165,122 research outputs found
Vegetation height products between 60° S and 60° N from ICESat GLAS data.
No full textWe present new coarse resolution (0.5� ×0.5�)vegetation height and vegetation-cover fraction data sets between
60� S and 60� N for use in climate models and ecological
models. The data sets are derived from 2003–2009 measurements collected by the Geoscience Laser Altimeter System (GLAS) on the Ice, Cloud and land Elevation Satellite (ICESat), the only LiDAR instrument that provides close to global coverage. Initial vegetation height is calculated from GLAS data using a development of the model of Rosette et al. (2008) with further calibration on desert sites. Filters are developed to identify and eliminate spurious observations in the GLAS data, e.g. data that are affected by clouds, atmosphere
and terrain and as such result in erroneous estimates
of vegetation height or vegetation cover. Filtered GLAS vegetation height estimates are aggregated in histograms from 0 to 70m in 0.5m intervals for each 0.5�×0.5�. The GLAS vegetation height product is evaluated in four ways. Firstly, the Vegetation height data and data filters are evaluated using aircraft LiDAR measurements of the same for ten sites in the Americas, Europe, and Australia. Application of filters to the GLAS vegetation height estimates increases the correlation with aircraft data from r =0.33 to r =0.78, decreases the root-mean-square error by a factor 3 to about 6m (RMSE) or 4.5m (68% error distribution) and decreases the bias from 5.7m to −1.3 m. Secondly, the global aggregated GLAS vegetation height product is tested for sensitivity towards the choice of data quality filters; areas with frequent cloud cover and areas with steep terrain are the most sensitive to the choice of thresholds for the filters. The changes in height estimates by applying different filters are, for the main part, smaller than the overall uncertainty of 4.5–6m established from the site measurements. Thirdly, the GLAS global vegetation height product is compared with a global vegetation height product typically used in a climate model, a recent global tree height product, and a vegetation greenness product and is shown to produce realistic estimates of vegetation height. Finally, the GLAS bare soil cover fraction is compared globally with the MODIS bare soil fraction (r = 0.65) and with bare soil cover fraction estimates derived from AVHRR NDVI data (r =0.67); the GLAS treecover fraction is compared with the MODIS tree-cover fraction (r =0.79). The evaluation indicates that filters applied to the GLAS data are conservative and eliminate a large proportion of spurious data, while only in a minority of cases at the cost of removing reliable data as well. The new GLAS vegetation height product appears more realistic than previous data sets used in climate models and ecological models and hence should significantly improve simulations that involve the land surface
ICESat/GLAS Data as a Measurement Tool for Peatland Topography and Peat Swamp Forest Biomass in Kalimantan, Indonesia
No full textIndonesian peatlands are one of the largest near-surface pools of terrestrial organic carbon. Persistent logging, drainage and recurrent fires lead to huge emission of carbon each year. Since tropical peatlands are highly inaccessible, few measurements on peat depth and forest biomass are available. We assessed the applicability of quality filtered ICESat/GLAS (a spaceborne LiDAR system) data to measure peatland topography as a proxy for peat volume and to estimate peat swamp forest Above Ground Biomass (AGB) in a thoroughly investigated study site in Central Kalimantan, Indonesia. Mean Shuttle Radar Topography Mission (SRTM) elevation was correlated to the corresponding ICESat/GLAS elevation. The best results were obtained from the waveform centroid (R2 = 0.92; n = 4,186). ICESat/GLAS terrain elevation was correlated to three 3D peatland elevation models derived from SRTM data (R2 = 0.90; overall difference = −1.0 m, ±3.2 m; n = 4,045). Based on the correlation of in situ peat swamp forest AGB and airborne LiDAR data (R2 = 0.75, n = 36) an ICESat/GLAS AGB prediction model was developed (R2 = 0.61, n = 35). These results demonstrate that ICESat/GLAS data can be used to measure peat topography and to collect large numbers of forest biomass samples in remote and highly inaccessible peatland forests
Glas, de J. Derrida
No full textBlanchard Gérard. Glas, de J. Derrida. In: Communication et langages, n°26, 1975. pp. 114-115
Glas, de J. Derrida
No full textBlanchard Gérard. Glas, de J. Derrida. In: Communication et langages, n°26, 1975. pp. 114-115
A conversion disorder
No full textInterrogating the relationship between reading, writing and ‘conversion disorder’, this creative-critical essay explores the eversion of the glove in the work of Woolf, Genet, Freud and Derrida. Gathering together reflections on gloves and glove anaesthesia, doubles and pairs, and flowers and the death knell (glas), it offers a series of literary, philosophical and psychoanalytic conversions in order to return to and rethink the question of ‘disorder’
Teelt van radijs onder glas
No full textDeze brochure is een 3e geheel herziene druk van destijds geschreven brochure over de teelt van radijs onder glas
[Report to Chief J. E. Curry, by an unknown author #1]
No full textReport to Chief J. E. Curry, by an unknown author. The report contains a list of officers who gave depositions to the United States Attorney
[Report to Chief J. E. Curry, by an unknown author #2]
No full textReport to Chief J. E. Curry, by an unknown author. The report contains a list of officers who gave depositions to the United States Attorney
Ludo-epistemology: Playing with the Rules in Citizen Science Games
No full textIn their chapter, Glas and Lammes critically investigate the limitations of citizen science game design when it comes to having amateurs playfully participate in the production of scientific knowledge. Moving away from the traditional distance between the scientist as expert and the citizen as layperson, and between science as serious and play as trivial, they argue for a recognition of play as fundamental to the scientific endeavor and see rule breaking and bending as an essential part of this process. From this perspective, they consider an approach to citizen science game design that includes playing with the rules as a more critical way of having citizens think about and participate in science
Reinigungs-Anstalt, Baum Carl, Wien VI, Kaserneng. 11, Telef. 7255, Gegr.-1883, Glas u. Zimmerputzarbeiten, Desinfektionen, Vacuum cleaner, Tapetenputz ect., J. Streicher, Wien XV
No full textREINIGUNGS-ANSTALT, BAUM CARL, WIEN VI, KASERNENG. 11, TELEF. 7255, GEGR.-1883, GLAS U. ZIMMERPUTZARBEITEN, DESINFEKTIONEN, VACUUM CLEANER, TAPETENPUTZ ECT., J. STREICHER, WIEN XV
Reinigungs-Anstalt, Baum Carl, Wien VI, Kaserneng. 11, Telef. 7255, Gegr.-1883, Glas u. Zimmerputzarbeiten, Desinfektionen, Vacuum cleaner, Tapetenputz ect., J. Streicher, Wien XV ( -
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