Three frequency false-color image of Prince Albert, Canada

STS059-S-079 (18 April 1994) --- This is a false-color, three frequency image of Prince Albert, Canada, centered at 53.91 north latitude and 104.69 west longitude. It was produced using data from the X-Band, C-Band and L-Band radars that comprise the Spaceborne Imaging Radar-C and X-Band Synthetic Aperture Radar (SIR-C/X-SAR). SIR-C/X-SAR acquired this image on the 20th orbit of the Space Shuttle Endeavour. The area is located 40 kilometers north and 30 kilometers east of the town of Prince Albert in the Saskatchewan province of Canada. The image covers the area east of the Candle Lake, between gravel surface Highways 120 and 106 and west of 106. The area in the middle of the image covers the entire Nipawin (Narrow Hills) provincial park. The look angle of the radar is 30 degrees and the size of the image is approximately 20 by 50 kilometers. The red, green, and blue colors represent L-Band total power, C-Band total power, and XVV respectively. The changes in the intensity of each color are related to various surface conditions such as frozen or thawed forest, fire, deforestation and areas of regrowth. Most of the dark blue areas in the image are the ice covered lakes. The dark area on the top right corner of the image is the White Gull Lake north of the intersection of Highway 120 and 913. The right middle part of the image shows Lake Ispuchaw and Lower Fishing Lake. The deforested areas are shown by light blue in the image. Since most of the logging practice at the Prince Albert area is around the major highways, the deforested areas can be easily detected as small geometrically shaped dark regions along the roads. At the time these data were taken, a major part of the forest was either frozen or undergoing the spring thaw. In such conditions, due to low volume of water in the vegetation, a deeper layer of the canopy is imaged by the radar, revealing valuable information about the type of trees, the amount of vegetation biomass and the condition of the surface. As the frequency increases, the penetration depth in the canopy decreases. Over forest canopies, the X-Band radar contains information about the top of the canopy. Whereas, C-Band and L-Band radar returns show contributions from the crown and trunk areas respectively. The bright areas in the image are dense mixed aspen and old jackpine forests where the return from all three bands is high. The reddish area corresponds to more sparse old jack pine (12 to 17 meters in height and 60 to 75 years old) where the L-Band signal penetrates deeper in the canopy and dominates C-Band and X-Band returns. Comparison of the image with the forest cover map of the area indicates that the three band radar can be used to classify various stands. SIR-C/X-SAR is part of NASA's Mission to Planet Earth (MTPE). SIR-C/X-SAR radars illuminate Earth with microwaves allowing detailed observations at any time, regardless of weather or sunlight conditions. SIR-C/X-SAR uses three microwave wavelengths: L-Band (24 cm), C-Band (6 cm), and X-Band (3 cm). The multi-frequency data will be used by the international scientific community to better understand the global environment and how it is changing. The SIR-C/X-SAR data, complemented by aircraft and ground studies, will give scientists clearer insights into those environmental changes which are caused by nature and those changes which are induced by human activity. SIR-C was developed by NASA's Jet Propulsion Laboratory (JPL). X-SAR was developed by the Dornire and Alenia Spazio Companies for the German Space Agency, Deutsche Agentur fuer Raumfahrtangelegenheiten (DARA), and the Italian Space Agency, Agenzia Spaziale Italiana (ASI). JPL Photo ID: P-43929