REMOTE SENSING OF THE CRYOSPHERE: EXERCISES 1. Glacier outlines: Without conferring with your classmates, mark on the following images where you would consider the glacier outline to be: A. B. C. Now, compare your outlines with others. How do they differ? Where do they differ? Provide some reasons for the differences. What additional information might you use to improve the accuracy of your area estimates? How would quantify the uncertainty in a glacier area estimate? A) should all be similar B) Differences may be caused by snow cover and shadowing C) Differences may be caused by debris cover Additional information: - in situ measurements - DEM for surface slopes - Multispectral band composite image (e.g. Landsat 543) - Velocity map to show which debris-covered parts are flowing 2. Electromagnetic Spectrum Below is a schematic of the electromagnetic spectrum. For each of the categories in the table, describe possible cryosphere satellites and applications (you should be able to come up with ~3 applications for each wavelength). Underline one application for each wavelength; for that application, describe some advantages and disadvantages of using this sensor. Waveleng Satellite/Sen Application Advantag Disadvanta th sor s es ges Historical extent/mappi High res. No images in photos ng cloud, night, Visible Landsat Structures or winter MODIS DEM ASTER velocity Sentinel-2 Thermal Landsat Infrared Thermal cams SSMI Microwav SMAP e Sentinel-1 TerraSarX Radar Radarsat ERS 1/2 3. Structural Mapping The following two images show Byrd Glacier, Antarctica passing through the Transantarctic Mountains and entering the western margin of the Ross Ice Shelf. The first image (a) is an optical image acquired by Canada’s RADARSAT satellite. Identify and highlight glaciological structures that you can identify on either image. What differences are due to sensor type? A. B. Shear zones are much more defined in SAR images Buried crevasses are visible in SAR image (radar penetration into snow) 4. Feature tracking for ice velocity Part of the experimental design of a project to measure glacier velocities by feature tracking requires choosing satellite imagery at an appropriate time interval, given a sensor’s ground range resolution and the expected ice speed. Complete the following table to suggest appropriate time intervals in days for a robust velocity estimate, given different range resolutions and maximum glacier velocities. Ground range resolution (m) Glacier velocity 3 m 15 m 30 m (m/yr) 23 days 115 days 250 days 50 m/yr 4 days 18 days 37 days 300 m/yr 1 day 3-4 days 7 days 2000 m/yr.