Evolution of double vortices induce tropical cyclogenesis of Seroja over Flores, Indonesia

• Published in: Natural hazards (Dordrecht) 2023-07, Vol.117 (3), p.2675-2692
• Main Authors: Yulihastin, Erma, Taofiqurohman, Ankiq, Fathrio, Ibnu, Nauval, Fadli, Andarini, Dita Fatria, Hatmaja, Rahaden Bagas, Fahim, Akhmad, Perdani, Namira Nasywa, Satyawardhana, Haries, Ismail, M. Furqon Azis, Nugroho, Dwiyoga, Suaydhi, Sofiati, Iis, Avia, Lely Qodrita, Ratnawati, Herlina Ika
• Format: Article
• Language: English
• Subjects: Civil Engineering; Convergence zones; Coriolis effect; Cyclogenesis; Cyclones; Earth and Environmental Science; Earth Sciences; Environmental Management; Equatorial waves; Geophysics/Geodesy; Geotechnical Engineering & Applied Earth Sciences; Heat waves; Hurricanes; Hydrogeology; Intertropical convergence zone; Madden-Julian oscillation; Natural Hazards; Original Paper; Planetary waves; Rossby waves; Synoptic scale waves; Tropical cyclogenesis; Tropical cyclones; Vortices; Vorticity; Wave packets; Wave trains
• ISSN: 0921-030X; 1573-0840
• DOI: 10.1007/s11069-023-05961-8

Over one hundred years of vigorous progress in tropical cyclone (TC) research, the genesis of the cyclone (hereafter, tropical cyclogenesis) is remarkable as a doubtful subject. Furthermore, predicting tropical cyclogenesis, particularly in the lesser latitude, remains a significant challenge. Therefore, understanding the complex interactions in developing tropical cyclogenesis over the region is vital to improving tropical cyclogenesis forecasting. Hence, the Indonesia Maritime Continent is a tropical cyclone-free region due to decreasing the Coriolis effect. However, Seroja TC hit Flores (8.6° S, 120° E), east Nusa Tenggara, Indonesia, on 4 April 2021, and was recorded as the first TC that occurred over the mainland, which brought a catastrophic disaster in the region. This study investigated the tropical cyclogenesis of Seroja by using observational and numerical studies. The results indicate that a marine heatwave and double vortices were favorable conditions that produced preconditions for developing tropical cyclogenesis over the Maluku Sea. Thus, tropical cyclogenesis is formed by the breakdown of the intertropical convergence zone (ITCZ) associated with synoptic-scale wave train driven under the interaction of the Madden Julian oscillation (MJO) and equatorial Rossby waves. Moreover, our finding suggested that an extensive background cyclonic vorticity under the cold pool mechanisms is responsible for maintaining tropical cyclogenesis into a persistent Seroja TC.