We develop a method for describing the periodicity of noisy 'quasi-cyclic' time-series based on integrals of their power spectra corresponding to different frequency intervals that we use to classify time-series as 'strongly cyclic', 'weakly cyclic' or 'non-cyclic'. We apply this analysis to over 300 time-series of shooting records of red grouse from 289 moors located in 20 regions of the UK. T...

thunderstorms are climatical phenomena, which sometimes can cause irreparable damage to the ecology. in this study to identify any trends in the frequency of days with thunderstorms in iran, long-term statistics of 33 synoptic stations, from the beginning until 2005 was used. at first by applying nonparametric man-kendall and sen’s estimator methods on four seasonal time series, and one annua...

There are numerous methods for data fillingin hydrology. Most, however, are based oncorrelations with nearby stations in a generalscheme of regionalization. These methods,though robust, fail to function when andwhere all the near stations are missed-datatoo. The Mashhad synoptic station has annualrainfall data over a 50 year period from 1951to 2000 and historic rainfall data from 1893 to1940, j...