HR: 0800h
AN: C31A-1108    [Abstracts]
TI: Changes in Thaw Lake Morphometry on the Barrow Peninsula, Alaskan Arctic Coastal Plain, 1955-2002
AU: * Jones, B M
EM: bjones@usgs.gov
AF: Department of Geography, University of Cincinnati, Cincinnati, OH 45221-0131 United States
AU: * Jones, B M
EM: bjones@usgs.gov
AF: Current address: SAIC, Contractor to the USGS at the Alaska Science Center, 4230 University Drive, Anchorage, AK 99508 United States
AU: Hinkel, K M
EM: kenneth.hinkel@uc.edu
AF: Department of Geography, University of Cincinnati, Cincinnati, OH 45221-0131 United States
AU: Eisner, W R
EM: wendy.eisner@uc.edu
AF: Department of Geography, University of Cincinnati, Cincinnati, OH 45221-0131 United States
AU: Peterson, K M
EM: afkmp@uaa.alaska.edu
AF: Department of Biological Sciences, University of Alaska Anchorage, Anchorage, AK 99508 United States
AU: Frohn, R C
EM: robert.frohn@uc.edu
AF: Department of Geography, University of Cincinnati, Cincinnati, OH 45221-0131 United States
AU: Beck, R A
EM: RBeck@centralstate.edu
AF: International Center for Water Resources Management, Central State University , Wilberforce, OH 45384 United States
AB: Since the early 1950s, there have been several studies of thaw lakes on the Barrow Peninsula of northern Alaska that focused largely on lake orientation and morphometry. To date, a comprehensive examination of changes in lake area has not been conducted. Lake expansion can result from shoreline erosion and ground subsidence as permafrost thaws. Lake area reduction occurs in response to complete or partial drainage triggered by infilling, stream activity, or coastal erosion. This study examines the changes in lake area (those >10 hectares) over the period 1955 to 2002. The 1955 data was obtained by digitizing lakes from a digital raster graphic of the 1:63360 scale U.S.G.S. topographic map derived from 1955 aerial survey photography. More recently, lakes were identified on high-resolution ORRI and IFSAR data collected in 2002. During this period, total lake area decreased from 22.0% to 20.8%. The number of lakes decreased by 72, from 337 to 265, and average lake size increased from 139 ha in 1955 to 166 ha in 2002. These changes resulted from lake coalescence, or from partial drainage that reduced lake area below the 10 ha threshold. Of the 72 lakes that are no longer larger than 10 hectares, 22 have completely drained. It appears that 16 have drained by natural causes (headward erosion by streams or coastal erosion) and 6 have drained as a result of human disturbance. There are 4 lakes in 2002 that were not present in 1955; these appear to have resulted from the merger of smaller lakes. By increasing the size of interest to 40 ha to focus on larger lakes, the same general trend is observed. There are currently fewer lakes larger than 40 ha, average lake size has increased, yet aerial coverage of lakes larger than 40 ha has decreased. These results contrast to recent findings reported by Smith and colleagues for large lakes in the continuous permafrost zone of Siberia.
DE: 0702 Permafrost (0475)
DE: 0708 Thermokarst
DE: 0746 Lakes (9345)
SC: Cryosphere [C]
MN: Fall Meeting 2005