March 11, 2021 - Silver Rivers in the Democratic Republic of the Congo

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   Several rivers wind through the dense forests of the eastern Democratic
   Republic of the Congo. Most of these rivers wind towards the Lualaba
   River. In turn, the Lualaba flows into the Congo River—the second
   longest river in Africa. On March 11, 2021, when the Moderate
   Resolution Imaging Spectroradiometer (MODIS) on board NASA’s Terra
   satellite acquired a true-color image of the region, parts of several
   rivers glowed like liquid silver, dramatically contrasting against the
   deep green of the forest.

   The glowing silver is created by an optical phenomenon called
   “sunglint”. When sun reflects off a smooth surface—an ocean, lake, or
   river—at the same angle that a satellite sensor views it, the result is
   a mirror-like shine. An image captured at this moment will show a
   silver glow wherever the reflectance angle is exactly right. The “sweet
   spot” for sunglint is relatively narrow in the east-to-west direction
   but as the satellite is moving, it is longer along the track of the
   satellite. The sunglint is quite bright in the center and quickly
   becomes duller and disappears moving away from that central bright
   spot. Yet rivers several hundred miles away from each other are each
   affected by sunglint. The Lualaba River, running roughly south to north
   is seen in the western (left) section of the image. It is not in
   sunglint so appears dark.

   Image Facts
   Satellite:  Terra
   Date Acquired: 3/10/2021
   Resolutions:  1km (133.3 KB),  500m (351.3 KB),  250m (197.1
   KB)
   Bands Used: 1,4,3
   Image Credit: MODIS Land Rapid Response Team, NASA GSFC



https://modis.gsfc.nasa.gov/gallery/individual.php?db_date=2021-03-11
 
