Mystery Challenge 1
LOOK CAREFULLY AT THESE SATELLITE IMAGES
SAR Image © esa 1993, James Roush Thesis
SAR Image of Bering Glacier June 23, 1993 - Surging has become obvious.
Bracket 1. A region of bulges is beginning to flow downstream. Arrow 2. This line shows the surge front. Arrow 3. The dark line above the Grindle Hills may be a melt water pond on the surface in a dip formed by the surge. Circles 4a & 4b. Surface bulges.
SAR Image © esa 1993, James Roush Thesis
SAR Image of Bering Glacier Sept. 13, 1993 - The terminus is advancing!
Arrow 1. Terminus advance and calving is evident in Vitus Lake. Bracket 2. The crevasse is changing shape here, too. Arrow 3. Crevasse fields have grown larger.
1. Look at the satellite SAR images of Bering Glacier for June 23 and September 13. Do the images look different?
(Ice Worm Clue: The terminus has moved!)
SAR Image © esa 1993, James Roush Thesis
SAR Image of Bering Glacier August 9, 1993 - The surge front has moved!
Arrow 1. This line is where the wave or surge front has moved into the piedmont lobe of the terminus. Arrow 2. Crevassing and wide spread bulges. Circles 3a & 3b. Surface bulges.
SAR Image © esa 1993, James Roush Thesis
SAR Image of Bering Glacier August 25, 1993 - The surge front reaches the terminus!
Arrow 1. Advance has already begun in this arm of the glacier. Arrow 2. Surge front. Arrow 3. Crevassing has expanded up-glacier from the surge front.
2. On August 9, a line shows the location of the surge front. On August 25, a dotted line shows the location of the surge front. Has the surge front moved between August 9 and August 25?
Does the glacier look different?
3. On August 25, the glacier looks like it surged more on the left (west) side than the right (east). Do you see it? Look at arrow #1.
(Ice Worm Clue: If you look at both of the images really hard, then you can find other differences as well!)
Mystery Challenge 1, Continued
MORE QUESTIONS:
Computer Figure by James Roush
4. The surge-front map tracks the progress of the glacier's surface bulges. How wide an area does the map cover?
1 mile
4 kilometers
7 kilometers
(Ice Worm Clue: The top line on the map has two numbers on it.)
Did you know: 1 kilometer = 1000 meters
5. How many days passed from June 23 to August 9 while the surface bulges moved?
47 days
10 days
50 days
