The assessment of aridity conditions is a key factor for water management and the implementation of mitigation and adaptation policies in agroforestry systems. Towards this aim, three aridity indices were computed for the Iberian Peninsula (IP): the De Martonne Index (DMI), the Pinna Combinative Index (PCI), and the Erinç Aridity Index (EAI). These three indices were first computed for the baseline period 1961‒1990, using gridded observational data (E-OBS), and subsequently, for the periods 2011‒2040 (short range) and 2041‒2070 (medium range), using an ensemble of six regional climate model (RCM) experiments generated by the EURO-CORDEX project. Two representative concentration pathways (RCPs) were analyzed, an intermediate anthropogenic radiative forcing scenario (RCP4.5) and a fossil-intensive emission scenario (RCP8.5). Overall, the three indices disclose a strengthening of aridity and dry conditions in central and southern Iberia until 2070, mainly under RCP8.5. Strong (weak) statistically significant correlations were found between these indices and the total mean precipitation (mean temperature) along with projected significant decreasing (increasing) trends for precipitation (temperature). The prevalence of years with arid conditions (above 70% for 2041‒2070 under both RCPs) are projected to have major impacts in some regions, such as southern Portugal, Extremadura, Castilla-La Mancha, Comunidad de Madrid, Andalucía, Región de Murcia, Comunidad Valenciana, and certain regions within the Aragón province. The projected increase in both the intensity and persistence of aridity conditions in a broader southern half of Iberia will exacerbate the exposure and vulnerability of this region to climate change, while the risk of multi-level desertification should be thoroughly integrated into regional and national water management and planning.

中文翻译：

---

伊比利亚半岛干旱条件的气候变化预测

干旱状况的评估是水管理以及在农林复合系统中实施缓解和适应政策的关键因素。为实现这一目标，为伊比利亚半岛 (IP) 计算了三个干旱指数：De Martonne 指数 (DMI)、Pinna 组合指数 (PCI) 和 Erinç 干旱指数 (EAI)。这三个指数首先使用网格观测数据 (E-OBS) 在 1961-1990 年的基线期计算，随后在 2011-2040 年（短程）和 2041-2070（中程）期间，使用一组由 EURO-CORDEX 项目生成的六个区域气候模型 (RCM) 实验。分析了两个有代表性的浓度路径 (RCP)，中间人为辐射强迫情景 (RCP4.5) 和化石密集型排放情景 (RCP8.5)。全面的，这三个指数揭示了伊比利亚中部和南部的干旱和干旱状况在 2070 年之前的加强，主要是在 RCP8.5 下。在这些指数和总平均降水量（平均温度）以及降水（温度）的预测显着减少（增加）趋势之间发现了强（弱）统计显着相关性。预计干旱年份的发生率（两个 RCP 下 2041-2070 年均高于 70%）预计将对某些地区产生重大影响，例如葡萄牙南部、埃斯特雷马杜拉、卡斯蒂利亚-拉曼恰、马德里自治区、安达卢西亚、穆尔西亚地区、 Comunidad Valenciana 和阿拉贡省内的某些地区。