巴西强降雨的时间分布：基于290,164次亚日暴雨事件的经验Huff曲线
Time Distribution of Heavy Rainfall in Brazil: Empirical Huff Curves from 290,164 Sub-Daily Storm Events
- Stanford University（斯坦福大学）
- University of São Paulo（圣保罗大学）
- University of North Carolina at Charlotte（北卡罗来纳大学夏洛特分校）
机构由 AI 辅助整理，请以论文原文为准。
AI总结：
基于巴西290,164次亚日暴雨事件，构建首个全国尺度经验Huff曲线，发现前置型（Q1）模式主导，与Huff(1967)参考接近，且本地曲线可显著提高设计洪峰估算，提供多尺度校准参数。
AI中文摘要：
时间降雨分布被广泛用于设计暴雨的构建；然而，许多亚日观测数据有限的国家，如巴西，仍然依赖在不同水文气候条件下开发的框架。这种不匹配可能会在水文设计和水资源估算中引入偏差。在此，我们利用亚日降雨观测数据，开发了巴西首个全国尺度的经验Huff曲线。我们汇编了来自3,164个站点的数据，经过质量控制后，保留了2010年至2025年间1,045个站点的290,164次暴雨事件。经验累积降雨质量曲线被构建，并在站点、生物群落、州和市镇尺度上使用七次多项式进行拟合。我们的研究结果显示，第一四分位数（Q1；前置型）暴雨模式占主导地位，在全国94.4%的站点出现，在亚马逊和塞拉多生物群落中增加到99.2%，而在大西洋森林中降至88.7%。全国Q1中位数曲线与Huff（1967）参考曲线非常接近（平均绝对误差MAE = 0.045；最大偏差Dmax = 0.097），且自举不确定性窄。Q1主导性对事件间隔时间定义具有稳健性，84.7%的站点在2至12小时阈值间分类一致。一项在579个源头流域进行的土壤保护局曲线数实验表明，相对于伊利诺伊参考，巴西曲线使设计洪峰流量中位数增加8%，在塞拉多最高增加11%，表明使用非本地分布可能导致低估。生物群落、州和市镇尺度的参数以开放数据形式并通过交互式平台提供，为巴西提供了本地校准的设计暴雨替代方案。
英文摘要：
Temporal rainfall distributions are widely used in design storm construction; however, many countries with limited sub-daily observations, such as Brazil, still rely on frameworks developed under different hydroclimatic conditions. This mismatch may introduce bias in hydrological design and water resources estimation. Here, we develop the first national-scale empirical Huff curves for Brazil using sub-daily rainfall observations. We compiled data from 3,164 stations and, after quality control, retained 290,164 storm events from 1,045 stations spanning 2010 to 2025. Empirical cumulative rainfall mass curves were constructed and fitted using seventh-degree polynomials at station, biome, state, and municipality scales. Our findings show a dominance of first-quartile (Q1; front-loaded) storm patterns, occurring at 94.4% of stations nationally, increasing to 99.2% in the Amazon and Cerrado biomes and decreasing to 88.7% in the Atlantic Forest. The national Q1 median curve closely matches the Huff (1967) reference (MAE = 0.045; Dmax = 0.097), with narrow bootstrap uncertainty. Q1 dominance is robust to inter-event time definition, with 84.7% of stations showing consistent classification across 2 to 12 h thresholds. A Soil Conservation Service Curve Number experiment across 579 headwater catchments shows that Brazilian curves increase design peak discharge by a median of 8% and up to 11% in the Cerrado relative to the Illinois reference, indicating potential underestimation when using non-local distributions. Biome-, state-, and municipality-scale parameters are provided as open data and through an interactive platform, offering locally calibrated design-storm alternatives for Brazil.
