ISSN:0143-1161    

DOI:10.1080/01431168608954674

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

Nine distinct surface types have been identified by comparison of SEASAT SAR imagery with field observations in the Askja Caldera region of central Iceland. A map of radargeological surface type is presented, together with field descriptions and discussion of the influence of the surface types on radar signal return. Surface relief, surface roughness and clast size were found to have the greatest importance for imageinterpretation.

ISSN:0143-1161    

DOI:10.1080/01431168608954675

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

The objective of this paper is to review current knowledge concerning synthetic aperture radar applications to crops in Canada. Following a brief overview of studies during SURSAT (1978-1980) and RADARSAT (1981 and later) projects, several issues are considered. These include crop-classification accuracies achieved with SAR or SAR and VIR data at various sites, the importance of crop and soil parameters affecting SAR images, the procedures for digital SAR image analysis and the relationship between airborne SAR data and future satelliteSAR data. Finally, recent developments of new ground and airborne microwave instruments to be used in agricultural studies are described.

ISSN:0143-1161    

DOI:10.1080/01431168608954676

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

With the improvement in spatial resolution of thermal sensors over the past decade the employment of thermal infrared satellite data for soil and surface-material survey has become increasingly attractive. The individual orbital characteristics of each satellite provide the opportunity of acquiring monotemporal (same day, one time), multitemporal (same day, different times) and multidate (different days, same time) imagery. The time at which such imagery is acquired is of great importance since the emitted thermal response of any natural material is a function not only of the material's emissivity, but also of its temperature at the time of imaging. The implications of acquiring monotemporal, multitemporal and multi-date thermal infrared data are discussed in relation to thermal sensors in past, current and future satellites.

ISSN:0143-1161    

DOI:10.1080/01431168608954677

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

The perpendicular vegetation index (PVI) and normalized difference vegetation index (NDVI) were calculated from Mark II radiometer RED (0.63-0.69 μm) and NIR (0.76–0.90 μ) bidirectional radiance observations for wheat canopies. Measurements were taken over the plant development interval flag leaf expansion to watery ripeness of the kernels during which the leaf area index (LAI) decreased from 40 to 2-5. Spectral data were taken on four cloudless days five times (09.30, 11.00, 12.30, 14.00 and 15.30 hours (central standard time, C.S.T.) at five view zenith, Zv (0, 15, 30,45 and 60°) and eight view azimuth angles relative to the Sun, Av(0, 45, 90, 135, 180, 225, 270 and 315°). The PVI was corrected to a common solar irradiance (PVIC) based on simultaneously observed insolation readings.

ISSN:0143-1161    

DOI:10.1080/01431168608954678

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

Off-nadir remote sensing of vegetation can cause undesirable variability in measured spectral reflectance resulting from non-Lambertian characteristics of the canopy. The Suits model of radiative transfer in a vegetation canopy was evaluated as a means to simulate this variability. Comparison was made between model calculations and reflectance of a salt marsh cord grass canopy measured under a variety of solar- and viewing-angle conditions using an in situ radiometer. The model was effective in simulating both the sense and magnitude of reflectance changes due to variable angles of observation. However, the model did not reproduce the observed dependence of nadir canopy reflectance on solar zenith angle. A simple subtractive normalization procedure resulted in high correlation of modelled red and infrared reflectance with values measured at observation angles varying from 10 to 60° off-nadir and with solar zenith angles ranging from 18 to 55°. The modelling procedure was extended to simulate view-angle effects on aircraft scanner imagery of a coastal marsh with good results despite significant variability in biomass and leaf-area index of cord grass within the imaged area. Modelling appears to have potential in predicting view-angle effects and in reducing angular variability in remotely sensed data derived from aerial and orbital sensors.

ISSN:0143-1161    

DOI:10.1080/01431168608954679

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

The observed rise of the concentration of carbon dioxide over the last 30 years has intensified interest in the study of the global carbon cycle. The key role of vegetation in this cycle is clearly demonstrated by the semi–annual variations of the carbon dioxide concentration in a given hemisphere. The primary variables of interest are the net primary productivity and the biomass on a global scale and the key to their estimation is the leaf-area index (LAI). A global determination of the LAI is practical only with remote-sensing satellite systems. A hierarchical approach to obtaining a LAI map of deciduous boreal forests, which contain a significant part of the total global carbon reservoir using satellite data is presented. The results show that it is very important to understand the nature of the basic physical interaction of solar radiation with canopy biophysical characteristics, if meaningful estimates of these variables are to be made. This understanding has been achieved using ground, helicopter and aircraft measurements made very near to the area covered by the LANDSAT satellite.

ISSN:0143-1161    

DOI:10.1080/01431168608954680

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

Satellite remote sensing provides a means of providing knowledge and inventory of natural resources in developing countries. This theme is examined in relation to Tunisia, and general conclusions drawn.

ISSN:0143-1161    

DOI:10.1080/01431168608954681

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

ISSN:0143-1161    

DOI:10.1080/01431168608954682

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

ISSN:0143-1161    

DOI:10.1080/01431168608954683

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor