Mendenhall Research Seminar
Changing Lake Mass in Interior Alaska: How is the Water Moving and Why?
Steven Jepsen, USGS, Denver, CO
Wednesday, May 23, 2012 – at 12 Noon
USGS National Center, Reston, VA – Room 4C315
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Rapid changes in lake surface elevation (e.g., ~ 1 m decade-1) have been observed in the zone of discontinuous permafrost of Yukon Flats, interior Alaska, since the early 1980’s, yet little is known about the mechanisms causing them. The goal of this research is to identify processes that could potentially produce some of these lake surface elevation changes, with a focus on the study area of Twelvemile Lake. Multiple hydrological-scenarios of change are tested using flow approximations and constraints from permafrost surveying, remotely-sensed lake surface elevation, and historical climate records. The general finding is that the rapid changes in lake surface elevation could potentially occur as a result of changes in snow/rain partitioning and/or changes in permafrost distribution (permafrost-table elevation or open-talik diameter) along permeable, through-going areas of sand and gravel.