The aim of this study has been to derive quantitative sediment information on Amazonian rivers from photographic transparencies of Landsat multispectral scanner data covering the spectral range 0.5 to 1.1 rm. Various factors such as scattering and absorption, determining the volume reflectance of a water body are discussed with particular emphasis on the significance of particle size to Mie scattering by suspended particles. The changes in signal due to atmo~pheric conditions are.exRDined. Ratios of signals in selected spectral bands are shown to be effective in measurinG suspended sediment in individual North American water bodies suppressing atmospheric and solar elevation effects. The question of extrapolation of this technique between areas and the constraints involved are analysed. The errors involved in extracting signal values from NASA transparencies are estimated by comparing computer compatible tape and transparency derived values. Suspended sediment values are estimated for Amazonia using a calibration from North American water bodies. Comparisons with field measurements show the broad validity of this technique. Seasonal and downstream variations are investigated for some of the princip~l tributaries as are the problems of vertical and horizontal variations in the river cross sections. The Amazonian sediment values are used as part of a broad classification of Amazonian rivers including a discussion of their morphologies. Concentrations of suspended sediment estimated for the tributaries rising in the Andes and its foothills are found to be much higher than those for tributaries originating in the Brazil and Guiana Shields.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:238566 |
| Date | January 1980 |
| Creators | Bradley, J. |
| Publisher | Royal Holloway, University of London |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
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