1989 Vol. 8, No. 2
Display Method:
1989, (2): 161-170.
Abstract:
Starting from satellite remote sensing data, the dynamical processes of shear waves occurring at the boundary between the western boundary current and the shelf slope water are studied and dynamically analyzed in this study. The average wavelength is 75 km, and the average amplitude (from crest to trough)17 km. the average phase speed 100 cms-1 for the shear waves along the north wall of the Gulf Stream to the east of Cape Hatteras measured from NOAA satellite IR (infrared) images. The average wavelength of shear waves along the north wall of the Kuroshio Current is 57 km, and the average amplitude 17 km. For the shear waves occurring along the west wall of the Gulf Stream to the south of Cape Hatteras, the average wavelength is 131 km, and the average amplitude 33 km measured from Seasat SAR (synthetic aperture radar)images. The time for one cycle of shear wave event is about one week.
In order to explore the dynamical mechanisms of shear waves, we solved the vorticity equation for a stratified fluid, and obtained an analytical expression of dispersion relation of shear waves. The results indicated that there was a parabolic relation between the phase speed and the wavelength of shear waves, and the mean flow field was an important factor in the dispersion relation. The latter point means that the horizontal tangent variation of velocity is a basic condition for shear wave occurrence. Theoretical analyses are confirmed by satellite remote sensing data.
Starting from satellite remote sensing data, the dynamical processes of shear waves occurring at the boundary between the western boundary current and the shelf slope water are studied and dynamically analyzed in this study. The average wavelength is 75 km, and the average amplitude (from crest to trough)17 km. the average phase speed 100 cms-1 for the shear waves along the north wall of the Gulf Stream to the east of Cape Hatteras measured from NOAA satellite IR (infrared) images. The average wavelength of shear waves along the north wall of the Kuroshio Current is 57 km, and the average amplitude 17 km. For the shear waves occurring along the west wall of the Gulf Stream to the south of Cape Hatteras, the average wavelength is 131 km, and the average amplitude 33 km measured from Seasat SAR (synthetic aperture radar)images. The time for one cycle of shear wave event is about one week.
In order to explore the dynamical mechanisms of shear waves, we solved the vorticity equation for a stratified fluid, and obtained an analytical expression of dispersion relation of shear waves. The results indicated that there was a parabolic relation between the phase speed and the wavelength of shear waves, and the mean flow field was an important factor in the dispersion relation. The latter point means that the horizontal tangent variation of velocity is a basic condition for shear wave occurrence. Theoretical analyses are confirmed by satellite remote sensing data.
1989, (2): 171-178.
Abstract:
Starting from vorticity equation, the triggering mechanism and amplitude decay of shear waves in the ocean are discussed in this paper. The theoretical analysis indicates that by the action of stripped external force (for examples, the sudden setting of stripped wind, moving stripped wind, etc.), shear waves can be triggered. This is qualitatively consistent with satellite observations. The amplitude decay process of shear waves by the action of side friction is also discussed in the paper. The theoretical model is quantitatively consistent with satellite observations.
Starting from vorticity equation, the triggering mechanism and amplitude decay of shear waves in the ocean are discussed in this paper. The theoretical analysis indicates that by the action of stripped external force (for examples, the sudden setting of stripped wind, moving stripped wind, etc.), shear waves can be triggered. This is qualitatively consistent with satellite observations. The amplitude decay process of shear waves by the action of side friction is also discussed in the paper. The theoretical model is quantitatively consistent with satellite observations.
1989, (2): 179-190.
Abstract:
A two-dimensional.nonlinear numerical model is used to study the residual current generated by tides in the East China Sea (ECS) and the South Huanghai Sea (SHS). At first, the principal semidiurnal lunar tide (M2) and the tidal current are derived in these areas. The results obtained with the model are strongly supported by the observational results available. Then, the tide-induced residual flow is determined by using the currents generated by the tidal input. The main features of the residual current in ECS and SHS are presented by analyzing the calculated results. Some of the problems are discussed such as the cause of generating residual current and the contribution of the residual current to the observed current.
