1987 Vol. 6, No. 1
Display Method:
1987, (1): 1-7.
Abstract:
In the first part of our studies, the unified solutions of existing waves have been obtained by using the linear wave equations without making the assumptions of irrotation and hydrostatic pressure.In this paper, the second part of our studies, we shall devote to linear long wave equations without the assumption of hydrostatic pressure.All the solutions in the case of ω=f are found.A set of solutions is also obtained, with a similarity to the unified solutions of the Sverdrup waves and the Poincare waves, but the corresponding waves represented by such a set have a different vertical structure of velocities.The set is not included in the solutions of linear long wave equations under the assumption of hydrostatic pressure and, therefore, is regarded as possible waves filtered out by the assumption of hydrostatic pressure.
In the first part of our studies, the unified solutions of existing waves have been obtained by using the linear wave equations without making the assumptions of irrotation and hydrostatic pressure.In this paper, the second part of our studies, we shall devote to linear long wave equations without the assumption of hydrostatic pressure.All the solutions in the case of ω=f are found.A set of solutions is also obtained, with a similarity to the unified solutions of the Sverdrup waves and the Poincare waves, but the corresponding waves represented by such a set have a different vertical structure of velocities.The set is not included in the solutions of linear long wave equations under the assumption of hydrostatic pressure and, therefore, is regarded as possible waves filtered out by the assumption of hydrostatic pressure.
1987, (1): 8-19.
Abstract:
Two-dimensional non-linear hydrodynamical equations are solved by using perturbation method and treating slopping beaches as bottom boundary conditions so that a kind of solution for nonlinear progressing waves is obtained.The first order of approximation is the same potential function as used by Biesel, and the second order is calculated numerically.Based on the solution, wave characteristics before breaking, especially the wave set-down, are discussed.It turns out that for the whole course of waves propagating from deep to shallow waters the theory proposed in this paper has a wider valid range of application than others.
Two-dimensional non-linear hydrodynamical equations are solved by using perturbation method and treating slopping beaches as bottom boundary conditions so that a kind of solution for nonlinear progressing waves is obtained.The first order of approximation is the same potential function as used by Biesel, and the second order is calculated numerically.Based on the solution, wave characteristics before breaking, especially the wave set-down, are discussed.It turns out that for the whole course of waves propagating from deep to shallow waters the theory proposed in this paper has a wider valid range of application than others.
1987, (1): 20-28.
Abstract:
On the basis of observational data of the eastern part of the West Pacific Ocean, a diagnostic calculation of equatorial flow for this region is performed by using the authors' model equations and computing scheme and methods.For the first cruise (January 3-March 4, 1979), the results show:(ⅰ) The primary driving force of the equatorial surface flows comes from the prevailing northeasterly wind field, with an average uniform wind speed Vw=6.3 m/s.The steady westward wind produces divergent westward flows in the surface layers, causing an upwelling near the equator.The importance of the steady wind stress in the upper layer (120 m) decreases with depth and becomes insignificant at the level of z=75 mor z=100 m, (ⅱ) The equatorial undercurrent is a strong eastward and equator-ward flow, with its eastward component of undercurrent larger than its meridional component.The core of the undercurrent is at the thermocline, and its maximum velocity is 88-90 cm/s at the level of z=200 m.The deeper flows in this region are discussed briefly.
On the basis of observational data of the eastern part of the West Pacific Ocean, a diagnostic calculation of equatorial flow for this region is performed by using the authors' model equations and computing scheme and methods.For the first cruise (January 3-March 4, 1979), the results show:(ⅰ) The primary driving force of the equatorial surface flows comes from the prevailing northeasterly wind field, with an average uniform wind speed Vw=6.3 m/s.The steady westward wind produces divergent westward flows in the surface layers, causing an upwelling near the equator.The importance of the steady wind stress in the upper layer (120 m) decreases with depth and becomes insignificant at the level of z=75 mor z=100 m, (ⅱ) The equatorial undercurrent is a strong eastward and equator-ward flow, with its eastward component of undercurrent larger than its meridional component.The core of the undercurrent is at the thermocline, and its maximum velocity is 88-90 cm/s at the level of z=200 m.The deeper flows in this region are discussed briefly.
1987, (1): 29-36.
