HR: 0800h
AN: G51C-0859    [Abstracts]
TI: InSAR water vapour correction models: GPS, MODIS, MERIS and InSAR integration
AU: * Li, Z
EM: zhli@ge.ucl.ac.uk
AF: COMET, Department of Geomatic Engineering, Universtiy College London, Gower Street, London, WC1E 6BT United Kingdom
AU: Fielding, E J
EM: Eric.J.Fielding@jpl.nasa.gov
AF: Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109 United States
AU: Cross, P
EM: paul.cross@ge.ucl.ac.uk
AF: COMET, Department of Geomatic Engineering, Universtiy College London, Gower Street, London, WC1E 6BT United Kingdom
AU: Muller, J
EM: jpmuller@ge.ucl.ac.uk
AF: Department of Geomatic Engineering, Universtiy College London, Gower Street, London, WC1E 6BT United Kingdom
AU: Wright, T
EM: Tim.Wright@earth.ox.ac.uk
AF: COMET, Department of Earth Sciences, University of Oxford, Parks Road, Oxford, OX1 3PR United Kingdom
AB: A major source of error for repeat-pass InSAR is the phase delay in radio signal propagation through the atmosphere (especially the part due to tropospheric water vapour). To date, we have developed three water vapour correction models to reduce water vapour effects on InSAR measurements using GPS, MODIS and/or MERIS data: (1) GPS Topography-dependent Turbulence Model (GTTM) (Li et al., 2005a); (2) GPS/MODIS integrated water vapour correction model (Li, 2004; Li et al., 2005c); (3) MERIS water vapour correction model (Li, 2005, Li et al., 2005b; Li et al., manuscript in preparation, 2005). Application of all the three correction models to ASAR data over the Los Angeles region shows that the order of water vapour effects on interferograms can be reduced from ~10 mm to ~5 mm using the GTTM, the GPS/MODIS integrated, or the MERIS models. It is also clearly shown that these three water vapour correction models are complementary. On the one hand, GPS can collect high temporal resolution (e.g. 30 seconds) observations day and night, and GPS water vapour product is insensitive to the presence of clouds. However, only a few dense continuous GPS networks such as the Southern California Integrated GPS Network (SCIGN) operate across the globe, and its spatial resolution is also limited from a few kilometres to a few hundred kilometres. On the other hand, MODIS and MERIS have a global coverage with a finer spatial resolution as compared with current Continuous GPS (CGPS) networks. But MODIS and MERIS near IR water vapour products are only available for the daytime, and are sensitive to the presence of clouds. We also investigate the impacts of time difference between water vapour products and SAR data on the reduction of water vapour effects on InSAR measurements, as well as the influence of the spatial resolution of water vapour products.
DE: 1241 Satellite geodesy: technical issues (6994, 7969)
DE: 1295 Integrations of techniques
DE: 6924 Interferometry (1207, 1209, 1242)
SC: Geodesy [G]
MN: Fall Meeting 2005