ISSN:0143-1161    

DOI:10.1080/014311697217288

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

The Spaceborne Imaging Radar-C, X-Band Synthetic Aperture Radar (SIR-C/X-SAR) was the first multi-frequency and multi-polarization SAR system to be launched into space. SIR-C/X-SAR imaged over 300 sites around the Earth returning 143 terabits of data. There has been a tremendous advancement of knowledge in the field of radar remote sensing accomplished in the last two years, as well as verification of earlier findings since the two successful SIR-C/X-SAR missions. This review article presents the current status of optimal SAR parameters for various key issues within the disciplines of ecology, geology, hydrology, and oceanography. A polarimetric X- and L-band radar is suggested as a result of our review for future SAR sensors. The design of a single frequency, albeit polarimetric, SAR satellite, limits applications, as can be deduced from the tables.

ISSN:0143-1161    

DOI:10.1080/014311697217297

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

A number of new geological structures have been revealed in the Great Nicobar Island, Indian Ocean, from the analysis of airborne synthetic aperture radar (SAR) data. The advantages of SAR images for mapping geological structures over other images for the Great Nicobar Island, the southern most island of Andaman-Nicobar arc, have been highlighted. A visual analysis of lineaments in the southern part of the Great Nicobar Island using SAR and Landsat TM colour composites, TM bands 2, 3, and 4, and TM bands 4, 2 and SAR, reveals a wealth of structural information not shown on previous maps. Other identified features include lithological units derived from landforms, northwest-southeast trending faults, faults trending towards the mouth of Galathea river, the graben valley, and many other new faults. The geological features reported in this work were verified using limited ground checking.

ISSN:0143-1161    

DOI:10.1080/014311697217305

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

The Jinchuan intrusion, situated in the Gansu province of China some 30 km NE of Yongcang city is an ultramafic dyke-like body emplaced in the Longshoushan uplifted terrain on the southwest margin of the Sino-Korea platform. The intrusion is 6 km long, 35 m wide and hosts a major Ni-Cu sulfide deposit. The main stratigraphic units include the highly metamorphosed Lower Proterozoic Longshoushan group and the less extensively metamorphosed Dongzigou and Hanmushan groups of Middle and Upper Proterozoic age. The Longshoushan group consists of serpentine marble, schist, gneiss and plagioclase amphibolite. The Dongzigou group comprises schists and granitic rocks. The Hanmushan group basically is represented by a large variety of volcanics. Small mafic-ultramafic intrusions are located along faults in the Jinchuan terrain. These ultramafic rock bodies show a concentric zoning with a core of dunites and olivine pyroxenites forming the margins of the bodies. Hydrothermal alteration (mainly serpentinization) has affected the rocks of the ultramafic bodies to a variable extent; the dunites are extensively altered whereas the pyroxene rich units are relatively fresh. Field spectroscopy is used to spectrally characterize the major rock units. Imaging spectrometer data was flown during the end of July until beginning of August of 1993 with a Chinese imaging spectrometer instrument called MAIS: the Modular Airborne Imaging Spectrometer. Feature characterization permits lithologic mapping from MAIS data. This aids in mineral potential mapping in the Jinchuan region and permits the identification of areas of possible Ni-Cu deposits.

ISSN:0143-1161    

DOI:10.1080/014311697217314

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

Land surface characteristics: soil and vegetation and rainfall inputs are distributed in nature. Representation of land surface characteristics and inputs in models is lumped at spatial scales corresponding to the grid size or observation density. Complete distributed representation of these characteristics or inputs is infeasible due to excessive computational costs or costs associated with maintaining dense observational networks. The measurements of microwave brightness temperatures by the SSM/I (Special Sensor Microwave Imager) are at resolutions of the order of 56km 56km for 19 GHz and 33 km 33 km for 37 GHz. At these resolutions, soil moisture and vegetation are not homogeneous over the measurement area. The experiments carried out in this study determine the effect of heterogeneities in vegetation (leaf area index) and input rainfall on simulated soil moisture and brightness temperatures and the inversion of brightness temperatures to obtain soil moisture estimates. This study would help us to understand the implications of using the SSM/I microwave brightness temperatures for soil moisture estimation. The consequences of treating rainfall inputs and vegetation over large land surface areas in a lumped fashion is examined. Simpler methods based on dividing the leaf area index or input rainfall into classes rather than explicit representation for representing heterogeneities in leaf area index and spatial distribution of rainfall is tested. It is seen that soil moisture is affected by the representation (lumped vs distributed) of rainfall and not leaf area index. The effect of spatially distributed soil moisture on the inversion of observed SSM/I brightness temperatures to obtain soil moisture estimates is investigated. The inversion process does not exhibit biases in the retrieval of soil moisture. The methodology presented in this paper can be used for any satellite sensor for purposes of analysis and evaluation.

