The National Oceanic and Atmospheric Administration's (NOAA) CoastWatch program provides near real-time satellite observations and in-situ Great Lakes data. Visitors can view AVHRR imagery, contour maps, GOES imagery, and other Great Lakes data imagery. The website offers data on the physical characteristics of the Great Lakes as well as data on the average surface water temperature and current and historic water levels. QuickTime movies illustrate changes in water temperature throughout a given year. Users can download a number of software programs to decompress image data.