Abstract:
A solution is obtained via Green's function for steady wind-driven flows on shallow continental shelf with linearly bottom slope.Friction is parameterized in terms of constant horizontal and vertical eddy viscosities, with flow patten illustrated.
A solution is obtained via Green's function for steady wind-driven flows on shallow continental shelf with linearly bottom slope.Friction is parameterized in terms of constant horizontal and vertical eddy viscosities, with flow patten illustrated.
1987, (1): 37-45.
Abstract:
The current elements of the Kuroshio in the East China Sea are analysed and discussed using the temperature-salinity and GEK data of the PN section obtained during 1972-1983.The calculations have proved (ⅰ) that the 12-year's mean volume transport of the Kuroshio at PN in the 0-800 m layer is about 20×106m3/s; (ⅱ) that the mean volume transport has seasonal variations, i.e.slightly stronger in spring and summer than in the other seasons; and (ⅲ) that the period of high-volume transport thereof corresponds to the appearance of a meander of the Kuroshio south of Japan.It is also discovered that this Kuroshio meander usually appears after a sharp increase in such volume transport.Finally, the differences of the Kuroshio volume transport between the PN, E and Suao-Yonakuni-jima sections are discussed.
The current elements of the Kuroshio in the East China Sea are analysed and discussed using the temperature-salinity and GEK data of the PN section obtained during 1972-1983.The calculations have proved (ⅰ) that the 12-year's mean volume transport of the Kuroshio at PN in the 0-800 m layer is about 20×106m3/s; (ⅱ) that the mean volume transport has seasonal variations, i.e.slightly stronger in spring and summer than in the other seasons; and (ⅲ) that the period of high-volume transport thereof corresponds to the appearance of a meander of the Kuroshio south of Japan.It is also discovered that this Kuroshio meander usually appears after a sharp increase in such volume transport.Finally, the differences of the Kuroshio volume transport between the PN, E and Suao-Yonakuni-jima sections are discussed.
1987, (1): 46-54.
Abstract:
Based on linear theory of sea waves, the height distribution of the intersections of wave surface with its envelope is derived.The distribution may be regarded as that of the significant crest heights under certain conditions.Some properties of this distribution are discussed in analogy to maxima theory.Data are found to be in good agreement with the theoretical curve.
Based on linear theory of sea waves, the height distribution of the intersections of wave surface with its envelope is derived.The distribution may be regarded as that of the significant crest heights under certain conditions.Some properties of this distribution are discussed in analogy to maxima theory.Data are found to be in good agreement with the theoretical curve.
1987, (1): 55-63.
Abstract:
Since the mode filtering is a certain sort of "space filtering", the matter of the utmost concerns the "side lobe" produced by some simplified processing in practice instead of the ideal orthogonal operation.In this paper, the following problems are discussed theoretically:(1) "side lobe" produced by using an integration in the water column instead of halfspace; (2) "side lobe" produced by using a finite discrete sampling; (3) "side lobe" produced by a hard-clipped eigenfunction; and (4) "side lobe" produced by the inclination of the vertical array.Some analytic results and numerical examples are shown for a special case in which the sound speed profile is isovelocity in the water column.It is found that the effect of array inclination is serious and an approach of phase compensation in proposed.
Since the mode filtering is a certain sort of "space filtering", the matter of the utmost concerns the "side lobe" produced by some simplified processing in practice instead of the ideal orthogonal operation.In this paper, the following problems are discussed theoretically:(1) "side lobe" produced by using an integration in the water column instead of halfspace; (2) "side lobe" produced by using a finite discrete sampling; (3) "side lobe" produced by a hard-clipped eigenfunction; and (4) "side lobe" produced by the inclination of the vertical array.Some analytic results and numerical examples are shown for a special case in which the sound speed profile is isovelocity in the water column.It is found that the effect of array inclination is serious and an approach of phase compensation in proposed.
1987, (1): 64-67.
Abstract:
Discussed in this paper is the deep scattering layer (DSL) observed during the experiment in the South China Sea in October 1983.The authors have investigated the acoustic characteristics of the DSL, such as the volume scattering strength of the water column, the thickness of the layer and the coefficient of the backscattering.Resonant scattering, presumably caused by the swimbladder of fishes, is responsible for the bulk of observed reverberation.In addition, the size of the swimbladder forming the acoustic scatter of the DSL is also estimated.
