NOAA Image of the Day

Black Body Friday

Black Body Friday

Ever wonder why the ocean in VIIRS true color images isn't blue? It is because these images are not pictures, but generated from a variety of surface reflectance and radiation measurements. The ocean acts like a black body, absorbing most of the visible light and radiating energy in the near-infrared to longwave infrared spectrums. Because of the lack of reflected visible light, especially blue, the ocean appears almost black in these images, except where there are oceanographic features such as turbidity or plankton blooms, which alter the black body nature of the ocean surface. This NOAA/NASA Suomi NPP VIIRS image from July 4, 2017 shows the stark contrast between the highly reflective snow covered surfaces of northern Canada and Greenland, next to the areas of open water that appear black. Areas with sea ice appear to have a bluish color.

HiRes Image

Courtesy of NOAA Environmental Visualization Laboratory