The temporal and spatial trends of 16 climate extreme indices based on daily maximum and minimum temperatures during the period 1987–2016 at 28 stations distributed across Israel and Palestine territories in the Levant region were annually and seasonally analysed. The nonparametric Man‐Kendall test and the Sen's slope estimator were employed for the trend analysis. Results showed that the region has significantly experienced a dominant warming trend for the last three decades, with more intense changes for minimum temperatures than for maximum. At annual scale, maximum values of minimum temperatures exhibited significant increasing trends up to 0.68°C/decade. For percentile‐based extreme temperature indices, changes detected were more pronounced than those for the absolute extreme temperature indices, with 93 and 89% of stations significantly showed increasing trends in TX90p and TN90p, respectively. The duration and fixed threshold extreme indices confirmed the trend toward a warming, with the 86% of the stations exhibited significant increasing trends in the annual occurrence of summer days (SU25) and tropical nights (TR20). Moreover, 57% of stations showed significant increasing trends in their very summer days (SU30) index. At seasonal scale, the analysis of trends for extreme temperature indices showed intense and broad significant increasing trends in all absolute extreme temperature indices. In summer, more than 75% of total stations exhibited significant increasing trends for warm days and warm nights (TX90p and TN90p). In winter and spring, 71% of the total stations also showed significant increasing trends in SU25 index, whereas the percentage of stations reached 82% in summer and 64% in autumn for significant increasing trends in TR20 index. Finally, the influence of large‐scale circulation patterns on temperature extremes was examined. The results highlighted the presence of significant correlations between most of the selected extreme temperature indices and the North Sea‐Caspian pattern at annual and seasonal scales.

Climate change leads to altered spatial and temporal patterns of precipitation due to activating the hydrological cycle. This study analyzes the distribution of precipitation concentration over the Levant in 1970–2018 for the first time at various time scales. The precipitation concentration index (PCI) was calculated using a quality-controlled time series from 167 meteorological stations. Trends were calculated using a Mann–Kendall nonparametric test, and a nonparametric Mann–Whitney test was used to determine the statistical significance of the differences between the mean sub-periods. The Levant can be divided into three regions, a strongly irregular concentration in south Palestine and Jordan as well as east Jordan; an irregular concentration in center/north Palestine, north Jordan, and east Syria; and a moderately irregular concentration over the Syrian coast. The annual precipitation concentration index (PCI) for the Levant, Palestine, and Syria non-significantly increased by 0.33, 0.32, and 0.22 unit/decade, respectively. Significant increasing trends occurred in the northwest of the West Bank, with averages of 0.75 unit/decade. The seasonal rainfall distribution tends to be uniform in winter and spring, mainly for south Levant, whereas the annual rainfall tends to be more concentrated. The autumn PCI significantly decreased for the Levant, Palestine, and Syria by −0.46, −0.61, and −0.54 units/decade, respectively.

This study aims to provide a comprehensive spatio-temporal analysis of the annual and seasonal extreme rainfall indices over the southern Levant from 1970 to 2020. For this, temporal and spatial trends of 15 climate extreme indices based on daily precipitation at 66 stations distributed across Israel and Palestine territories were annually and seasonally analyzed through the nonparametric Mann–Kendall test and the Sen’s slope estimator. The annual averages for frequency-based extreme indices exhibited decreasing trends, significantly for the Consecutive Dry Days. In contrast, the percentiles- and intensity-based extreme indices showed increasing trends, significant for extremely wet days, Max 1- and 3-day precipitation amount indices. The study area had expanding periods of extreme dry spells for spring and correspondingly shortening extreme wet spells for spring, winter and the combined winter–spring. Moreover, most of spring indices showed negative trends. Conversely, most winter indices displayed positive trends. Regarding the influence of large-scale circulation patterns, the North Sea Caspian pattern, the Western Mediterranean Oscillation, and ENSO were the primary regulators of the winter, spring, and autumn extreme indices, respectively. These findings contribute to a better understanding of extreme rainfall variability in the Levant region and could be utilized in the management of water resources, drought monitoring, and flood control.

This study aimed at analysis of the general-index change for the mean annual and seasonal precipitation in six stations in Latakia Governorate (Syria). The data of precipitation were collected for 40 consecutive years (1970–2010) in order to figure out the extent of the changes and variability in precipitation rates and the impact of this change on changes in the potential density that might cause extremely high or low precipitation rates according to Gumbel distribution of the extreme precipitation rates. Results revealed a decrease of the annual precipitation rates in all stations, the reduction in precipitation ranged from 46 to 210 mm during the whole period of the study. Spring, however, recorded the highest and statistically significant reduction, which reached 46–210 mm, while winter precipitation increased by 21–82 mm. Spring also has witnessed a decrease of about 3–9% of the total annual precipitation as compared to winter precipitation which increased by 5–8% of the total. The potential density of extremely high winter precipitation rates increased in all stations as indicated from Gumbel distribution in winter, and a greater increase took place in the probabilities of occurrence of the extremely low spring precipitation rates. This shows significant probability of occurrence of drought during spring season. By contrast, probabilities of winter precipitation rates increased more, thus winter is relatively more humid than before and spring is relatively drier than before.

Este estudio tiene como objetivo analizar los cambios en los promedios anuales y estacionales de la temperatura del aire y las precipitaciones en la gobernación de Lattakia durante 1970-2016. Las tendencias anuales y estacionales para la temperatura y la precipitación se calcularon utilizando la prueba no paramétrica de Mann-Kendall. Las diferencias de medias entre los dos períodos (1970-2000) / (2001-2016) se evaluaron en los niveles anuales y estacionales mediante el uso de la prueba no paramétrica de Mann-Whitney U. Además, la aparición de valores extremadamente altos / bajos se analizó a nivel anual mediante el uso de la curva de distribución normal. El estudio encontró que los promedios anuales de temperatura aumentaron significativamente (p <0.05) en 0.22 ˚C / década y 0.17 ˚C \ década, en las estaciones de Lattakia y Hiffeh, respectivamente, durante 1970-2016. El verano reveló tendencias fuertes y significativas al alza (a nivel 0.01) en sus promedios de temperatura en 0.39 ˚C / década en Lattakia, y en 0.34 ˚C / década en Hiffeh. El promedio de precipitaciones de primavera disminuyó significativamente en -6.5 mm / década en Lattakia y en -12.1 mm / década en Hiffeh. La probabilidad de la aparición del valor de 20.2 ˚C o más como valor extremo aumentó en la estación de Lattakia durante 2001-2016 en un 40.8%.