Progress Report
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Typhoon Control Research Aiming for a Safe and Prosperous Society[2] Engineering Approach
Progress until FY2025
1. Outline of the project
Effective typhoon intervention methods utilizing meteorological models have been studied by the meteorological approach team. However, to evaluate the practical feasibility of the proposed intervention methods, concurrent studies on specific intervention devices are required. Furthermore, while the impact assessment team estimates the amount of damage that could be reduced through typhoon control, it is also necessary to assess the costs and practical feasibility of implementing these methods to determine whether control actions should be undertaken. The engineering approach team conducts research to address these challenges.
2. Outcome so far
In the meteorological approach, cloud seeding has been identified as one of the promising methods for intervening in typhoons. Since FY2025, engineering studies have been conducted to realize this method in practice, with a primary focus on intervention approaches using ships and aircraft.
First, the use of ships has been investigated as a maritime platform for implementing interventions such as cloud seeding in the lower layer of typhoons. Model experiments in a large towing tank at Yokohama National University (Fig. 1), together with numerical simulations, were carried out to evaluate ship motions under strong winds and high waves conditions, and to assess the feasibility of operations in severe environments. The results indicate that ship-based operations are feasible under certain conditions even in typhoon environments. In addition, the effects of appendages installed on the ship bottom on motion characteristics were examined, providing insights into improving operational stability (Fig. 2).
Furthermore, a simulation tool has been developed using historical typhoon track data to evaluate the feasibility of ship-based interventions. This enables quantitative assessment of the extent to which intervention is possible depending on the typhoon’s track and propagation speed. Operational conditions such as departure timing, approach routes, and operation duration, assuming tracking of a moving typhoon, are also being investigated. These studies also provide insights into operational constraints under severe sea conditions. They help clarify key factors affecting the feasibility of sustained operations in typhoon environments.
Next, the use of aircraft, such as large transport planes, has been investigated as a means of deploying seeding materials from above a typhoon. Based on assumed aircraft performance, payload capacity, flight range, and operational modes have been examined, confirming that wide-area and rapid intervention is feasible. In addition, aircraft behavior when flying into a typhoon has been analyzed through simulations, providing fundamental insights into flight characteristics and control under strong wind conditions (Fig. 3). Furthermore, the effects of wind field distribution around the typhoon are considered, and studies on optimal intervention locations and timing for seeding material deployment are being conducted. These results also contribute to a better understanding of the practical constraints and operational considerations for real-world implementation.
Finally, when applying these methods in practice, it is essential to determine how much seeding material can be transported and how it can be delivered into the typhoon. Therefore, for both ships and aircraft, transport capacity, injection system configurations, and associated costs have been evaluated. In addition, injection systems have been investigated, and their applicable ranges and technical challenges have been identified.
Other approaches, including increasing surface friction, seawater spraying, thermal environment control, and suppression of ocean surface evaporation, have also been examined in terms of their technology readiness levels and estimated implementation costs.
3. Future plans
We will continue to advance the studies on the various intervention methods investigated so far, with the aim of their practical implementation. In particular, with a focus on cloud seeding, we will further develop ship- and aircraft-based approaches and clarify their applicable conditions. In addition, through close collaboration with the meteorological approach, we will examine the feasibility of interventions under realistic typhoon conditions, while also broadly exploring new approaches.