Blar i forfatter "Rypdal, Martin wibe"

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    • 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 ...

    • Clustering and climate associations of Kawasaki Disease in San Diego County suggest environmental triggers 

      Rypdal, Martin wibe; Rypdal, Veronika Gjertsen; Burney, Jennifer A.; Cayan, Daniel; Bainto, Emelia; Skochko, Shannon; Tremoulet, Adriana H.; Creamean, Jessie; Shimizu, Chisato; Kim, Ji-Hoon; Burns, Jane C. (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-11-12)
      Kawasaki Disease (KD) is the most common cause of pediatric acquired heart disease, but its etiology remains unknown. We examined 1164 cases of KD treated at a regional children’s hospital in San Diego over a period of 15 years and uncovered novel structure to disease incidence. KD cases showed a well-defined seasonal variability, but also clustered temporally at much shorter time scales (days to ...

    • Early-warning signals for the onsets of Greenland interstadials and the younger dryas-preboreal transition 

      Rypdal, Martin wibe (Journal article; Tidsskriftartikkel; Peer reviewed, 2016-05-20)
      The climate system approaches a tipping point if the prevailing climate state loses stability, making a transition to a different state possible. A result from the theory of randomly driven dynamical systems is that the reduced stability in the vicinity of a tipping point is accompanied by increasing fluctuation levels and longer correlation times (critical slowing down) and can in principle serve ...

    • 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 ...

    • Long-range memory in internal and forced dynamics of millennium-long climate model simulations 

      Østvand, Lene; Nilsen, Tine; Rypdal, Kristoffer; Divine, Dmitry, V.; Rypdal, Martin wibe (Journal article; Tidsskriftartikkel; Peer reviewed, 2014)
      Northern Hemisphere (NH) temperature records from a palaeoclimate reconstruction and a number of millennium-long climate model experiments are investigated for long-range memory (LRM). The models are two Earth system models and two atmosphere–ocean general circulation models. The periodogram, detrended fluctuation analysis and wavelet variance analysis are applied to examine scaling properties ...

    • Power-law scaling of uncorrelated plasma bursts 

      Theodorsen, Audun; Garcia, Odd Erik; Rypdal, Martin wibe (Conference object; Konferansebidrag, 2019-07)

    • Statistics of Regional Surface Temperatures after 1900: Long-Range versus Short-Range Dependence and Significance of Warming Trends 

      Løvsletten, Ola; Rypdal, Martin wibe (Journal article; Tidsskriftartikkel; Peer reviewed, 2016)
      This paper studies regional climate variability for the time period 1900–2013 using parsimonious stochastic models. Instrumental data records on 5° × 5°, 2° × 2°, and equal-area grids are examined. A long-range dependent (LRD) stochastic process is used as a simplified description of the multitude of response times in the climate system. Fitting a linear trend to the global mean surface temperature ...

    • Warming trends and long-range dependent climate variability since year 1900: A Bayesian approach 

      Myrvoll-Nilsen, Eirik; Fredriksen, Hege-Beate; Sørbye, Sigrunn Holbek; Rypdal, Martin wibe (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-08-21)
      Temporal persistence in unforced climate variability makes detection of trends in surface temperature difficult. Part of the challenge is methodological since standard techniques assume a separation of time scales between trend and noise. In this work we present a novel Bayesian approach to trend detection under the assumption of long-range dependent natural variability, and we use estimates of ...