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 Visible (0.63 µm, left) and Shortwave Infrared (3.9 µm, right) images [click to play animation]

A comparison of McIDAS images of 1-km resolution GOES-13 (GOES-East) Visible (0.63 µm) and 4-km resolution Shortwave Infrared (3.9 µm) data (above) 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 imagery.

A more detailed view of the ship tracks was provided using AWIPS images of 1-km resolution MODIS Visible (0.65 µm), Shortwave Infrared (3.7 µm) and Infrared Window (11.0 µm) images (below). Note that the ship track features could not be identified on the 11.0 µm image, since the cloud-top infrared brightness temperatures were essentially the same over that region.

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

MODIS Visible (0.65 µm), Shortwave Infrared (3.7 µm) and Infrared Window (11.0 µm) images [click to enlarge]