Index :

GOES-8 Visible

GOES-8 Short Wave Infrared (3.9 micron)

GOES-8 Long Wave Infrared (10.7 micron)

Explanation of images

The lines in the cloud to the northwest of Erika are "ship tracks". Aerosols from the ship engines enter the cloud and modify the cloud microphysical properties. The cloud particles become, in general, smaller in size. This makes the cloud more reflective, particularly in the 3.9 micron channel which is very sensitive to particle size. The 3.9 micron channel radiation arises from thermal emission and reflection of solar energy. The increased reflection of the solar energy makes the ship tracks appear warmer than the surrounding cloud (and hence darker in the imagery). The additional cloud condensation nuclei that emanate from the ship also change the cloud amount, as observed in a comparison between the ship track and surrounding clouds in the visible (total reflection) and 11 micron IR images (all thermal emission, hence cooler signal since less warmer earth radiation is being sensed).

For more information on the Short Wave Infrared Channel, please see the GOES 3.9 micron Channel Tutorial by NOAA/NESDIS/CIRA.