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Reflectivity of Water A Selkirk Island, Chile story

Coasts  / 
Water
  1. Earthshots
  2. Selkirk Island, Chile
  3. Reflectivity of Water
Description

Have you noticed that in these images, clouds look white but the ocean looks black? Both are made of the same substance, water—why would they appear as opposite colors?

Landsat satellites see solar energy that reflects off the earth (or atmosphere) and back to the satellite. When light hits water, whether ocean or cloud droplet, most of the light reflects at the same angle it came in, like a basketball bounce-pass. Calm water lets the light bounce away, like a mirror, so little light reflects toward the satellite; the ocean looks dark. But a cloud’s millions of droplets bounce the light around like pinballs, so some light always scatters toward the satellite; therefore, the cloud looks bright. This is the same reason a choppy ocean with whitecaps looks brighter than a calm ocean.

View Related Imagery & Stories

Location

Sept. 15, 1999, Landsat 7 (path/row 6/83) — close up of Selkirk Island vortex street

Sept. 15, 1999, Landsat 7 (path/row 6/83) — close up of Selkirk Island vortex street

Selkirk Island, Chile Additional Imagery & Stories

A Note on the Images
A Note on the Images

The Landsat images that are shown on Earthshots are combinations of three different wavelengths of the electromagnetic spectrum. Typically, the images...

Read More
More Selkirk Cloudscapes
More Selkirk Cloudscapes

Since its launch in 1999, Landsat 7 has not again seen such nice vortices over Selkirk Island. A single vortex formed on March 25, 2000, from a simila...

Read More
Other Vortices
Other Vortices

Selkirk Island is not the only place where Landsat has seen vortex streets. Other places where this phenomenon is common are nearby Robinson Crusoe Is...

Read More
Rare Clear Views
Rare Clear Views

April 19, 2009, could have been a rare clear view of the island, but some of the data are missing because of Landsat 7’s Scan Line Corrector (SLC) mal...

Read More
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