Project Details
Projekt
Combined Ocean Tide Analysis by GRACE and Altimetry data (COTAGA)
Applicants
Dr.-Ing. Wolfgang Bosch; Professor Dr.-Ing. Frank Flechtner; Professor Dr.-Ing. Torsten Mayer-Gürr
Subject Area
Geodesy, Photogrammetry, Remote Sensing, Geoinformatics, Cartography
Term
from 2006 to 2015
Project identifier
Deutsche Forschungsgemeinschaft (DFG) - Project number 30061353
Precise models of ocean tides are crucial because (i) the effect of ocean tides has to be removed from CHAMP and GRACE observations in order to obtain gravity field models describing exclusively the Earth gravity and (ii) altimetric sea surface heights should be ¿tidefree¿ in order to be comparable with each other and to be assimilated into numerical models. Deficiencies for ocean tides over continental shelves and in polar oceans are well known ¿ even for the most recent models. The present project therefore focuses on two strategies:1) Empirical improvements to the widely used state-of-the-art ocean tide model FES2004 by (a) solving residuals for major tidal constituents with a spatial resolution as short as 300 km from GRACE data only (long wavelength) and (b) applying response and harmonic analysis to multi-mission altimeter data to estimate in particular for shallow water areas corrections for the dominant tidal constituents and non-linear effect like M4 (short wavelength). Both, corrections will be validated and combined to an upgraded FES2004-model subsequently used for a more precise de-aliasing of the GRACE gravity field models and for improved corrections of altimetry data.2) Hydrodynamic modelling to further enhance the Hamburg Tide Model. Revising expertise these investigations shall provide a quantitative dynamical tide modelling with assimilation in open ocean and shallows sea, capable to overcome the deficiencies of current tide models.
DFG Programme
Priority Programmes
International Connection
Austria
