Ship tracks in the Atlantic Ocean

April 13th, 2013 |
GOES-13 0.63 µm visible (left) and 3.9 µm shortwave IR (right) images (click image to play animation)

GOES-13 0.63 µm visible (left) and 3.9 µm shortwave IR (right) images (click image to play animation)

A comparison of McIDAS images of 1-km resolution GOES-13 0.63 µm visible channel with the corresponding 4-km resolution 3.9 µm shortwave IR channel data (above; click image to play animation) revealed a number of ship tracks in the marine boundary layer stratocumulus cloud deck over the western Atlantic Ocean on 13 April 2013. Aerosols from the exhaust of ships causes a “cloud seeding effect”, which results in a higher concentration of smaller cloud droplets compared to the surrounding undisturbed cloud deck. These smaller cloud droplets are more effective reflectors of sunlight, resulting in a warmer (darker gray) signature on the 3.9 µm shortwave IR imagery.

A more detailed view of the ship tracks was provided using AWIPS images of 1-km resolution MODIS 0.65 µm visible channel, 3.7 µm shortwave IR channel, and 11.0 µm longwave IR channel images (below). Note that the ship track features could not be identified on the 11.0 µm longwave IR (or “IR window”) image.

MODIS 0.65 µm visible channel, 3.7 µm shortwave IR channel, and 11.0 µm longwave IR channel images

MODIS 0.65 µm visible channel, 3.7 µm shortwave IR channel, and 11.0 µm longwave IR channel images

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