Bathymetry Estimation Using the Gravity-Geologic Method in High Latitude Areas
Speaker:Chia-Chin He
Abstract
Estimating accurate bathymetry is important for un-derstanding many of the Earth¡¦s physical properties.Although shipborne sonar sounding provides better spatial resolution along shipborne tracking, coverage is severely limited. One of the geophysical methods for predicting ba-thymetry is the gravity-geologic method (GGM), which was originally developed for predicting the depth to basement overlain by lower density glacial drift deposits (Ibrahim and Hinze 1972). This method can be readily applied in estimat-ing bathymetry with sparse known shipborne depth values and altimetry-derived gravity Compared to other methods, the advantage of GGM lies in its suitabil-ity for large-scale areas.
Recent studies have taken into consideration many methods to determine the real density contrast by observations One of these techniques is the downward continuation (DWC) method.
In this presentation is to introduce GGM approach to estimate more accurate bathymetry by determining the density contrast between the seawater and the ocean bottom topography. To this end, DWC was applied in predicting the density contrasts in two study areas: south of Greenland (40 - 50¢XW and 50 - 60¢XN) and south of Alaska (140 - 150¢XW and 45 - 55¢XN). Finally, we used global ba-thymetric models and selected shipborne measurement data to validate the GGM estimated models by comparing their statistics.
- Hsiao, Y. S., J. W. Kim, K. B. Kim, B. Y. Lee, and C. Hwang, 2011: Bathymetry estimation using the gravity-geologic method: An investigation of density contrast predicted by the downward continuation method. Terr. Atmos. Ocean. Sci., 22, 347-358, doi: 10.3319/TAO.2010.10.13.01(Oc)
Ibrahim, A. and W. J. Hinze, 1972: Mapping buried bedrock topography with gravity. Ground Water, 10, 18-23, doi: 10.1111/j.1745-6584.1972.tb02921.x.