Synergistic Analysis of Moisture Flux and Convective Asymmetry in Tropical Cyclone Senyar
DOI:
https://doi.org/10.23960/jpg.v14.i2.94Keywords:
Tropical Cyclone Senyar, Moisture Flux, Convective Asymmetry, Atmospheric InstabilityAbstract
Tropical Cyclone Senyar was a rare near-equatorial tropical cyclone that triggered hydrometeorological disasters in Aceh and North Sumatera. This study aims to quantify the role of moisture flux convergence (MFC), intensity of shear convective asymmetry, and rainfall intensity and distribution of Senyar Tropical Cyclone during 23 – 28 November 2025. A quantitative descriptive approach used ERA5 reanalysis (streamline, moisture transport, Moisture Flux Convergence (MFC), and Vertical Wind Shear (VWS)), Himawari-9 convective index (CI), and GSMaP rainfall, partitioned into four shear-relative quadrants to calculate an Asymmetry Index (AI). Upper-air sounding data from Kualanamu Meteorological Station provided in situ validation of these remote sensing and reanalysis results through convective available potential energy (CAPE) and convective inhibition (CIN). A closed 850 hPa circulation with winds exceeding 45 knots developed together with strengthening MFC over northern Sumatra and the Malacca Strait, and the sounding showed CAPE of 2,041 J/kg on 25 November. Under weak to moderate VWS (12–19 knots), convection and rainfall concentrated in the downshear-left quadrant on 25 and 27 November (AI of rainfall = 0.97 and 2.64), but AI did not scale with VWS, and decay on 28 November followed landfall. Moisture supply governed the magnitude and persistence of rainfall, while shear organized its distribution.
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Ashcroft, J., Schwendike, J., Griffiths, S. D., Ross, A. N., & Short, C. J. (2021). The impact of weak environmental steering flow on tropical cyclone track predictability. Quarterly Journal of the Royal Meteorological Society, 147(741), 4122–4142.
Badan Meteorologi Klimatologi dan Geofisika. (2025, November). Siklon Tropis Senyar terbentuk, BMKG minta siaga cuaca ekstrem di Aceh dan Sumut.
Banacos, P. C., & Schultz, D. M. (2005). The use of moisture flux convergence in forecasting convective initiation: Historical and operational perspectives. Weather and Forecasting, 20(3), 351–366.
Barton, E. J., Klein, C., Taylor, C. M., Marsham, J., Parker, D. J., Maybee, B., Feng, Z., & Leung, L. R. (2025). Soil moisture gradients strengthen mesoscale convective systems by increasing wind shear. Nature Geoscience, 1–7.
Bi, M., Wang, R., Li, T., & Ge, X. (2023). Effects of vertical shear on intensification of tropical cyclones of different initial sizes. Frontiers in Earth Science, 11, 1106204.
Callaghan, J. (2024). Development of strong asymmetric convection leading to rapid intensification of tropical cyclones. Tropical Cyclone Research and Review, 13(4), 239–260.
Chambers, C. R. S., & Li, T. (2007). Simulation of formation of a near-equatorial typhoon Vamei (2001). Meteorology and Atmospheric Physics, 98(1), 67–80.
Chang, C., Liu, C., & Kuo, H. (2003). Typhoon Vamei: An equatorial tropical cyclone formation. Geophysical Research Letters, 30(3).
Chang, C.-P., Wang, Z., McBride, J., & Liu, C.-H. (2005). Annual cycle of Southeast Asia—Maritime Continent rainfall and the asymmetric monsoon transition. Journal of Climate, 18(2), 287–301.
Chen, S. S., Knaff, J. A., & Marks Jr, F. D. (2006). Effects of vertical wind shear and storm motion on tropical cyclone rainfall asymmetries deduced from TRMM. Monthly Weather Review, 134(11), 3190–3208.
Chen, X., Rozoff, C. M., Rogers, R. F., Corbosiero, K. L., Tao, D., Gu, J.-F., Judt, F., Hendricks, E. A., Wang, Y., & Bell, M. M. (2023). Research Advances on Internal Processes Affecting Tropical Cyclone Intensity Change from 2018–2022. Tropical Cyclone Research and Review, 12(1), 10–29.
Corbosiero, K. L., & Molinari, J. (2002). The effects of vertical wind shear on the distribution of convection in tropical cyclones. Monthly Weather Review, 130(8), 2110–2123.
