发表机构
University of Iowa; Desert Research Institute; University of Maryland, College Park（爱荷华大学; 沙漠研究所; 马里兰大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究通过结合MCS跟踪数据、ERA5再分析、赤道罗斯贝波诊断和自组织映射，发现莫科阿山洪事件源于可重现的大尺度环境，而非孤立不可预测事件，从而证明部分中尺度对流系统可提前数小时至数天预测，支持灾害天气预报。
AI 中文摘要
中尺度对流系统（MCSs）产生了影响北南美洲（NOSA）的许多极端降水、洪水和滑坡，但由于它们强烈受局地过程控制，因此仍然难以预测。2017年3月31日晚，一个中尺度对流系统在哥伦比亚莫科阿引发了灾难性的山洪暴发——这一事件的严重性未能提前足够时间预见以采取应急行动，而应急行动通常需要几小时到几天的时间。受这次灾害的启发，本研究调查了此类事件是否出现在可重现的环境中，这些环境提供了大尺度可预测性的来源，而不是作为孤立的、本质上不可预测的事件出现。我们结合了21年（2001–2021）的中尺度对流系统跟踪数据集、ERA5再分析资料、赤道罗斯贝（ER）波诊断以及自组织映射（SOM），以识别与奥里诺科-亚马逊盆地中尺度对流系统发生相关的重现环境。莫科阿环境映射到九种重现配置之一，其特征是增强的低层湿度、中性的奥里诺科低层急流条件、有利的高层环流以及强烈的赤道罗斯贝波活动。我们进一步将对流前兆追溯到圭亚那高地的一个上游源区，该源区在到达莫科阿地区前最多24小时。综合这些结果，表明莫科阿事件并非气候学上的异常，而是可重现的、部分可预测的大尺度状态的一种高影响表现，证明了部分中尺度对流系统的可预测性源于可重现的大尺度条件，这些条件可以在数小时到数天前被监测，并支持北南美洲及其他热带地区的灾害性天气预报。
英文摘要
Mesoscale convective systems (MCSs) produce much of the extreme precipitation, floods, and landslides that affect northern South America (NOSA), yet remain difficult to anticipate because they are strongly governed by local processes. On the night of 31 March 2017, an MCS triggered a catastrophic flash flood in Mocoa, Colombia ---an event whose severity was not foreseen with sufficient lead time for emergency action, which typically requires several hours to a couple of days. Motivated by this disaster, this study investigates whether such events emerge within recurrent environments that provide a source of large-scale predictability, rather than as isolated and inherently unpredictable occurrences. We combine a 21-year (2001--2021) MCS tracking dataset, ERA5 reanalysis, equatorial Rossby (ER) wave diagnostics, and a Self-Organizing Map (SOM) to identify recurrent environments associated with MCS occurrence in the Orinoco--Amazon basin. The Mocoa environment maps onto one of nine recurrent configurations characterized by enhanced low-level moisture, neutral Orinoco low-level jet conditions, favorable upper-level circulation, and strong ER-wave activity. We further trace convective precursors to an upstream source region over the Guiana Highlands up to 24~h before arrival in the Mocoa region. Together, these results show that the Mocoa event was not climatologically exceptional but a high-impact expression of a recurrent, partly predictable large-scale regime, demonstrating that portion of MCS predictability arise from recurring large-scale conditions that can be monitored hours to days in advance, and support hazardous weather forecasting in NOSA and other tropical regions.
Comments36 pages, 17 Figures
