1996 Vol. 15, No. 2
Display Method:
1996, (2): 145-158.
Abstract:
Based on the quasi-geostrophic vorticity equation,the present paper simulates the water mixing process in the formation of ocean shear waves using large eddy simulation methods.From Lagrangian tracing,we study the ocean shear wave's changing from wave character to vortex character.The distance between tracer groups increases near the ocean shear wave area,and decreases between ocean shear waves.The tracers that are uniformally distributed in space do not retain the uniform character in the mixing process.The frequency shift of the perturbation waves is caused by their nonlinear interaction.The wave number ratio and phase lag of the initial perturbation waves effect the mixing process,but the results show tittle difference.The increase of the visrnsity coefficient will restrain the mixing process.
Based on the quasi-geostrophic vorticity equation,the present paper simulates the water mixing process in the formation of ocean shear waves using large eddy simulation methods.From Lagrangian tracing,we study the ocean shear wave's changing from wave character to vortex character.The distance between tracer groups increases near the ocean shear wave area,and decreases between ocean shear waves.The tracers that are uniformally distributed in space do not retain the uniform character in the mixing process.The frequency shift of the perturbation waves is caused by their nonlinear interaction.The wave number ratio and phase lag of the initial perturbation waves effect the mixing process,but the results show tittle difference.The increase of the visrnsity coefficient will restrain the mixing process.
1996, (2): 159-177.
Abstract:
The origin of the Tsushima Warm Current Water (TWCW) in summer is studied mainly on the basis of the CTD data and the observations of satellite-traced surface drifters of Coastal Ocean Process Experiment of the East China Sea (COPEX-ECS) conducted by Korea Ocean Research and Development Institute.The main results are as follows: (1) The structures of the TWCW show obvious regional varitaions.The TWCW can be divided into three layers in the northern Okinawa Trough west of Kyushu and into two layers on the continental shelf and in the Tsushima/Korea Strait.(2) The surface TWCW,characterized by a sub-high salinity (33.5-34.10),comes mainly from the coastal water composed largely of the Changjiang Diluted Water,the surface Kuroshio water and the shelf water in the area south of the East China Sea (ECS).(3) The middle TWCW is sub-grouped into two parts: the water of salinity (S) larger than 34.50 located below the thermocline originates from the climbed sub-surface Kuroshio water;the TWCW lying in the thermocline is a mixture of the Kuroshio water and the shelf water with low salinity.(4) In the strait,the water from the source area is denatured obviously due to mixing unceasingly wth the shelf water and coastal water.The high salinity water of S > 34.5 appears only in the bottom layer with depths > 50m.
The origin of the Tsushima Warm Current Water (TWCW) in summer is studied mainly on the basis of the CTD data and the observations of satellite-traced surface drifters of Coastal Ocean Process Experiment of the East China Sea (COPEX-ECS) conducted by Korea Ocean Research and Development Institute.The main results are as follows: (1) The structures of the TWCW show obvious regional varitaions.The TWCW can be divided into three layers in the northern Okinawa Trough west of Kyushu and into two layers on the continental shelf and in the Tsushima/Korea Strait.(2) The surface TWCW,characterized by a sub-high salinity (33.5-34.10),comes mainly from the coastal water composed largely of the Changjiang Diluted Water,the surface Kuroshio water and the shelf water in the area south of the East China Sea (ECS).(3) The middle TWCW is sub-grouped into two parts: the water of salinity (S) larger than 34.50 located below the thermocline originates from the climbed sub-surface Kuroshio water;the TWCW lying in the thermocline is a mixture of the Kuroshio water and the shelf water with low salinity.(4) In the strait,the water from the source area is denatured obviously due to mixing unceasingly wth the shelf water and coastal water.The high salinity water of S > 34.5 appears only in the bottom layer with depths > 50m.
1996, (2): 179-191.
Abstract:
Abstract-Hydraulic falis and asymptotic mean levels of two-layer flow are determined by means of AfKdV equation in phase coordinate theoretically.By present theory,the hydraulic falls HMr depend on a characteristic value of the AfKdV equation at the subcritical cutoff points F.It is proved that the differences of the asymptotic mean levels upstream and downstream at the subcritical cutoff points ate equal to 2F.A relation between F and the asymptotic mean levels at the subcritical cutoff points is also found in teens of the solution of the hydraulic falls.Because the AfKdV equation is derived based on the small topography assumption,for semicircular topography the valid region of this theory is α < 0.35,in which α is radius of the semicircular topography.An experiment is carried out to examine the theory of the present paper.From comparisons between the theoretical and experimental results,it is shown that they are in better agreement.Under conditions of different stratified parameters,the hydraulic falls of two-layer flow are predictad theoretically.
