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Abstract

A study of the different types of dual-vortex interactions or “Fujiwara effects” between two storms is crucial for considerably improving weather forecasts. This study combined remote sensing images, empirical formulas based on the possibility of storm interaction (Liou–Liu formula), and vector addition techniques to accurately analyze In-Fa and Cempaka typhoons and the surrounding weather patterns during the 2021 typhoon season in the North Pacific. Although the distance separating the typhoons In-Fa and Cempaka was 1,800–2,040 km, the influence of middle air flow and a tropical depression (TD) caused a "vector superposition TD-mosaic double-vortex" interaction between the two typhoons. Therefore, this paper proposes a new dual-vortex interaction between the typhoons studied here. This newly discovered interaction is different from the normally observed double-vortex interaction between storms. In the same context, these interactions caused strong typhoons with eye diameters of 20, 25, 55, 60, 65, 75, and 100 km and led to the turning and U-turn trajectories of the typhoons In-Fa and Cempaka. This paper uses linear (vector) space technology, namely vector addition diagrams, to describe the vector addition TD-mosaic double-vortex interaction between tropical cyclones and TDs.

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