2 0 0 0 OA 風波砕波によるホワイトキャップ現象の高速ビデオカメラによる可視化
大気-海洋間の気体輸送現象に対するホワイトキャップの影響を明らかにするため,3台の高速ビデオカメラを用いた画像計測法により,風波界面近傍の流れ場計測技術を開発し,ホワイトキャップが生じている近傍の流れ場を明らかにした.さらに,気流と風波発達の関係も画像計測により明らかにした.また,砕波により生じた気泡の特性を画像計測により明らかにした.さらに,全球規模での大気-海洋間の気体輸送に対する砕波の影響も現地計測データや衛星データを用いて評価した.
- 著者
- 鈴木 直弥 上田 陽平 高垣 直尚 植木 巌 池田 篤俊
- 出版者
- Advanced Marine Science and Technology Society
- 雑誌
- 海洋理工学会誌 (ISSN:13412752)
- 巻号頁・発行日
- vol.27, no.1, pp.73-79, 2022-07-30 (Released:2022-08-27)
- 参考文献数
- 23
Drag coefficient on the ocean surface is determined by various studies based on different mechanisms, such as turbulence and wave breaking, closely related to wind speed. The global ocean datasets of wind speed are distributed by various temporal resolutions based on reanalysis, assimilation, and satellite data. Recently, the wind speed data with higher temporal resolution have been provided. Using 6-hourly and hourly wind datasets, the air-sea momentum fluxes were estimated by several drag coefficient models proposed by Large & Yeager (2009), Andreas et al. (2012), Takagaki et al. (2012), & Hwang (2018). The globally averaged annual mean air-sea momentum fluxes were derived from the different drag coefficient models. The maximum difference of the annual mean values among the models reaches approximately 30% of annual mean values. The meridional structure of zonally averaged annual mean air-sea momentum flux has double peak at relatively higher latitudes from 40°S/N to 60°N/S. At those peaks maximum difference among the models reaches more than 30% of the zonally averaged annual mean. In terms of differences in temporal resolution on the wind speed datasets on each grid, the differences between hourly and 6-hourly wind data became larger with decreasing average period. The maximum difference of 66.7% was recognized on daily mean. The large difference was remarkable in higher wind speed regions, such as typhoon’s paths in the western Pacific. The effects of wind variability on different temporal resolution datasets are significant for estimating the air-sea momentum flux.