Dong, W., Lin, Y., Wright, J. S., Xie, Y., Yin, X., & Guo, J. (2019). Precipitable Water and CAPE Dependence of Rainfall Intensities in China. Climate Dynamics, 52(5), 3357–3368.
Emerton, R., Hodges, K. I., Stephens, E., Amelie, V., Mustafa, M., Rakotomavo, Z., Coughlan de Perez, E., Magnusson, L., & Vidale, P. (2024). How well can global ensemble forecasts predict tropical cyclones in the southwest Indian Ocean? Meteorological Applications, 31(3), e2195.
Fang, R., Chen, S., Zhou, M., Li, W., Xiao, H., Zhan, T., Wu, Y., Liu, H., & Tu, C. (2021). Periodic cycles of eyewall convection limit the rapid intensification of Typhoon Hato (2017). Advances in Meteorology, 2021(1), 5557448.
Fibriantika, E., & Alhaqq, R. I. (2018). Profil vertikal atmosfer selama aktifitas siklon tropis Cempaka dan Dahlia. Jurnal Meteorologi Dan Geofisika, 19(2), 49–58.
Fitri, N., Muliadi, M., & Adriat, R. (2022). Analisis Dampak Siklon Tropis Pabuk terhadap Unsur Cuaca di Kalimantan Barat. Prisma Fisika, 10(1), 14–18.
Frank, W. M., & Ritchie, E. A. (2001). Effects of Vertical Wind Shear on the Intensity and Structure of Numerically Simulated Hurricanes. Monthly Weather Review, 129(9), 2249–2269.
Fu, H., & O’Neill, M. E. (2025). A quasi-2D model of convectively coupled vortices. Journal of the Atmospheric Sciences.
Holton, J. R., & Hakim, G. J. (2013). An introduction to dynamic meteorology (Vol. 88). Academic press.
Houze Jr, R. A. (2010). Clouds in tropical cyclones. Monthly Weather Review, 138(2), 293–344.
Huang, Q., Ge, X., & Peng, M. (2021). Simulation of Rapid Intensification of Super Typhoon Lekima (2019). Part I: Evolution Characteristics of Asymmetric Convection Under Upper-Level Vertical Wind Shear. Frontiers in Earth Science, 9, 739507.
Ji, D., & Qiao, F. (2023). What Are the Balanced and Unbalanced Dynamics of a Tropical Cyclone? Journal of the Atmospheric Sciences, 80(7), 1719–1737.
Kieu, C., Rotunno, R., & Wang, Q. (2020). Frictionally induced feedback in a reduced dynamical model of tropical cyclone intensification. Journal of the Atmospheric Sciences, 77(11), 3821–3831.
Kilroy, G., Smith, R. K., & Montgomery, M. T. (2020). An idealized numerical study of tropical cyclogenesis and evolution at the Equator. Quarterly Journal of the Royal Meteorological Society, 146(727), 685–699.
Kim, D., Park, D.-S. R., Nam, C. C., & Bell, M. M. (2022). The Parametric Hurricane Rainfall Model with Moisture and Its Application to Climate Change Projections. Npj Climate and Atmospheric Science, 5(1), 86.
Kim, S., Lee, W., Won, S., Kang, H.-W., Kim, K. O., & Kang, S. K. (2025). Sensitivity analysis of drag coefficient and length scale of wind influence on tropical cyclone intensity change using net energy gain rate. Frontiers in Marine Science, 12, 1536014.
Kubota, T., Shige, S., Hashizume, H., Aonashi, K., Takahashi, N., Seto, S., Hirose, M., Takayabu, Y. N., Ushio, T., & Nakagawa, K. (2007). Global precipitation map using satellite-borne microwave radiometers by the GSMaP project: Production and validation. IEEE Transactions on Geoscience and Remote Sensing, 45(7), 2259–2275.
Li, Y., Jiang, Y., Chan, J. C. L., & Cheung, K. K. W. (2024). Development of Asymmetric Convection in a Tropical Cyclone under Environmental Uniform Flow and Vertical Wind Shear. Advances in Atmospheric Sciences, 41(12), 2399–2418.
Marquis, J. N., Varble, A. C., Robinson, P., Nelson, T. C., & Friedrich, K. (2021). Low-level mesoscale and cloud-scale interactions promoting deep convection initiation. Monthly Weather Review, 149(8), 2473–2495.
