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Modeling of the eddy viscosity by breaking waves

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Acta Oceanologica Sinica 2007年第6期26卷 116-123页

作者： ZHANG Shuwen yuan yeli ZHENG Quan＇ an South China Sea Environmental Institute Guangdong Ocean University Zhanjiang 524088 China Key Laboratory of Marine Science and Numerical Modeling of State Oceanic Administration First Institute of Oceanography State Oceanic Administration Qingdao 266061 China Department of Meteorology Maryland University Maryland 20742 USA

Breaking wave induced nearsurface turbulence has important consequences for many physical and biochemical processes including water column and nutrients mixing, heat and gases exchange across air-sea interface. The energy loss from wave breaking and the bubble plume penetration depth are estimated. As a consequence, the vertical distribution of the turbulent kinetic energy （TKE）, the TKE dissipation rate and the eddy viscosity induced by wave breaking are also provided. It is indicated that model results are found to be consistent with the observational evidence that most TKE generated by wave breaking is lost within a depth of a few meters near the sea surface. High turbulence level with intensities of eddy viscosity induced by breaking is nearly four orders larger than vw1（ = κu ＊wz）, the value predicted for the wall layer scaling close to the surface, where u ＊w is the friction velocity in water, κ with 0. 4 is the yon Kármán constant, and z is the water depth, and the strength of the eddy viscosity depends both on wind speed and sea state, and decays rapidly through the depth. This leads to the conclusion that the breaking wave induced vertical mixing is mainly limited to the near surface layer, well above the classical values expected from the similarity theory. Deeper down, however, the effects of wave breaking on the vertical mixing become less important.

关键词： air-sea interface near-surface dynamics TKE dissipation rate eddy viscosity

Statistical model on the surface elevation of waves with breaking

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Science China Earth Sciences 2008年第5期51卷 759-768页

作者： yuan yeli HUA Feng ZHANG ShuWen HAN Lei Marine Science and Numerical Modeling Laboratory SOAQingdao 266061China First Institute of Oceanography SOAQingdao 266061China South China Sea Environmental Institute Guangdong Ocean UniversityZhanjiang 524088China

In the surface wind drift layer with constant momentum flux, two sets of the consistent surface eleva- tion expressions with breaking and occurrence conditions for breaking are deduced from the first in- tegrals of the energy and vortex variations and the kinetic and mathematic breaking criterions, then the expression of the surface elevation with wave breaking is established by using the Heaviside function. On the basis of the form of the sea surface elevation with wave breaking and the understanding of small slope sea waves, a triple composite function of real sea waves is presented including the func- tions for the breaking, weak-nonlinear and basic waves. The expression of the triple composite func- tion and the normal distribution of basic waves are the expected theoretical model for surface elevation statistics.

关键词： first integrals for energy and vortex variations in wind drift layer kinetic and mathematic wave breaking criterions triple composite function of the real sea waves normal distribution of the basic waves

Mesoscale characteristics of Antarctic Intermediate Water in the South Pacific

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Acta Oceanologica Sinica 2015年第11期34卷 92-101页

作者： FENG Ying CHEN Xianyao WANG Qin yuan yeli College of Ocean and Earth Sciences Xiamen University Key Laboratory of Physcial Oceanography Ocean University of China Marine Monitoring and Forecasting Center of Zhejiang Key Laboratory of Marine Science and Numerical Modeling the First Institute of OceanographyState Oceanic Administration

The Argo float observations are used to investigate the mesoscale characteristics of the Antarctic Intermediate Water （AAIW） in the South Pacific in this paper. It is shown that a subsurface mesoscale phenomenon is probably touched by an Argo float during the float＇s ascent-descent cycles and is identified by the horizontal salinity gradient between the vertical temperature-salinity profiles. This shows that the transportation of the AAIW may be accompanied with the rich mesoscale characteristics. To derive the spatial length, time, and propagation characteristics of the mesoscale variability of the AAIW, the gridded temperature-salinity dataset ENACT/ENSEMBLE Version 3 constructed on the in-situ observations in the South Pacific since 2005 is used. The Empirical Mode Decomposition method is applied to decompose the isopycnal-averaged salinity anomaly from 26.8 cr0-27.4 ao, where the AAIW mainly resides, into the basin scale and two mesoscale modes. It is found that the first mesoscale mode with the length scale on the order of 1 000 km explains nearly 50% variability of the mesoscale characteristics of the AAIW. Its westward-propagation speeds are slower in the mid-latitude （around 1 cm/s） and faster in the low latitude （around 6 cm/s）, but with an increasing in the latitude band on 25^-30~S. The second mesoscale mode is of the length scale on the order of 500 km, explaining about 30% variability of the mesoscale characteristics of the AAIW. Its westward-propagation speed keeps nearly unchanged （around 0.5 cm/s）. These results presented the stronger turbulent motion of the subsurface ocean on the spatial scale, and also described the significant role of Argo program for the better understanding of the deep ocean.

