HR: 0800h
AN: G31C-0817    [Abstracts]
TI: GRAVITY FIELD CHANGES DUE TO LONG-TERM SEA LEVEL CHANGES
AU: Makarynskyy, O
EM: makaryno@vesta.curtin.edu.au
AF: Western Australian Centre for Geodesy, Curtin University of Technology GPO Box U1987, Perth, WA 6845 Australia
AU: * Kuhn, M
EM: M.Kuhn@curtin.edu.au
AF: Western Australian Centre for Geodesy, Curtin University of Technology GPO Box U1987, Perth, WA 6845 Australia
AU: Featherstone, W E
EM: W.Featherstone@curtin.edu.au
AF: Western Australian Centre for Geodesy, Curtin University of Technology GPO Box U1987, Perth, WA 6845 Australia
AB: Long-term sea level changes caused by climatic changes (e.g. global warming) will alter the system Earth. This includes the redistribution of ocean water masses due to the migration of cold fresh water from formerly ice-covered regions to the open oceans mainly caused by the deglaciation of polar ice caps. Consequently also a change in global ocean circulation patterns will occur. Over a longer timescale, such mass redistributions will be followed by isostatic rebound/depression due to the changed surface un/loading, resulting in variable sea level change around the world. These, in turn, will affect the gravity field, location of the geocentre, and the Earth's rotation vector. This presentation focuses mainly on gravity field changes induced by long-term (hundredths to many thousand years) sea level changes using an Earth System Climate Model (ESCM) of intermediate complexity. In this study, the coupled University of Victoria (Victoria, Canada) Earth System Climate Model (Uvic ESCM) was used, which embraces the primary thermodynamic and hydrological components of the climate system including sea and land-ice information. The model was implemented to estimate changes in global precipitation, ocean mass redistribution, seawater temperature and salinity on timescales from hundreds to thousands years under different greenhouse warming scenarios. The sea level change output of the model has been converted into real mass changes by removing the steric effect, computed from seawater temperature and salinity information at different layers also provided by Uvic ESCM. Finally the obtained mass changes have been converted into changes of the gravitational potential and subsequently of the geoid height using a spherical harmonic representation of the different data. Preliminary numerical results are provided for sea level change as well as change in geoid height.
DE: 1212 Earth's interior--composition and state (8105)
DE: 1234 Regional and global gravity anomalies and Earth structure
DE: 1299 General or miscellaneous
SC: Geodesy [G]
MN: 2004 AGU Fall Meeting