Abstract-Hydraulic falis and asymptotic mean levels of two-layer flow are determined by means of AfKdV equation in phase coordinate theoretically.By present theory,the hydraulic falls HMr depend on a characteristic value of the AfKdV equation at the subcritical cutoff points F.It is proved that the differences of the asymptotic mean levels upstream and downstream at the subcritical cutoff points ate equal to 2F.A relation between F and the asymptotic mean levels at the subcritical cutoff points is also found in teens of the solution of the hydraulic falls.Because the AfKdV equation is derived based on the small topography assumption,for semicircular topography the valid region of this theory is α < 0.35,in which α is radius of the semicircular topography.An experiment is carried out to examine the theory of the present paper.From comparisons between the theoretical and experimental results,it is shown that they are in better agreement.Under conditions of different stratified parameters,the hydraulic falls of two-layer flow are predictad theoretically.
1996, (2): 193-208.
Abstract:
In this paper,the long-term variation trend of the Antarctic sea ice in 1973-1994 and the inter-decade variation rule of the global sea level are analyzed.It is found that the sex ice area in the Antarctic in the 1980s was significantly less than in the 1970s and the average global sea level height value in the 1980s was also significantly higher than in the 1970s.Connecting variation of both and analyzing their physical mechanism,it indicates that the accumulated sea ice anomaly value in the 1980s less than in the 1970s means a global climate warming,the sea water temperature and air temperature were obviously higher in the 1980s it introduced the long-term accumulated sea ice decreased greatly;a higher sea water temperature introduced sea water volume expanding,and more icebergs transporting from the ice cover in the Antarctic continent to ocean in the warmer year.As a result induced by these mufti-causes,the global sea level raised significantly in the 1980s.The global average sea level value in the 1980s,was 22 mm higher than in the 1970s.The sea level raising (SLR) was distributed unevenly.It is especially true in the Pacific Ckean with two expensive sea level raising regions in the Northeast Pacific and Southeast Pacific as well as a raising region near the Bering Sea;and with two descent regions in the Northwest and Southwest Pacific.It is considered that this kind of uneven SLR distribution closely relates to the sustained decreasing of the Mtarctic sea ice.The higher sea water temperature in the south ocean introduces a rather warmer water temperature of the Peru Cold Current which is a north ward branch of the South Oceanic Current along the South American continent,then it is easier to the occurrence of El Nino event.When El Nino eventcx:curs,the prevailed tropical easterlies over the Pacific weaken and the westerlies intensify.Normally,the sea level is higher in the west and low in the east.A lot of sea water is transported from west to east caused by gravity and wind dynamics in this situation.The uneven distribution of raising in the eastern Pacific and descending in the western Pacific was introduced.
In this paper,the long-term variation trend of the Antarctic sea ice in 1973-1994 and the inter-decade variation rule of the global sea level are analyzed.It is found that the sex ice area in the Antarctic in the 1980s was significantly less than in the 1970s and the average global sea level height value in the 1980s was also significantly higher than in the 1970s.Connecting variation of both and analyzing their physical mechanism,it indicates that the accumulated sea ice anomaly value in the 1980s less than in the 1970s means a global climate warming,the sea water temperature and air temperature were obviously higher in the 1980s it introduced the long-term accumulated sea ice decreased greatly;a higher sea water temperature introduced sea water volume expanding,and more icebergs transporting from the ice cover in the Antarctic continent to ocean in the warmer year.As a result induced by these mufti-causes,the global sea level raised significantly in the 1980s.The global average sea level value in the 1980s,was 22 mm higher than in the 1970s.The sea level raising (SLR) was distributed unevenly.It is especially true in the Pacific Ckean with two expensive sea level raising regions in the Northeast Pacific and Southeast Pacific as well as a raising region near the Bering Sea;and with two descent regions in the Northwest and Southwest Pacific.It is considered that this kind of uneven SLR distribution closely relates to the sustained decreasing of the Mtarctic sea ice.The higher sea water temperature in the south ocean introduces a rather warmer water temperature of the Peru Cold Current which is a north ward branch of the South Oceanic Current along the South American continent,then it is easier to the occurrence of El Nino event.When El Nino eventcx:curs,the prevailed tropical easterlies over the Pacific weaken and the westerlies intensify.Normally,the sea level is higher in the west and low in the east.A lot of sea water is transported from west to east caused by gravity and wind dynamics in this situation.The uneven distribution of raising in the eastern Pacific and descending in the western Pacific was introduced.
1996, (2): 209-229.
Abstract:
Distribution pattern of ostracodes in the western part of the Huanghai Sea was re-analyzed using the occurrence data of 142 species from 175 surface sediment samples.The high values of ostracode specimen density are generally restricted to depths shallower than 40 m.The species diversity H(S) is higher in the southern part and lower in the northern part of the area studied,the trend which is correspondent to the change of water temperature in the Huanghai Sea.In the area where radial tidal sands is distributed,H(S) reaches its maximum average value.
Six ostracode biofacies were delineated using Q-mode factor analysis,based on the data of 77 samples and 69 species.Their distributions are correspondent with environmental parameters such as water temperature,salinity and substrate type.