关键词： mesoscale characteristics subsurface ocean Antarctic Intermediate Water (AAIW) Argo

Multi-core structure of the main part of the Kuroshio at G-PN section in the East China Sea

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Chinese Science Bulletin 2006年第6期51卷 738-746页

作者： CHEN Hongxia yuan yeli HUA Feng Institute of Oceanology Chinese Academy of Sciences Qingdao266071 China First Institute of Oceanography State Oceanic Administration Qingdao 266061 China Graduate School of Chinese Academy of Sciences Beijing 100039China

Sectional velocity distribution of the East China Sea Kuroshio is one of the basic points in the study of the Kuroshio. Hydrographic temperature and salinity data at G-PN section in the East China Sea from June 1955 to November 2001 are collected and properly processed to calculate the geostrophic cur-rent using dynamic height method at the transect of the Kuroshio. After analysis of calculation results, the basic current structure of the Kuroshio in its main part is examined together with scalar estimate and char-acters of multi- core structure, and spacial-temporal variations of current cores’ position. Main result shows that (1) single-core structure, double-core structure and multi-core structure are basic forms in axial part of the Kuroshio; (2) abvious temporal varia-tions exist in current structure of the Kuroshio; (3) the current of structure of the Kuroshio has distinctly seasonal association. The number of current cores is on the high side of core numbers in average and multi-core stucture appears in fall mostly.

关键词：黑潮中国东海日本洋流多中心结构速度分布

Seasonal variability of the wind-generated near-inertial energy flux in the South China Sea

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Acta Oceanologica Sinica 2019年第4期38卷 136-145页

作者： Baonan Sun Zhan Lian yeli yuan Haiyang Xu College of Oceanic and Atmospheric Sciences Ocean University of China Key Laboratory of Marine Science and Numerical Modeling First Institute of OceanographyMinistry of Natural Resources Laboratory for Regional Oceanography and Numerical Modeling Pilot National Laboratory for Marine Science and Technology (Qingdao)

After validated by the in-situ observation, the slab model is used to study the wind-generated near-inertial energy flux(NIEF) in the South China Sea(SCS) based on satellite-observed wind data, and its dependence on calculation methods and threshold criteria of the mixed layer depth(MLD) is investigated. Results illustrate that the total amount of NIEF in the SCS could be doubled if different threshold criteria of MLD are adopted. The NIEF calculated by the iteration and spectral solutions can lead to a discrepancy of 2.5 GW(1 GW=1×109 W). Results also indicate that the NIEF exhibits spatial and temporal variations, which are significant in the boreal autumn,and in the southern part of the SCS. Typhoons are an important generator of NIEF in the SCS, which could account for approximately 30% of the annual mean NIEF. In addition, deepening of the MLD due to strong winds could lead to a decrease of NIEF by approximately by 10%. We re-estimate the annual mean NIEF in the SCS,which is(10±4) GW and much larger than those reported in previous studies.

关键词： near-inertial energy flux mixed layer depth South China Sea typhoon

The role of surface waves in the ocean mixed layer

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Acta Oceanologica Sinica 2008年第3期27卷 30-37页

作者： QIAO Fangli YANG Yongzeng XIA Changshui yuan yeli First Institute of Oceanography State Oceanic Administration Qingdao 266061 China

Previously, most ocean circulation models have overlooked the role of the surface waves. As a result, these models have produced insufficient vertical mixing, with an under - prediction of the ,nixing layer （ML） depth and an over - prediction of the sea surface temperature （SST）, particularly during the summer season. As the ocean surface layer determines the lower boundary conditions of the atmosphere, this deficiency has severely limited the performance of the coupled ocean - atmospheric models and hence the climate studies. To overcome this shortcoming, a new parameterization for the wave effects in the ML model that will correct this systematic error of insufficient mixing. The new scheme has enabled the mixing layer to deepen, the surface excessive heating to be corrected, and an excellent agreement with observed global climatologic data. The study indicates that the surface waves are essential for ML formation, and that they are the primer drivers of the upper ocean dynamics; therefore, they are critical for climate studies.

