Application of SAR interferometry for studies of Caspian coast covers
Vvedensky square, 1,
ERS SAR data and ENVISAT ASAR interferometric data sets obtained under AO-3 and ENVISAT-AO projects are used here for study of the peculiar properties of signal backscatter in North-Western Caspian coast area and temporal stability of the backscatter in interferometric sense as well as effects of the signal propagation in troposphere.
Interferograms and coherency maps produced on the relatively short period of time – from one day till half a year are the basis of our study. From tandem mission it was possible to observe unusual dynamics of the reflecting surface in Caspian avandelta, namely, 10-20 cm oscillations of water surface level because of double bounce scattering effect in the areas of flooded reed. SIR-C polarimetric SAR data available for the area of study confirmed presence of such a rare scattering mechanism. Another effect observed on the tandem interferogram was manifestation of fluctuations of SAR signal phase because of troposphere irregularities, what allowed us to estimate the extent and spatial size of the irregularities mentioned.
Analysis of ENVISAT ASAR interferometric data set in various combinations allowed us to estimate temporal stability of the coastal vegetation covers in the case of different spatial and temporal baselines as well as different seasonal conditions. The coherency maps produced allowed us to make more reliable mapping of coastal line as well as vegetation covers location. We may state that a series of coherence map is an independent way of characterization of the Earth covers study.