dust storms on Earth and Mars.
These rare seasonal consequences are not only visually interesting: they contain useful information for climatologists. Carbonate sediment suspensions affect the global carbon cycle on Earth. These events typically occur during hurricanes and tropical cyclones, which sequester material in deeper waters. However, researchers know much less about how cold fronts facilitate similar situations. By better understanding these rarer phenomena, climatologists hope to learn more about the local sequestration of ocean carbon.
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