the meteorological satellite NOAA 4, is given in Figure 11. Landsat data, from the 
Canadian "Quick Look" facility in Price Albert, Saskatchewan, and transmitted by 
facsimile, are occasionally used to fill in the gaps and to provide details. 
Information received at the Ice Forecasting Central in Ottawa is interpreted and 
compiled during the night and sent to the users by the next morning as short-term 
forecasts and charts showing daily ice conditions. Figure 12 shows part of such an 
ice chart. In addition, a weekly composite chart of ice conditions is provided. 
Plans are made to incorporate on-board interpretation systems for infrared 
scanners and side-looking radar into the data collection system and to shorten the 
delivery time of charts and forecasts by using a VHF channel on a communications 
satellite for transmissions between aircraft, Ottawa, and the ships using the data. 
  
April 5, 1976 April 6, 1976 
FIGURE 11. Portions of NOAA 4 weather satellite coverage of parts of Lakes 
Huron, Erie and Ontario, showing the change in ice conditions in a 
24 hour period. Viewed in stereo, the displacements appear as 
changes in relief. (Imagery courtesy of Atmospheric Environment 
Service, Department of the Environment).