Through tracing the geographical distribution of ostracode species in the Huanghai Sea and the East China Sea,it is reconfirmed that the discontinuity of species distribution between the two areas,located at around 32°N,coincides with the boundary of subtropical/warm temperate zones of China seas.
Distribution pattern of ostracodes in the western part of the Huanghai Sea was re-analyzed using the occurrence data of 142 species from 175 surface sediment samples.The high values of ostracode specimen density are generally restricted to depths shallower than 40 m.The species diversity H(S) is higher in the southern part and lower in the northern part of the area studied,the trend which is correspondent to the change of water temperature in the Huanghai Sea.In the area where radial tidal sands is distributed,H(S) reaches its maximum average value.
Six ostracode biofacies were delineated using Q-mode factor analysis,based on the data of 77 samples and 69 species.Their distributions are correspondent with environmental parameters such as water temperature,salinity and substrate type.
Through tracing the geographical distribution of ostracode species in the Huanghai Sea and the East China Sea,it is reconfirmed that the discontinuity of species distribution between the two areas,located at around 32°N,coincides with the boundary of subtropical/warm temperate zones of China seas.
1996, (2): 231-249.
Abstract:
On the basis of the materials collected from six cruises during 1986-1990 in the Kuroshio and its adjacent waters of the East China Sea,the spatial and temporal changes of zooplankton biomass and the relation to certain environmental factors are analysed in this paper.The results indicated that the biomass peaked in autumn,followed by spring and summer and was the lowest in winter.Its horizontal distribution pattern was higher in the continental shelf area than in the Kuroshio area and in the north than in the south of the surveyed area.The higher biomass regions usually occurred in the fronts between different currents and water masses and in the upwelling region of the Kuroshio subsurface water,and were mainly composed of warm-water eurytopic species and tropic oceanic eurytopic species.The relationship between the vertical distribution of zooplankton biomass(Zw)and water depth(D) might be expressed by the formual LnZw=a+bXD.The biomass was observed higher in the upper 100 m.The positive correlation between the biomass of bait-animal and the abundance of larval and juvenile fishes was significant.In addition,the higher biomass region in the northern study area (in the vicinity of 29°N,126°E) overlapped the fishing ground of mackerel and scads in the middle East China Sea.
On the basis of the materials collected from six cruises during 1986-1990 in the Kuroshio and its adjacent waters of the East China Sea,the spatial and temporal changes of zooplankton biomass and the relation to certain environmental factors are analysed in this paper.The results indicated that the biomass peaked in autumn,followed by spring and summer and was the lowest in winter.Its horizontal distribution pattern was higher in the continental shelf area than in the Kuroshio area and in the north than in the south of the surveyed area.The higher biomass regions usually occurred in the fronts between different currents and water masses and in the upwelling region of the Kuroshio subsurface water,and were mainly composed of warm-water eurytopic species and tropic oceanic eurytopic species.The relationship between the vertical distribution of zooplankton biomass(Zw)and water depth(D) might be expressed by the formual LnZw=a+bXD.The biomass was observed higher in the upper 100 m.The positive correlation between the biomass of bait-animal and the abundance of larval and juvenile fishes was significant.In addition,the higher biomass region in the northern study area (in the vicinity of 29°N,126°E) overlapped the fishing ground of mackerel and scads in the middle East China Sea.
1996, (2): 251-259.
Abstract:
The recorded 15 species of Chaetognatha are studied in the zooplanktonic samples collected in the waters of the western central Pacific (0°-50N,160°-165°E) within January and February,and within April and May in 1979.A primary analysis is conducted on the relations of Chaetognatha species composition and numerical distribution with their environmental conditions in the waters by taking into account the field hydrological data.
The recorded 15 species of Chaetognatha are studied in the zooplanktonic samples collected in the waters of the western central Pacific (0°-50N,160°-165°E) within January and February,and within April and May in 1979.A primary analysis is conducted on the relations of Chaetognatha species composition and numerical distribution with their environmental conditions in the waters by taking into account the field hydrological data.
1996, (2): 261-272.
Abstract:
Based on the principle of wave action flux conservation,the following problems are analyzed in the present study: the transformation of wave and wave spectrum in currents,the change of current velocity profile alongside water depth due to the existence of waves,the breaking criteria of irregular waves,a new hybrid method for the analysis of wave transformation and breaking on slope,the VOF mehtod for calculating broken waves and the transformation of directional wave spectrum in currents.
Based on the principle of wave action flux conservation,the following problems are analyzed in the present study: the transformation of wave and wave spectrum in currents,the change of current velocity profile alongside water depth due to the existence of waves,the breaking criteria of irregular waves,a new hybrid method for the analysis of wave transformation and breaking on slope,the VOF mehtod for calculating broken waves and the transformation of directional wave spectrum in currents.
1996, (2): 273-282.
Abstract:
