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Acta Oceanologica Sinica 2015年第12期34卷 1-10页

作者： yuan yaochu ZHU Xiaohua ZHOU Feng State Key Laboratory of Satellite Ocean Environment Dynamics Second Institute of Oceanography State Oceanic Administration

The influence of the Kuroshio on neighboring Chinese seas and the Ryukyu Current is a very important subject of interest in physical oceanography. To deeply explain the research progress made by Chinese scientists from July2010 to May 2015, the following three aspects are reviewed in this paper. The first concerns the Kuroshio intrusion into the South China Sea（SCS） and its circulation around the Luzon Strait. There are two very important points to be explained： the seasonal and inter-annual variation of the Kuroshio intrusion and the mechanisms of the Kuroshio intrusion and the influence of the Kuroshio on currents in the Luzon Strait and circulation in the northern SCS. The second concerns the variability of the Kuroshio and its interaction with the East China Sea（ECS）. There are following four interesting topics to be explained： an overview of studies on the Kuroshio in the ECS; the Kuroshio intrusion into the ECS, water exchange, and dynamic impacts; the downstream increase of nutrient transport by the Kuroshio; and the application of satellite remote sensing on terrestrial material transport by the Kuroshio intrusion into the ECS. Third, the interaction between the Ryukyu Current and Kuroshio in the ECS are also discussed. Finally, the main results are summarized and areas of further study are simply discussed.

关键词： Kuroshio intrusion circulation South China Sea East China Sea currents in Luzon Strait Ryukyu Current

Circulation in the South China Sea in summer of 1998

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Chinese Science Bulletin 2000年第18期45卷 1648-1655页

作者： LIU Yonggang yuan yaochu SU Jilan JIANG Jingzhong Second Institute of Oceanography State Oceanic Administration(SOA)Hangzhou 310012China Key Lab of Ocean Dynamic Processes and Satellite Oceanography SOAHangzhou 310012China

Based on the CTD and meteorological data obtained by R/V Xiangyanghong No. 14 in the South China Sea (SCS) in the summer of 1998, both current velocity and volume transport are calculated by using a modified inverse model. Circulation in the SCS is analyzed by combining the calculated results with ADCP data. The following results are obtained, (i) The most important feature of the circulation in the northeastern SCS is that a branch of the Kuroshio intrudes into the SCS with a small volume transport. It flows anticyclonically through the Bashi Strait and towards the southwest off the Taiwan Island, and it does not intrude into the inner SCS. (ii) The northern SCS is dominated mainly by a cyclonic circulation system with two cold eddies, (iii) The central and southwestern SCSs are mainly occupied by anticyclonic circulation systems, including three anticyclonic and one stronger cyclonic eddies, (iv) In the southeastern SCS, there is a large scope of cyclonic circulation extending in the SW-NE direction,

关键词： SCS circulation in summer multi-eddy phenomenon modifled inverse model.

The diel vertical migration of sound scatterers observed by an acoustic Doppler current profiler in the Luzon Strait from July 2009 to April 2011

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Acta Oceanologica Sinica 2013年第11期32卷 1-9页

作者： YANG Chenghao LIAO Guanghong yuan yaochu CHEN Hong ZHU Xiaohua State Key Laboratory of Satellite Ocean Environment Dynamics Second Institute of OceanographyState Oceanic Administration

Acoustic Doppler current profiler （ADCP） receives echoes from sound scatterers, then their speed is calcu- lated by the Doppler effect. In the open ocean, most of these backscatterers are from the plankton. The sound scatterers descend down to depth at around dawn, their mean speed is 2.9 cm/s, then they ascend up to the surface layer at around dusk with a mean speed of 2.1 cm/s, in the Luzon Strait. The descending speed is faster, which suggests that this zooplankton population may accelerate its downward migration under the action of the gravity. The vertical distribution of a mean volume backscattering strength （MVB- S） in the nighttime has two peaks, which locate near the upper and lower boundary layers of halocline, respectively. However, the backscatterers only aggregate near the surface layer in the daytime. The diel ver- tical migration （DVM） of sound scatterers has several characteristic patterns, it is stronger in summer, but weaker in winter, and the maximum peak occurs in September. The DVM occurrence is synchronous with the seawater temperature increasing at around dawn and dusk, it may affect the ocean mixing and water stratification,

关键词： diel vertical migration acoustic Doppler current profiler mean volume backscattering strength,Luzon Strait water stratification

Variability of the currents in the Luzon Strait during spring of 2002 obtained from observations and satellite geostrophic currents and spectral analyses

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Science China Earth Sciences 2009年第4期52卷 519-531页