Discussed in this paper is the deep scattering layer (DSL) observed during the experiment in the South China Sea in October 1983.The authors have investigated the acoustic characteristics of the DSL, such as the volume scattering strength of the water column, the thickness of the layer and the coefficient of the backscattering.Resonant scattering, presumably caused by the swimbladder of fishes, is responsible for the bulk of observed reverberation.In addition, the size of the swimbladder forming the acoustic scatter of the DSL is also estimated.
CHARACTERISTICS ON INTERANNUAL VARIATIONS OF NORTH PACIFIC SST AND ITS RELATION TO EAST ASIA CLIMATE
1987, (1): 68-79.
Abstract:
The interannual variations of the monthly sea surface temperature (SST) in the North Pacific (including Equatorial East Pacific) during 1951-1980 are analysed by means of EOF method.The findings are:
(1) In the cold and warm ocean current areas, such as the North Pacific Current, the California Current and the Equatorial East Pacific areas, the convergence speeds are the fastest, while in the Kuroshio and the western part of the North Equatorial Current areas they are fast only in winter.
(2) The physical features of the first 3 eigenvectors are obvious.The first eigenvector shows that the SST values are high in the south and low in the north in the latitudinal distribution of the SST field.The warm current area, i.e.the northwestern part of the North Pacific is positive and the cold current area, i.e.the southeastern part of the North Pacific including the Eastern Equatorial Pacific is negative.The zero line of the 2nd eigenvector field runs from northeast to southwest, in the same direction as the 1st term.For the 3rd eigenvector field, the role of the Kuroshio area is striking.The sign of components of this eigenvector is negative in the north, the North Pacific Current area; on the contrary, the other 3 ocean current areas show positive.The Central Pacific is weakly negative.
(3) The characteristics of the annual variation of the monthly SST are obtained from analyses of time amplitude coefficients associated with eigenvectors.There are quasi-periodic oscillations of 5-6 years in the 1950's and early 1960's, while 2-3 years in the 1960's and 1970's.These characteristics affect the interannual variation of East Asia climate.
The interannual variations of the monthly sea surface temperature (SST) in the North Pacific (including Equatorial East Pacific) during 1951-1980 are analysed by means of EOF method.The findings are:
(1) In the cold and warm ocean current areas, such as the North Pacific Current, the California Current and the Equatorial East Pacific areas, the convergence speeds are the fastest, while in the Kuroshio and the western part of the North Equatorial Current areas they are fast only in winter.
(2) The physical features of the first 3 eigenvectors are obvious.The first eigenvector shows that the SST values are high in the south and low in the north in the latitudinal distribution of the SST field.The warm current area, i.e.the northwestern part of the North Pacific is positive and the cold current area, i.e.the southeastern part of the North Pacific including the Eastern Equatorial Pacific is negative.The zero line of the 2nd eigenvector field runs from northeast to southwest, in the same direction as the 1st term.For the 3rd eigenvector field, the role of the Kuroshio area is striking.The sign of components of this eigenvector is negative in the north, the North Pacific Current area; on the contrary, the other 3 ocean current areas show positive.The Central Pacific is weakly negative.
(3) The characteristics of the annual variation of the monthly SST are obtained from analyses of time amplitude coefficients associated with eigenvectors.There are quasi-periodic oscillations of 5-6 years in the 1950's and early 1960's, while 2-3 years in the 1960's and 1970's.These characteristics affect the interannual variation of East Asia climate.
1987, (1): 80-86.
Abstract:
A correlation characteristics analysis of monthly sea surface temperature of 13 sea areas (mainly strong ocean-current areas) and 15 subtropical highs is made, and the characteristics of the time-space variation of high-correlation areas are discussed.On the basis of a preliminary analysis of the possible physical mechanism for several related phenomena, it is concluded that SST affects subtropical high through a variety of ways.
A correlation characteristics analysis of monthly sea surface temperature of 13 sea areas (mainly strong ocean-current areas) and 15 subtropical highs is made, and the characteristics of the time-space variation of high-correlation areas are discussed.On the basis of a preliminary analysis of the possible physical mechanism for several related phenomena, it is concluded that SST affects subtropical high through a variety of ways.
1987, (1): 87-93.
