5:15 PM - 6:45 PM
[AAS06-P01] Simultaneous Atmospheric and Oceanic Observation of Typhoon Khanun in 2023
Keywords:Typhoon, Wave glider
The impact of typhoons on the environment and social infrastructure has been a serious problem. In order to prepare early for typhoons, it is necessary to accurately grasp the condition of typhoons developing at sea before landfall. The authors have been working on the typhoon observation by Wave Glider (WG), which is an autonomous surface vehicle with the propulsion from waves [1],[2]. In this study, we report the results of the observation experiment near the center of Typhoon Khanun in 2023. The observation area was the south sea of Okinawa Island. As soon as the typhoon forecast was announced by the Japan Meteorological Agency, WGs were moved to observation points based on the forecasted track [2]. Typhoon Khanun (July 28 to August 10) occurred in the east of the Philippines, moved westward on the south side of the Okinawa Island and passed between 2 WGs. After that, the course was changed to the eastward, and it approached Okinawa Island again and went north.
Simultaneous atmospheric and oceanic data were obtained around 9:00 a.m. JST on August 2, when the typhoon was closest. The wind speed during the passage of the typhoon was observed about 75km to the right (north) and about 111km to the left (south) of the track by SV2 and SV3, respectively, in the storm area. The observation data show that the wind direction changes with the passage of the typhoon, and that the wind speed increases and decreases before and after the passage of the typhoon. In addition to important observation data related to the intensity and structure of the typhoon, observation data of ocean side such as wave and seawater temperature were also acquired, and the change with the passage of the typhoon was confirmed.
In this study, the simultaneous observation experiment of the atmosphere and the ocean by 2 WGs was carried out near the center of the typhoon. It was confirmed that the wind direction observed by WGs turned to the opposite direction as the typhoon passed between them. In the future, we would like to optimize the observation method including the observation equipment, while arranging the observation requirements for the prediction accuracy improvement.
References:
[1] S. Mitarai and J. C. McWilliams, “Wave glider observations of surface winds and currents in the core of Typhoon Danas,” GRL, 43, 11312-11319, 2016. doi:10.1002/2016GL071115
[2] N. Kosaka, et al., “Synchronous observations of atmosphere and ocean directly under typhoons using autonomous surface vehicles,” SOLA, 19, 116−125, 2023. doi:10.2151/sola.2023-016
Simultaneous atmospheric and oceanic data were obtained around 9:00 a.m. JST on August 2, when the typhoon was closest. The wind speed during the passage of the typhoon was observed about 75km to the right (north) and about 111km to the left (south) of the track by SV2 and SV3, respectively, in the storm area. The observation data show that the wind direction changes with the passage of the typhoon, and that the wind speed increases and decreases before and after the passage of the typhoon. In addition to important observation data related to the intensity and structure of the typhoon, observation data of ocean side such as wave and seawater temperature were also acquired, and the change with the passage of the typhoon was confirmed.
In this study, the simultaneous observation experiment of the atmosphere and the ocean by 2 WGs was carried out near the center of the typhoon. It was confirmed that the wind direction observed by WGs turned to the opposite direction as the typhoon passed between them. In the future, we would like to optimize the observation method including the observation equipment, while arranging the observation requirements for the prediction accuracy improvement.
References:
[1] S. Mitarai and J. C. McWilliams, “Wave glider observations of surface winds and currents in the core of Typhoon Danas,” GRL, 43, 11312-11319, 2016. doi:10.1002/2016GL071115
[2] N. Kosaka, et al., “Synchronous observations of atmosphere and ocean directly under typhoons using autonomous surface vehicles,” SOLA, 19, 116−125, 2023. doi:10.2151/sola.2023-016