December 04, 2001
A cloud signature produced over the ocean by a large ship is somewhat similar to a contrail produced by jet aircraft. However, they're usually only observable on satellite imagery. These clouds, known as 'ship tracks', form in the wake of ships and can last several hours. They're typically between 0.5-5 km wide and are caused by condensation nuclei from the ship's exhaust, which induce the formation of shallow, stratus clouds. On the above near-infrared NOAA (GOES) satellite photo, numerous ship tracks can be seen in the Pacific Ocean, off the coast of Washington. On this image, the ship tracks and low clouds are gray, land is shown in green, high clouds are light blue and clear sky over cold water is dark blue.