发表机构
Instituto de Astronomía y Meteorología (IAM), Departamento de Física, Centro Universitario de Ciencias Exactas e Ingenierías (CUCEI), Universidad de Guadalajara; Agencia Mexicana de Meteorología y Geociencias (GEOSMET); Centro de Investigaciones sobre Desertificación, Consejo Superior de Investigaciones Científicas (CIDE, CSIC-UV-GVA); Unidad Académica de Estudios Territoriales Yucatán (UAETY), Instituto de Geografía, Universidad Nacional Autónoma de México (UNAM); Colorado State University; University of Valladolid; Agencia Estatal de Meteorología (AEMET); Complutense University of Madrid（瓜达拉哈拉大学; 墨西哥气象与地球科学署; 西班牙国家研究委员会沙漠化研究中心; 墨西哥国立自治大学; 科罗拉多州立大学; 巴利亚多利德大学; 西班牙国家气象局; 马德里康普顿斯大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究利用ERA5和CHIRPS数据评估GDI在墨西哥的气候学表现，提出基于OLR和降水事件条件分布的区域校准对流等级尺度，提升复杂地形下的对流判别能力。
AI 中文摘要
加尔维斯-戴维森指数（GDI）是一种热力学诊断指标，旨在概括热带地区的对流有利性，但其在复杂地形和异质水文气候中的可迁移性仍不确定。在此，我们利用ERA5逐小时场和CHIRPS日降水数据（1981年至2024年），评估了GDI在墨西哥的气候学行为及其与降水的相关性。我们刻画了GDI的季节循环和空间差异，并通过格点和区域尺度的皮尔逊与斯皮尔曼相关系数，评估了日最大GDI与日降水量之间的关联。为引入独立的对流代理变量，我们还量化了逐小时GDI与ERA5向外长波辐射（OLR）之间的关系。事件级别的判别能力通过受试者工作特征（ROC）曲线及曲线下面积（AUC）在各区域和月份中进行了评估。虽然GDI与降水的相关性为中等水平且随区域变化，但GDI与OLR的耦合始终更强，部分原因在于一旦深对流发展，OLR趋近于下界，这支持其作为热力学有利性与降水之间的中间代理变量的用途。然而，由于该指数基于气压层公式，GDI值在高海拔地形上系统性偏低，在山区解读GDI时应考虑此因素。ROC结果表明，在几乎所有区域-月份组合中，判别能力均优于随机水平，且在核心对流季节AUC常超过0.75。基于这些诊断，我们提出了一个适用于5月至10月的区域校准GDI对流等级尺度，该尺度改编自原始GDI框架，但根据墨西哥情况，利用由OLR和降水定义的事件条件分布并通过自助法不确定性量化进行了重新校准。
英文摘要
The Gálvez Davison Index (GDI) is a thermodynamic diagnostic designed to summarize convective favorability in the tropical regions, yet its transferability across complex terrain and heterogeneous hydroclimates remains uncertain. Here we assess the climatological behavior and precipitation relevance of the GDI over Mexico using ERA5 hourly fields and CHIRPS daily precipitation for 1981 to 2024. We characterize the seasonal cycle and spatial contrasts of GDI and evaluate its association with rainfall using grid point and regional Pearson and Spearman correlations between daily maximum GDI and daily precipitation. To introduce an independent convective proxy, we also quantify the relationship between hourly GDI and ERA5 outgoing longwave radiation (OLR). Event level discrimination skill is assessed with receiver operating characteristic (ROC) curves and area under the curve (AUC) across regions and months. While GDI precipitation correlations are moderate and region dependent, GDI OLR coupling is consistently stronger, partly because OLR approaches a lower bound once deep convection develops, supporting its use as an intermediate proxy between thermodynamic favorability and rainfall. However, GDI values are systematically lower over elevated terrain because of the pressure level formulation of the index, which should be considered when interpreting the GDI over mountainous regions. ROC results indicate skill above random chance in nearly all region month combinations, with AUC frequently exceeding 0.75 during the core convective season. Building on these diagnostics, we propose a regionally calibrated GDI convective regime scale for May to October, adapted from the original GDI framework but recalibrated for Mexico using event conditioned distributions defined from OLR and precipitation and quantified with bootstrap uncertainty.
CommentsAccepted for publication in Earth Systems and Environment
