NASA’s Terra satellite looked down on the Canary Islands on June 15, 2013 and acquired this image. The Atlantic Ocean has a silvery or milky color in much of the image. That color is the result of sunglint being reflected off of the ocean surface directly back at the satellite imager.
This play of light from the ocean surfaces reveals details about the sea surface or circulation that are otherwise invisible.
In the image above, wavy, windsock-like tails stretch to the southwest from each of the islands. The patterns are likely the result of winds roughening or smoothing the water surface in different places. Prevailing winds in the area come from the northeast, and the rocky, volcanic islands create a sort of wind shadow—blocking, slowing, and redirecting the air flow. That wind, or lack of it, piles up waves and choppy water in some places and calms the surface in others, changing how light is reflected.
Why are we posting this image this week? It’s because the image is the winner of this year’s second annual Tournament: Earth, a reader-driven competition to choose the previous year’s top NASA image of Earth. The tournament ended on April 7. NASA said this image “romped through the tournament in 2014.” And no wonder. It’s interesting … and it’s beautiful.