Accessing extremes of mid-latitudinal wave activity: Methodology and application

R. Vitolo, P.M. Ruti, A. Dell'Aquila, M. Felici, V. Lucarini, A. Speranza

Research output: Contribution to journalArticle

10 Citations (Scopus)


A statistical methodology is proposed and tested for the analysis of extreme values of atmospheric wave activity at mid-latitudes. The adopted methods are the classical block-maximum and peak over threshold, respectively based on the generalized extreme value (GEV) distribution and the generalized Pareto distribution (GPD). Time-series of the 'Wave Activity Index' (WAI) and the 'Baroclinic Activity Index' (BAI) are computed from simulations of the General Circulation Model ECHAM4.6, which is run under perpetual January conditions. Both the GEV and the GPD analyses indicate that the extremes of WAI and BAI are Weibull distributed, this corresponds to distributions with an upper bound. However, a remarkably large variability is found in the tails of such distributions; distinct simulations carried out under the same experimental setup provide sensibly different estimates of the 200-yr WAI return level. The consequences of this phenomenon in applications of the methodology to climate change studies are discussed. The atmospheric configurations characteristic of the maxima and minima of WAI and BAI are also examined. © Journal compilation © 2009 Blackwell Munksgaard.
Original languageEnglish
Pages (from-to)35 - 49
Number of pages15
JournalTellus, Series A: Dynamic Meteorology and Oceanography
Volume61 A
Issue number1
Publication statusPublished - 2009
Externally publishedYes


All Science Journal Classification (ASJC) codes

  • Oceanography
  • Atmospheric Science

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