ISSN:0143-1161    

DOI:10.1080/014311697217323

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

POLDER (POLarization and Directionality of the Earth's Reflectances) is a new instrument devoted to the globalobservation of the polarization and directionality of solar radiation reflected by the Earth surface-atmosphere system. This radiometer has been on board the Japanese ADEOS platform since August 1996. This paper describes the main algorithms of the POLDER 'Earth radiation budget (ERB) & clouds' processing line used to derive products on a routine basis in the early phase of the mission. In addition to the bidirectional reflectance and polarization distribution functions, the main products will be the cloud optical thickness, pressure (from two different methods) and thermodynamic phase. Airborne POLDER observations support the present algorithms for the cloud detection and the derivation of cloud properties.

ISSN:0143-1161    

DOI:10.1080/014311697217332

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

The bidirectional reflectance effects in NOAA AVHRR data have been investigated for forest and pasture sites in New Zealand. The impact of surface anisotropy has been examined for channel 1, channel 2, and the derived Normalized Difference Vegetation Index (NDVI) over a 14-day period in the southern hemisphere summer of 1992/1993. Results show a bidirectional effect which persists through atmospheric correction processing and the generation of the NDVI. Comparison is made with previously published results and models, which show consistency for this limited data set.

ISSN:0143-1161    

DOI:10.1080/014311697217341

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

The in-flight absolute calibration of spaceborne instruments working in the solar reflective region (0.4-2.5 mu m) has often been performed with large uniform ground areas, such as White Sands, U.S.A., or La Crau, France. The method presented here describes an alternative for high spatial resolution sensors employing artificial small ground targets. The required target size is seven times the size of the sensor's spatial resolution, the ground projected instantaneous field-of-view (GIFOV), if the Gaussian full width 2 sigma of the image point spread function (PSF), atmospheric blurring removed, is less or equal to 1.5 * GIFOV. For near-future multispectral instruments with a spatial resolution of 1 to 10 m the required ground reference areas with very homogeneous reflectance properties will be sized 7 m * 7 m to 70 m * 70 m, respectively. The proposed method can also be employed for panchromatic sensors.

ISSN:0143-1161    

DOI:10.1080/014311697217350

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

Data on mineralogy and diffuse reflectance spectra, obtained from 56 samples of Brazilian lateritic soils, were used to establish quantitative relationships between spectral parameters and iron oxides contents (hematite and goethite). A redness index RI H calculated from Helmholtz chromatic co-ordinates ( lambda d, P e, Y) and correlated to hematite content is found. A good estimate of the ratio Hematite/ (Hematite + Goethite) is given by the dominant wavelength lambda which takes into account a large proportion of the tint detected on the soil sample. Based on these laboratory results, radiometric indices were elaborated by combining only those parts of the visible spectrum that correspond to Thematic Mapper (TM) channels: (i) a hematite index I Hm to estimate hematite concentration; and (ii) a ferric index I Fe to estimate the ratio hematite/(hematite goethite). The hematite index, applied to a TM image of the area around Brasilia, allowed hematite contents in the surface horizons of lateritic soils to be mapped accurately.

ISSN:0143-1161    

DOI:10.1080/014311697217369

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

A procedure is presented for ground water exploration in terms of depth and quality in an alluvial terrain with shallow groundwater occurrence. The study area forms a part of the marginal Gangetic terrain with a clay-sand sequence. Variation in groundwater quality has been mapped in earlier research on the basis of field sampling and chemical analysis of groundwater. In the present study, a scheme of image processing and GIS techniques using false colour composites, vegetation indices, density slicing, image registration, overlaying, and supervised classification has been applied on IRS-1B LISS II data. Various zones established within the terrain based on our research are in conformity with ground water salinity and depth contours.

ISSN:0143-1161    

DOI:10.1080/014311697217378

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor