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Geoscience and Remote Sensing, IEEE Transactions on

Issue 2 • Date April 1982

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Displaying Results 1 - 20 of 20
  • [Front cover - IEEE Transactions on Geoscience And Remote Sensing]

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  • IEEE Geoscience And Remote Sensing Society

    Page(s): c2
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  • Table of contents

    Page(s): nil1
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  • Estimation of Atmospheric Species Concentrations from Remote Sensing Data

    Page(s): 142 - 153
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    A basic problem in the interpretation of atmospheric remote sensing data is to estimate species concentration distributions. Typical remote sensing data involve a field of view that moves across the region and represent integrated species burdens from the ground to the altitude of the instrument. The estimation problem arising from this special measurement configuration is solved based on the partial differential equation for atmospheric diffusion and Wiener-Hopf theory. The estimation of the concentration distribution downwind of a hypothetical continous ground-level source of pollutants is studied numerically. View full abstract»

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  • Detection of Regional Air Pollution Episodes Utilizing Satellite Digital Data in the Visual Range

    Page(s): 154 - 158
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    A comparative analysis of satellite digital data in the visual range and ground-based aerosol measurements was carried out for July 21 and 22, 1978, representing a significant pollution episode based on low surface visibility and high sulfate levels. Quantitative information on total aerosol loading derived from the satellite digitized data using an atmospheric radiative transfer model agrees well with the results obtained from the ground-based measurements. It is also shown that the extent and transport of the haze pattern can be monitored from the satellite data over the period of maximum intensity of the episode. The model simulation demonstrates the potential of utilizing satellites to monitor both the magnitude and areal extent of pollution episodes. View full abstract»

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  • On the Information Time Scale of Geophysical Records in Maximum Entropy Spectral Analysis

    Page(s): 158 - 161
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    The length of maximum entropy spectral analysis (MESA) filter M must be such that it contains all, and only, the physical information. A new original, conceptually simple criterion is suggested for estimating M on the basis of intrinsic memory time of the signal that is obtained from the autocovariances ÿt by means of the following quantity: begin{equation*}frac{Sigma_t |phi_t|}{phi_0}.end{equation*} This approach appears particularly suitable when it is applied to geophysical data set. View full abstract»

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  • Enhancement of Poles in Spectral Analysis

    Page(s): 161 - 168
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    This paper presents a new technique for detecting a small pole in the presence of a nearby strong pole. By simultaneously applying the chirp z-transform (CZT) and a recently developed window, the new technique is shown to be able to detect and resolve a small pole. The CZT is efficient since it employs the fast Fourier transform (FFT) to evaluate a convolution. But unlike the FFT which is limited to the evaluation of the spectrum on the jw-axis, the CZT can evaluate the z-transform on the whole complex plane. And with the use of the new window, which is designed to have a near-sidelobe level of any specified value, the CZT is shown to be able to resolve two closely spaced poles with a large difference in amplitudes. Unlike the Prony's method, the new technique does not require predetermining the system order. No matrix inversion or solution of polynomial roots is required. Further, the new technique is a linear operation. Thus even under noisy environments it yields accurate, stable results for extraction of poles from transient response data. View full abstract»

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  • Digitizing Methods And Errors in Conductivity-Temperature-Depth Systems

    Page(s): 168 - 173
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    Digitizing is a critical process because loss of resolution or inaccuracy introduced at this point cannot be rectified. It is suggested that conductivity-temperature-depth (CTD) systems ideally should measure these parameters to a precision of at least 150 ppm. Digitizing methods employed in CTD systems are discussed and evaluated. A worst-case error analysis of several CTD systems is presented. It is shown that two of the digitizing methods are less suitable than the others when errors and other factors are taken into consideration. View full abstract»

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  • Application of Legendre Transform for Decorrelation of Random Variables

    Page(s): 174 - 177
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    Karhunen-Loeve (K-L) transform yields a set of uncorrelated random variables from a set of correlated random variables of a data vector. However, K-L transform is computationally not efficient and hence other fast transforms have been investigated for use in their place. Possible use of Legendre transforms in this application has been investigated. View full abstract»

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  • A System Design for a Multispectral Sensor Using Two-Dimensional Solid-State Imaging Arrays

    Page(s): 177 - 179
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    The architecture of a system for the simultaneous capture of up to four images from solid-state two-dimensional image sensors is described. The system has been developed for remote sensing from light aircraft in the 400-1100-nm wavelength range. Software generation of sensor drive signals is incorporated in the system. View full abstract»

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  • On the Electromagnetic Interference Fringes Method in Geophysical Prospecting Applications

    Page(s): 180 - 188
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    The method of electromagnetic interference fringes for the prospecting of conductive subsurfaces inside the earth is reviewed. The fields radiated by an electrically small horizontal loop situated on the earth's surface are derived and expressed in terms of different interfering wave components. The variable distance interference fringes (VDIF) method and the variable frequency interference (VFIF) method of prospecting are considered, and an interpretation procedure using the data obtained from both methods is suggested. View full abstract»

