Use of moderate resolution ENVISAT ASAR imagery for operational ice observation.
Sean Helfrich(1) , Pablo Clemente-Colón(1) , Towanda Street(1) , and Gary Premo(1)
National Ice Center,
FB4, 4251 Suitland Rd.,
Washington, DC 20395,
The launch of ENVISAT in 2002 has provided new possibilities for the science of sea ice and lake ice detection. The Advanced Synthetic Aperture Radar (ASAR) allows for all weather near-real time global monitoring of ice conditions. The Global Monitoring Mode (GMM) data has proven to be particularly useful to operational ice observation services, like the U.S. National Ice Center (NIC), due to the manageable data size, cloud-free observations, global depiction of data, and moderate resolution (1 km). However, questions remain regarding the optimal scale of observation for sea ice and what can be observed at one kilometer resolution.
This presentation addresses key issues relating what sea ice information can be conveyed at 1 km compared to higher resolution imagery. Since ASAR backscatter has a non-linear relationship with sea ice stage of development, pixels containing multiple ice stages may provide a blended return value that is indicative of neither ice stage found in the pixel. Reduction of ice concentrations at GMM sub-pixel scale imagery may also lead to false identification of ice types.