伊朗骤旱的频率与强度并不同步：《科学报告》检出 7044 次骤发事件、16.9% 持续逾 90 天、数据跨 2003 至 2023 年
《科学报告》2026 年 11 月 11 日刊出 Hossein Shafizadeh-Moghadam 的研究，量化伊朗主要水文流域骤旱的三个不同特征。分析采用 ERA5-Land 与 GLDAS-2.1 数据推导的候尺度、0 至 100 厘米深度平均土壤湿度百分位，覆盖 2003 年至 2023 年。
事件判定标准为：土壤湿度在 4 个候内从第 40 百分位以上降至第 20 百分位以下，平均下降速率至少每候 5 个百分点。按此标准，分析共检出 7044 次快速发生的像元事件，其中 1188 次、占 16.9% 持续超过 90 天，另有 88 个右删失候选事件被排除在已完成事件的持续性计算之外。
流域尺度的差异明显。流域平均值范围为：事件频率每像元每年 0.004 至 0.707 次，强化速率每候 12.33 至 17.72 个百分点，受限持续时间 33.56 至 54.78 天。研究以 PAM 方法把流域分为三组，分别为 13 个、12 个和 5 个流域，显示伊朗国内存在实质差异；但其轮廓系数 0.254 和自助法 Jaccard 值 0.591 至 0.627 表明，这一划分是探索性的、而非定论。
趋势方面，5 个流域指标趋势的原始 p 值小于 0.05，但经错误发现率校正后均不再显著。作者结论为：骤旱的复发、发生速度和亚季节持续性是相互关联但不可互换的三个维度。本稿数字均以论文摘要为准。
Flash Drought Frequency and Intensity Do Not Move Together in Iran: Scientific Reports Detects 7,044 Rapid-Onset Events, 16.9 Percent Lasting over 90 Days, in Data from 2003 to 2023
Scientific Reports published a study by Hossein Shafizadeh-Moghadam on November 11, 2026, quantifying three distinct characteristics of flash drought across the major hydrological basins of Iran. The analysis used pentad-scale, 0 to 100 centimeter depth-averaged soil-moisture percentiles derived from ERA5-Land and GLDAS-2.1, covering 2003 to 2023.
Events were detected when soil moisture declined from above the 40th to below the 20th percentile within four pentads, at a mean rate of at least five percentile points per pentad. The analysis identified 7,044 rapid-onset pixel events. Of these, 1,188, or 16.9 percent, continued beyond 90 days, and 88 right-censored candidates were excluded from completed-event persistence.
Basin means ranged from 0.004 to 0.707 events per pixel per year, from 12.33 to 17.72 percentile points per pentad for intensification rate, and from 33.56 to 54.78 days for restricted persistence. A three-group PAM typology of 13, 12 and 5 basins revealed substantive within-country heterogeneity, although its silhouette score of 0.254 and bootstrap Jaccard values of 0.591 to 0.627 indicate an exploratory rather than definitive partition.
Five basin-metric trends had raw p values below 0.05, but none remained significant after false-discovery-rate correction. The author concludes that recurrence, onset rapidity and subseasonal persistence are related but non-interchangeable dimensions of flash drought behavior. All figures follow the abstract of the paper.
来源：《科学报告》
发布：GSM·美国（发布链接）
图片来源：图：图中是干裂的土地表面。图中是干旱土地的实物照片，为骤旱研究题材通用配图，非伊朗实地照片。Tomas Castelazo，CC BY 3.0，经Wikimedia Commons。 / Photo: file photo. Tomas Castelazo, CC BY 3.0, via Wikimedia Commons.
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