Blar i forfatter Artikler, rapporter og annet (fysikk og teknologi) "Rypdal, Martin"
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Modeling temporal fluctuations in avalanching system
Rypdal, Martin; Rypdal, Kristoffer (Working paper; Arbeidsnotat, 2008-07-22)We demonstrate how to model the toppling activity in avalanching systems by stochastic differential equations (SDEs). The theory is developed as a generalization of the classical mean field approach to sandpile dynamics by formulating it as a generalization of Itoh’s SDE. This equation contains a fractional Gaussian noise term representing the branching of an avalanche into small active clusters, ... -
Statistical significance of rising and oscillatory trends in global ocean and land temperature in the past 160 years
Østvand, Lene; Rypdal, Kristoffer; Rypdal, Martin (Journal article; Tidsskriftartikkel, 2014-10-30)Various interpretations of the notion of a trend in the context of global warming are discussed, contrasting the difference between viewing a trend as the deterministic response to an external forcing and viewing it as a slow variation which can be separated from the background spectral continuum of long-range persistent climate noise. The emphasis in this paper is on the latter notion, and a ... -
A stochastic theory for temporal fluctuations in self-organized critical systems
Rypdal, Martin; Rypdal, Kristoffer (Journal article; Tidsskriftartikkel; Peer reviewed, 2008) -
A stochastic theory for temporal fluctuations in self-organized critical systems
Rypdal, Martin; Rypdal, Kristoffer (Working paper; Arbeidsnotat, 2008-07-22)A stochastic theory for the toppling activity in sandpile models is developed, based on a simple mean-field assumption about the toppling process. The theory describes the process as an anti-persistent Gaussian walk, where the diffusion coefficient is proportional to the activity. It is formulated as a generalization of the Itˆo stochastic differential equation with an anti-persistent fractional ... -
The Structure of Climate Variability Across Scales
Franzke, Christian L.E.; Barbosa, Susana; Blender, Richard; Fredriksen, Hege-Beate; Laepple, Thomas; Lambert, Fabrice; Nilsen, Tine; Rypdal, Kristoffer; Rypdal, Martin; Scotto, Manuel G; Vannitsem, Stephane; Watkins, Nicholas W.; Yang, Lichao; Yuan, Naiming (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-03-05)One of the most intriguing facets of the climate system is that it exhibits variability across all temporal and spatial scales; pronounced examples are temperature and precipitation. The structure of this variability, however, is not arbitrary. Over certain spatial and temporal ranges, it can be described by scaling relationships in the form of power laws in probability density distributions and ...