作者： yuan yaochu LIAO GuangHong WANG HuiQun LOU RuYun CHEN Hong State Key Laboratory of Satellite Ocean Environment Dynamics Second Institute of OceanographyState Oceanic AdministrationHangzhou 310012China

The structure and variability of the currents in the Luzon Strait during spring of 2002 are studied, based on the current measurements at the average position of the mooring station (20°49′57"N, 120°48′12"E) from March 17 to April 15, 2002, satellite geostrophic currents in the Luzon Strait, and the spectral analyses, using the maximum entropy method. The subtidal currents at the mooring station show de-creased amplitudes downward with an anti-cyclonic rotation, suggesting that the currents enter and exit the South China Sea in the upper and intermediate layers, respectively. The vertical structure of the currents in the Luzon Strait suggests strongly the sandwiched structure of the LST, even though the bottom part of the profile is not resolved by the observational grid. The spectral analyses show the following periods of significant spectral peaks: (1) the tidal currents variability in the vertical direction; (2) the period about 4-6 d for the two cases of frequency f >0 and f0; (3) The fluctuation in the period range is about 2-3 days for the two cases of f >0 and f<0 at the 200, 500 and 800 m levels, namely the Luzon Strait currents exhibit significant synoptical variability throughout the water column up to 800 m deep. Both direct current measurements and in situ hydrographic and satellite survey suggest no Kuroshio loop current in the Luzon Strait during the spring of 2002.

关键词： currents in the Luzon Strait tidal currents and synoptical variability satellite geostrophic currents sandwiched structure Kuroshio loop current

Effects of mesoscale eddies on the internal solitary wave propagation

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Acta Oceanologica Sinica 2012年第5期31卷 26-40页

作者： LIAO Guanghong YANG Chenghao XU Xiaohua SHI Xingang yuan yaochu HUANG Weigen State Key Laboratory of Satellite Ocean Environment Dynamics Second Institute of OceanographyState Oceanic AdministrationHangzhou 310012China College of Information Science and Technology Ocean University of ChinaQingdao 266100China Beijing Branch of China National Offshore Oil Corporation Energy Technology and Services Limited Beijing 100027China

The mesoscale eddy and internal wave both are phenomena commonly observed in oceans. It is aimed to investigate how the presence of a mesoscale eddy in the ocean affects wave form deformation of the internal solitary wave propagation. An ocean eddy is produced by a quasi-geostrophic model in f-plane, and the one-dimensional nonlinear variable-coefficient extended Korteweg-de Vries （eKdV） equation is used to simulate an internal solitary wave passing through the mesoscale eddy field. The results suggest that the mode structures of the linear internal wave are modified due to the presence of the mesoscale eddy field. A cyclonic eddy and an anticyclonic eddy have different influences on the background environment of the internal solitary wave propagation. The existence of a mesoscale eddy field has almost no prominent impact on the propagation of a smallamplitude internal solitary wave only based on the first mode vertical structure, but the mesoscale eddy background field exerts a considerable influence on the solitary wave propagation if considering high-mode vertical structures. Furthermore, whether an internal solitary wave first passes through anticyclonic eddy or cyclonic eddy, the deformation of wave profiles is different. Many observations of solitary internal waves in the real oceans suggest the formation of the waves. Apart from topography effect, it is shown that the mesoscale eddy background field is also a considerable factor which influences the internal solitary wave propagation and deformation.

关键词： mesoscale eddy internal solitary wave variable-coefficient extended Korteweg-de Vries equation wave deformation

Analysis of internal tidal characteristics in the layer above 450 m from acoustic Doppler current profiler observations in the Luzon Strait

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Science China Earth Sciences 2011年第7期54卷 1078-1094页

作者： LIAO GuangHong yuan yaochu Kaneko ARATA YANG ChengHao CHEN Hong Taniguchi NAOKAZU Gohda NORIAKI College of Information Science and Technology Ocean University of China Qingdao 266100 China State Key Laboratory of Satellite Ocean Environment Dynamics Second Institute of Oceanography State Oceanic Administration Hangzhou 310012 China Graduate School of Engineering Hiroshima University Higashi-Hiroshima 739-8527 Japan

The characteristics of internal tides in the upper layer of the Luzon Strait are investigated on the basis of direct-observation current data recorded on April 25 and September 26, 2008 by an acoustic Doppler current profiler. Spectral analysis and energy estimation show that the diurnals and semidiurnals carry most of the energy of internal tides. Values of the depth-integrated total energy E for the three frequency bands of diurnal, semidiurnal, and high frequencies are 31, 6.9, and 3.4 kJ·m, respectively. Near-inertial peaks are only present in the baroclinic component. The behavior of typical tidal frequencies (i.e., O1, K1, M2, MK3, and M4) and the near-inertial frequency is basically consistent with linear internal wave theory, which predicts E + (ω)/E (ω)=(ω f) 2 /(ω+f) 2 at depths above 66 m, while not all prominent tidal components coincide well with the relation of the linear internal wave field at other depths. Examinations of depth structures of the baroclinic tides and temporal variations show that the surface tides and internal tides are both of mixed type, having diurnal inequality and spring-neap fortnight periods. The K1 and O1 tides have comparable cross-and along-shelf components, while the M2 and S2 tides propagate toward the shelf in the northern South China Sea as wave beams. The amplitude and phase of internal tides vary with time, but M2 and S2 tides appear to have structures dominated by the first mode, while the K1 and O1 tides resemble second-mode structures. The minor to major axis ratios are close to expected values of f/ω in the thermocline.

关键词：声学多普勒流速剖面仪潮汐特征上层海峡观测时空变化规律能量估计高频率

Circulations　east　of　Taiwan　and　in　East　China　Sea　and　east　of　Ryukyu　Islands　during　early　summer　1985

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Acta Oceanologica Sinica 1996年第4期15卷 423-435页

作者： yuan yaochu Cho-teng Liu Pan Ziqin and Shi-pei Zhend Second Institute of Oceanography State Oceanic Administration Hangzhou 310012 China Institute of Oceanography Taiwan University Taipei Taiwan

A modified inverse method is used to compute the circulations east of Taiwan and in the East China Sec and east of the Ryukyu Islands with hydrographic data obtained during early summer of 1985. The computational region covers an area west of 129°E and from 21°45'N to 35°N. The computed results show that: (1 ) The net volume transport (VT ) of the Kuroshio through 21°45'N Section east of Ta Taiwan and west of 123°E is about 45 × 10￣6 m￣3/sduring early summer of 1985. The Kuroshio has. two current cores. One is located near Taiwan, and its velocity isvery large and its maximum velocity is 226 cm/s at the 100 m level, which is close to the maximum velocity of the beginning of the Kuroshio east of the Philippines. The other is located further to the east, and its maximum velocity is159 cm/s at the 100m level; (2) through a transect northwest Of Miyakojima Island and a transect southwest of Okinawa laaed the volume transports of the Kuroshio in the East China Sea both are about 25 × 10￣6 m￣3/s. The maximumvelocity of the Kuroshio at these two sections is 194 and 128 cm/s, respectively, and both are located on the shelfbreak; (3) beneath and east of the Kurohio there are the countercurrent (4) southeast of Okinawa Island there is anortheastward current, and its VT at Section HI is about 12. 6 × 10￣6 m￣3/s, and it comes from a westward flow at 129° This project was supported by the National Natural Science Foundation of China under contract No. 49476278.(Second Institute of Oceanography, State Oceanic Administration, Hongzhou310012, China) (Institute of Oceanography, Taiwan University, Taipei, China)E Section and the recirculating gyre, and does not originate from the Kuroshio east of Taiwan during early summer of 1985. There is a southwestward abyssal current east of Okinawa Islands (5) there are several different scale eddies in this computational region. For example, there is a meso-scale strong cyclonic eddy east of Miyakojima Island.

关键词： Circulation area east of Taiwan East China Sea area east of the Ryukyu Islands

A three-dimensional model study on ocean dynamic response to traveling cyclone over the Huanghai Sea

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Acta Oceanologica Sinica 2005年第1期24卷 60-75页

作者： QINZenghao LIYongping yuanyaochu YURunling ShanghaiTyphoonInstitute ChinaMeteorologicalAdministrationShanghai200030China／／SecondInstituteofOceanographyStateOceanicAdministratianHangzhou310012China ShanghaiTyphoonInstitute ChinaMeteorologicalAdministrationShanghai200030China SecondInstituteofOceanography StateOceanicAdministratianHangzhou310012China／／KeyLaboratoryofOceanDynamicProcessesandSatelliteOceanographyofStateOceanicAdministrationHangzhou310012China

On the basis of numerical simulation of the mean circulation and relevant thermal-salinity fields in June with a three-dimensional o-cean model (ECOM-si), the model outputs are used as first guess of initial fields for numerical integration of the model equations and the numerical results are applied to investigating the dynamical responses of the Huanghai Sea and the East China Sea (HECS) in the course of a weak land-to-sea cyclone's passage over the Huanghai Sea on 15-16 June 1999. Predominance of the dynamic impact of cyclone over the thermal one in June in the HECS is justified using observations and model simulations.The cyclone and its surrounding weather system, i.e., subtropical high ridge to its south could influence current and thermal fields in the Bohai Sea, the Huanghai Sea and the northern East China Sea even though the intensity of cyclone was rather weak. The response of oceanic currents to the wind stresses driven by the cyclone and its soumern subtropical high were strongly characterized by the wind drift with its extent of equivalent scale of cyclone in the horizontal and of Ekman layer in the vertical. The sea response at a given site was closely related to the transient local wind speed and direction.especially was sensitive to the local wind direction,which is demonstrated at three points locating at the southern and western Huanghai Sea and the northern East China Sea. So the sea responses at locations differed considerably from one another. Current responded to the wind stress in a simple way:directly to the wind-driven current and subsequent gradient current and slope current, etc., whereas sea temperature responded to the wind stress in two ways: directly to the cyclone-induced cooling and indirectly to water movements both in the horizontal and the vertical by the cyclone' s wind stress. So the sea temperature variation under the influence of cyclone was more complicate than the current. The HECS in response to the cyclone and its ambient weather system was likely to be a fast process a

