1994 Vol. 13, No. 1
Display Method:
1994, (1): 1-21.
Abstract:
This study analytically examines the possible presence of double Kelvin waves along the Okinawa Trough in the East China Sea. Not only was the response of sea level to transient and time-periodic wind forcing from the north confirmed following Mysak (1969),but also to steady-state and moving wind forcings was examined according to the realistic wind fields in the East China Sea. Double Kelvin waves generated by these forcings, due to the discontinuous depth trapping, propagate southward and disperse. Finally, these dispersive waves shift to free ones. The moored current meter observations in summer and winter of 1987 along the Okinawa Trough supported the analytic solutions. There was a southward propagating current fluctuation with a speed of 0.32 m/s along the escarpment which was documented by Lin and Guo (1990).
This study analytically examines the possible presence of double Kelvin waves along the Okinawa Trough in the East China Sea. Not only was the response of sea level to transient and time-periodic wind forcing from the north confirmed following Mysak (1969),but also to steady-state and moving wind forcings was examined according to the realistic wind fields in the East China Sea. Double Kelvin waves generated by these forcings, due to the discontinuous depth trapping, propagate southward and disperse. Finally, these dispersive waves shift to free ones. The moored current meter observations in summer and winter of 1987 along the Okinawa Trough supported the analytic solutions. There was a southward propagating current fluctuation with a speed of 0.32 m/s along the escarpment which was documented by Lin and Guo (1990).
1994, (1): 23-29.
Abstract:
On the basis of the second order solution of two-dimensional random gravity waves in finite uniform depth, which is tederived by a perturbation expansion method, the analytical expression of the second order spectrum is strictly deduced, and for infinite depth, the correct form of the kernel function is given for each octant domain. In fact,the present study improves and corrects the generally accepted results obtained by Tick[1959,Journal of Mathematics and Mechanics, 8(5),643-651].
On the basis of the second order solution of two-dimensional random gravity waves in finite uniform depth, which is tederived by a perturbation expansion method, the analytical expression of the second order spectrum is strictly deduced, and for infinite depth, the correct form of the kernel function is given for each octant domain. In fact,the present study improves and corrects the generally accepted results obtained by Tick[1959,Journal of Mathematics and Mechanics, 8(5),643-651].
1994, (1): 31-46.
Abstract:
On the basis of oceanographic data over years of the China seas, 19 elements affecting the oceano-graphical climate are sorted out to make R-type principal component analysis. The first 6 principal synthetic factors are found with 91.06% of the accumulative ratio of their eigenvalue's variances to population variance, representing fullythe original information. In order to polarize the loading values of every principal factor tending to 1 or 0, varimax orthogonal rotation to the loading matrix of 6 principal factors is made.
On the basis of oceanographic data over years of the China seas, 19 elements affecting the oceano-graphical climate are sorted out to make R-type principal component analysis. The first 6 principal synthetic factors are found with 91.06% of the accumulative ratio of their eigenvalue's variances to population variance, representing fullythe original information. In order to polarize the loading values of every principal factor tending to 1 or 0, varimax orthogonal rotation to the loading matrix of 6 principal factors is made.
1994, (1): 47-55.
Abstract:
A numerical model on typhoon sea surface wind is developed and then tested. The model is devided into two parts. The first part is the derivation of the vertically averaged boundary layer dynamic equation and from the equation, a quasi-steady state of vertically averaged wind field of typhoon for a given pressure field is obtained; the second part is to convert vertically averaged wind to that at 10-m elevation. With observed Marex buoy data of three typhoon cases in the South China Sea, the model wind is calibrated.
The results show that, at buoy sites, the correlation coefficient is about 0.95 between the hindcast and the observed wind speeds. The error statistics show that the error of maximum value of wind speed is smaller than 2 m/s and the absolute mean relative error of wind speeds about 10% and wind direction 15° or so. With the hindcast wind as an input of the third generation wave model, the wave hindcast results are also well calibrated.