Moon, I.-J., Knutson, T. R., Kim, H.-J., Babanin, A. V, & Jeong, J.-Y. (2022). Why do eastern North Pacific hurricanes intensify more and faster than their western-counterpart typhoons with less ocean energy? Bulletin of the American Meteorological Society, 103(11), E2604–E2627.
Mulia, I. E., Shimada, U., Ueda, N., Miyoshi, T., & Maulana, M. T. (2025). Multi-horizon prediction of tropical cyclone intensity and its interpretability with temporal fusion transformer. Scientific Reports, 15(1), 31284.
Nebylitsa, S., Nolan, D. S., McNoldy, B. D., & Majumdar, S. J. (2025). Rapid versus slow intensification of idealized tropical cyclones using soundings from reanalysis. Quarterly Journal of the Royal Meteorological Society, e5011.
Nelson, T. C., Marquis, J., Peters, J. M., & Friedrich, K. (2022). Environmental controls on simulated deep moist convection initiation occurring during RELAMPAGO-CACTI. Journal of the Atmospheric Sciences, 79(7), 1941–1964.
Pinuji, S., Kurniawan, A., & Wicaksono, F. Y. E. (2025). Gerak Cepat di Tengah Katastrofe: Pendataan Terpilah untuk Respons Bencana yang Tepat dan Inklusif di Tiga Provinsi - Aceh, Sumatra Utara, dan Sumatra Barat (T. Harjito, N. Pramudhiarta, A. C. Utomo, & F. Irawan, Eds.). Pusat Data, Informasi dan Komunikasi Kebencanaan Badan Nasional Penanggulangan Bencana.
Reasor, P. D., Rogers, R., & Lorsolo, S. (2013). Environmental flow impacts on tropical cyclone structure diagnosed from airborne Doppler radar composites. Monthly Weather Review, 141(9), 2949–2969.
Riemer, M., Montgomery, M. T., & Nicholls, M. E. (2010). A new paradigm for intensity modification of tropical cyclones: Thermodynamic impact of vertical wind shear on the inflow layer. Atmospheric Chemistry and Physics, 10(7), 3163–3188.
Rios-Berrios, R., Finocchio, P. M., Alland, J. J., Chen, X., Fischer, M. S., Stevenson, S. N., & Tao, D. (2024). A review of the interactions between tropical cyclones and environmental vertical wind shear. Journal of the Atmospheric Sciences, 81(4), 713–741.
Sahu, R., Tyagi, B., Vissa, N., & Mohapatra, M. (2022). Pre-monsoon thunderstorm season climatology of convective available potential energy (CAPE) and convective inhibition (CIN) over eastern India. Mausam, 73(3), 565–586.
Steenkamp, S. C., Kilroy, G., & Smith, R. K. (2019). Tropical cyclogenesis at and near the Equator. Quarterly Journal of the Royal Meteorological Society, 145(722), 1846–1864.
Tang, B., & Emanuel, K. (2010). Midlevel ventilation’s constraint on tropical cyclone intensity. Journal of the Atmospheric Sciences, 67(6), 1817–1830.
Tao, D., & Zhang, F. (2019). Evolution of dynamic and thermodynamic structures before and during rapid intensification of tropical cyclones: Sensitivity to vertical wind shear. Monthly Weather Review, 147(4), 1171–1191.
Tompkins, A. M., & Semie, A. G. (2017). Organization of tropical convection in low vertical wind shears: Role of updraft entrainment. Journal of Advances in Modeling Earth Systems, 9(2), 1046–1068.
Ushio, T., Sasashige, K., Kubota, T., Shige, S., Okamoto, K., Aonashi, K., Inoue, T., Takahashi, N., Iguchi, T., & Kachi, M. (2009). A Kalman filter approach to the Global Satellite Mapping of Precipitation (GSMaP) from combined passive microwave and infrared radiometric data. 気象集誌. 第 2 輯, 87, 137–151.
Wilcox, E. M., Yuan, T., & Song, H. (2023). Deep convective cloud system size and structure across the global tropics and subtropics. Atmospheric Measurement Techniques, 16(21), 5387–5401.
Zhao, D., Yu, Y., & Chen, L. (2021). Impact of the monsoonal surge on extreme rainfall of landfalling tropical cyclones. Advances in Atmospheric Sciences, 38(5), 771–784.
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Copyright (c) 2026 Adilaksa Kharisma, Muhammad Fadhillah, Yosafat Donni Haryanto, Eriska Febriati (Author)
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