Blar i forfatter Artikler, rapporter og annet (matematikk og statistikk) "Nilsen, Tine"

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    • Are there multiple scaling regimes in Holocene temperature records? 

      Nilsen, Tine; Rypdal, Kristoffer; Fredriksen, Hege-Beate (Journal article; Tidsskriftartikkel; Peer reviewed, 2016-04-28)
      In this article it is discussed how temperature variability on centennial timescales and longer can be described in a simplistic way. By analysing the scaling in late Holocene temperature reconstructions and longer temperature records from Greenland and Antarctic ice cores, we find that the choice of model depends heavily on the data material and timescale one chooses to emphasize. Ignoring data ...

    • Are there multiple scaling regimes in Holocene temperature records? 

      Nilsen, Tine; Rypdal, Kristoffer; Fredriksen, Hege-Beate (Journal article; Tidsskriftartikkel, 2015-07-17)
      The concept of multiple scaling regimes in temperature time series is examined, with emphasis on the question whether or not a mono-scaling model can be rejected from the data at hand. A model with only one regime is simpler and is preferred if this 5 explains the observed variability. Our analysis of spectra from reconstructed air temperature from Greenland and Antarctica ice cores shows that ...

    • Assessing the performance of the BARCAST climate field reconstruction technique for a climate with long-range memory 

      Nilsen, Tine; Werner, Johannes; Divine, Dmitry V; Rypdal, Martin wibe (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-06-29)
      The skill of the state-of-the-art climate field reconstruction technique BARCAST (Bayesian Algorithm for Reconstructing Climate Anomalies in Space and Time) to reconstruct temperature with pronounced long-range memory (LRM) characteristics is tested. A novel technique for generating fields of target data has been developed and is used to provide ensembles of LRM stochastic processes with a prescribed ...

    • Constraining two climate field reconstruction methodologies over the North Atlantic realm using pseudo-proxy experiments 

      Nilsen, Tine; Talento, Stefanie; Werner, Johannes P (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-07-06)
      This study presents pseudo-proxy experiments to quantify the reconstruction skill of two climate field reconstruction methodologies for a marine proxy network subject to age uncertainties. The BARCAST methodology (Bayesian Algorithm for Reconstructing Climate Anomalies in Space and Time) is tested for sea surface temperature (SST) reconstruction for the first time over the northern North Atlantic ...

    • Is there a break in scaling on centennial time scales in Holocene temperature records? 

      Nilsen, Tine; Rypdal, Kristoffer; Fredriksen, Hege-Beate (Conference object; Konferansebidrag, 2017)

    • Long-Range Memory in Millennium-Long ESM and AOGCM Experiments 

      Nilsen, Tine (Others; Andre, 2014)
      Consider the Earth’s global mean surface temperature time series (GMST) as a realization of a stochastic process. Based on a number of studies, a long-range memory (LRM) stochastic process seems to describe the GMST better than a shortrange memory model, such as the AR(1)-process. We want to study the persistence in climate model simulations, to find out if simulated temperature data exhibit the ...

    • Spatio-temporal variability of Arctic summer temperatures over the past 2 millennia 

      Werner, Johannes; Divine, Dmitry V; Ljungqvist, Fredrik Charpentier; Nilsen, Tine; Francus, Pierre (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-04-24)
      <p>In this article, the first spatially resolved and millennium-length summer (June–August) temperature reconstruction over the Arctic and sub-Arctic domain (north of 60°N) is presented. It is based on a set of 44 annually dated temperature-sensitive proxy archives of various types from the revised PAGES2k database supplemented with six new recently updated proxy records. As a major advance, an ...