Blar i forfatter Artikler, rapporter og annet (matematikk og statistikk) "Østvand, Lene"
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Long-range memory in Earth's surface temperature on time scales from months to centuries
Rypdal, Kristoffer; Østvand, Lene; Rypdal, Martin wibe (Journal article; Tidsskriftartikkel; Peer reviewed, 2013)The paper explores the hypothesis that the temporal global temperature response can be modeled as a long-range memory (LRM) stochastic process characterized by a Hurst exponent 0.5 < H≲1.0 on time scales from months to decades. The LRM is a mathematical representation of the multitude of response times associated with the various subsystems. By analysis of instrumental and reconstructed temperature ... -
Statistical significance of rising and oscillatory trends in global ocean and land temperature in the past 160 years
Østvand, Lene; Rypdal, Kristoffer; Rypdal, Martin Wibe (Journal article; Tidsskriftartikkel, 2014-03-20)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 general ... -
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 ...