Glacier Surface Type - Svalbard

• Main Author: König, Max
• Format: Dataset
• Language: unknown
• Published: Norwegian Polar Institute 2013
• Subjects: GEOSCIENTIFIC INFORMATION; Surface Type; Firn; superimposed ice; glacier ice; glaciology; EARTH SCIENCE; CLIMATE INDICATORS; CRYOSPHERIC INDICATORS; GLACIAL MEASUREMENTS; GLACIER FACIES; CRYOSPHERE; GLACIERS/ICE SHEETS; GLACIERS; Svalbard; glacier
• Online Access: http://data.npolar.no/dataset/d756f766-de33-11e2-8993-005056ad0004

On many glaciers in Svalbard, three surface types are visible on SAR images, the dark glacier ice at the glacier's lower end, the brighter superimposed ice in the middle, and the white firn at the higher elevations. Surface classification of these types is valuable especially since the retreat or advance of the firn area provides information on the status of the glacier. While the snowline reacts immediately to annual changes, the firn area smoothes out these short-term changes and shows, similar to the glacier front, longer-term changes of the glaciers. GST uses a Otsu three-category algorithm to separate the image into these three surface types for selected Svalbard glaciers. The method works very well on glacier with distinct surface types, the main weakness is crevasses and rough areas being classifed as superimposed ice. A quality number indicates if an individual classification is ideal (1), good (2) or of medium quality (3). The quality number mainly indicates how much crevasses are classified as superimposed ice. The firn area should be displayed correctly for all selected glaciers.