23 research outputs found

    Forest biomass retrieval approaches from earth observation in different biomes

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    The amount and spatial distribution of forest aboveground biomass (AGB) were estimated using a range of regionally developed methods using Earth Observation data for Poland, Sweden and regions in Indonesia (Kalimantan), Mexico (Central Mexico and Yucatan peninsula), and South Africa (Eastern provinces) for the year 2010. These regions are representative of numerous forest biomes and biomass levels globally, from South African woodlands and savannas to the humid tropical forest of Kalimantan. AGB retrieval in each region relied on different sources of reference data, including forest inventory plot data and airborne LiDAR observations, and used a range of retrieval algorithms. This is the widest inter-comparison of regional-to-national AGB maps to date in terms of area, forest types, input datasets, and retrieval methods. The accuracy assessment of all regional maps using independent field data or LiDAR AGB maps resulted in an overall root mean square error (RMSE) ranging from 10 t ha−1 to 55 t ha−1 (37% to 67% relative RMSE), and an overall bias ranging from −1 t ha−1 to +5 t ha−1 at pixel level. The regional maps showed better agreement with field data than previously developed and widely used pan-tropical or northern hemisphere datasets. The comparison of accuracy assessments showed commonalities in error structures despite the variety of methods, input data, and forest biomes. All regional retrievals resulted in overestimation (up to 63 t ha−1) in the lower AGB classes, and underestimation (up to 85 t ha−1) in the higher AGB classes. Parametric model-based algorithms present advantages due to their low demand on in situ data compared to non-parametric algorithms, but there is a need for datasets and retrieval methods that can overcome the biases at both ends of the AGB range. The outcomes of this study should be considered when developing algorithms to estimate forest biomass at continental to global scale level

    Selective logging of tropical forests observed using L- and C-band SAR satellite data

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    SIBERIA - 2nd Progress Report

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    This report describes the work done during the second six month period of the SIBERIA project. With the increasing availability of ground truth information and ERS SAR imagery methodological questions could be adressed accordingly. Procedures for calculating geocoded incidence angle mask (GIMs), masking of shadow and layover areas, co-registration of satellite and GIS data, calibration of ERS images, filtering, rule- and data-based classification, accuracy assessment, and data transfer have been developed and tested. The results so far suggest that the ERS coherence and the JERS amplitude are the most important parameters for forest and landcover classification

    SIBERIA - 1st Progress Report

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    This report describes the porgress made and the problems encountered in the first six months of the SIBERIA project. The limited data availability has hampered methodological development and has caused a delay of approximately three months. Nevertheless, preparatory work and first tests based on sample imagery have been performed
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