HR: 0800h
AN: GC41A-0091    [Abstracts]
TI: Glacial Velocity Changes of Batura Glacier, Western Karakoram Himalaya
AU: * Mertes, J R
EM: jmertes@mail.unomaha.edu
AF: Department of Geography and Geology, University of Nebraska at Omaha, Omaha, NE 68182, United States
AU: Bishop, M P
EM: mpbishop@mail.unomaha.edu
AF: Department of Geography and Geology, University of Nebraska at Omaha, Omaha, NE 68182, United States
AU: Shroder, J F
EM: jshroder@mail.unomaha.edu
AF: Department of Geography and Geology, University of Nebraska at Omaha, Omaha, NE 68182, United States
AU: Haritashya, U K
EM: uharitashya@mail.unomaha.edu
AF: Department of Geography and Geology, University of Nebraska at Omaha, Omaha, NE 68182, United States
AU: Bulley, H N
EM: hbulley@mail.unomaha.edu
AF: Department of Geography and Geology, University of Nebraska at Omaha, Omaha, NE 68182, United States
AU: Olsenholler, J A
EM: jolsenholler@mail.unomaha.edu
AF: Department of Geography and Geology, University of Nebraska at Omaha, Omaha, NE 68182, United States
AB: Glacier fluctuations represent direct and indirect indicators of climate change. Many glaciers around the world are retreating and downwasting, thereby increasing glacial meltwater, as well as debris cover. These variations can cause variations in glacier-flow dynamics including changes in ice velocity and surging. Our objective was to evaluate ice-flow velocity variations on the Batura Glacier in the western Karakoram Himalaya by combining historical data and diagrams from the Chinese Batura Investigation Group of the early 1970s with information gathered from satellite image analysis (ASTER 29/Oct/2003, 13/Sep/2004). Modern ice-flow velocity estimates were generated utilizing ortho-rectified satellite imagery and feature tracking to produce ice-flow velocity fields. Feature tracking was accomplished using original spectral bands and texture images. We generated an average velocity gradient for the Chinese data (12m/yr/100m) and satellite-derived data (23m/yr/100m) using regression analysis. The Chinese mapping of Batura Glacier delineated the end of the lowermost (south-side) white ice stream at ~3.2 km from the Karakoram Highway in 1975. Due to down wasting and increasing supraglacial debris cover the white ice stream has retreated up-ice to ~5.9 km as of 2004. Comparison with historical data shows a possible increase in the annual-velocity gradient yet a decrease in the overall-velocity magnitude. Changes in meltwater at the base from warmer temperatures, or increased mass flux from increased precipitation at altitude, could both change the velocity gradient but not decrease the overall velocities. Downwasting and thinning ice could explain overall decrease in velocities and increased debris loads although attendant frictional increases on sides and base might have some influence.
DE: 0720 Glaciers
DE: 0758 Remote sensing
DE: 0762 Mass balance (1218, 1223)
DE: 0776 Glaciology (1621, 1827, 1863)
DE: 1621 Cryospheric change (0776)
SC: Global Environmental Change [GC]
MN: 2007 Fall Meeting