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Direct measurements of surface and mid-depth circulationin the Shikoku Basin by Argo profiling floats

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Acta Oceanologica Sinica 2007年第2期26卷 1-11页

作者： ZHOU Hui guo peifang XU Jianping SHI Maochong Institute of Marine Environment Ocean University of China Qingdao 266100 China Key Laboratory of Ocean Dynamic Process and Satellite Oceanography Second Institute of Oceanography State Oceanic Administration Hangzhou 310012 China

The circulation in the Shikoku Basin plays a very important role in the pathway of the Kuroshio and the water exchange in the subtropical gyre in the North Pacific Ocean. The Argo profiling floats deployed in the Shikoku Basin are used to study the circulations and water masses in the basin. The trajectories and parking depth velocity fields derived from all Argo floats show an anticyclonic circulation at 2 000 m in the Shikoku Basin. There are inhanced eddy activities in the Shikoku Basin, which have large influence on the Shikoku Basin circulation patterns. The characteristics of temperature - salinity curves indicate that there are North Pacific Ocean tropical water （NPTW）, North Pacific Ocean subtropical mode water （NPSTMW） and North Pacific Ocean intermediate water （NPIW） in the Shikoku Basin. The NPTW is only exists south of 32°N. In the middle part of the basin, which is 28°～31°N,133°～135°E, there is a confluence region. Water masses coming from the Kuroshio mix with the water in the Shikoku Basin.

关键词： Argo,Kuroshio,anticyclonic eddy mid-depth current,water mass,Shikoku Basin

Responses of the circulation and water mass in the Beibu Gulf to the seasonal forcing regimes

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Acta Oceanologica Sinica 2014年第7期33卷 1-11页

作者： GAO Jingsong SHI Maochong CHEN Bo guo peifang ZHAO Dongliang Ocean University of China Guangxi Key Laboratory of Marine Environmental Science Guangxi Academy of Sciences

In the past 20 a, the gulf-scale circulation in the Beibu Gulf has been commonly accepted to be driven by a wind stress or density gradient. However, using three sensitive experiments based on a three-dimensional baroclinic model that was verified by observations, the formation mechanisms were revealed： the circula- tion in the northern Beibu Gulf was triggered by the monsoon wind throughout a year; whereas the southern gulf circulation was driven by the monsoon wind and South China Sea （SCS） circulation in winter and sum- mer, respectively. The force of heat flux and tidal harmonics had a strong effect on the circulation strength and range, as well as the local circulation structures, but these factors did not influence the major circulation structure in the Beibu Gulf. On the other hand, the Beibu Gulf Cold Water Mass （BGCWM） would disappear without the force of heat flux because the seasonal thermocline layer was generated by the input of heat so that the vertical mixing between the upper hot water and lower cold water was blocked. In addition, the wind-induced cyclonic gyre in the northern gulf was favorable to the existence of the BGCWM. However, the coverage area of the BGCWM was increased slightly without the force of the tidal harmonics. When the model was driven by the monthly averaged surface forcing, the circulation structure was changed to some extent, and the coverage area of the BGCWM almost extended outwards 100%, implying the circulation and water mass in the Beibu Gulf had strong responses to the temporal resolution of the surface forces.

关键词： Princeton ocean model (POM) Beibu Gulf (Gulf of Tonkin) circulation cold water mass response

The Research on Typhoon Wave Spectrum in Northwestern South China Sea

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Journal of Ocean University of China 2017年第1期16卷 8-14页

作者： SHI Hongyuan CAO Xuefeng WEN Xianhua SHI Maochong ZHAO Dongliang guo peifang Physical Oceanography Laboratory Ocean University of ChinaQingdao 266100P.R.China Centre for Ports and Coastal Disaster Mitigation Ludong UniversityYantai 264025P.R.China Tianjin Research Institute of Water Transport Engineering of Ministry of Transport Tianjin 300456P.R.China

