ISSN:0143-1161    

DOI:10.1080/01431169308904305

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

The Landsat thermal band has been used to map the thermal pattern in three lakes of the English Lake District, Cumbria. The patterns arc clearly associated with the variations in the depth. The cause of the formation of this pattern is thought to be solar warming of water. The influence of water volume and altitude and the surface temperature and the relation among them were formalised in an equation involving 16 lakes.

ISSN:0143-1161    

DOI:10.1080/01431169308904306

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

This paper describes an experiment where sea water quality parameters were determined using data from the Landsat Thematic Mapper (TM) satellite remote sensing system over a coastal sewage outfall area. The parameters determined included turbidity, chlorophyll-a, chlorophyll-i, phaeopigment and total pigment. The area investigated was a sewage outfall site off the North Head of Sydney Harbour, Australia. The method used multiple regression to relate site sampled parameters to digital Landsat-TM data, and the results verified using data not used in the regression. Multiple correlation coefficients in excess of R = 0. 9 resulted from the regression analysis, which used Landsat-TM variables in a Chebyshev Series form. However due to the limited number of ocean samples only the results for turbidity were considered significant. Nevertheless a satisfactory methodology is proposed.

ISSN:0143-1161    

DOI:10.1080/01431169308904307

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

The microwave sensor SSM/I (Special Sensor Microwave/Imager) on board of the DMSP satellite can be used to develop a retrieval method for the water vapour content in the atmospheric boundary layer close to the sea surface, by means of radiative transfer calculations. It is found that the SSM/ I measurements are sufficiently sensitive to the water vapour w1in the lowermost 500 m of the atmosphere to allow a retrieval of w, from the 19, 22, 37 GHz vertical and 19 GHz horizontal polarization measurements with an accuracy of 0-06 g cm−The technique is validated with globally distributed radiosonde measurements located together with satellite soundings during the months July and August 1987. A linear relationship is established statistically to determine the near-surface specific humidity from w, with an accuracy of l-2gKg−1

ISSN:0143-1161    

DOI:10.1080/01431169308904308

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

Video imaging systems are noi radiometrically calibrated, thus it is difficult to obtain quantitative remotely-sensed imagery for natural resource applications. Video camera automatic gain controls (AGC) present potential problems in calibrating video systems for quantitative analysis because they compensate for changing solar illumination conditions. In this experiment aerial video calibrations to ground reflectance standards were compared for AGC turned on and off, The calibrated aerial video was evaluated for guinea grass (Panicum maximum L.) biomass treatments on two dates. Results showed that there was more atmospheric light scattering in the red than in the NIR video band. Light scattering affects could be detected only when the AGC was ofT because when AGC was on light scattering affects were masked. These results also showed that video imagery produced significant correlations with guinea grass biomass that were comparable to ground reflectance measurements.

ISSN:0143-1161    

DOI:10.1080/01431169308904309

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

Possible use of synthetic aperture radars (SAR) for monitoring agricultural canopies is investigated in this paper. Data have been acquired on the Orgcval watershed during the AGRISCATT'88 campaign. Four radar experiments were carried out with the airborne scattcrometer ERASME (C and X bands, HH and VV polarizations, multi-incidence angles). Simultaneous ground measurements (soil moisture, leaf area index, water content of the canopy) were conducted on 11 wheat fields. Backscattering coefficients of the canopies arc interpreted in the framework of semi-empirical ‘water-cloud’ models. A simple paramctrization of the angular effect of soil roughness is introduced, allowing the simultaneous use of multi-incidence angle radar data. With a unique set of parameters for each radar configuration ‘ frequency and polarization’ the water-cloud model appears to describe adequately the backscattering of all the fields, over the range of incidence angles. It is shown that in this case, attenuation is the dominant effect of the vegetation and an inversion algorithm is proposed for estimating the water content of vegetation. This algorithm requires measurements at two different incidence angles and various combinations of radar configurations are then tested.

ISSN:0143-1161    

DOI:10.1080/01431169308904310

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

We applied the Santa Barbara canopy backscatter model to model radar backscatter from mangrove forest stands in the Ganges delta of southern Bangladesh, and assessed the feasibility of delineating flooding boundaries within the stands. Modelled L-band (0-235 m wavelength) HH backscatter showed that canopy volume scattering dominated for stands under nonflooded ground surface. Double bounce trunk-ground term were enhanced by the presence of water under trees. For flooded mangrove forest, the trunk-ground term was dominant at small radar incidence angles; the trunk-ground term dominancy reduced as the incidence angle increased. Shuttle Imaging Radar (SIR-B) data and model results showed that for the mangrove forest, radar data with small incidence angles should be used to delineate the flooding boundaries.

ISSN:0143-1161    

DOI:10.1080/01431169308904311

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

The unified full wave approach is used to generate polarimctric images of composite rough surfaces illuminated by high resolution radar (i.e., real or synthetic aperture radars with small effective footprints). The unified full wave solutions account for Bragg scattering and specular point scattering in a self-consistent manner, therefore it is not necessary to decompose the surface into two surfaces with large and small roughness scales. The like and cross-potarized scattering cross-sections for the rough sea surface are tilt modulated due to the presence of swell or ship wakes. Hydrodynamic effects such as velocity bunching arc not considered here. The normal to an arbitrarily oriented mean plane associated with the illuminated resolution cell (pixel) is characterized by the tilt angles Q and t, in and perpendicular to, a fixed reference plane of incidence associated with the radar. The like and cross polarized backscatter cross sections of a tilted resolution cell are expressed in terms of the angle of incidence θ”in the fixed reference coordinate system, the tilt angles of the resolution cell O and r, and elements of the Phase (Mueller) matrix that completely characterizes electromagnetic scattering from an untitled resolution cell.

ISSN:0143-1161    

DOI:10.1080/01431169308904312

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

Due to soil erosion processes fertile soils are washed out almost anywhere in the world. Soil erosion protection measures are necessary, especially for food security reasons. This study uses the well-known Universal Soil Loss Equation (USLE) to assess the long-term soil erosion in a small catchment area and to simulate various soil protection alternatives. After completion at this test site the techniques can be applied for larger regions to detect areas that are most afTected by soil erosion and to guide precisely the efficient soil erosion prevention measures that proved to be valuable according to the computer simulation results.

ISSN:0143-1161    

DOI:10.1080/01431169308904313

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

Abstract. A regional survey (1978-1982) in the Virunga National Park (Zaire) led to the mapping of land systems with the help of aerial photographs and fieldwork, following the morphopedological approach. The use of classification techniques on Landsat Thematic Mapper data (1987 scene) enabled us to assess the detectability of the morphopedological limits.

ISSN:0143-1161    

DOI:10.1080/01431169308904314

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor