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Geoscience and Remote Sensing, IEEE Transactions on

Issue 2 • Date Feb 2002

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Displaying Results 1 - 25 of 33
  • Comparison of the physical optics and small slope theories for polarimetric thermal emission from the sea surface

    Publication Year: 2002 , Page(s): 500 - 504
    Cited by:  Papers (7)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (282 KB) |  | HTML iconHTML  

    A comparison of the physical optics and small slope theories of emission from the sea surface is described. It is shown that the two theories produce identical results for "long wave" contributions to sea emission azimuthal variations up to third order in long wave surface slope when shadowing effects are neglected View full abstract»

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  • The characteristic polarization states and the equi-power curves

    Publication Year: 2002 , Page(s): 305 - 313
    Cited by:  Papers (4)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (360 KB) |  | HTML iconHTML  

    Characteristic polarization state theory is restudied for the symmetric coherent Sinclair scattering matrix case. First, the geometric relations of the characteristic polarization states on the Poincare sphere are derived. Based on these relations, simple formulas are given for all of the characteristic polarization states of this Sinclair matrix in Stokes vector form. From the formulation, it is clear that the CO-POL Nulls are fundamental characteristic polarization states for the symmetric coherent Sinclair scattering matrix case, in that the others can straightforwardly be obtained from the Stokes vectors of the CO-POL Nulls. For further study of the characteristic polarization state and the distribution of the received powers on the Poincare sphere, the authors introduce the concept of the equi-power curve. It is defined as the curve on the Poincare sphere on which the received powers in some defined channel have the same value. They deal with the characteristics of the equi-power curves for various special cases. In addition, they show how the characteristic polarization states are generated by the equi-power curves. It is demonstrated that the characteristic polarization states can usually be regarded as the points of contact of the Poincare sphere and a conicoid representing a power-related quadratic form. This leads to a new method to introduce the characteristic polarization states View full abstract»

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  • FDTD modeling and analysis of a broadband antenna suitable for oil-field imaging while drilling

    Publication Year: 2002 , Page(s): 434 - 442
    Cited by:  Papers (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (428 KB) |  | HTML iconHTML  

    This paper develops a finite-difference time-domain (FDTD) approach suitable for modeling general antenna structures which include cylindrical dipoles. The medium averaging is a key factor of the method since the FDTD grid size is comparable to the dimensions of the antenna. It is essential in the FDTD calculation to account for the effective media seen by different electric field components. The input impedance calculated by the FDTD approach agrees well with the published results for a cylindrical dipole, although only one cell in the transverse direction is assigned as the metallic conductor. This FDTD approach is then used to model and analyze a novel broadband antenna which can be used in a borehole radar system for oil-field imaging while drilling. The antenna is essentially a horizontal cut on a metallic drill collar with a vertical cylindrical dipole placed across the cut and loaded at the ends. Based on the modeling results, we found that a proper resistive loading is the key in order to increase the bandwidth of the antenna and reduce ringing. When properly loaded, the antenna has a fairly flat input impedance ranging from 50 MHz to 600 MHz. The real part of the input impedance varies favorably around 75 Ω. In addition, the input impedance of the antenna is not very sensitive to the surrounding medium. The simulated antenna radiation of the electric field shows good azimuthal discrimination. For a lossless medium with a permittivity of 20 ε0 the front-back ratio climbs from around 15 dB at 100 MHz to about 45 dB at 600 MHz View full abstract»

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  • Interpolation of digital elevation models using AMLE and related methods

    Publication Year: 2002 , Page(s): 314 - 325
    Cited by:  Papers (11)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1536 KB) |  | HTML iconHTML  

    Interpolation of digital elevation models becomes necessary in many situations, for instance, when constructing them from contour lines (available e.g., from nondigital cartography), or from disparity maps based on pairs of stereoscopic views, which often leaves large areas where point correspondences cannot be found reliably. The absolutely minimizing Lipschitz extension (AMLE) model is singled out as the simplest interpolation method satisfying a set of natural requirements. In particular, a maximum principle is proven, which guarantees not to introduce unnatural oscillations which is a major problem with many classical methods. The authors then discuss the links between the AMLE and other existing methods. In particular, they show its relation with geodesic distance transformation. They also relate the AMLE to the thin-plate method, that can be obtained by a prolongation of the axiomatic arguments leading to the AMLE, and addresses the major disadvantage of the AMLE model, namely its inability to interpolate slopes as it does for values. Nevertheless, in order to interpolate slopes, they have to give up the maximum principle and authorize the appearance of oscillations. They also discuss the possible link between the AMLE and Kriging methods that are the most widely used in the geoscience literature View full abstract»

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  • A novel 3-D subsurface radar imaging technique

    Publication Year: 2002 , Page(s): 443 - 452
    Cited by:  Papers (23)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (849 KB) |  | HTML iconHTML  

    The problem of the formation of subsurface images using stand-off forward looking radar is by far more severe than that of forming the radar images in the free-space. A subsurface image needs to be accurately focused taking into account both the refraction and dispersion of the wavefield. This paper presents a novel imaging algorithm specially tailored for subsurface sensing. A simple and effective characterization technique for the retrieval of the dielectric permittivity is outlined. The proposed soil characterization and subsurface imaging techniques are validated experimentally. Results show that the geometric distortion in the subsurface images due to the refraction and dispersion of the wavefields is successfully corrected View full abstract»

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  • Subpixel variability of remotely sensed soil moisture: an inter-comparison study of SAR and ESTAR

    Publication Year: 2002 , Page(s): 326 - 337
    Cited by:  Papers (24)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (909 KB) |  | HTML iconHTML  

    The representation of subpixel variability in soil moisture estimates from passive microwave data was investigated through sensitivity analysis and by comparison against the spatial structure of soil moisture fields derived from radar data. This work shows that the subpixel variability not represented in brightness temperature fields is directly associated with the spatial organization of soil hydraulic properties and the spatial distribution of vegetation. The significant implication of this result is that the physical connection between soil moisture estimates at the pixel scale and local values within the pixel weakens strongly as the sensor resolution decreases. Subsequently, the application of scaling and fractal interpolation principles to downscale passive microwave data to the spatial resolution of radar data was investigated as a means to recover spatial structure. In particular, ESTAR soil moisture data was successfully downscaled from 200 to 40 m using only one radar frequency (e.g., L-band). This application suggests that the combined use of active and passive single-band microwave remote-sensing of soil moisture is a viable approach to improve the spatial resolution of soil moisture remote-sensing View full abstract»

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  • A generalized power law spectrum and its applications to the backscattering of soil surfaces based on the integral equation model

    Publication Year: 2002 , Page(s): 271 - 280
    Cited by:  Papers (32)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (326 KB) |  | HTML iconHTML  

    A generalized power law spectrum is proposed to describe the random rough surfaces in this paper. The parameters of the spectrum are related to the traditional physical parameters of root mean square (rms) height and correlation length. It can naturally reduce to the spectra of Gaussian and exponential correlation functions. The corresponding correlation functions are also derived. It can provide wider range of spectra to describe the random rough surfaces than other spectra. Based on the proposed spectrum, backscattering of soil surfaces is studied by using the integral equation model (IEM). The simulation results are compared with the experimental measurements of real soil surfaces at L, C, and X bands for the different roughness scales and moisture conditions. The reasonably good agreements between the measurements and the simulations are observed for all three-frequency bands and different incidence angles with the same sets of the physical roughness parameters View full abstract»

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  • Multifrequency reconstruction of moderately rough interfaces via quasi-ray Gaussian beams

    Publication Year: 2002 , Page(s): 453 - 460
    Cited by:  Papers (16)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (461 KB) |  | HTML iconHTML  

    In this paper, we present a new technique for determining the surface profile of a moderately rough interface between air and a homogeneous dielectric half-space. Based on sparsely sampled step-frequency ground penetrating radar measurements, the proposed inversion scheme uses a quasi-ray Gaussian beam fast forward model, coupled with a low-order parameterization of the surface profile in terms of B-splines. The profile estimation problem is posed as a parameter optimization problem, which is solved using a multiresolution continuation method via frequency hopping. Numerical experiments establish that the algorithm is efficient and yields accurate reconstructions throughout most of the illuminated region even in noisy environments, losing accuracy only in regions with very weak illumination View full abstract»

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  • Measurements of the propagation parameters of tree canopies at MMW frequencies

    Publication Year: 2002 , Page(s): 298 - 304
    Cited by:  Papers (6)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (312 KB) |  | HTML iconHTML  

    The presence of trees in a given scene can hamper detection of nearby targets by millimeter-wave (MMW) radars especially at near grazing incidence. Proper characterization of scattering and attenuation in tree canopies is important for optimal detection algorithms. In this paper, a new technique for determining the extinction and volume backscattering coefficients in tree canopies using the measured radar backscatter response is proposed and verified experimentally. The technique, which can be applied to already available wideband radar backscatter data, is used to compute the extinction and volume backscattering coefficients of different tree canopies under various physical conditions. The dynamic range of these coefficients are presented and results at 35 GHz are compared with results at 95 GHz View full abstract»

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  • Low-grazing-angle (LGA) sea-spike backscattering from plunging breaker crests

    Publication Year: 2002 , Page(s): 523 - 526
    Cited by:  Papers (16)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (210 KB) |  | HTML iconHTML  

    The low-grazing-angle (LGA) microwave backscattering from a series of wave profiles representing the time evolution of a plunging breaker water wave is numerically calculated and compared with modeled predictions. The crest regions of the waves are isolated to remove large-scale multiple back-reflection paths that give interference. The horizontally polarized backscatter (HH) significantly exceeds that at vertical polarization (VV) during the breaking, despite the lack of multipath. Existing scattering models with some heuristic corrections are applied to the profiles to identify the dominant scattering mechanisms. The large HH-to-VV ratio is predicted from single scattering using an extended geometrical optics (EGO) approach. The initial rise in the backscatter as the wave steepens is predicted as diffraction from inflection points in the surface curvature at the crest using a modification of the geometrical theory of diffraction. The calculations show that the LGA backscattering from breaking wave crests is very complicated even in the absence of multipath and simple optically based models that treat the crest cross sections as equal at the two polarizations will be inaccurate View full abstract»

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  • The line segment match method for extracting road network from high-resolution satellite images

    Publication Year: 2002 , Page(s): 511 - 514
    Cited by:  Papers (19)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (232 KB) |  | HTML iconHTML  

    This paper presents an approach, with emphasis on the newly proposed line segment matching method, for extracting urban road networks from high-resolution satellite images. The approach is based on the characteristics of the images, knowledge about road networks, and the related mathematical models. The approach is applied to several images of urban areas and is proved to be effective in both visual effect and positional accuracy View full abstract»

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  • Evaluation of late summer passive microwave Arctic sea ice retrievals

    Publication Year: 2002 , Page(s): 348 - 356
    Cited by:  Papers (22)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (756 KB)  

    The melt period of the Arctic sea ice cover is of particular interest in studies of climate change due to the albedo feedback mechanisms associated with meltponds and openings in the ice pack. The traditionally used satellite passive microwave sea ice concentration algorithms have deficiencies during the summer months due to the period's highly variable surface properties. A newly developed ice concentration algorithm overcomes some of these deficiencies. It corrects for low ice concentration biases caused by surface effects through the use of 85 GHz data in addition to the commonly used 19 and 37 GHz data and, thus, the definition of an additional ice type representing layering and inhomogeneities in the snow layer. This new algorithm will be the standard algorithm for Arctic sea ice concentration retrievals with the EOS Aqua advanced microwave scanning radiometer (AMSR-E) instrument. In this paper, we evaluate the performance of this algorithm for the summer period of 1996 using data from the special sensor microwave imager (SSM/I) which has frequencies similar to the AMSR instrument. The temporal evolution of summertime passive microwave sea ice signatures are investigated and sea ice concentration retrievals from the standard NASA team and the new algorithm are compared. The results show that the introduction of the additional sea ice type in the new algorithm leads to improved summertime sea ice concentrations. The SSM/I sea ice retrievals are validated using SAR-derived ice concentrations that have been convolved with the SSM/I antenna pattern to ensure an appropriate comparison. For the marginal ice zone, with ice concentrations ranging from 40% to 100%, the correlation coefficient of SAR and SSM/I retrievals is 0.66 with a bias of 5% toward higher SAR ice concentrations. For the central Arctic, where ice concentrations varied between 60% and 100%, the correlation coefficient is 0.87 with a negligible bias View full abstract»

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  • On the stability of the FDTD algorithm for elastic media at a material interface

    Publication Year: 2002 , Page(s): 474 - 481
    Cited by:  Papers (12)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (346 KB) |  | HTML iconHTML  

    In this paper, the stability behavior of the first-order finite-difference time-domain algorithm for elastodynamics at the interface between two different materials is investigated. A necessary condition for stability is established, which, dependent on the material properties of the two media, might be more restrictive than the well-known Courant condition. It is shown that this more restrictive stability condition can be avoided if the material properties are averaged on the boundary View full abstract»

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  • Cloud tracking by scale space classification

    Publication Year: 2002 , Page(s): 405 - 415
    Cited by:  Papers (9)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (441 KB) |  | HTML iconHTML  

    The problem of cloud tracking within a sequence of geo-stationary satellite images has direct relevance to the analysis of cloud life cycles and to the detection of cloud motion vectors (CMVs). The proposed approach first identifies a homogeneous consistent cloud mass for tracking and then establishes motion correspondence within an image sequence. In contrast to the crosscorrelation based approach as adopted in automatic CMV detection analysis, a scale space classifier is designed to detect cloud mass in the source image taken at time t and the destination image at time t+δt. Boundaries of the extracted cloud segments are matched by computing a correspondence between high curvature points. This shape based method is capable of tracking in the cases of rotation, scaling, and shearing, while the correlation technique is limited to translational motion. The final tracking results provide motion magnitude and direction for each contour point, allowing reliable estimation of meteorological events and wind velocities aloft. With comparable computational expense, the scale space classification technique exceeds the performance of the traditional correlation-based approach in terms of reduced localization error and false matches View full abstract»

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  • Computation of storm-surge damage using distributed models and remote sensing data: a case study for the super cyclone in Orissa State, India

    Publication Year: 2002 , Page(s): 497 - 499
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (266 KB) |  | HTML iconHTML  

    This paper describes two spatial distributed models based on one-dimensional (1-D) energy balance equation to assess land surface damage caused by a storm surge. IRS LISS III and RADARSAT SAR data were used to generate critical model input parameters. The model's performance was validated for the Orissa super cyclone storm surge, India View full abstract»

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  • Fuzzy rule-based classification of remotely sensed imagery

    Publication Year: 2002 , Page(s): 362 - 374
    Cited by:  Papers (36)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (448 KB) |  | HTML iconHTML  

    The purpose of this paper is to investigate the applicability of fuzzy rule-based modeling to classify a LANDSAT TM scene from 1984 of an area located in the south of Germany. Both a land cover map with four different categories and an image depicting the degree of ambiguity of the classification for each pixel is the expected output. The fuzzy classification algorithm will use a rule system derived from a training set using simulated annealing as an optimization algorithm. The results are then validated and compared with a common classification method in order to judge the effectiveness of the proposed technique. It will also be shown that the proposed method with only nine rules for four different land cover classes performs slightly better than the maximum likelihood classifier (MLC). For error assessment, the traditional error matrix and fuzzy operators have been used View full abstract»

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  • A derivative-aided hyperspectral image analysis system for land-cover classification

    Publication Year: 2002 , Page(s): 416 - 425
    Cited by:  Papers (25)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (520 KB) |  | HTML iconHTML  

    The large number of spectral bands in hyperspectral data seriously complicates their use for classification. Selection of a useful subset of bands or derived features (spectral ratios, differences, derivatives) is always desirable, strongly affects the accuracy of the classification, and is often a practical necessity to keep the processing speed and memory requirements under control. This paper examines one possible procedure for selecting spectral derivatives to improve supervised classification of hyperspectral images. The procedure is designed to identify derivative features that are more effective at separating target classes and then add them to a base subset of features for classification. The goal is to create the smallest set of features that will result in the best classification result. A key issue in this process is the interplay of the number of features and the size of the training data sets since classification accuracy declines if the dimensionality of the feature space is too large relative to the number of training samples View full abstract»

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  • Comparison of GENIE and conventional supervised classifiers for multispectral image feature extraction

    Publication Year: 2002 , Page(s): 393 - 404
    Cited by:  Papers (30)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (421 KB) |  | HTML iconHTML  

    The authors have developed an automated feature detection/classification system, called GENetic Imagery Exploitation (GENIE), which has been designed to generate image processing pipelines for a variety of feature detection/classification tasks. GENIE is a hybrid evolutionary algorithm that addresses the general problem of finding features of interest in multispectral remotely-sensed images. The authors describe their system in detail together with experiments involving comparisons of GENIE with several conventional supervised classification techniques, for a number of classification tasks using multispectral remotely sensed imagery View full abstract»

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  • Development and validation of altimeter wind speed algorithms using an extended collocated Buoy/Topex dataset

    Publication Year: 2002 , Page(s): 251 - 260
    Cited by:  Papers (15)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (559 KB) |  | HTML iconHTML  

    The development and validation of altimeter wind speed algorithms is investigated following the collation of the largest dataset to-date of coincident altimeter/buoy open ocean measurements. Nonlinear relationships between buoy wind and Topex backscatter are fitted to the 4500 points dataset using least-squares (LSQ). The addition of altimeter significant wave height (SWH) information causes a small but significant reduction of about 10% in root-mean-square (rms) error. The new LSQ algorithms yield significant improvement of the global wind speed bias and rms error compared to earlier models, but describe the wind to backscatter relationship poorly at extreme wind speeds. Best results are obtained with the Gourrion et al. (2000) model, improving on the Witter and Chelton (WC91) (1991) model used operationally. A residual dependence on sea state persists in all wind algorithms, which underestimate winds in young sea conditions on average by 1-1.5 m/s. A case study confirms that ordinary LSQ attribute excessive weight to the peak of the wind speed histogram and yield algorithms with poor performance at extreme winds. Measurement errors are shown to greatly influence the fitted models performance, as accounting for normally distributed errors in both altimeter and buoy measurements with orthogonal distance regressions (ODRs) yields significant improvements View full abstract»

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  • On reconciling ground-based with spaceborne normalized radar cross section measurements

    Publication Year: 2002 , Page(s): 494 - 496
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (259 KB) |  | HTML iconHTML  

    This study examines differences in the normalized radar cross section, derived from ground-based versus spaceborne radar data. A simple homogeneous half-space model, indicates that agreement between the two improves as 1) the distance from the scatterer is increased; and/or 2) the extinction coefficient increases View full abstract»

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  • Analyzing low-frequency electromagnetic scattering from a composite object

    Publication Year: 2002 , Page(s): 426 - 433
    Cited by:  Papers (10)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (428 KB) |  | HTML iconHTML  

    In this paper, we present a method for solving electromagnetic scattering from a composite object at low frequencies using the method of moments (MoM) and loop-tree basis. Many applications involve composite objects which consist of several homogeneous regions. The loop-tree basis used for analyzing scattering from a homogeneous body at low frequencies could not be directly applied to analyze the low-frequency scattering from a composite object. In general, it is very difficult, if not impossible, to find a set of loop-tree basis functions that is valid for the structures on both sides of the interfaces. In this paper, we treat a composite object as a limiting case of multibody problem so that we could setup the MoM equation using the loop-tree basis found on each single body. A process is then developed to eliminate the redundant unknowns. The proposed method makes it possible to analyze low-frequency scattering from an arbitrary composite object. The validity and applications are illustrated with representative numerical examples View full abstract»

