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The sampling error variances of the 5° ϫ 5° Global Historical Climatological Network (GHCN) monthly surface air temperature data are estimated from January 1851 to December 2001. For each GHCN grid box and for each month in the above time interval, an error variance is computed. The authors' error estimation is determined by two parameters: the spatial(More)
An accurate creeping ray-tracing algorithm is presented in this paper to determine the tracks of creeping waves (or creeping rays) on arbitrarily shaped free-form parametric surfaces [nonuniform rational B-splines (NURBS) surfaces]. The main challenge in calculating the surface diffracted fields on NURBS surfaces is due to the difficulty in determining the(More)
—This paper presents a study of the microwave backscattering from 2-D time-evolving nonlinear surfaces of a sea with finite depth by using the second-order small-slope approximation. According to the shallow-water dispersion relation, the revised nonlinear hydrodynamic choppy wave model in connection with an experiment-verified sea spectrum for finite-depth(More)
Based on the physical optics (PO) theory, the radar cross section (RCS) of a metal sphere is numerically calculated and analyzed at high frequency limits in the Terahertz region. To obtain the relation between RCS and frequency, the scattered electric fields are estimated by using the integral equations under far field approximations for various beam widths(More)
Modern wide-band radar system could resolve the refined sea surface structure, which results from the strong instantaneous clutter spike appearing in the background echo, and severely affects the target detection efficiency in searching process. It is important for radar design and efficiency-improving to investigate the high-resolution clutter restraint(More)
To solve EM scattering by complex target with plasma coat, a new conformal method is put forward based on the shift operator finite-difference time-domain (SO-FDTD) method in this paper, by equaling electric parameters in the grids located at the intersection of dispersive media and non-dispersive media, and modifying the EM field recursive formula. The(More)
SAR simulation plays an important role in SAR community and attracts more and more attention in recent years. The paper proposes a new SAR raw data simulation method, which uses high frequency electromagnetic computation to acquire the responses of 3-D extended scene, and transforms them to time-domain according the signal model of LFM radar. Compared to(More)
To solve the radar echo simulation of moving targets, a new method is put forward based on the high resolution range profile (HRRP) of the target in this paper. Although this method demands much storage, it avoids the complicated parameter estimation, and is more close to the scattering features of target. The accuracy and efficiency of the proposed method(More)
To overcome the competition between the side lobe suppression and the main lobe spread in radar imaging, we introduce a super-resolution imaging algorithm based on the iterative processes of the reshaped window function. The side lobes of the target imaging are sensitively dependent on the structures of reshaped window function, and the main lobes, however,(More)