HR: 14:40h
AN: H33I-05    [Abstracts]
TI: Current Measurements in Rivers by Spaceborne Along-Track Interferometric Synthetic Aperture Radar
AU: * Romeiser, R
EM: romeiser@ifm.uni-hamburg.de
AF: University of Hamburg, Institute of Oceanography, Bundesstrasse 53, Hamburg, 20146, Germany
AU: Gruenler, S
EM: steffen.gruenler@zmaw.de
AF: University of Hamburg, Institute of Oceanography, Bundesstrasse 53, Hamburg, 20146, Germany
AU: Stammer, D
EM: detlef.stammer@zmaw.de
AF: University of Hamburg, Institute of Oceanography, Bundesstrasse 53, Hamburg, 20146, Germany
AB: The along-track interferometric synthetic aperture radar (along-track InSAR) technique permits a high-resolution imaging of ocean surface current fields all over the world from satellites. Results of the Shuttle Radar Topography Mission (SRTM) in early 2000 and theoretical findings indicate that spaceborne along-track InSARs are also suitable for current retrievals in rivers if the water surface is at least 200-300 m wide and sufficiently rough for microwave backscattering at slanting incidence. Accordingly, the technique is quite attractive for global river runoff monitoring, where it can complement water level and surface slope measurements by advanced radar altimeters and other efforts. The German satellite TerraSAR-X, which was launched in June 2007, will permit along-track interferometry in an experimental mode of operation. This will be the first opportunity for repeated current measurements from space at selected test sites during a period of several years. In this presentation we give an overview of basic principles and theoretical limits of current measurements by along-track InSAR, example results from SRTM, and predicted along-track InSAR capabilities of TerraSAR-X. An SRTM-derived surface current field in the lower Elbe river (Germany) agrees well with numerical hydrodynamic model results; characteristic lateral current variations around a pronounced main flow channel in the 1500 m wide river are resolved. Despite clearly suboptimal instrument parameters, TerraSAR-X simulations indicate an even better data quality. Depending on width, surface roughness, and relative flow direction of a river, current estimates with an accuracy better than 0.1 m/s will be possible with an effective spatial resolution of a few hundred meters to kilometers.
DE: 1855 Remote sensing (1640)
DE: 1860 Streamflow
DE: 1895 Instruments and techniques: monitoring
SC: Hydrology [H]
MN: 2007 Fall Meeting