Images
August 30, 2014 - Low clouds along western South America
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A broad bank of low clouds (fog) stretched over the South Pacific Ocean and coastal Chile in late August, 2014. The Moderate Resolution Imaging Spectroradiometer (MODIS) aboard NASA's Terra satellite captured this true-color image on August 20, 2014.
The dense, bright white cloud cover stretches hundreds of kilometers along the coast, and in southern Chile the cloud butts against the western slopes of the tall, snow-covered peaks of the Andes Mountains. The capital city of Chile, Santiago, sits on the coast just south of the center and is concealed underneath the fog. To the west, far over the Pacific Ocean, the cloud bank thins and joins marine stratocumulus clouds.
This area of the South Pacific Ocean is a well-known site for fog formation. A semi-permanent high pressure system that lies off the coast forces low level southerly wind movement off the coast of South America. Coastal upwelling along the coast also brings cold water to the surface. The air that is high aloft subsides, and dries, forming an inversion layer over the moister air. As the moist air moves upwards, it can become saturated and form a cloud. With the inversion in place, such banks of cloud may be widespread and long-lasting.
The low clouds off the coast of South America have been identified as the largest deck of stratocumulus clouds over the subtropical oceans. Because they are highly reflective, they play a significant role in global and regional climate maintenance and change.
Image Facts
Satellite:
Terra
Date Acquired: 8/20/2014
Resolutions:
1km ( B), 500m ( B), 250m ( B)
Bands Used: 1,4,3
Image Credit:
Jeff Schmaltz, MODIS Land Rapid Response Team, NASA GSFC
A broad bank of low clouds (fog) stretched over the South Pacific Ocean and coastal Chile in late August, 2014. The Moderate Resolution Imaging Spectroradiometer (MODIS) aboard NASA's Terra satellite captured this true-color image on August 20, 2014.
The dense, bright white cloud cover stretches hundreds of kilometers along the coast, and in southern Chile the cloud butts against the western slopes of the tall, snow-covered peaks of the Andes Mountains. The capital city of Chile, Santiago, sits on the coast just south of the center and is concealed underneath the fog. To the west, far over the Pacific Ocean, the cloud bank thins and joins marine stratocumulus clouds.
This area of the South Pacific Ocean is a well-known site for fog formation. A semi-permanent high pressure system that lies off the coast forces low level southerly wind movement off the coast of South America. Coastal upwelling along the coast also brings cold water to the surface. The air that is high aloft subsides, and dries, forming an inversion layer over the moister air. As the moist air moves upwards, it can become saturated and form a cloud. With the inversion in place, such banks of cloud may be widespread and long-lasting.
The low clouds off the coast of South America have been identified as the largest deck of stratocumulus clouds over the subtropical oceans. Because they are highly reflective, they play a significant role in global and regional climate maintenance and change.
Image Facts
Satellite:
Terra
Date Acquired: 8/20/2014
Resolutions:
1km ( B), 500m ( B), 250m ( B)
Bands Used: 1,4,3
Image Credit:
Jeff Schmaltz, MODIS Land Rapid Response Team, NASA GSFC