A two-dimensional.nonlinear numerical model is used to study the residual current generated by tides in the East China Sea (ECS) and the South Huanghai Sea (SHS). At first, the principal semidiurnal lunar tide (M2) and the tidal current are derived in these areas. The results obtained with the model are strongly supported by the observational results available. Then, the tide-induced residual flow is determined by using the currents generated by the tidal input. The main features of the residual current in ECS and SHS are presented by analyzing the calculated results. Some of the problems are discussed such as the cause of generating residual current and the contribution of the residual current to the observed current.
1989, (2): 191-198.
Abstract:
During the second course of USA-PRC joint air sea interaction experiment in 1986, the temperature structure parameters CT2 were measured by sodar over the Western Pacific Ocean. Based on similarity theory, a method is discussed to calculate the sensible heat flux over the ocean in unstable stratification. Becausehumidity is great over the ocean, so we have to consider the influence of water vapor structure parameter Ce2 and the correlation coefficient betweene and T on the calculation of sensible heat flux using CT2 profiles measured by sodar. A new formula is suggested in terms of parameterization. The sensible heat flux calculated by sodar measurements is compared with that by bulk transfer method, and the results agree well.
During the second course of USA-PRC joint air sea interaction experiment in 1986, the temperature structure parameters CT2 were measured by sodar over the Western Pacific Ocean. Based on similarity theory, a method is discussed to calculate the sensible heat flux over the ocean in unstable stratification. Becausehumidity is great over the ocean, so we have to consider the influence of water vapor structure parameter Ce2 and the correlation coefficient betweene and T on the calculation of sensible heat flux using CT2 profiles measured by sodar. A new formula is suggested in terms of parameterization. The sensible heat flux calculated by sodar measurements is compared with that by bulk transfer method, and the results agree well.
1989, (2): 199-208.
Abstract:
In this paper, by using two sets of composite data of developed and undeveloped depressions over the South China Sea, we analyze and compare the dynamic structures, the heating fields and the vorticity budget residuals of two different types of depressions. Our conclusions are as follows:
The two types of depressions are similar in thermodynamical and dynamical structures. The main differ ences are:in the high layer of developed depression there is a divergence field, with a center near the zero line of vertical wind shear, and over undeveloped depression, the divergence field is weaker and the vertical wind at its center is greater than 5 m s-1. The thermodynamical field of the former is asymmetrical and that of the latter is quasi-symmetrical. As far as the dynamics structure is concerned, the convergence in the lower layer and the difference of divergence between the upper and lower layers of developed depression is three tmies larger than that of undeveloped depression. The upward motion and heating field at the center of developed depression is also stronger than that of undeveloped one.
The vorticity budget of the two types of depressions is mainly determined by the divergence term, the vorticity advection term and the vertical transport term. The residual term is also important. The principal contribution comes from the divergence term.This is more significant for developed depression than for undeveloped depression.
In this paper, by using two sets of composite data of developed and undeveloped depressions over the South China Sea, we analyze and compare the dynamic structures, the heating fields and the vorticity budget residuals of two different types of depressions. Our conclusions are as follows:
The two types of depressions are similar in thermodynamical and dynamical structures. The main differ ences are:in the high layer of developed depression there is a divergence field, with a center near the zero line of vertical wind shear, and over undeveloped depression, the divergence field is weaker and the vertical wind at its center is greater than 5 m s-1. The thermodynamical field of the former is asymmetrical and that of the latter is quasi-symmetrical. As far as the dynamics structure is concerned, the convergence in the lower layer and the difference of divergence between the upper and lower layers of developed depression is three tmies larger than that of undeveloped depression. The upward motion and heating field at the center of developed depression is also stronger than that of undeveloped one.
