Geographia Polonica (1995) vol. 65

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Reflections on climate variability within selected monthly mean time series in Libya and neighboring countries

Ali A. Almabruk

Geographia Polonica (1995) vol. 65, pp. 51-62


This paper contains some results of long-time series analysis with respect to climate variability and change. The data are the mean monthly air temperature, precipitation and humidity at different stations located in Libya and neighbouring countries. At our disposal were 26 time series of monthly and annual mean values with an average length of ca. 51 years. It is to be hoped that the data are free from any anthropogenic influences.The hypothesis that the mean values or variances are homogeneous has been subject to the falsification procedure of non-parametric tests: the runs test, the Mann-Kendall test for trends in the mean or the variance, Lombard's test of the number of change-points, and the Pettitt change-point test.Appropriate statistical computations led the author to conclude that the climate characterized by the investigated processes of monthly and annual values should be considered unstable.

Keywords: Statistical non-parametric tests, climate change — Libyan case

Ali A. Almabruk, Institute of Geophysics, Polish Academy of Sciences ul. Księcia Janusza 64, 01-452 Warszawa, Poland