A numerical model on typhoon sea surface wind is developed and then tested. The model is devided into two parts. The first part is the derivation of the vertically averaged boundary layer dynamic equation and from the equation, a quasi-steady state of vertically averaged wind field of typhoon for a given pressure field is obtained; the second part is to convert vertically averaged wind to that at 10-m elevation. With observed Marex buoy data of three typhoon cases in the South China Sea, the model wind is calibrated.
The results show that, at buoy sites, the correlation coefficient is about 0.95 between the hindcast and the observed wind speeds. The error statistics show that the error of maximum value of wind speed is smaller than 2 m/s and the absolute mean relative error of wind speeds about 10% and wind direction 15° or so. With the hindcast wind as an input of the third generation wave model, the wave hindcast results are also well calibrated.
1994, (1): 57-72.
Abstract:
A two-dimensional mesoscale model is used to investigate the effect of background wind field and character of the underlying surface on the coastal frontogenesis along the east continental coast when cold air outbreak. The results of numerical experiments indicate that the coastal frontogenesis mainly appears near ground at night. When the background wind is easterly, it is favorable to coastal frontogenesis in the lower layer of the atmosphere. When the background wind is westerly, it is unfavorable to coastal frontogenesis in the lower layer of the atmosphere. The vertical shear of the background wind has important influence on the coastal frontogenesis. The coastal frontogenesis at lower layer at night is strengthened with increasing temperature difference between sea and air. The effect of coastal sloping terrain on the coastal frontogenesis is little when the topography sloping angle is lesser.
The analysis of the physical mechanism of frontogenesis shows that the main factor influencing the coastal frontogenesis is the deformation field of horizontal wind speed.
A two-dimensional mesoscale model is used to investigate the effect of background wind field and character of the underlying surface on the coastal frontogenesis along the east continental coast when cold air outbreak. The results of numerical experiments indicate that the coastal frontogenesis mainly appears near ground at night. When the background wind is easterly, it is favorable to coastal frontogenesis in the lower layer of the atmosphere. When the background wind is westerly, it is unfavorable to coastal frontogenesis in the lower layer of the atmosphere. The vertical shear of the background wind has important influence on the coastal frontogenesis. The coastal frontogenesis at lower layer at night is strengthened with increasing temperature difference between sea and air. The effect of coastal sloping terrain on the coastal frontogenesis is little when the topography sloping angle is lesser.
The analysis of the physical mechanism of frontogenesis shows that the main factor influencing the coastal frontogenesis is the deformation field of horizontal wind speed.
1994, (1): 73-84.
Abstract:
In this paper, on the basis of the Antarctic sea ice data from 1972 to 1989 issued by the America Joint Ice Center, the distribution features of the Antarctic sea ice is analyzed, the net sea ice area indexes are calculated. and the long-range variation periods of the sea ice area index are analyzed with the maximum entropy spectrum, finally the distribution pattern of the Antarctic sea ice and its variation features are obtained.
According to its spatial distribution feature, the Antarctic Sea ice is divided into three large regions. Region Ⅰ (0°-120°E) is a zonal area which includes the Prydz Bay area, and sea ice area extending from the Weddell Sea, Region Ⅰ (120°E-120°W) mainly includes the Ross Sea area, and Region Ⅱ(120°W-0°) mainly the Weddell Sea area. Of all the regions, the ice area in Region,is the largest, and that in Region Ⅰ is the smallest.
In this paper, on the basis of the Antarctic sea ice data from 1972 to 1989 issued by the America Joint Ice Center, the distribution features of the Antarctic sea ice is analyzed, the net sea ice area indexes are calculated. and the long-range variation periods of the sea ice area index are analyzed with the maximum entropy spectrum, finally the distribution pattern of the Antarctic sea ice and its variation features are obtained.
According to its spatial distribution feature, the Antarctic Sea ice is divided into three large regions. Region Ⅰ (0°-120°E) is a zonal area which includes the Prydz Bay area, and sea ice area extending from the Weddell Sea, Region Ⅰ (120°E-120°W) mainly includes the Ross Sea area, and Region Ⅱ(120°W-0°) mainly the Weddell Sea area. Of all the regions, the ice area in Region,is the largest, and that in Region Ⅰ is the smallest.
