This is a time series of AVHRR thermal infrared (band 4, 10.3-11.3 um) images for the Great Lakes spanning January 31-February 13, 1996. Image brightness is proportional to scene radiance, so bright=higher physical temperature and dark=colder physical temperature. Click on an image for an enlarged version.
This time series shows typical conditions for a well-developed ice season. Clouds obscuring the Lakes' surfaces are common. (These images were selected from a larger time series on the basis of being relatively "cloud free" for Lake Superior.) Open water and leads (particularly shore leads) appear as bright white areas. Ice appears as grey tones, with colder (thicker, generally older) ice being darker grey.
Naming convention, n12.96031.2356: NOAA 1 2, julian day 31 of 1996, Greenwich Mean Time of acquisition 23:56 (18:56 local EST).
Great Lakes Snow and Ice Web Page