关键词： wave - induced mixing ocean circulation model mixing layer

Barrier and compensation layers in the East China Sea

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Acta Oceanologica Sinica 2008年第3期27卷 70-78页

作者： CHEN Xianyao QIAO Fangli WANG Qin WANG Xiuhongx yuan yeli Key Laboratory of Marine Science and Numerical Modeling of State Oceanic Administration First Institute of Oceanography State Oceanic Administration Qingdao 266061 China

Climatology of the isothermal layer depth （ILD） and the mixed layer depth （MLD） has been produced from in-situ temperaturesalinity observations in the East China Sea （ECS） since 1925. The methods applied on the global are used to compute the ILD and the MLD in the ECS with a temperature criterion AT=0. 8 ℃ for the ILD, and a density criterion with a threshold △σθ corresponding to fixed △T=0. 8 ℃ for the MLD, respectively. With the derived climatology ILD and MLD, the monthly variations of the barrier layer （BL） and the compensation layer （CL） in the ECS are analyzed. The BL mainly exists in the shallow water region of the ECS during April-June with thickness larger than 15 m. From December to next March, the area along the shelf break from northeast of Taiwan Island to the northeast ECS is characterized by the CL. Two kinds of main temperature - salinity structures of the CL in this area are given.

关键词： isothermal layer depth mixed layer depth barrier layer compensation layer East China Sea

Principal-component estimates of the Kuroshio Current axis and path based on the mathematical verification between satellite altimeter and drifting buoy data

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Acta Oceanologica Sinica 2020年第1期39卷 14-24页

作者： Zhanpeng Zhuang Zhenli Hui Guangbing Yang Xinhua Zhao yeli yuan The First Institute of Oceanography Ministry of Natural ResourcesQingdao 266100China Laboratory for Regional Oceanography and Numerical Modeling Qingdao National Laboratory for Marine Science and TechnologyQingdao 266237China Institute of Oceanology Chinese Academy of SciencesQingdao 266071China

We used satellite altimetry data to investigate the Kuroshio Current because of the higher resolution and wider range of observations. In previous studies, satellite absolute geostrophic velocities were used to study the spatiotemporal variability of the sea surface velocity field along the current, and extraction methods were employed to detect the Kuroshio axes and paths. However, sea surface absolute geostrophic velocity estimated from absolute dynamic topography should be regarded as the geostrophic component of the actual surface velocity, which cannot represent a sea surface current accurately. In this study, mathematical verification between the climatic absolute geostrophic and bin-averaged drifting buoy velocity was established and then adopted to correct the satellite absolute geostrophic velocities. There were some differences in the characteristics between satellite geostrophic and drifting buoy velocities. As a result, the corrected satellite absolute geostrophic velocities were used to detect the Kuroshio axis and path based on a principal-component detection scheme. The results showed that the detection of the Kuroshio axes and paths from corrected absolute geostrophic velocities performed better than those from satellite absolute geostrophic velocities and surface current estimations. The corrected satellite absolute geostrophic velocity may therefore contribute to more precise day-to-day detection of the Kuroshio Current axis and path.

关键词： Kuroshio axis detection Kuroshio path detection mathematical verification satellite absolute geostrophic velocity principal-component detection

An efficient parallel algorithm for ocean circulation numerical model based on irregular rectangle decomposition scheme

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Acta Oceanologica Sinica 2016年第5期35卷 18-23页

作者： ZHUANG Zhanpeng yuan yeli ZHANG Jie HAN Lei YANG Jungang College of Physical and Environmental Oceanography Ocean University of China The First Institute of Oceanography State Oceanic Administration

A parallel algorithm of circulation numerical model based on message passing interface（MPI） is developed using serialization and an irregular rectangle decomposition scheme. Neighboring point exchange strategy（NPES） is adopted to further enhance the computational efficiency. Two experiments are conducted on HP C7000 Blade System, the numerical results show that the parallel version with NPES（PVN） produces higher efficiency than the original parallel version（PV）. The PVN achieves parallel efficiency in excess of 0.9 in the second experiment when the number of processors increases to 100, while the efficiency of PV decreases to 0.39 rapidly. The PVN of ocean circulation model is used in a fine-resolution regional simulation, which produces better results. The capability of universal implementation of this algorithm makes it applicable in many other ocean models potentially.

关键词： irregular rectangle decomposition scheme message passing interface(MPI) neighboring point exchange strategy data communication