Scholarlink

<p>The 2021 Peninsular Malaysia Flood, triggered by Tropical Depression 29&#xa0;W (TD 29&#xa0;W), displaced over 125,000 people and claimed 54 lives. This study demonstrates that the event was driven by a convergence of synoptic-scale disturbances and equatorial wave interactions. Synoptic analyses revealed the influence of Typhoon Rai and enhanced monsoonal flow on the trajectory and intensification of TD 29&#xa0;W. Equatorial waves—specifically the Madden–Julian Oscillation (MJO), convectively coupled Kelvin waves (CCKWs), and equatorially coupled Rossby waves (CCERWs)—were found to modulate convective activity and contribute to the evolution of the Borneo Vortex (BV), which later intensified into TD 29&#xa0;W. Using a 15-year climatological baseline (2006–2020) of GPM IMERG precipitation data, we quantified wave contributions through regression-based diagnostics. Simple linear regression (SLR) showed that CCKW was the dominant contributor, accounting for 64.40&#xa0;mm of the total 166.23&#xa0;mm rainfall anomaly, followed by MJO (20.08&#xa0;mm) and CCERW (13.65&#xa0;mm), with the combined SLR reconstruction showing strong agreement with observed rainfall anomalies (<i>r</i> = 0.79). To isolate independent wave effects, multiple linear regression (MLR), which accounts for covariability among wave modes, was applied and likewise achieved high predictive skill (<i>r</i> = 0.79), confirming that all three wave types jointly influenced the event. In the MLR framework, Kelvin waves remained the strongest independent contributor (12.53&#xa0;mm), followed by MJO (9.68&#xa0;mm) and ER waves (8.20&#xa0;mm), indicating substantial overlap and constructive interaction among the wave modes. Further analyses of wave propagation and vertical wind structure revealed that low-level winds played a key role in the quasi-stationary behavior of the system. This study underscores the importance of equatorial wave interactions in extreme rainfall development and highlights their relevance for improving flood prediction in the Maritime Continent.</p>

错误：搜索内容不能为空，请输入英文关键词
错误：关键词超出字数限制，请精简
高级检索

Equatorial wave embedded within the Madden-Julian oscillation leading to the 2021 Peninsular Malaysia flood

  • 期刊论文

  • 发表日期：

    2026年7月31日

查看全文
  • Jackson Hian-Wui Chang,
  • Maggie Chel-Gee Ooi,
  • Juneng Liew,
  • Yong Jie Wong,
  • Fuei Pien Chee,
  • Justin Sentian,
  • Putu Aryastana,
  • Jason Pajimola Punay,
  • Neng-Huei Lin

摘要

The 2021 Peninsular Malaysia Flood, triggered by Tropical Depression 29 W (TD 29 W), displaced over 125,000 people and claimed 54 lives. This study demonstrates that the event was driven by a convergence of synoptic-scale disturbances and equatorial wave interactions. Synoptic analyses revealed the influence of Typhoon Rai and enhanced monsoonal flow on the trajectory and intensification of TD 29 W. Equatorial waves—specifically the Madden–Julian Oscillation (MJO), convectively coupled Kelvin waves (CCKWs), and equatorially coupled Rossby waves (CCERWs)—were found to modulate convective activity and contribute to the evolution of the Borneo Vortex (BV), which later intensified into TD 29 W. Using a 15-year climatological baseline (2006–2020) of GPM IMERG precipitation data, we quantified wave contributions through regression-based diagnostics. Simple linear regression (SLR) showed that CCKW was the dominant contributor, accounting for 64.40 mm of the total 166.23 mm rainfall anomaly, followed by MJO (20.08 mm) and CCERW (13.65 mm), with the combined SLR reconstruction showing strong agreement with observed rainfall anomalies (r = 0.79). To isolate independent wave effects, multiple linear regression (MLR), which accounts for covariability among wave modes, was applied and likewise achieved high predictive skill (r = 0.79), confirming that all three wave types jointly influenced the event. In the MLR framework, Kelvin waves remained the strongest independent contributor (12.53 mm), followed by MJO (9.68 mm) and ER waves (8.20 mm), indicating substantial overlap and constructive interaction among the wave modes. Further analyses of wave propagation and vertical wind structure revealed that low-level winds played a key role in the quasi-stationary behavior of the system. This study underscores the importance of equatorial wave interactions in extreme rainfall development and highlights their relevance for improving flood prediction in the Maritime Continent.