ABSTRACT Predicting the impacts of climate change on water resources remains a challenging task and requires a good understanding of the dynamics of the forcing terms in the past. In this study, the variability of precipitation and drought patterns is studied over the Mediterranean catchment of the Medjerda in Tunisia based on an observed rainfall dataset collected at 41 raingauges during the period 1973–2012. The standardized precipitation index and the aridity index were used to characterize drought variability. Multivariate and geostatistical techniques were further employed to identify the spatial variability of annual rainfall. The results show that the Medjerda is marked by a significant spatio-temporal variability of drought, with varying extreme wet and dry events. Four regions with distinct rainfall regimes are identified by utilizing the K-means cluster analysis. A principal component analysis identifies the variables that are responsible for the relationships between precipitation and drought variability.

中文翻译：

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地中海南部跨界流域的干旱评估

摘要 预测气候变化对水资源的影响仍然是一项具有挑战性的任务，需要很好地了解过去强迫项的动态。在这项研究中，基于 1973 年至 2012 年期间在 41 个雨量计上收集的观测降雨数据集，研究了突尼斯 Medjerda 地中海流域的降水和干旱模式的变化。标准化降水指数和干旱指数用于表征干旱变异性。进一步采用多变量和地质统计技术来确定年降雨量的空间变异性。结果表明，Medjerda 的特点是干旱的显着时空变异性，具有不同的极端干湿事件。利用 K 均值聚类分析确定了具有不同降雨情况的四个区域。主成分分析确定了造成降水和干旱变异性之间关系的变量。