May 21, 2022 - Saharan Dust approaching South America
Saharan Dust approaching South America
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On May 19, 2022, a cloud of dust from Africa’s Sahara Desert was
captured approaching northeastern South America by the Moderate
Resolution Imaging Spectroradiometer (MODIS) on board NASA’s Aqua
satellite. The leading edge of a thick pulse of tan dust, which appears
to be mixed in with the white clouds, can be seen to the east (right)
in this image, sitting about 860 miles (1,85 km) off the coast of
Venezuela and heading southwest. A thinner veil of dust has already
crossed the Atlantic Ocean to move over the Lesser Antilles, Venezuela,
Guyana, Suriname, and French Guiana.
A wide silvery-tan band that crosses the image from north to south is
actually caused by an optical phenomenon known as “sunglint”. This
occurs when sunlight reflects off the surface of water at the same
angle that a satellite sensor views it. The result is a mirror-like
reflection of sunlight off water and back at the sensor, creating a
silver streak in an image. While the quantity of dust suspended in the
atmosphere in the streak of sunglint is the same as the area
surrounding it, the streak appears darker due to the sunglint.
The dust seen in this image is just the leading edge of a long train of
dust created by repetitive pulses of dust that have blown off of
Western Africa from May 12 through May 19. By May 17, the Trinidad and
Tobago Weather Center warned that a “significant and high”
concentration of dust was set to move across the Lesser Antilles on May
18 – 20, and elevated Saharan Dust levels are expected to remain across
that country until May 27. Over the next several days the dust is
expected to move northward over the Gulf of Mexico to impact the Gulf
Coast of the United States, including parts of Texas and most of
Florida, with impacts the heaviest on or around May 24.
Image Facts
Satellite: Aqua
Date Acquired: 5/19/2022
Resolutions: 1km (2.7 MB), 500m (7.8 MB), 250m (5.8 MB)
Bands Used: 1,4,3
Image Credit: MODIS Land Rapid Response Team, NASA GSFC
https://modis.gsfc.nasa.gov/gallery/individual.php?db_date=2022-05-21
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