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  • Locating a Buried Magnetic Dipole

    Page(s): 188 - 192
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    Five measurements of the magnetic-field vector near the surface of the earth are shown to be sufficient to determine the orientation and location of a buried magnetic dipole. A discussion of field experiments which demonstrate the location concept is included. View full abstract»

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  • Electric Drill Stem Telemetry

    Page(s): 193 - 197
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    Use of the drill stem-earth system for electric down-hole-to- surface telemetry at low frequencies is considered in this article. Estimates of signal attenuation for both the perfectly conducting drill stem and a drill stem with finite conductivity are obtained and compared with previously reported work. It appears that a link of several kilometers length can be operated at frequencies in the hertz range in 10-100-¿ · m earth at power levels of the order of a few watts. View full abstract»

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  • Electromagnetic Coupling Between Parallel Lines on a Uniform Earth

    Page(s): 197 - 200
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    Electromagnetic (EM) coupling between parallel lines on a uniform earth influences the results of induced polarization and electromagnetic surveys This paper presents a simplified analysis which allows a fast calculation of EM coupling in the time domain for the dipole-dipole and Schlumberger arrays. The simplified results are in good agreement with the results of other workers. View full abstract»

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  • First Comparisons of Rainfall Rates Derived from Radar Differential Reflectivity And Disdrometer Measurements

    Page(s): 201 - 204
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    A comparison between radar-derived rainfall rates and those obtained from a ground-based disdrometer located at the radar site is presented. The radar measurements were made in the vicinity of Chicago, IL, on August 2, 1978, with the CHILL radar of the Illinois State Water Survey. Three radar-derived profiles of rainfall rate versus distance from the radar were obtained for a single storm in the direction of the storm path toward the radar. These profiles indicated the storm motion and the variability of rainfall as the storm progressed toward the radar. The last two profiles support the hypothesis that the storm was in steady state as it passed over the radar site. This provided an opportunity to compare the radar-derived rates with an apparent rate versus distance profile derived from a disdrometer time record of rainfall rate obtained at the radar site. Excellent agreement between the radar and disdrometer measurements of rainfall resulted. View full abstract»

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  • The Recognition of Extended Targets: SAR Images for Level And Hilly Terrain

    Page(s): 205 - 211
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    An experiment was performed using radar image simulation techniques to determine what a SAR image would look like for a collection of area extensive targets, first with flat underlying terrain and second, in the presence of moderate relief. Although compression, layover, and shadow are well known from the one-dimensional geometry analyses, it has not been previously demonstrated in a pictorial fashion what happens to the appearance of the same controlled reflectivity pattern, for level and hilly ground. It is not surprising to radargrammetrists that even modest elevation changes seriously affect the detection and recognition of boundaries and shapes. The image results clearly demonstrate these effects, and are valuable for many researchers who have previously used, or are just beginning to apply SAR imagery to crops and soils, minerals, and water resources assessment, etc. This research was performed during the course of an investigation to establish the performance of the Seasat-A SAR, in terms of user-oriented features, thus the radar system model and geometry are pertinent to that sensor, although the results can be applied to radar imaging in general. A review of range perspective imaging is included, since information extraction from radar imagery necessitates the knowledge of geometry/propagation effects. View full abstract»

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  • Radar Scattering from a Diffuse Vegetation Layer over a Smooth Surface

    Page(s): 212 - 216
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    A simple model is presented for the oblique backscatter and bistatic scatter from a smooth surface overlain by a diffuse layer. Only single scattering in the diffuse layer is taken into account. The model analysis shows that the combination of volume scattering and oblique reflection at the surface may increase appreciably the waves scattering. The scattering strongly depends on the properties of the smooth surface. These results support some of the observations made with the Seasat spaceborne imaging radar over flooded regions with heavy vegetation cover. View full abstract»

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  • Retrieval of Ocean Surface And Atmospheric Parameters from Multichannel Microwave Radiometric Measurements

    Page(s): 217 - 224
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    This paper discusses the retrieval from Scanning Multichannel Microwave Radiometer (SMMR) data of ocean surface temperature, surface wind speed, rain rate, cloud height, and the amount of water vapor and nonprecipitating liquid water over the ocean. The sensitivity of the algorithms that retrieve the wind speed and seasurface temperature in the absence of rain to the (undetected) presence of rain, and the accuracy of a more general method that retrieves rain rate along with other meteorological parameters are discussed. These investigations are based on models of the microwave emission from the Earth's atmosphere over the ocean in the presence of rain. The modeling technique and the retrieval methods are also discussed. View full abstract»

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  • Information for authors

    Page(s): 224a
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  • Institutional listings

    Page(s): 224b
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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.

 

Full Aims & Scope

Meet Our Editors

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