Physio-Géo (Oct 2024)
L'évolution de la sécheresse météorologique dans la partie centrale de la plaine de la Beqaa (Liban) : enseignements de l'indice standardisé de précipitations sur la période 1933-2020 dans le secteur Rayak - Tal Amara
Abstract
The study focuses on the temporal evolution of meteorological drought in a semi-arid agricultural territory located in the heart of the Beqaa plain in Lebanon. To define this climatic hazard, the Standardized Precipitation Index (SPI), recommended by the World Meteorological Organization, was used. This index, based on rainfall data alone, was calculated at three scales (12, 6 and 3 months), over a period going from September 1933 to August 2020.The results provided by the annual data (SPI-12) and data for the six months from October to March (SPI-6) show that the study area has experienced more frequent droughts since 1956-57, with successive dry years spanning 6, 7 and even 9 years. On a seasonal scale, winter (December-February), by far the wettest season, also shows a decrease in rainfall and an increase in dry droughts since 1956-57. On the other hand, autumn and spring data are characterised by the presence of two breaks, the first (1962-63 for spring and 1963-64 for autumn) resulting in an increase in rainfall and the second (1984-85 for spring and 1996-97 for autumn) in a decrease. The frequency of droughts has been particularly high since the second break. Despite their large number, droughts have remained of limited intensity. Even in 2013-14, the driest year in the series, only the October-March half-year was extremely dry (SPI of 2.03). On all time scales, light droughts (SPI < -1.0) were by far the majority.Translated with DeepL.com (free version)
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