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  • A new method to separate ground clutter and atmospheric reflections in the case of similar Doppler velocities

    Publication Year: 2002 , Page(s): 239 - 246
    Cited by:  Papers (6)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (511 KB) |  | HTML iconHTML  

    This paper introduces a new ground clutter suppression technique which preserves weather echoes. This clutter suppression method uses both statistical and polarimetric properties of the target and clutter. This technique is intended for use in atmospheric studies for weather echoes the spectral properties of which do not differ much from those of ground clutter. This technique can be applied both to the total signal or to its separate Doppler frequency components View full abstract»

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  • Thermal analysis of buried land mines over a diurnal cycle

    Publication Year: 2002 , Page(s): 461 - 473
    Cited by:  Papers (11)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2409 KB) |  | HTML iconHTML  

    The passive infrared (IR) imaging signature of buried mines under three different soil surface conditions is investigated in this work. The three-dimensional (3-D) nature of the mine, the site, and the temporal attributes of surrounding climate and exposed radiation are accounted for with large and moderate-scale clutter surfaces as well as a smooth surface. The effect of the short- and long-wavelength radiation as well as the convective heat transfer is incorporated in this analysis and the temporal development of the temperature distribution over a diurnal cycle is presented for different surface conditions. The occurrence of false alarm mine spots is demonstrated using the moderate scale clutter surface and a critical period of time for the landmine signature is established for different soil surface conditions. The present results show that mines buried at moderate depths in the soil would not produce a direct signature View full abstract»

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  • A simplified method for estimating the total water vapor content over sea surfaces using NOAA-AVHRR channels 4 and 5

    Publication Year: 2002 , Page(s): 357 - 361
    Cited by:  Papers (6)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (256 KB)  

    A simplified method for estimating the total amount of atmospheric water vapor, W, over sea surfaces using NOAA-AVHRR Channels 4 and 5 is presented. This study has been carried out using simulated AVHRR data at 11 and 12 μm (with MODTRAN 3.5 code and the TIGR database) and AVHRR, PODAAC, and AVISO databases provided by the Louis Pasteur University (Strasbourg-France), NASA-NOAA, and Meteo France, respectively. The method is named linear atmosphere-surface temperature relationship (LASTR). It is based on a linear relationship between the effective atmospheric temperature in AVHRR Channel 4 and sea surface temperature. The LASTR method was compared with the linear split-window relationship (LSWR), which is based on a linear regression between W and the difference of brightness temperature measured in the same channels (ΔT=T4-TS). The results demonstrate the advantage of the LASTR method, which is capable of estimating W from NOAA-14 afternoon passes with a bias accuracy of 0.5 g cm-2 and a standard deviation of 0.3 g cm-2, compared with the W obtained by the AVISO database. In turn, a global bias accuracy of 0.1 g cm-2 and a standard deviation within 0.6 g cm-2 have been obtained in comparison with the W included in the PODAAC database derived from the special sensor microwave/imager (SSM/I) instrument View full abstract»

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  • Characterization and correction of a drift in calibration of the TOPEX microwave radiometer

    Publication Year: 2002 , Page(s): 509 - 511
    Cited by:  Papers (12)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (209 KB) |  | HTML iconHTML  

    Characterization of the drift in the 18-GHz brightness temperature (TB) measured by the TOPEX microwave radiometer (TMR) is presented. The appropriate correction is not a constant drift but varies with TB. Using this correction results in a more accurate path delay retrieval that varies appropriately with cloud cover and surface wind speed View full abstract»

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Aims & Scope

 

IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING (TGRS) is a monthly publication that focuses on the theory, concepts, and techniques of science and engineering as applied to sensing the land, oceans, atmosphere, and space; and the processing, interpretation, and dissemination of this information.

 

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Meet Our Editors

Editor-in-Chief
Antonio J. Plaza
University of Extremadura