Publikasjoner
NIBIOs ansatte publiserer flere hundre vitenskapelige artikler og forskningsrapporter hvert år. Her finner du referanser og lenker til publikasjoner og andre forsknings- og formidlingsaktiviteter. Samlingen oppdateres løpende med både nytt og historisk materiale. For mer informasjon om NIBIOs publikasjoner, besøk NIBIOs bibliotek.
2003
Sammendrag
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Sammendrag
Spatio-temporal analyses of non-epidemic bark beetle populations may provide insight in dynamics predisposing for outbreaks. The present article presents a spatio-temporal analysis of the population dynamics of Ips typographus based on pheromone trap data from southeast and mid-Norway in the post-epidemic period 19792002. The analyses include regression analyses, hierarchical cluster analysis, and analysis of spatial synchrony of beetle time series and climatic data by means of nonparametric spatial covariance functions. The mean abundance of beetles declined linearly with latitude. In addition, the time series means were higher in areas with high forest productivity and rocky soils predisposed to drought. The time series patterns differed significantly between northern and southern study areas. The regional synchrony of the time series was fairly high (0.38), indicating that some large-scale climatic factor may influence the dynamics. Windfelling was the external variable showing the most parallel pattern of correlation to the beetle dynamics. We thus posit that large windfall events may be a major instigator and synchronizer of beetle outbreaks in areas subjected to regionalized weather systems.
Forfattere
Anders LunnanSammendrag
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Forfattere
K. Dahl Halvor SolheimSammendrag
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Forfattere
Holger LangeSammendrag
For the intepretation of multifractal properties of experimental time series, two prominent procedures used are the double trace method (DTM) and the universal multifractal (UM) approach. We calculated multifractal spectra for a collection of long-term precipitation, air temperature and river discharge records, covering a wide range of spatial scales.Considering K(q) in this framework leads to an effective classification of dynamical behavior. Comparison of the DTM and UM methodologies, however, reveals substantial differences which make them difficult to reconcile. This is in particular true for the discharge case.The scaling exponent is generally larger in magnitude for the DTM and in some cases even extends into the non-analytical regime. Part of previous work thus could not be confirmed. Whether the description of river flow as multifractal process is feasible remains an open question. http://www.cosis.net/abstracts/EAE03/05092/EAE03-J-05092.pdf
Forfattere
Ole Martin BollandsåsSammendrag
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Forfattere
Torjus Bolkesjø Hans Fredrik HoenSammendrag
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Sammendrag
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Sammendrag
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Forfattere
Tor MykingSammendrag
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