Statistical assessment of changes in climate extremes over Greece (1955–2002)

This article focuses on extreme events of high and low temperatures and precipitation and their amplitude and frequency changes over the last 50 years in Greece. Sixteen climate indices have been calculated and their trends were analysed to identify possible changes over a network of measurement stations covering the region quite homogeneously. Furthermore, the changes in the probability distribution of the indices were examined. In addition, we analyzed the temporal evolution of the amplitude and frequency of extreme events through the parameters of extreme value distribution. The temporal stability of the fitted distributions is examined and the spatial distribution of their trend as well as the changes in the 5‐year return levels is investigated. Half of the examined climatic indices exhibit significant regional trend; most of them are sole functions of minimum temperature or precipitation. A shift was found in the tail distribution of the peak minimum temperatures, with the 5‐year return value in the last quartile of the twientieth century to be equal to the 7‐year return value in the previous quartile. Warming was also apparent for the maximum temperature, mainly in the summer months, but of smaller magnitude. Total precipitation shifted towards drier climate over the domain while extreme rainfall events exhibit increased variability without following any coherent regional pattern. The changes in the peak temperature extremes are most sensitive to the changes in the location of the distribution of annual extremes. Changes in the precipitation extremes are associated with changes in both the scale and location of the fitted distribution. The highest range of change was found for the scale parameter for both temperature and precipitation extremes, pointing out that the most influenced factor is the interannual variability of the extremes.