海洋表層鉛直混合におよぼす波浪の影響

Abstract

沿岸域における台風時の強風時の表層近くの強混合鉛直混合を対象に着目し，現地観測と数値計算を実施した。両者の解析結果から台風接近時に顕著な水温の低下が観測され，極浅海で生じる低温水が沖に輸送されて沿岸部の水温を低下される。海面での海面粗度やTKEフラックスを波浪のスペクトルから与えることにより，台風最接近時の水温低下が再現されている。

Since major driving forces of vertical mixing processes are wind and wind wave mixing, the boundary condition of turbulent kinetic energy flux at the ocean face is formulated as cubic of friction velocity by Craig-Banner relation. It is not well verified in general conditions including wave conditions and shallow water environment. This study estimates effects of wave conditions on vertical mixing processes at the ocean upper layers in the stormy condition. The field observation was conducted during typhoon Melor in 2009. The observed water temperature distributions indicate importance of wind and wave induced mixing in the nearshore. The numerical results show that the wave induced vertical turbulent flux significantly influences on the water temperature and the current, respectively.