Improved Goldstein filter for InSAR noise reduction based on local SNR

Although the modified Goldstein filter based on the local signal-to-noise （SNR） has been proved to be superior to the classical Goldstein and Baran filters with more comprehensive filter parameter, its adaptation is not always sufficient in the reduction of phase noise. In this work, the local SNR-based Goldstein filter is further developed with the improvements in the definition of the local SNR and the adaption of the filtering patch size. What＇s more, for preventing the loss of the phase signal caused by the excessive filtering, an iteration filtering operation is also introduced in this new algorithm. To evaluate the performance of the proposed algorithm, both a simulated digital elevation model （DEM） interferogram and real SAR deformation interferogram spanning the L＇ Aquila earthquake are carried out. The quantitative results from the simulated and real data reveal that up to 79.5% noises can be reduced by the new filter, indicating 9%-32% improvements over the previous local SNR-based Goldstein filter. This demonstrates that the new filter is not only equipped with sufficient adaption, but also can suppress the phase noise without the sacrifice of the phase signal.

Effects of Terrain Morphology Model on Excess Water Inundation and Phosphorus Transport Modeling

An integrated hydrological model has been applied for a rural-urban catchment of the Szamos-Kraszna interfluve geographic area, using the WateRisk integrated hydrological model system. The aim of the hydrological simulations was to identify the role that the relief plays in the water coverage formation process, and to highlight the possible consequences of it on phosphorus transport processes. To support this aim, the rainfall-runoff and the one-dimensional flow routing modules have been modelled, and maximal water cover has been calculated. Measured water coverage data by remote sensing have been compared to calculated maximum water cover in several ways. Results support the existing perspective on excess water formation namely that the process is very complex, therefore, the coincidence of the locations of measured water cover with calculated maximum water cover based on the DEM （digital elevation model） and the river network is low. Analysis shows that as far as the larger depressions of the area are concerned, the error of the DEM is not high, but it is likely that at locations with small altitude differences, the error of DEM can cause larger errors. The results foreshadow the importance of the micro relief of the area on phosphorus transport.

Evaluation of Dynamic Behavior of Bedrock Foundation Based on FEM and DEM Simulations

The seismic behavior of the bedrock foundation during earthquakes concerns the stability and safety of nuclear power plants. Discontinuities like joints and faults existing in rock masses affect significantly the dynamic behavior of bedrock. The dynamic FEM （finite element method） has been commonly utilized to analyze the seismic responses of bedrock, however, it cannot well represent the large deformation behavior of discontinuities. The DEM （distinct element method） has a better capability of simulating the sliding and separation of discontinuities existing in the bedrock, which influence the propagation of seismic waves. In this study, the dynamic FEM and DEM simulations were carried out to investigate the seismic behavior of the bedrock foundation under a nuclear power plant, and the differences between those two methods were illuminated. Numerical simulation results indicate that the FEM underestimates the attenuation effect of faults on the propagation of seismic waves. With the capability of simulating large deformation behavior of discontinuities, the DEM can be regarded as a better method for studying the seismic responses of bedrock foundation which contains discontinuities.