期刊名称：ISPRS Annals of the Photogrammetry, Remote Sensing and Spatial Information Sciences
印刷版ISSN：2194-9042
电子版ISSN：2194-9050
出版年度：2004
卷号：XXXV Part B7
页码：996-1001
出版社：Copernicus Publications
摘要：Tropical coastal environments around the world have undergone rapid changes which made consequent of their ecosystems degradation inevitable. Despite numerous attempts to map their extent and distribution from space, the ability to relate the surface signals reflected and subsequently measured by remote imaging sensors to the biophysical characteristics of coastal habitat targets have been given inadequate attention. The dynamic characteristic of the coastal shallow water areas including tidal and wave forcing, water quality and environmental stresses, both natural and anthropogenic complicate this task. Hence there is a need to consider these factors in understanding images obtained from different sources taken at various periods. This research focuses on synergistic methods in multi-source image processing for assessing benthic coastal habitats such as corals, seagrass, and algae by examining image data covering these types of environment from space through the aid of theoretical remote sensing approaches. Our study area covers the Fukido river mouth area and Shiraho reef of Ishigaki Island located in southern Ryukus, Japan. Images were acquired from satellite-borne Ikonos, SPOT, ASTER and Landsat respectively in 2002. Principles of BRDF (bidirectional reflectance distribution functions) modelling, shallow water optics and radiative transfer have been utilized to explain shallow water reflectance values with biophysical properties such as distribution, abundance, morphology and depth as controlling parameters. To reinforce parameterizations and to validate computational results, field surveys were conducted to gather in-situ data including water quality (mainly chlorophyll-a and turbidity), sea surface conditions, benthic habitat cover, abundance and distribution, some of which are synchronous with image acquisition. Spectral profiles across the reef area benthic cover were also used for calibrating reflectance. The developed reflectance model was applied to the image datasets by utilizing model inversion techniques, hence obtaining depth and benthic cover estimates. Results showed relative proximity of image-derived reflectance to processed in-situ spectral reflectance. The accuracy of the cover and depth estimates satellite sensor source image for the same area are also presented. The model provides a physical basis for relating different image datasets from different sources