Based upon the one-year wind wave measurement data, collected from the South China Sea(SCS) at coordinates 20? 36.298?N, 110?45.433?E. by Acoustic Wave And Current(AWAC), we analyzed the wave characteristics and concluded that the most common wave direction was E and the second most common direction was ENE,the mean and the maximum values of significant height was 1.2 m and 4.36 m, respectively. The mean period was 4.0 s. We also evaluated the wave spectrums under conditions existing in three typhoons: Rumbi, Jeti and Utor. We found that unimodal spectrums occurred more often than others, and the maximum spectrum peak was 30.7911 m2 s. The minimum peak frequency was 0.0625 Hz, and the mean peak frequency was 0.126 Hz. The wave period is important for the design of marine structures, especially the position of peak frequency had a great influence on the stress calculation. Spectral analysis showed that the values of peak frequency distributed between 0.063 Hz and 0.217 Hz, with the mean value 0.114 Hz. We fit the normalized spectrum with 6 theoretical spectral models, out of which, the Wen spectrum, JONSWAP spectrum and Wallops spectrum were proved to give the best fit. What distinguished the Wen Spectrum from the rest was that it does not rely on the measured spectrum for parameter estimation. Hence, we recommend that the Wen spectrum should be widely used in marine construction.

关键词： typhoon wave wave spectrum theoretical wave spectrum

Model-Simulated Coastal Trapped Waves Stimulated by Typhoon in Northwestern South China Sea

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Journal of Ocean University of China 2017年第6期16卷 965-977页

作者： CAO Xuefeng SHI Hongyuan SHI Maochong guo peifang WU Lunyu DING Yang WANG Lu College of Oceanic and Atmospheric Sciences Ocean University of China Qingdao 266100 P. R. China National Marine Environmental Monitoring Center Dalian 116023 P. R. China Ludong University School of Civil Engineering Yantai 264000 P. R. China The First Institute of Oceanography SOA Qingdao 266061 P. R. China

In this paper, we apply an unstructured grid coastal ocean model to simulate variations in the sea level and currents forced by two typhoons in the northwestern South China Sea(SCS). The model simulations show distinct differences for the two cases in which the typhoon paths were north and south of the Qiongzhou(QZ) Strait. In both cases, coastal trapped waves(CTWs) are stimulated but their propagation behaviors differ. Model sensitivity simulations suggest the dominant role played by alongshore wind in the eastern SCS(near Shanwei) and southeast of Hainan Island. We also examine the influence of the Leizhou Peninsula by changing the coastline in simulation experiments. Based on our results, we can draw the following conclusions: 1) The CTWs stimulated by the northern typhoon are stronger than the southern CTW. 2) In the two cases, the directions of the current structures of the QZ cross-transect are reversed. The strongest flow cores are both located in the middle-upper area of the strait and the results of our empirical orthogonal function analysis show that the vertical structure is highly barotropic. 3) The simulated CTWs divide into two branches in the QZ Strait for the northern typhoon, and an island trapped wave(ITW) around Hainan Island for the southern typhoon. 4) The Leizhou Peninsula plays a significant role in the distribution of the kinetic energy flux between the two CTW branches. In the presence of the Leizhou Peninsula, the QZ branch has only 39.7 percent of the total energy, whereas that ratio increases to 72.2 percent in its absence.

关键词： coastal trapped waves typhoon surge coastline influence South China Sea ocean modeling

A FVCOM-Based Unstructured Grid Wave, Current,Sediment Transport Model,*** Description and Validation

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Journal of Ocean University of China 2011年第1期10卷 1-8页

作者： WU Lunyu CHEN Changsheng guo peifang SHI Maochong QI Jianhua GE Jianzhong Physical Oceanography Laboratoo Ocean University of China Qingdao 266100 P. R. China First Institute of Oceanography State Oceanic Administration Qingdao 266061 P. R. China School for Marine Science anti Technology University of Massachusetts-Dartmouth New Bedford Massachusetts USA State Key Laboratory of Estuarine and Coastal Research East China Normal University Shanghai 200062 P. R. China

An effort was made to couple FVCOM (a three-dimensional (3D),unstructured grid,Finite Volume Coastal Ocean Model) and FVCOM-SWAVE (an unstructured grid,finite-volume surface wave model) for the study of nearshore ocean processes such as tides,circulation,storm surge,waves,sediment transport,and morphological *** coupling between FVCOM and FVCOM-SWAVE was achieved through incorporating 3D radiation stress,wave-current-sediment-related bottom boundary layer,sea surface stress parameterizations,and morphology *** also includes a 3D sediment transport *** accurate fitting of irregular coastlines,the model provides a unique tool to study sediment dynamics in coastal ocean,estuaries,and wetlands where local geometries are characterized by inlets,islands,and intertidal marsh *** model was validated by two standard benchmark tests: 1) spectral waves approaching a mild sloping beach and 2) morphological changes of seabed in an idealized tidal *** Test 1,model results were compared with both analytical solutions and laboratory experiments.A further comparison was also made with the structured grid Regional Ocean Model System (ROMS),which provides an insight into the performance of the two models with the same open boundary forcing.