Abstract:
A new and simple method for separation and determination of U and Th in manganese nodules has been developed.The results show that the addition of NH4NO3 to the dilute HNO3 medium increases the selectivity of anion-exchange separation of U and Th.The simple procedure and high recoveries of the method make it valuable to the analyses of U and Th in manganese nodules.
A new and simple method for separation and determination of U and Th in manganese nodules has been developed.The results show that the addition of NH4NO3 to the dilute HNO3 medium increases the selectivity of anion-exchange separation of U and Th.The simple procedure and high recoveries of the method make it valuable to the analyses of U and Th in manganese nodules.
1987, (1): 159-159.
Abstract:
1987, (1): 159-160.
Abstract:
1987, (1): 94-103.
Abstract:
Three types of crust exist in the area studied.There was an assembled continent at the end of the Hercynian-Indosinian cycle.Since the Cenozoic the area has shown a trend of tension, thinning and oceanization in varying degrees, which is manifested in the creeping and obduction of the Asian continent as well as the spreeding and subduction of West Pacific Ocean, thus bringing about the continental rifts, maginal basins and arc-thrence systems in this area.
Geotectonic cycle usually begins with a tensional phase and ends with a compressional phase.When tension predominates, various rifts can be formed on the continental crust and the crust is in the trend of oceanization.When compression predominates, the rifts disappears, the crust is in the trend of continentization and, in the end, folded mountain belts and geosutures can be formed.Thus, the crust is tending towards "maturatity" and thickening.
Three types of crust exist in the area studied.There was an assembled continent at the end of the Hercynian-Indosinian cycle.Since the Cenozoic the area has shown a trend of tension, thinning and oceanization in varying degrees, which is manifested in the creeping and obduction of the Asian continent as well as the spreeding and subduction of West Pacific Ocean, thus bringing about the continental rifts, maginal basins and arc-thrence systems in this area.
Geotectonic cycle usually begins with a tensional phase and ends with a compressional phase.When tension predominates, various rifts can be formed on the continental crust and the crust is in the trend of oceanization.When compression predominates, the rifts disappears, the crust is in the trend of continentization and, in the end, folded mountain belts and geosutures can be formed.Thus, the crust is tending towards "maturatity" and thickening.
1987, (1): 104-115.
Abstract:
Based on micropalaeontological information of over 150 drill holes, this paper discusses the problem on the naming of Quaternary transgressions in the west-southern coast plain of Bohai Sea.We consider that palaeotide and sedimentation have a great influence on the distribution of micropalaeontological fossils.In view of the present technical level, it is necessary for transgression sequence to be established under the following conditions:full evidence of fossils; clear climate; and stable sedimentary beds.In establishing a transgression, its contents of time and phase concept must be proposed, and its biofacies, sedimentary facies and palaeoclimatology must be analysed synthetically.
Based on micropalaeontological information of over 150 drill holes, this paper discusses the problem on the naming of Quaternary transgressions in the west-southern coast plain of Bohai Sea.We consider that palaeotide and sedimentation have a great influence on the distribution of micropalaeontological fossils.In view of the present technical level, it is necessary for transgression sequence to be established under the following conditions:full evidence of fossils; clear climate; and stable sedimentary beds.In establishing a transgression, its contents of time and phase concept must be proposed, and its biofacies, sedimentary facies and palaeoclimatology must be analysed synthetically.
1987, (1): 116-123.
Abstract:
The underground salt water in Huang-Huai-Hai-Liao (Rivers) Plains, just like an underground salt sea, is buried around the Huanghai Sea and Bohai Sea.A lot of data show that the salt water bed and marine bed were formed at the same time, i.e.the salt water was the result of transgression.At present, the concentration of the salt water is not strong and it is getting freshened under the effects of both surface and underground runoff.In view of such development, it would be possible to reconstruct paleogeography on the one hand and to change the salt water into fresh water through the dual actions of man and Nature.
The underground salt water in Huang-Huai-Hai-Liao (Rivers) Plains, just like an underground salt sea, is buried around the Huanghai Sea and Bohai Sea.A lot of data show that the salt water bed and marine bed were formed at the same time, i.e.the salt water was the result of transgression.At present, the concentration of the salt water is not strong and it is getting freshened under the effects of both surface and underground runoff.In view of such development, it would be possible to reconstruct paleogeography on the one hand and to change the salt water into fresh water through the dual actions of man and Nature.
