Research Of Wave Parameters Extraction Method By TerraSAR-X Images In HH Polarization

The main problem of wave research is the study of wave spectrum, the wave spectrum describes the internal structure of the waves, all information of waves can be achieved through the direction of wave spectrum.Synthetic Aperture Radar(SAR) has high resolution, therefore can obtain the wave directionspectrum information continuously.TerraSAR-X is the first has full polarization, high spatial resolution, along the track interference model of X-band synthetic aperture radarin the world, so developing the TerraSAR-X data application research has a very broad prospects.In recent years, SAR has developed a single retrieval of sea surface wind or wave parameter method, but in fact both methods are inseparable, the single retrieval sea surface wind field and wave parameter method, not only need to repeatedly enter the external wind field information costing extra operation time, the external wind field information and the space of the SAR does not match can also lead to the retrieval results are not accuracy.This paper firstly introduces the sea surface wind field and wave parameters retrieval researchesby different bands(X-band/C-band) SAR imagesin recent years.Then describes the X-band Geophysical Model Functions(GMFs) of sea surface wind field retrieval XMOD1 and XMOD2.Since XMODs are based on vertical-vertical(VV) polarization SAR images retrieval sea surface development of geophysical model functions, when retrieving horizontal-horizontal(HH) polarization SAR images,need to use Polarization Ration(PR) and GMF. In this paper, discuss three PRs in X-band SAR(Thompson-XP, Elfouhaily-XP, X-PR) practicability.Using these three PRs with XMOD1 and XMOD2 retrieve sea surface wind field by 36 HH polarization TerraSAR-X images. Overall, the retrieval comparison results of bias and root-mean-square-error(RMSE) using XMOD2 and X-PR smaller than other retrieval models.Currently, the retrieval wave spectrum models by SAR images mainly have two kinds: one kind is the MPI, the other is the SPRA. On the basis of the two methods, introduces the retrieval model in this paper: the parameterized first-guess spectrum model. The retrieval wind field information as the initial condition is applied to the parameterized first-guess spectrum model, then obtaining the wave spectrum and wave parameters information.The retrieval results compare with the third wave model WaveWatch? and in suit buoy measurements, it is shown that the absolute errors of wind field information and wave parameters information are within the acceptable range, verify using the retrieval methods can effectively retrieve wave parameters information.But the causes of errors need further analysis.