Remote Sensing: Visible

VIIRS natural-color image of the Arctic Ocean
Daily natural-color images of the polar regions, captured by the VIIRS sensor, are available from NASA Worldview.

The light that our eyes detects is visible radiation from the sun, reflected off objects around us. "Whiter" objects (those with a high albedo) reflect more radiation than "darker" objects. Sea ice has a higher albedo than the surrounding ocean, which makes it easy to detect from visible remote sensing instruments. Some limitations in using reflected visible light to observe sea ice from space include the following:

  • Since these sensors measure reflected radiation from the sun, visible data can only be collected during the daytime. The inability to measure at night is a problem for measuring sea ice, which exists in polar regions where darkness prevails.
  • Because clouds also reflect visible radiation, a cloudy sky prevents satellites from viewing visible light reflected from sea ice. Unfortunately, ice-covered polar regions tend to be cloudy, with clouds obscuring sea ice 70 to 90 percent of the time.
  • Newly formed ice is very thin and dark, so it can be difficult to distinguish from the ocean.

The following satellites and sensors are a selection of those that observe visible radiation; these are often used to identify and map sea ice.

Last updated: 3 April 2020