1987, (1): 124-131.
Abstract:
Resting spores are important in ecology and taxonomy of diatoms as well known to every dia-tomist.If NO3-N and NO2-N in the cultures drop down to 4 μg I-1, or at a relatively small amount of N, higher in number of individuals and sudden increasing of salinity, the resting spores will produce after 24 h.Paired spores are present in the newborn spore-mother cells.At 20℃ and 6000 lx in a fresh medium, spores will be germinated into vegetative cells within 48 h.
Resting spores are important in ecology and taxonomy of diatoms as well known to every dia-tomist.If NO3-N and NO2-N in the cultures drop down to 4 μg I-1, or at a relatively small amount of N, higher in number of individuals and sudden increasing of salinity, the resting spores will produce after 24 h.Paired spores are present in the newborn spore-mother cells.At 20℃ and 6000 lx in a fresh medium, spores will be germinated into vegetative cells within 48 h.
1987, (1): 132-141.
Abstract:
In this paper Cohort Analysis (VPA) with the data on catch in number by age and year is used to estimate independently fishing mortality, abundance and actual number of spawning stock of the Pacific herring in the Huanghai Sea.The results show that catch rate of the fishery is very high, and that the fishing mortality of the dominant age group aged 2-4 was 0.87-2.97 during the years 1971-1984.The size of year class has been decreased since 1982 although the variability for this species in the Huanghai Sea is frequent.This results in reducing the recruitment of the fishery, the abundance and the actual number of spawning stock.Therefore, an urgent management measure should be considered.
The magnitude of several sources of errors in Cohort Analysis (VPA) are examined, and the precision of the estimates is mainly dependent on an accurate natural mortality.
In this paper Cohort Analysis (VPA) with the data on catch in number by age and year is used to estimate independently fishing mortality, abundance and actual number of spawning stock of the Pacific herring in the Huanghai Sea.The results show that catch rate of the fishery is very high, and that the fishing mortality of the dominant age group aged 2-4 was 0.87-2.97 during the years 1971-1984.The size of year class has been decreased since 1982 although the variability for this species in the Huanghai Sea is frequent.This results in reducing the recruitment of the fishery, the abundance and the actual number of spawning stock.Therefore, an urgent management measure should be considered.
The magnitude of several sources of errors in Cohort Analysis (VPA) are examined, and the precision of the estimates is mainly dependent on an accurate natural mortality.
1987, (1): 142-152.
Abstract:
The effect of salinity on the distribution of copepoda in the Jiulong Estuary is studied in the present paper.The analysis of the samples collected during February 1983-January 1984 shows that the salinity of the Jiulong Estuary varies from 0.04 at Station E (head of estuary) to 31.7 at Station C (mouth of estuary).The distribution of copepoda is obviously affected by salinity.The results of the investigation show that the number of species, Shannon-Weaver H' index of diversity, species richness d and species evenness J' of copepoda increase with increasing salinity.Especially between the Station D and the Station C, being dominated by three predominant species.But, on the other hand, the total number of individuals apears to decrease with increasing salinity.According to the relation of distribution of copepoda with salinity, the copepoda may be divided into five ecological groups, i.e.fresh-water, low-salinity estuarine, meso-salinity estuarine, neritic and oceanic groups.Their horizontal succession at the investigated region reflects the rule of salinity variation.
The effect of salinity on the distribution of copepoda in the Jiulong Estuary is studied in the present paper.The analysis of the samples collected during February 1983-January 1984 shows that the salinity of the Jiulong Estuary varies from 0.04 at Station E (head of estuary) to 31.7 at Station C (mouth of estuary).The distribution of copepoda is obviously affected by salinity.The results of the investigation show that the number of species, Shannon-Weaver H' index of diversity, species richness d and species evenness J' of copepoda increase with increasing salinity.Especially between the Station D and the Station C, being dominated by three predominant species.But, on the other hand, the total number of individuals apears to decrease with increasing salinity.According to the relation of distribution of copepoda with salinity, the copepoda may be divided into five ecological groups, i.e.fresh-water, low-salinity estuarine, meso-salinity estuarine, neritic and oceanic groups.Their horizontal succession at the investigated region reflects the rule of salinity variation.
1987, (1): 153-158.
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1987, (1): 160-160.
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