Equatorial Waves Triggering Extreme Rainfall and Floods in Southwest Sulawesi, Indonesia
Equatorial Waves Triggering Extreme Rainfall and Floods in Southwest Sulawesi, Indonesia
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DOI：
10.1175/mwr-d-20-0262.1
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发表时间：
2021-03
影响因子：
3.2
通讯作者：
Beata Latos;T. Lefort;M. Flatau;P. Flatau;Donaldi S Permana;D. Baranowski;J. A. I. Paski;E. Makmur;Eko Sulystyo;P. Peyrillé;Zhe Feng;A. Matthews;Jerome M. Schmidt
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文献类型：
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作者：
Beata Latos;T. Lefort;M. Flatau;P. Flatau;Donaldi S Permana;D. Baranowski;J. A. I. Paski;E. Makmur;Eko Sulystyo;P. Peyrillé;Zhe Feng;A. Matthews;Jerome M. Schmidt
通过对案例研究和长期气候学的详细分析，结果表明，赤道波及其相互作用是印度尼西亚苏拉威西岛西南部海洋大陆中部地区极端降雨和洪水事件的前兆。对 2019 年 1 月 22 日导致该地区强降雨和毁灭性洪水的气象条件进行了研究。结果表明，嵌入马登-朱利安振荡（MJO）增强对流阶段的大尺度包络内的对流耦合开尔文波（CCKW）和对流耦合赤道罗斯比波（CCERW）促成了爪哇海上空发展的中尺度对流系统的爆发。 CCKW 的低层辐合迫使中尺度对流组织和湿空气在苏拉威西岛西南部山坡上空上升。气候学分析显示，该地区 92% 的 12 月至 2 月洪水和 76% 的极端降雨事件发生前都出现了低层西风异常。据估计，CCKW 和 CCERW 在苏拉威西岛上空传播，使洪水和极端降雨事件发生的可能性增加了一倍，而在其联合活动期间发生此类危险事件的概率是随机一天的 8 倍。虽然 MJO 是影响热带大气变化的关键组成部分，但事实表明，它作为极端天气驱动的灾害预测的单一因素的有用性是有限的。
On the basis of detailed analysis of a case study and long-term climatology, it is shown that equatorial waves and their interactions serve as precursors for extreme rain and flood events in the central Maritime Continent region of southwest Sulawesi, Indonesia. Meteorological conditions on 22 January 2019 leading to heavy rainfall and devastating flooding in this area are studied. It is shown that a convectively coupled Kelvin wave (CCKW) and a convectively coupled equatorial Rossby wave (CCERW) embedded within the larger-scale envelope of the Madden–Julian oscillation (MJO) enhanced convective phase, contributed to the onset of a mesoscale convective system that developed over the Java Sea. Low-level convergence from the CCKW forced mesoscale convective organization and orographic ascent of moist air over the slopes of southwest Sulawesi. Climatological analysis shows that 92% of December–February floods and 76% of extreme rain events in this region were immediately preceded by positive low-level westerly wind anomalies. It is estimated that both CCKWs and CCERWs propagating over Sulawesi double the chance of floods and extreme rain event development, while the probability of such hazardous events occurring during their combined activity is 8 times greater than on a random day. While the MJO is a key component shaping tropical atmospheric variability, it is shown that its usefulness as a single factor for extreme weather-driven hazard prediction is limited.