关键词： sea response Huanghai Sea East China Sea Bohai Sea weak cyclone numerical study

Variability of the Kuroshio in the East China Sea in 1992

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Acta Oceanologica Sinica 1999年第1期18卷 1-15页

作者： Liu Yonggang and yuan yaochu Second Institute of Oceanography State Oceanic Administration Hangzhou 310012 China

Based on the hydrographic data of the four cruises in 1992, a modified inverse method is used to compute the velocity, volume and heat transports of the Kuroshio in the East China Sea. The computed results show that: (1)There are two current cores of the Kuroshio at Section PN in spring and autumn, but one core in winter and summer.The main core always lies over the shelf break.The Kuroshio is strongest in spring, secondary in winter and summer and weakest in autumn. There are also countercurrents under and east of the Kuroshio at Section PN. (2) There are two current cores of the Kuroshio at Section TK in winter, three cores in spring and summer. Countercurrents exist in the southern Part and the deep layer of the Tokara Strait. (3) The Tsushima Warm Current (TSWC) at action A is strongest in autumn and weakest in winter, and is stronger than the Huanghai Warm Current which lies to the west of the TSWC. (4) The net northeastward volume transport (hereafter VT) through Section PN is largest in summer and smallest in autumn with an average of 28. 0 ×106m3/s in the four cruises of 1992. The net eastward VT at Section TK is also largest in summer. The net northward VT at Section A is largest in autumn. (5) The average heat transport through Section PN during the four cruises is 2. 03×1015 W, and that through Section TK is 2. 00×1015 W during the three cruises. (6) In the computation area, heat transfer is from the ocean to the atmosphere during winter,spring and autumn, but from the atmosphere to the ocean in summer. The average rate of heat transfer is largest in winter, but smallest in summer.

关键词： East China Sea Kuroshio seasonal variability

Variability of the Kuroshio in the East China Sea in 1993 and 1994

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Acta Oceanologica Sinica 1999年第1期18卷 17-36页

作者： Liu Yonggang and yuan yaochu Second Institute of Oceanography State Oceanic Administration Hangzhou 310012 China

Based on the hydrographic data obtained by the R/V Chofu Maru of eight cruises of 1993~1994, a modified inverse method is used to compute the velocity, volume and heat transports of the Kuroshio in the East China Sea. The calculated results show that: (1) At Section PN, there are two current cores of the Kuroshio in autumn, one or two cores in other seasons. The main cores always lie over the shelf break. Countercurrents always exist east of and in the deep layer under the Kuroshio. (2) At Section TK, the velocity distribution is more complicated, and it may have one, two or three current cores of the Kuroshio. The current cores often appear in the middle and northern parts of the Tokara Strait. There are westward countercurrents in the southern end and deep layer of the strait, and the countercurrent in the southern end of the strait is the strongest in autumn. (3) At Section A, the Tsushima Warm Current (hereafter TSWC) core lies in the shelf break area, and its Vmax varies between 26~46 cm/s. The Huanghai Warrn Current (hereafter HWC) lies to the west of the TSWC, and it is weaker. (4) In 1993 and 1994 the volume transport (hereafter VT) of the Kuroshio is the smallest in spring, but it is the largest or has a larger value in summer. The average net northward VT of the Kuroshio during the four seasons each year, for example, through Section PN, almost has the same value for 1993 and 1994, but both are smaller than that in 1992. The average net northward VT through Sections PN and TK during the eight cruises are 27. 1×106 and 25. 0 ×106 m3/s, respectively. (5) The average heat transports (hereafter HT) through Sections PN and TK are 1. 99 × 1015 and 1. 78× 1015 W, respectively. (6) At the computation area, heat transfer is from the ocean to the atmosphere in autumn and winter, but the direction reverses in summer, and the direction of heat transfer is uncertain in spring. The average rate of heat transfer is the largest in winter, but smaller in spring and summer.

关键词： East China Sea Kuroshio Seasonal variability