SOME TESTS OF TREND AND CHANGE POINT DETECTION ON CLIMATE DATA FOR SLOVENIA

Na podlagi podatkov o temperaturah zraka in količini padavin, ki smo jih pridobili iz arhivov urada Agencije Republike Slovenije za okolje (ARSO), smo proučevali trende v Sloveniji od leta 1951 do 2010. Iz povprečnih dnevnih temperatur zraka in dnevnih količin padavin smo za 13 reprezentativnih meteoroloških postaj izračunali letna in polletna povprečja za temperature ter letno in polletno količino padavin. Rezultati različnih testov za ugotavljanje trendov so v večini primerov pokazali značilne trende povprečnih letnih in polletnih temperatur. Izjema je bil Portorož pri vseh analiziranih časovnih vrstah, prav tako statistično značilnega trenda nismo opazili pri hladni polovici leta v Jeruzalemu, Črnomlju, Kredarici in Bilju. Letne in polletne količine padavin v opazovanem obdobju niso kazale značilnih trendov, pri tem je bila izjema Kočevje pri vseh časovnih vrstah in Bilje v hladni polovici leta. Nadalje smo z računalniškim programom Change-Point Analyser ugotavljali prelomna leta za vse časovne vrste izbranih meteoroloških postaj. Ugotovili smo, da je bilo prelomno leto za časovno vrsto povprečnih temperatur zraka v topli polovici leta pri večini postaj okoli leta 1981, za hladno polovico okoli leta 1987 in za celoletno obdobje okoli leta 1988. Pri podatkih o količini padavin smo prelomna leta zaznali le za nekatere meteorološke postaje.On the basis of data on air temperatures and precipitation rates available in the archives of the Slovenian Environmental Agency (SEA) we studied the trends in Slovenia from 1951 until 2010. From data on mean daily air temperatures and daily precipitation rates of 13 representative meteorological stations we calculated annual and semiannual mean temperatures and precipitation rates. Using various trend tests significant trends were detected for mean annual and semiannual temperatures in almost all stations. The exceptions were Portorož for all observed time series, and Jeruzalem, Črnomelj, Kredarica and Bilje for the cold part of the year. In time series of annual and semiannual precipitation rates no significant trends were detected with the exception of Kočevje for all time series and Bilje for the cold part of the year. The data were also processed using the computer software Change-Point Analyser to detect change-points in all the time series of the selected meteorological stations. For temperature time series of the warm part of the year it was found that for almost all stations the change-points occurred around the year 1981, for the cold part of the year around 1987 and for the whole-year period around 1988. The results on precipitation rates showed that the change-points were detected only for some meteorological stations