The vorticity budget of the two types of depressions is mainly determined by the divergence term, the vorticity advection term and the vertical transport term. The residual term is also important. The principal contribution comes from the divergence term.This is more significant for developed depression than for undeveloped depression.
1989, (2): 209-215.
Abstract:
In this paper, a strong lTCZ process and an lTCZ-absent process during FGGE in 1979 were selected for comparison to explore how they were subject to the influence of the evolution of the upper easterly jets.
In this paper, a strong lTCZ process and an lTCZ-absent process during FGGE in 1979 were selected for comparison to explore how they were subject to the influence of the evolution of the upper easterly jets.
1989, (2): 217-221.
Abstract:
The relationship between meridional wind in mid-latitudes of East Asia and SST in the Equatorial Eastern Pacific is analysed in this paper. It is pointed out that there exist close relations between the seasonal changes of the meridional wind in mid-latitudes of East Asia and SST in the Equatorial Eastern Pacific. The intensification of north winds over East Asia also plays an important role in the rise of SST in Equatorial Eastern Pacific one year later. The strong winter monsoon usually occurs in previous winter of El Nino and it causes low temperature to a great extent in China. The low temperature in China can be regarded as a precursor of El Nino.
The relationship between meridional wind in mid-latitudes of East Asia and SST in the Equatorial Eastern Pacific is analysed in this paper. It is pointed out that there exist close relations between the seasonal changes of the meridional wind in mid-latitudes of East Asia and SST in the Equatorial Eastern Pacific. The intensification of north winds over East Asia also plays an important role in the rise of SST in Equatorial Eastern Pacific one year later. The strong winter monsoon usually occurs in previous winter of El Nino and it causes low temperature to a great extent in China. The low temperature in China can be regarded as a precursor of El Nino.
1989, (2): 223-235.
Abstract:
The five chemical bound forms of Fe, Al and Mn in sediments in the main channel of the Zhujiang River.and its estuary, namely, exchangeable, carbonic, oxidative, organic and residual (in crystal) forms, were determined. The method of sequential extraction was used for separating the five bound forms.
The main chemical form of the three elements in the sediments of the Zhujiang River and its estuarine zone is the residual one. The exchangeable form exists only in a small fraction.
Correlationships between the concentration of a certain form of heavy metals and Eh. pH and salinity were discussed. The principles of geochemistry are used to explain the mechanism of heavy metal transport in the river.
It was also found that the distribution rule of the chemical forms of Fe, Al and Mn in sediments in the lower reaches of the Zhujiang River was similar to the one in the lower reaches of the Yamaska River.
The five chemical bound forms of Fe, Al and Mn in sediments in the main channel of the Zhujiang River.and its estuary, namely, exchangeable, carbonic, oxidative, organic and residual (in crystal) forms, were determined. The method of sequential extraction was used for separating the five bound forms.
The main chemical form of the three elements in the sediments of the Zhujiang River and its estuarine zone is the residual one. The exchangeable form exists only in a small fraction.
Correlationships between the concentration of a certain form of heavy metals and Eh. pH and salinity were discussed. The principles of geochemistry are used to explain the mechanism of heavy metal transport in the river.
It was also found that the distribution rule of the chemical forms of Fe, Al and Mn in sediments in the lower reaches of the Zhujiang River was similar to the one in the lower reaches of the Yamaska River.
1989, (2): 237-251.
Abstract:
Effects of heavy metals on Isochrysis galbana (Parke) were studied in our laboratory. The research focused on toxic effects of metals on algal cells, effects of water-soluble and lipid-soluble organic ligands on metal toxicity and processes of metal uptake by cells. Interactions between two metals and the mechanisms involved were also studied in detail. Finally, some relationships between toxicity and chemical property of metals were revealed.
Effects of heavy metals on Isochrysis galbana (Parke) were studied in our laboratory. The research focused on toxic effects of metals on algal cells, effects of water-soluble and lipid-soluble organic ligands on metal toxicity and processes of metal uptake by cells. Interactions between two metals and the mechanisms involved were also studied in detail. Finally, some relationships between toxicity and chemical property of metals were revealed.
