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Climate variability in Jordan is very sensitive to water resources, which are at the verge of depletion because annual per-capita water is at one of the lowest levels in the world. In order to address such sensitivity, it is necessary to examine effective meteorological factors such as annual, seasonal and monthly precipitation and extreme (maximum and minimum) temperature time series. Fourteen representative meteorological stations are chosen for the study of climate variability calculations in Jordan. Annual and monthly time series of precipitation, maximum and minimum temperatures are tested by the runs (Swed-Eisenhart) homogeneity test. Consequently, the sequential version of the Mann-Kendall rank trend and the linear trend tests are applied to the interannual means, coefficient of variation and skewness parameters. Signals of climate trends such as warming in maximum temperature, more statistically significant warming in minimum temperature, decreasing trends in daily temperature range and statistically insignificant decreasing precipitation trends are detected, which are enhanced by heat island, urbanization, pollution and aerosols effects. Two spells are recognized in the time series, where the first spell started in the early 1970s and the second beyond the year 1992 with a warming trend in maximum temperature and a farther warming in minimum temperature resulting in a decreasing trend in the diurnal temperature range that is associated with a slight decrease in precipitation. The interannual coefficient of variation of maximum and minimum temperatures reveals increasing trends in the majority of the stations while they exhibit an apparent decreasing trend in diurnal temperature range and a general, but insignificant, decreasing trend in precipitation is observed.

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Abstract. Potential effects of the E1 Nifio-Southern Oscillation (ENSO) warm extreme on the Turkish monthly precipitation totals between 1931 and 1990 were investigated using precipitation data from more than one hundred and eight Turkish meteorological stations. The data were normalized by using the annual total precipitation to minimize the probable topographical effects. A quiet standard annual variation was determined by month-by-month averaging for each annual month of the Neutral years. The anomalies in percent of the Turkish precipitation data were then calculated by subtracting E1 Nifio-year monthly percent precipitation from the corresponding quiet standard value. The obtained anomalies were sorted after the E1 Nifio high ENSO index month and analyzed by superposed epoch method. Distract effects of high ENSO index months were found so that a large part of the month-to-month variability may be attributed to E1 Nifio event. Spatially coherent and statistically significant precipitation responses to E1Nifio were shown in some regions of Turkey.