摘要:

Focusing of a monochromatic ocean wave image by either a regular or an interferomeric SAR (INSAR) is studied. The model developed simulates the images of both SAR and INSAR for an arbitrary focus setting. The effects of the various operational parameters, i.e., integration and scene coherence times, ocean wave length, direction and amplitude, etc., on the focus sensitivity of both SAR and INSAR is examined. A dimensionless focusing parameter a which depends on the platform velocity and on the azimuthal component of. the phase velocity of the imaged ocean wave is introduced. It is shown that a is the major parameter which determines the image contrast of the regular SAR output, as well as that of the magnitude and the phase components of INSAR. The focus sensitivity, however, is also a function of the imaged ocean wave parameters. The effects of the varying SAR integration time and of the scene coherence time on the contrast of the resulting image is also examined.

ISSN:0143-1161    

DOI:10.1080/01431169508954452

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

An atmospheric correction algorithm due to Deschampset al.(1981) has been applied to MEIS-II data. Some atmospheric conditions such as continental and maritime aerosol models have been used in this work. Simulation on 5S code was made with Thematic Mapper Band 4 and Spot band 3. All these pieces of the puzzle permitted the qualification of algal concentration in an intertidal area, which was the aim of this work. Continental or maritime aerosol models gave a similar result due probably to the specific area, located between land and nearshore. Apparent radiance is smaller than corrected radiance because absorption process takes place in this part of the spectrum (0.8 to 0.9μm). When apparent radiance is higher than 30 Wm−2sr−1μm−1algal concentration is overestimated by up to 60 per cent.

ISSN:0143-1161    

DOI:10.1080/01431169508954453

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

A white light optical fibre fluorosensor for water quality measurements of the phytoplankton population is reported. The excitation light is amplitude modulated and a phase sensitive detection system is employed. The spectral properties of two typical samples of phytoplankton obtained off the coast of Scotland have been characterised and used in laboratory tests of the fluorosensor. Initial results show that this system is capable of resolving fluorescein concentrations in water of 10−8mol 1−1and phytoplankton populations of 0.1 μgl.

ISSN:0143-1161    

DOI:10.1080/01431169508954454

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

A major issue when using NOAA AVHRR derived NDVI data in terrestrial applications is the acquisition of sufficient ground information lo relate to NDVI. The usual method of acquiring pasture productivity ground data is from pasture-cuts beneath movable cages. In this study, milk fat production data collected daily from dairy farms in three 25 km2study sites in New Zealand is used as a surrogate for pasture production. The results show a probable causal relation between the AVHRR-derived NDVI and milk fat production and identify a need to use farm production models to further quantify the relationship. Our aim is to use successive years NOAA AVHRR data to monitor trends in pasture and milk fat production.

ISSN:0143-1161    

DOI:10.1080/01431169508954455

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

Assessment of regional soil moisture conditions is important for agricultural water management, crop yield modelling and meteorological and climatic studies. This paper presents the results of an integrated remote sensing-based modelling study to estimate and map root-zone soil moisture potential, using a soil-plant system-heat and moisture balance model. The model utilizes satellite derived surface temperature, albedo, land cover and soil textural data bases and ground collected agro-meteorological data as inputs.

ISSN:0143-1161    

DOI:10.1080/01431169508954456

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

Radiometric data from an airborne scanner have been obtained for a grazing experiment on dune grassland. The experiment consists of 32 fenced plots exposed to a range of sheep grazing intensities. Differential grazing intensities have changed the vegetation since the experiment was set up, and there are positive correlations between sheep population densities and both near-infrared and thermal-infrared radiance levels within each of the two different grassland communities (dune ridge and dune slack) of the experiment. These grazing-induced differences are of a similar magnitude to the radiometric differences between ridge and slack vegetation. The implications for using remote sensing to monitor grazed vegetation are discussed.

ISSN:0143-1161    

DOI:10.1080/01431169508954457

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor