Publications
NIBIOs employees contribute to several hundred scientific articles and research reports every year. You can browse or search in our collection which contains references and links to these publications as well as other research and dissemination activities. The collection is continously updated with new and historical material.
2011
Abstract
Remote sensing of the activity of vegetation in relation to environmental conditions provides an invaluable basis for investigating the spatiotemporal dynamics and patterns of variability for ecosystem processes. We investigate the fraction of Absorbed Photosynthetically Active Radiation (fAPAR) using SeaWiFS satellite observations from 1998 to 2005 and ancillary meteorological variables from the CRU-PIK dataset with a global coverage at a spatial resolution of 0.5o x 0.5o. A pixel-by-pixel spectral decomposition using Singular System Analysis leads to a global “classification” of the terrestrial biosphere according to prevalent time-scale dependent dynamics of fAPAR and its relation to meteorology. A complexity analysis and a combined subsignal extraction and dimensionality reduction reveals a series of dominant geographical gradients, separately for different time scales. At the annual scale, which explains around 50% of the fAPAR variability as a global average, patterns largely resemble the biomes of the world as mapped by biogeographical methods, and are driven by temperature and by pronounced rain seasons in the tropics. On shorter time scales, fAPAR fluctuations are exclusively driven by water supply, inducing, e.g., semiannual cycles in the equatorial belt of Africa or the Indo-Gangetic Plain. For some regions however, in particular South America, altitude, mean temperature, drought probability and fire occurrences are parameters that seem to shape the spatial patterns of fAPAR across time scales. Overall, we provide a first global multiscale characterization of fAPAR and highlight different mechanisms in land-surface-climate couplings.
Abstract
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Authors
Merete Wiken Dees Arild Sletten Ricardo Holgado Eldrid Lein Molteberg Tor J. Johansen May Bente Brurberg Vinh Hong Le Ragnhild Nærstad Arne HermansenAbstract
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Abstract
As in many countries throughout Europe, there has been a polarisation within the agricultural landscape of Norway during the last decades. On the one hand there is an increasing trend of intensified use of favourable areas, while on the otherhand there is an increase in the amount of land abandonment of extensively managed or marginal areas (Fjellstad Dramstad 1999, Robinson Sutherland 2002, Haines-Younget al. 2003). Among the main impact factors for biodiversity in agricultural landscapes are increased amount of built-up areas, intensification of agriculture and land abandonment. But different land use practices has been shown to have differential effects on biodiversity (Haines-Young 2009). Finding the relationships between land use practices and effects on biodiversity are fundamental to understand the links between people and their environment and development of sustainable agriculture ....
Authors
Clara Antón-Fernández Harold E. Burkhart Mike Strub Ralph L. AmateisAbstract
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Authors
May Sæthre I. Godonou S. Leclercq G.T. Yoto B JamesAbstract
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Authors
Jihong Liu Clarke Carl Jonas Jorge Spetz Sissel Haugslien Merete Dees Roar Moe Dag-Ragnar BlystadAbstract
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