关键词： FVCOM coupling radiation stress wave-current-sediment-related bottom boundary layer morphology

A hybrid model for numerical wave forecasting and its implementation-Ⅱ .The discrete part and implementation of the model

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Acta Oceanologica Sinica 1992年第2期11卷 157-178页

作者： Zhang Dacuo, Wu Zengmao, Jiang Decai, Wang Wei, Chen Bohai, Tai Weitao, Wen Shengchang,Xu Qichun and guo peifang

In the first part of the present paper we have explained why we manage to formulate another wave prediction model when so many of them, including the so-called third generation model, have already been in use. The wind-wave part of the proposed model has also been given. Now we proceed to discuss the swell part,the implementation of the model as a prediction method,mumerical experiments done with ideal wind fields and hindcasts made in the Bohai Sea,in the neighboring seas adjacent to China and in the Northwest Pacific.

关键词： wave The discrete part and implementation of the model A hybrid model for numerical wave forecasting and its implementation

The equilibrium range of wind wave frequency spectrum

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Acta Oceanologica Sinica 1990年第1期9卷 1-11页

作者： Wen Shengchang (S. C. Wen) , Zhang Dacuo, Chen Bohai and guo peifang Institute of Physical Oceanography, Ocean University of Qingdao, Qingdao, China

-Theoretical form of equilibrium range is given on the basis of the wind wave frequency spectra proposed by Wenel al. (1988a,b,c, 1989a,b). The effects of peakness factor and water depth are discussed. In the case of deep water the e-quilibrium range is reduced to the form first proposed by Toba (1973) and the coefficient of the formula is shown to be the function of nondimensional fetch or peak frequency. Results of the present paper have been verified through field data.

关键词： The equilibrium range of wind wave frequency spectrum wave

Theoretical wind wave frequency spectra in deep water——Ⅰ. Form of spectrum

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Acta Oceanologica Sinica 1988年第1期 1-16页

作者： Wen Shengchang (S. C. Wen), Zhang Dacuo, Chen Bohai and guo peifang

In this part ot the paper theoretical wind-wave spectra nave been derived oy (I) expressing the spectrum in series composed of exponential terms; (2) assuming that the spectrum satisfies a high order linear ordinary differential equation; (3) introducing proper parameters in the spectrum; and (4) making use of some known charateristics of wind-wave spectrum, for instance, the law governing the equilibrium range. The spectrum obtained contains the zero order moment of the spectrum m0, the peak frequency ω0 and the ratio R =ω/ω0 (ω being the mean zero-crossing frequency) as parameters. The shape of the nondimensional spectrum S(ω) = ω0S(ω)/m0(ω=ω/ω0) changes with R and theoretically reduces to a Dirac delta function δ(ω-1) when R = 1. A spectrum of simplified form is given for practical uses, in which R is replaced by a peakness factor P=S(1).

关键词： Theoretical wind wave frequency spectra in deep water wave deep

Improved form of wind wave frequency spectrum

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Acta Oceanologica Sinica 1989年第4期8卷 467-483页

作者： Wen Shengchang (S. C. Wen ), Zhang Dacuo, guo peifang, Wang Wei, Chen Bohai and Tai Weitao Institute of Physical Oceanography, Ocean University of Qingdao, China

The lower frequency part of the theoretical wind wave spectrum proposed by the authors (Wen et al. , 1988a, b,c) has been improved and the form of spectrum is appreciably simplified. In addition to the field data collected in the Bohai Sea region and used in the previous papers, those obtained in the Huanghai Sea, the East China Sea and the South China Sea have been employed so that the improved spectra can be verified on a more extensive observational basis. Computed results agree with the observations well. Further comparisons have been made between the proposed spectra and the JONSWAP spectrum. Though the two types of spectrum are close to each other in form, the former shows, as a whole, better agreement with the observation than the latter. By introducing an improved relation between the peak-ness factor and significant wave steepness, the spectrum contains only significant wave height and period as parameters. For spectra given in this form, the computed peak frequencies coincide approximately with observed values and the computed peak magnitudes of spectra agree basically with observations, but, because of the statistic variability inherent in the measurements of significant wave heights and periods, there are certain discrepancies between computed and measured spectrum peak magnitudes.

关键词： wave Improved form of wind wave frequency spectrum