Full image, 132Kb jpg

The RADARSAT image of Ottawa, Ontario was acquired on January 19, 1996. At the time of the data acquisition the ground was covered by a blanket of wet snow. Wet snow masks the ground beneath and lowers the contrast between features in the image. Some identifiable features include agricultural fields (A and B), the Ottawa International Airport (C), the Ottawa River (D) and the city of Ottawa (E).

In many areas of the world, a significant proportion of the freshwater available for consumption, irrigation and hydroelectric generation is supplied from snowpack runoff. In order to make efficient use of runoff water, resource agencies must be able to make early predications of the amount of water stored in the form of snow. Areal extent, Snow Water Equivalent (SWE) and snowpack wetness are the most important parameters to be determined in this process. Research using SAR data for snow studies has shown promising results.

At the time this image was acquired an active radar calibration (ARC) device was being operated. A very bright star - or cross-shaped feature (F) marks the location of the ARC. The bright response on the image is due to the ARC's transmission of a microwave pulse of a known radar cross section. These devices are used to assess the stability of the RADARSAT system and validate calibration of the images.

Additional Ottawa RADARSAT images are available to allow a comparison between wet and dry snow conditions and a discussion on change detection monitoring.