Mapping and monitoring carbon stocks with satellite observations: a comparison of methods     

Scott J Goetz  Alessandro Baccini  Nadine T Laporte  Tracy Johns  Wayne Walker  Josef Kellndorfer  Richard A Houghton  Mindy Sun 《Carbon balance and management》2009,4(1):2-7

Mapping and monitoring carbon stocks in forested regions of the world, particularly the tropics, has attracted a great deal of attention in recent years as deforestation and forest degradation account for up to 30% of anthropogenic carbon emissions, and are now included in climate change negotiations. We review the potential for satellites to measure carbon stocks, specifically aboveground biomass (AGB), and provide an overview of a range of approaches that have been developed and used to map AGB across a diverse set of conditions and geographic areas. We provide a summary of types of remote sensing measurements relevant to mapping AGB, and assess the relative merits and limitations of each. We then provide an overview of traditional techniques of mapping AGB based on ascribing field measurements to vegetation or land cover type classes, and describe the merits and limitations of those relative to recent data mining algorithms used in the context of an approach based on direct utilization of remote sensing measurements, whether optical or lidar reflectance, or radar backscatter. We conclude that while satellite remote sensing has often been discounted as inadequate for the task, attempts to map AGB without satellite imagery are insufficient. Moreover, the direct remote sensing approach provided more coherent maps of AGB relative to traditional approaches. We demonstrate this with a case study focused on continental Africa and discuss the work in the context of reducing uncertainty for carbon monitoring and markets.  相似文献   

Differential sedimentation versus coring artifacts: a comparison of two widely used piston-coring methods   总被引：1，自引：0，他引：1  

André F. Lotter  Josef Merkt  Michael Sturm 《Journal of Paleolimnology》1997,18(1):75-85

In order to compare two widely used piston-coring techniques, parallel cores were taken with both a Kullenberg and a Livingstone corer in the deepest part of Soppensee (25 m), a small eutrophic Swiss lake containing varved sediments. The cores were taken within a horizontal distance of 3 m and yield comparable stratigraphic records. Differences in millimetre-scale microstructure are attributed to primary sedimentation processes at the water/sediment interface. Sediment thin-sections, as well as sediment x-radiograph investigations, reveal no difference in microstructure that could unequivocally be attributed to one of the coring methods used. The differences in deposition are therefore thought to reflect the inherent variability of lacustrine sedimentation in Soppensee.Major differences in overall core recovery do occur, however, in organic-rich, highly porous sediments. These variations are primarily attributed to differential gas expansion. Actual sediment-accumulation rates can therefore only be correctly estimated if the sedimentary record can be constrained within a high-resolution temporal framework, e.g. by annual laminations.  相似文献   

Reflections of the editor upon completion of the atlas of the Danubian countries     

Josef Breu 《GeoJournal》1990,21(3):283-287

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Beitrag zur Reduktion Elektronisch Gemessener Längen Nach Verstelle     

Josef Vykutil 《Studia Geophysica et Geodaetica》1961,5(2):175-178

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Revision der geologischen Zeittafel für Nordamerika     

Charles Schuchert  Josef Barrell 《International Journal of Earth Sciences》1914,5(5-6):371-392

Ohne Zusammenfassung  相似文献   

Le développement de la géodésie et cartographie tchécoslovaque de 1945 a 1940     

Josef Ryšavý 《Studia Geophysica et Geodaetica》1960,4(2):119-129

Sans résumé En collaboration avec les membres de la rédaction: prof. Ing. Ján Krajčí, Dr. Ing. Karel Kučera et Dr. Ing. Jan Kašpar. Adresse: Národní tř. 3, Praha 1.  相似文献   

Der Chemismus oberdevoniseher Flaserkalke des Gaisberges bei Graz     

Dr. Josef Hanselmayer 《Contributions to Mineralogy and Petrology》1951,2(6):492-497

Ohne Zusammenfassung  相似文献   

Soft proton scattering efficiency measurements on x-ray mirror shells     

Sebastian Diebold  Chris Tenzer  Emanuele Perinati  Andrea Santangelo  Michael Freyberg  Peter Friedrich  Josef Jochum 《Experimental Astronomy》2015,39(2):343-365

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Evaluation on the accuracy of digital elevation models     

TANG Guo-an  Josef Strobl  GONG Jian-ya  ZHAO Mu-dan  CHEN Zhen-jiang 《地理学报》2001,11(2):209-216

There is a growing interest in investigating the accuracy of digital elevation model (DEM). However people usually have an unbalanced view on DEM errors. They emphasize DEM sampling errors, but ignore the impact of DEM resolution and terrain roughness on the accuracy of terrain representation. This research puts forward the concept of DEM terrain representation error (Et) and then investigates the generation, factors, measurement and simulation of DEM terrain representation errors. A multi-resolution and multi-relief comparative approach is used as the major methodology in this research. The experiment reveals a quantitative relationship between the error and the variation of resolution and terrain roughness at a global level. Root mean square error (RMS Et) is regressed against surface profile curvature (V) and DEM resolution (R) at 10 resolution levels. It is found that the RMS Et may be expressed as RMS Et = (0.0061 × V+ 0.0052) × R - 0.022 × V + 0.2415. This result may be very useful in forecasting DEM accuracy, as well as in determining the DEM resolution related to the accuracy requirement of particular application.  相似文献   

Bestimmung der durchgangszeiten von sternen durch die methode der unterbrechung der gesichtsfeldbelichtung     

Josef Kabeláč  Ivan Synek 《Studia Geophysica et Geodaetica》1964,8(2):120-126

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