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The aim of the paper lies in the identification of possible significant linear trends at monthly, seasonal and annual timescales in the Mediterranean during the second half of the 20th century. Monthly and daily records of 63 stations have been used to elaborate several precipitation indices: sum of daily precipitation (SDP) for rainfall >0.1 mm, >10 mm and >95th percentile, of number of rainy days (RD) >0.1 mm and >10 mm and of mean daily precipitation (MDP) >0.1 mm and >10 mm. For each index the stations have been gathered together by Rotated Principal Component Analyses to determine 8 sub-areas which can be considered as identical for all the timescales at the spatial scale of the research. Trends have been estimated from the scores of each eigenvector retained in all RPCAs. They are mainly non existant or non significant decreasing, even if a few monthly trends appear to be significantly diminishing, primarily during winter months, March in the Atlantic region, October in the Mediterranean Spain, December in the Lions and Genoa Gulfs, January, winter and the year in Greece, winter and the year in Italy and winter in the Near East and increasing in April in the two gulfs. Correlation coefficients between SDP>0.1 mm and other indices have been computed: the significant trends seem mainly related to RD>10 mm, which represents a high percentage of the total rainfall amount. Greece is remarkable: SDP>0.1 mm and >10 mm decrease significantly during January, winter, the rainy season and the entire year whereas SDP>95th percentile increases significantly, in accordance with the climatic change scenarios for the end of this century as does the decreasing of the total monthly and seasonal rainfall. [ABSTRACT FROM AUTHOR]

Tropical days (TD) are defined as the days with a maximum air temperature greater than 30.0 °C. It is clear that the study of TD includes also the absolute maximum temperatures, which are of great interest for the description of a region’s climate. These days are considered as very hot, and they particularly are of great importance not only for bioclimatology and applied sciences, but also for the individuals who are sensitive in the heat-stress. The regime of the TD in Greece is the focus of this study. The aim is to demonstrate their changes from decade to decade, for the time period 1960–2000. For this study, the Annual Number of Tropical Days (ANTD) recorded by each of the 26 meteorological stations of National Meteorological Service, which are uniformly distributed in the Hellenic peninsula, was calculated and analysed. In terms of quantifying the conditions in a humanbiometeorological manner, the thermal index Physiological Equivalent Temperature (PET) and the consecutive days for Athens have been included in this study. The trends of the TD for each station were analysed through the Mann–Kendall technique, while the spatial distribution per decade reveals the regions with change (increase or decrease) in the ANTD during the examined period. Two characteristic periods of change for the ANTD appear in the majority of the meteorological stations in Greece. The first period (1955–1976) is determined by a negative trend, which is statistically significant (c.l. 95%), for adequate stations. In the period between 1976 and 2000, the increase in the ANTD and the maximum temperature exceed the corresponding maximum that appeared in the beginning of the 1950s for several of the examined meteorological stations. The human-biometeorological analysis shows that the consecutive days of PET > 35 °C have had a positive trend in the last two decades of the last century. [ABSTRACT FROM AUTHOR]

(1) The main objectives of this study are the spatial and temporal analysis of annual 24-hour extreme precipitation amounts for different return periods, and (2) the interannual variability of the frequency of month-to-month maximum rainfall using harmonic analysis. Long time series data from 110 well-scattered rain gauges are analysed using extreme values theory and harmonic analysis techniques. The results indicate that the Jenkinson solution is more appropriate than the linear Gumbel solution for the extreme value law. The maximum expected values of 180–200 mm are observed along the southern coasts of the Greek peninsula and in the islands close to the Turkish coast, as well as in the north–west parts of the country. The harmonic analysis showed that the highest percentage of variance for rainfall extremes explained by the first harmonic (PVR(1)) appears over the southern and south-eastern parts of Greece in association with the greatest values of the amplitude of this harmonic, therefore explaining more than 90% of the variation of the frequency of maximum annual 24-hour rainfall amounts. In contrast, for regions north of 38° N and especially mountainous regions, more harmonics (3–5) are necessary to describe the parameter under investigation. [ABSTRACT FROM AUTHOR]