1989, (2): 253-261.
Abstract:
Five manganese nodules collected from the Northern Mid-Pacific have been analysed for their U and Th isotopes.It is found that the enrichment of thorium compared to uranium is universal in deep-sea manganese, nodules and in the top sides of the nodules there are large excesses of 230Th and 231Pa decreasing exponentially with depth. For each of the nodules, the concordant growth rates are obtained from three different methods:230Thex 230Thex/232Th and 231Paex.The growth rates of manganese nodules are closely related to the chemical compositions of the nodules and the types of the underlying sediments. The growth rates of five nodules are determined to be in the range of 0.79-7.4 mm/106a, in agreement with those predicted from the chemical compositions of the nodules. By the comparison of the extrapolated 230Thex,230Thex/232Th and 231Paex data from the top and bottom surfaces of the nodule from Site M21 yields, the nodule turnover time is (9.83-13.7)×104a.
Five manganese nodules collected from the Northern Mid-Pacific have been analysed for their U and Th isotopes.It is found that the enrichment of thorium compared to uranium is universal in deep-sea manganese, nodules and in the top sides of the nodules there are large excesses of 230Th and 231Pa decreasing exponentially with depth. For each of the nodules, the concordant growth rates are obtained from three different methods:230Thex 230Thex/232Th and 231Paex.The growth rates of manganese nodules are closely related to the chemical compositions of the nodules and the types of the underlying sediments. The growth rates of five nodules are determined to be in the range of 0.79-7.4 mm/106a, in agreement with those predicted from the chemical compositions of the nodules. By the comparison of the extrapolated 230Thex,230Thex/232Th and 231Paex data from the top and bottom surfaces of the nodule from Site M21 yields, the nodule turnover time is (9.83-13.7)×104a.
1989, (2): 263-272.
Abstract:
Through the investigation on radioactive activities of water, sediment and some marine organismsin the Zhujiang Estuary, adjacent sea area and the distributary mouths of the Zhujiang River, activities of total α. radioactivity, total β radioactivity, artificial radioactive 90Srand 157Cs, and factors inflencing the distribution and the content of U in seawater are studied.
The mainly radioactive pollution substances and their sources in the sea area are studied by γ spectra obtained from sediment in the sea area. The results show that the main radioactivity substances are natural radioactivity U,Th series and 40K. which were produced by the modern industry and transported into the sea through the main current of the Zhujiang River.
Through the investigation on radioactive activities of water, sediment and some marine organismsin the Zhujiang Estuary, adjacent sea area and the distributary mouths of the Zhujiang River, activities of total α. radioactivity, total β radioactivity, artificial radioactive 90Srand 157Cs, and factors inflencing the distribution and the content of U in seawater are studied.
The mainly radioactive pollution substances and their sources in the sea area are studied by γ spectra obtained from sediment in the sea area. The results show that the main radioactivity substances are natural radioactivity U,Th series and 40K. which were produced by the modern industry and transported into the sea through the main current of the Zhujiang River.
1989, (2): 273-283.
Abstract:
South of Hangzhou Bay, Zhejiang Province, exhibits an embayed muddy coastline, with the muddy beaches of embayments extending continuously seaward.The source of sediments on this coast presents an interesting problem to marine geologists and geomorphologists.The total annual load of sediments from the rivers of Zhejiang is only 12×106t.These materials affect only the area near the river mouths. The paper showed that the sediment along the coast of Zhejiang mainly comes from the Changjiang Estuary through analysing the time and space variations of suspended sediment, the features of sediment and the sedimentary transport.
The Changjiang River is the largest river system in China, its sediment to the sea amounting to 468×106t. The sediment during summer transports mainly eastward, and is affected by the water body with high temperature, salinity and transparency; the winter season is the period with high sediment concentration. The sediment of the Changjiang Estuary transports together with the longshore current of the East China Sea southward, the southern boundary can reach the sea region approximately 500 km from the Shacheng Harbour.The accretion rate seaward has been about 10-30 m since the 16th century.The sediment movement combined the longitudinal with the lateral, so that the muddy flats progress continuously seaward under the construction of the seashore profile.
South of Hangzhou Bay, Zhejiang Province, exhibits an embayed muddy coastline, with the muddy beaches of embayments extending continuously seaward.The source of sediments on this coast presents an interesting problem to marine geologists and geomorphologists.The total annual load of sediments from the rivers of Zhejiang is only 12×106t.These materials affect only the area near the river mouths. The paper showed that the sediment along the coast of Zhejiang mainly comes from the Changjiang Estuary through analysing the time and space variations of suspended sediment, the features of sediment and the sedimentary transport.
The Changjiang River is the largest river system in China, its sediment to the sea amounting to 468×106t. The sediment during summer transports mainly eastward, and is affected by the water body with high temperature, salinity and transparency; the winter season is the period with high sediment concentration. The sediment of the Changjiang Estuary transports together with the longshore current of the East China Sea southward, the southern boundary can reach the sea region approximately 500 km from the Shacheng Harbour.The accretion rate seaward has been about 10-30 m since the 16th century.The sediment movement combined the longitudinal with the lateral, so that the muddy flats progress continuously seaward under the construction of the seashore profile.
1989, (2): 285-292.
Abstract:
From June 1984 to May 1985, monthly and seasonal panel tests of fouling organisms were carried out on rafts at Tuoji Island. Seventy-three species were obtained. The occurring frequencies of the following species are all at least 30%:Ectocarpus confervoides, Polysiphonia urceolata, Tubularia mesembryanthmum, Cfytia edwardsi, Tubulipora pulchra, Celleporella hyalina, Mytilus edulis, Hiatella arctica, Caprella acanthogaster, Corophium crassicome, Jassa cf.falcata and Podocerus cf. inconspicuus. Large or calcareous species are not dominant ones. The wet weight is comparatively light, the yearly wet weight being 9.12 kg m-2. Attaching seasons of major species are from June to October and no bio-attachment occurs between January and April. Fouling organisms at Tuoji Island differ rather greatly from those in the harbours along the continental coast, showing the charcteristics of fouling organisms in the northern island harbours of China.
From June 1984 to May 1985, monthly and seasonal panel tests of fouling organisms were carried out on rafts at Tuoji Island. Seventy-three species were obtained. The occurring frequencies of the following species are all at least 30%:Ectocarpus confervoides, Polysiphonia urceolata, Tubularia mesembryanthmum, Cfytia edwardsi, Tubulipora pulchra, Celleporella hyalina, Mytilus edulis, Hiatella arctica, Caprella acanthogaster, Corophium crassicome, Jassa cf.falcata and Podocerus cf. inconspicuus. Large or calcareous species are not dominant ones. The wet weight is comparatively light, the yearly wet weight being 9.12 kg m-2. Attaching seasons of major species are from June to October and no bio-attachment occurs between January and April. Fouling organisms at Tuoji Island differ rather greatly from those in the harbours along the continental coast, showing the charcteristics of fouling organisms in the northern island harbours of China.
1989, (2): 293-305.
Abstract:
As a summary of the finding from the investigation of fishes in Beitang Estuary,Tianjin,the paper deals with the young fishes' biomass, composition and change, and studies the spawning habit, spawning time, fecundity, age structure and type of the spawning stocks in the estuary.
As a summary of the finding from the investigation of fishes in Beitang Estuary,Tianjin,the paper deals with the young fishes' biomass, composition and change, and studies the spawning habit, spawning time, fecundity, age structure and type of the spawning stocks in the estuary.
1989, (2): 307-313.
Abstract:
1989, (2): 313-313.
Abstract:
