HR: 17:30h
AN: G44A-07    [Abstracts]
TI: Unraveling the Complexity of Sea-Level Trends in North America: Results From a New Generation of Glacial Isostatic Adjustment Models
AU: * Latychev, K
EM: latychev@physics.utoronto.ca
AF: University of Toronto, Dept. of Physics 60 St. George Street, Toronto, ON M5S1A7, Canada
AU: Davis, J E
AF: University of Toronto, Dept. of Physics 60 St. George Street, Toronto, ON M5S1A7, Canada
AU: Mitrovica, J X
AF: University of Toronto, Dept. of Physics 60 St. George Street, Toronto, ON M5S1A7, Canada
AU: Dalca, A
AF: University of Toronto, Dept. of Physics 60 St. George Street, Toronto, ON M5S1A7, Canada
AU: Kendall, R A
AF: University of Toronto, Dept. of Physics 60 St. George Street, Toronto, ON M5S1A7, Canada
AB: Estimating the impact of global change on regional sea-level trends within North America requires that observations be corrected for a suite of geophysical processes, most notably ongoing glacial isostatic adjustment (GIA). Unfortunately, the `decontamination' of the observations using numerical models of the GIA process is problematic, both because of uncertainties in our understanding of the Late Pleistocene ice history and viscoelastic Earth structure and as a consequence of assumptions adopted in the underlying post-glacial sea-level theory. An archetypal example of this issue was the long-standing suggestion that GIA-corrected tide gauge rates along the U.S. east coast were characterized by anomalous geographic trends. These trends were interpreted as reflecting, for example, oceanographic and neotectonic signals, and they were sometimes cited to justify ignoring the regional rates in estimates of global sea-level rise. However, subsequent work demonstrated that moderate changes in the radial viscosity profile adopted in the GIA predictions could nearly eliminate the trends. In this talk, we present sea-level predictions along the eastern and Gulf coasts of the U.S. based on a new generation of high-resolution GIA models. These models are based on a finite element numerical framework and they incorporate an accurate treatment of shoreline migration and surface loading processes, as well as realistic 3-D Earth structure. The latter includes lateral heterogeneity in mantle viscosity as well as transition in lithospheric strength from continent to oceanic environments. These new aspects of the modeling are shown to have a large effect on peripheral bulge and continental levering dynamics associated with GIA, and hence conclusions based on earlier modeling results (e.g., the regional GIA-corrected sea-level rate) may require significant revision.
DE: 1212 Earth's interior: composition and state (7207, 7208, 8105, 8124)
DE: 1223 Ocean/Earth/atmosphere/hydrosphere/cryosphere interactions (0762, 1218, 3319, 4550)
DE: 1225 Global change from geodesy (1222, 1622, 1630, 1641, 1645, 4556)
DE: 4556 Sea level: variations and mean (1222, 1225, 1641)
DE: 8120 Dynamics of lithosphere and mantle: general (1213)
SC: Geodesy [G]
MN: 2007 Fall Meeting