摘要
The near-inertial waves(NIWs)are important for energy cascade in the ocean.They are usually significantly reinforced by strong winds,such as typhoon.Due to relatively coarse resolutions in contemporary climate models,NIWs and associated ocean mixing need to be parameterized.In this study,a parameterization for NIWs proposed by Jochum in 2013(J13 scheme),which has been widely used,is compared with the observations in the South China Sea,and the observations are treated as model outputs.Under normal conditions,the J13 scheme performs well.However,there are noticeable discrepancies between the J13 scheme and observations during typhoon.During Typhoon Kalmaegi in 2014,the inferred value of the boundary layer is deeper in the J13 scheme due to the weak near-inertial velocity shear in the vertical.After typhoon,the spreading of NIWs beneath the upper boundary layer is much faster than the theoretical prediction of inertial gravity waves,and this fast process is not rendered well by the J13 scheme.In addition,below the boundary layer,NIWs and associated diapycnal mixing last longer than the direct impacts of typhoon on the sea surface.Since the energy dissipation and diapycnal mixing below the boundary layer are bounded to the surface winds in the J13 scheme,the prolonged influences of typhoon via NIWs in the ocean interior are missing in this scheme.Based on current examination,modifications to the J13 scheme are proposed,and the modified version can reduce the discrepancies in the temporal and vertical structures of diapycnal mixing.
基金
The National Natural Science Foundation of China under contract Nos 42125601 and 42076001
the Scientific Research Fund of the Second Institute of Oceanography,Ministry of Natural Resources,under contract Nos HYGG2003 and QNYC2002
the project supported by the Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai)under contract No.SML2021SP207
the Oceanic Interdisciplinary Program of Shanghai Jiao Tong University under contract No.SL2020MS032
the CEES Visiting Fellowship Program under contract No.CEESRS202001
the Innovation Group Project of Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai)under contract No.311021001。
