DocumentCode :
1301733
Title :
Numerical study on the along-track interferometric radar imaging mechanism of oceanic surface currents
Author :
Romeiser, Roland ; Thompson, Donald R.
Author_Institution :
Inst. fur Meereskunde, Hamburg Univ., Germany
Volume :
38
Issue :
1
fYear :
2000
fDate :
1/1/2000 12:00:00 AM
Firstpage :
446
Lastpage :
458
Abstract :
The phase information in along-track interferometric synthetic aperture radar (along-track INSAR, ATI) images is a measure of the Doppler shift of the backscattered signal and thus of the line-of-sight velocity of the scatterers. It can be exploited for oceanic surface current measurements from aircraft or spacecraft. However, as already discussed in previous publications, the mean Doppler frequency of the radar backscatter from the ocean is not exclusively determined by the mean surface current, but it includes contributions associated with surface wave motion. The authors present an efficient new model for the simulation of Doppler spectra and ATI signatures. The model is based on Bragg scattering theory in a composite surface model approach. They show that resulting Doppler spectra are consistent with predictions of an established model based on fundamental electrodynamic expressions, while computation times are reduced by more than one order of magnitude. This can be a key advantage with regard to operational applications of ATI. Based on model calculations for two simple current fields and various wind conditions and radar configurations, they study theoretical possibilities and limitations of oceanic current measurements by ATI. They find that best results can be expected from ATI systems operated at high microwave frequencies like 10 GHz (X band), high incidence angles like 60°, low platform altitude/speed ratios, and vertical (VV) polarization. The ATI time lag should be chosen long enough to obtain measurable phase differences, but much shorter than the decorrelation time of the backscattered field
Keywords :
oceanographic techniques; remote sensing by radar; synthetic aperture radar; Bragg scattering theory; Doppler shift; InSAR; SAR; along-track interferometric radar imaging mechanism; current; dynamics; measurement technique; numerical model; ocean; phase information; radar remote sensing; surface current; synthetic aperture radar; Current measurement; Doppler shift; Phase measurement; Radar imaging; Radar scattering; Sea measurements; Sea surface; Surface waves; Synthetic aperture radar interferometry; Velocity measurement;
fLanguage :
English
Journal_Title :
Geoscience and Remote Sensing, IEEE Transactions on
Publisher :
ieee
ISSN :
0196-2892
Type :
jour
DOI :
10.1109/36.823940
Filename :
823940
Link To Document :
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