[A-AS06] Advances in Tropical Cyclone Research: Past, Present, and Future

[AAS06-07] Application of Spectral Winds Observation during Typhoon Khanun

Satoshi Mitarai^1,4, *Tunggul Bhirawa¹, Melissa Tanaka¹, Heng Wu¹, Akinori Murata¹, Naoko Kosaka², Naoto Endou², Tsuneko Kura², Masaki Hisada², Koki Iida², Tomoya Shimura³, Nobuhito Mori³ (1.Okinawa Institute of Science and Technology (OIST), Japan, 2.NTT Space Environment and Energy Laboratories, Japan, 3.Kyoto University, Japan, 4.Typhoon Science and Technology Research Center (TRC), Japan)

Keywords:Tropical Cyclone, Typhoon, Ocean Observation, Air-Sea Interaction, Wind-wave equilibrium, Wind Energy Spectra

The role of air-sea interaction and momentum transfer across the interface remains critical, especially during extreme weather events such as typhoons. Ocean surface wind measurements are crucial for improving climate modeling, enhancing our comprehension of typhoon dynamics, and aiding in better forecasting and disaster preparedness. Given the logistical challenges of wind observation during typhoons, proxy measurements become invaluable. By utilizing spectral wave information within a high-frequency range and adhering to the wind-wave equilibrium proposed by Phillips (1985), proxy measurements offer a practical method for estimating wind speed from surface wave observations. Previous studies by Thomson et al. (2018), Voermans et al. (2020), and Shimura et al. (2022) have demonstrated wind speed measurements derived from wave observations. We further examine the feasibility of this proxy measurement under extreme wind regimes during typhoons. The study was conducted between July and August when Typhoon Khanun passed over Okinawa. We deployed Spotter buoys due to their compact size and sensitivity to high-frequency waves. Additionally, we utilized the maneuverability of Wave Gliders to intercept typhoons, as previously demonstrated by Mitarai and McWilliams (2016) during Typhoon Danas. The accuracy of the wind measurements is further evaluated by comparing them with data from the weather stations, numerical modelling, and anemometer readings aboard the Wave Glider.