As urban area undergoes a rapid change it will be necessary to review development and the urban plans once in five years in relation to important public and other decisions taken from time to time. In order to know th...
Collinear analysis technique is widely used for determining sea surface variability with Geosat altimeter data from its Exact Repeat Mission (ERM). But most of the researches have been only on global scale or in ocean...
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Collinear analysis technique is widely used for determining sea surface variability with Geosat altimeter data from its Exact Repeat Mission (ERM). But most of the researches have been only on global scale or in oceans deeper than 2000 m In shallow shelf waters this method is hampered by the inaccuracy of ocean tide data supplied with Geosat Geophysical Data Records (GDRs). This work uses a modified collinear analysis technique characterized by simultaneous separation of mean sea level and ocean tide with the least squares method, to compute sea surface variability in the Northwest Pacific Ocean and eastern China Seas. The mean sea level map obtained contains not only bathymetric but also dynamic features such as amphidromes, indicating considerable improvement over previous works. Our sea surface variability maps show dearly the main current system, the well-known Zhejiang coastal upwelling, and a northern East China Sea meso-scale eddy in good agreement with satellite sea surface temperature (SST) bservation and historical in situ measurement. These all suggest that meaningful and reliable oceanographic results can still be achieved in shallow shelf waters from Geosat altimetry as long as proper data processing techniques are applied.
remotely-sensed satellite data of Landsat 5 (TM) and IRS-1A (LISS II) covering parts of central portion of Chotanagapur plateau have been analysed visually to delineate some prominent lineaments in Ranchi district and...
Mapping and monitoring of land degradation processes such as soil erosion has become an important task for both agricultural and environmental planners. The potential of using SPOT-HRV data for assessing the types of ...
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Mapping and monitoring of land degradation processes such as soil erosion has become an important task for both agricultural and environmental planners. The potential of using SPOT-HRV data for assessing the types of soil erosion and land degradation is obvious. The spectral information and the spatial resolution of the multispectral data allow a high accuracy in local mapping and rapid regional assessment. In Basilicata, southern Italy, spectral mixture modelling (end-member techniques) has been applied to extract relevant information for assessing soil erosion. This method allows an estimate of the proportion of surface cover types (end-members) within the pixel. From the data sets average spectral responses were extracted for growing vegetation, non-green sclerophylous vegetation mixed with dry grasses and bare soil. Using these spectra as end-members in the model, it was possible to decompose the spectral information of all pixels into the three surface components, giving the percentage cover of the three types within every pixel. Classification of the pixels according to the percentage of surface cover or bare soil allows an assessment of erosion or erosion risk.
The sea ice backscatter signature observed in images of the ERS-1 SAR depends on a large number of geophysical parameters, some of which may vary considerably. Backscatter modeling is a useful tool, to investigate the...
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The sea ice backscatter signature observed in images of the ERS-1 SAR depends on a large number of geophysical parameters, some of which may vary considerably. Backscatter modeling is a useful tool, to investigate the sensitivity of radar signatures to various ice properties. Scattering models must be developed on the basis of ground based radar observations which are linked with ice characterization measurements. Results of model simulations help to specify constraints on observations using a single-frequency single polarization SAR as the one onboard ERS-1. This presentation will illustrate various sea ice conditions using backscatter modeling for the interpretation.< >
GMS-4/VISSR and NOAA-10/AVHRR data of Mt. Pinatubo area taken on June 15, 1991 reveal an aspect of the stratospheric diffusion of erupted volcanic dust. Erupted dust or Gasses reached a height of about 34 km above sea...
Radio occultation studies of the terrestrial atmosphere are possible through the use of signals transmitted by satellites of the Global Positioning System (GPS) and received by one or more other satellites in low eart...
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Radio occultation studies of the terrestrial atmosphere are possible through the use of signals transmitted by satellites of the Global Positioning System (GPS) and received by one or more other satellites in low earth orbit (LEO). The perturbed phase of the occulted signal gives direct information on the refractivity profile in the region of occultation, from which vertical profiles of density, pressure and temperature can be retrieved. The technique requires the use of the dual GPS frequencies in order to isolate and remove most of the ionospheric effect. Analysis of the effect of the ionosphere and methods of removing it will be presented. For the recovery of atmospheric profiles, two major issues are addressed. The first is how accurately can refractivity be retrieved for a region in which there is a large horizontal refractivity gradient;the second considers the separation of temperature and moisture in the lower troposphere. Based on model simulations, the capability of GPS to provide atmospheric profiles is assessed.
Spaceborne synthetic aperture radar (SAR) provides the possibility of producing topographic maps and cartographically corrected radar images using an interferometric method. The technique requires two SAR images of th...
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Spaceborne synthetic aperture radar (SAR) provides the possibility of producing topographic maps and cartographically corrected radar images using an interferometric method. The technique requires two SAR images of the same area gathered from slightly separated positions. The interferometric baseline may be optimized to minimize the topographic altitude error. This paper investigates the altitude error caused by the radar system and by the topography, and simulates an interferometric measurement based on ERS-1 SAR parameters. It is found that the terrain topography has a significant effect on the height error, which in many cases is more severe than baseline decorrelation.
The automatic mapping of land cover from satellite imagery requires optimal classification and spatial generalization procedures. Here we describe the use of functional ink neural networks, based on a flat perceptron ...
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ISBN:
(纸本)0819411779
The automatic mapping of land cover from satellite imagery requires optimal classification and spatial generalization procedures. Here we describe the use of functional ink neural networks, based on a flat perceptron net with an augmented feature vector, to generate high accuracy classification products. These can then be trained more rapidly than multi-layer perceptrons. The network output is then used to fix land cover class area statistics which control a low-level generalization procedure based on a combined iterative majority filtering and reduced class growing procedure.
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