1994, (1): 85-94.
Abstract:
The marine aerosols were collected in the atmosphere over the Kuroshio area for 2 a from 1987 to 1988. The ions of chlorine, magnesium. potassium, calcium, fluorine, sulfate, nitrate, water soluble and organic phosphorus, water and acid soluble manganese, iron. lead, copper, vanadium and cadmium were determined. The results show that the sources of species in the marine aerosol may be traced to sea water. land mineral dusts and continental air pollutants. The concentrations of continental source matter in the marine aerosol also have an obvious seasonal variation with greatest contents in the winter. The major components of the continental source aerosols are sulfate and nitrate, and mineral matters are secondary. The sequence of water solubility of the heavy metal is Cd > Mn > Pb > Cu > Fe > V. The air to sea fluxes of the matter in the marine aerosols are also discussed. A significant content of sulfate and nitrate, and a considerable content of mineral matter are deposited to the sea water from the air.
The marine aerosols were collected in the atmosphere over the Kuroshio area for 2 a from 1987 to 1988. The ions of chlorine, magnesium. potassium, calcium, fluorine, sulfate, nitrate, water soluble and organic phosphorus, water and acid soluble manganese, iron. lead, copper, vanadium and cadmium were determined. The results show that the sources of species in the marine aerosol may be traced to sea water. land mineral dusts and continental air pollutants. The concentrations of continental source matter in the marine aerosol also have an obvious seasonal variation with greatest contents in the winter. The major components of the continental source aerosols are sulfate and nitrate, and mineral matters are secondary. The sequence of water solubility of the heavy metal is Cd > Mn > Pb > Cu > Fe > V. The air to sea fluxes of the matter in the marine aerosols are also discussed. A significant content of sulfate and nitrate, and a considerable content of mineral matter are deposited to the sea water from the air.
1994, (1): 95-106.
Abstract:
On the basis of the data of two cruises in the Changjiang River mouth during the "rainy season" of August 1981 and the "dry season" of November of the same year, this article analyzes the horizontal distribution, the sectional distribution and the diurnal variations of total phosphorus (T. P.),organic phosphorus (O. P.)and phosphate (PO4),and at the same time summarizes their distributional patterns. It makes also statistic and correlative analyses on different species of phosphorus, their behaviours and characteristics of cycling process in the Changjiang Estuary.
On the basis of the data of two cruises in the Changjiang River mouth during the "rainy season" of August 1981 and the "dry season" of November of the same year, this article analyzes the horizontal distribution, the sectional distribution and the diurnal variations of total phosphorus (T. P.),organic phosphorus (O. P.)and phosphate (PO4),and at the same time summarizes their distributional patterns. It makes also statistic and correlative analyses on different species of phosphorus, their behaviours and characteristics of cycling process in the Changjiang Estuary.
1994, (1): 107-115.
Abstract:
A phillipsite as one of oceanic authigenic zeolites gradually forms from alteration of volcanic glass under low temperature and pressure. In this paper physical property and chemical and mineralogical compositions of some zeolite grains collected from the study area in the North Pacific Ocean are first comprehensively studied, and they are defined as phillipsite. Then, statistics of grain percentage of the phillipsite widely-distributed at 35 sites in the study area in the deep-sea sediments were made; it has been found that they mainly occur in the two sediments:red clay and calcareous ooze, and are rich in the former. Finally, the authors preliminarily discuss the formation process of the phillipsite on the basis of this study results, together with the view points of predecessors.
A phillipsite as one of oceanic authigenic zeolites gradually forms from alteration of volcanic glass under low temperature and pressure. In this paper physical property and chemical and mineralogical compositions of some zeolite grains collected from the study area in the North Pacific Ocean are first comprehensively studied, and they are defined as phillipsite. Then, statistics of grain percentage of the phillipsite widely-distributed at 35 sites in the study area in the deep-sea sediments were made; it has been found that they mainly occur in the two sediments:red clay and calcareous ooze, and are rich in the former. Finally, the authors preliminarily discuss the formation process of the phillipsite on the basis of this study results, together with the view points of predecessors.
1994, (1): 117-127.
Abstract:
Seasonal abundance of the marine cladoceran Penilia avirostris was studied in the Tolo Harbour, Hong Kong, from November 1987 to December 1989. P. aviroseris occurred in plankton throughout the year, but no clear seasonal pattern could be identified. In general, densities were the highest in the Tolo Channel and decreased progressively towards the inner parts of the Tolo Harbour. P. avirostris showed marked seasonal variations in body size and brood size. Body length of P. avirostris ranged from 0.3 to 1.0 mm. Average body length was greatest on March 1988 and January 1989, and the smallest in May 1988, although no clear seasonal trends could be detected. Brood size of P. avirostris ranged from 1 to 13 over the study period with a mean of 5.6. A significant positive relationship was found between body length and brood size. Diel vertical migration and diel feeding pattern of P. avirostris was followed over a 24 h period from July 31 to August 1.1991 at a station near the southern edge of the dam of the Plover Cove Reservoir. P. avirostris performed typical nocturnal vertical migration. Although animals were seldom found below 10 m during either day or night, a greater fraction of the population was found in the upper 1 to 3 m at night than during the day. A diel cycle in gut pigment content was observed in P. avirostris. Gut pigment contesnt was low during the day and increased sharply during the first 2 h after sunset. Gut pigment content at 21:00 and 03:00 was about 2 times higher than average daytime values. Chlorophyll a concentration was the highest near the surface and decreased towards the bottom, but water collected at 16 m still contained 1.79 ng/cm3 Chl. a.Because P. avirostris were usually found within the upper 10 m, we believe that the observed diel change in gut pigment content was likely the result of a real diel feeding rhythm, and was probably not the result of individual animals moving in and out of the food-rich layer.
Seasonal abundance of the marine cladoceran Penilia avirostris was studied in the Tolo Harbour, Hong Kong, from November 1987 to December 1989. P. aviroseris occurred in plankton throughout the year, but no clear seasonal pattern could be identified. In general, densities were the highest in the Tolo Channel and decreased progressively towards the inner parts of the Tolo Harbour. P. avirostris showed marked seasonal variations in body size and brood size. Body length of P. avirostris ranged from 0.3 to 1.0 mm. Average body length was greatest on March 1988 and January 1989, and the smallest in May 1988, although no clear seasonal trends could be detected. Brood size of P. avirostris ranged from 1 to 13 over the study period with a mean of 5.6. A significant positive relationship was found between body length and brood size. Diel vertical migration and diel feeding pattern of P. avirostris was followed over a 24 h period from July 31 to August 1.1991 at a station near the southern edge of the dam of the Plover Cove Reservoir. P. avirostris performed typical nocturnal vertical migration. Although animals were seldom found below 10 m during either day or night, a greater fraction of the population was found in the upper 1 to 3 m at night than during the day. A diel cycle in gut pigment content was observed in P. avirostris. Gut pigment contesnt was low during the day and increased sharply during the first 2 h after sunset. Gut pigment content at 21:00 and 03:00 was about 2 times higher than average daytime values. Chlorophyll a concentration was the highest near the surface and decreased towards the bottom, but water collected at 16 m still contained 1.79 ng/cm3 Chl. a.Because P. avirostris were usually found within the upper 10 m, we believe that the observed diel change in gut pigment content was likely the result of a real diel feeding rhythm, and was probably not the result of individual animals moving in and out of the food-rich layer.
1994, (1): 129-132.
Abstract:
In this study of meiofauna polychaeta from the Huanghai Sea, a previously undescribed species belonging to Pholoe has been found and described. 13 species of Pholoe were reported in the past. The new species differs from the other species of the genus Pholoe in having elytra with radiating rows of small surface papillae.
In this study of meiofauna polychaeta from the Huanghai Sea, a previously undescribed species belonging to Pholoe has been found and described. 13 species of Pholoe were reported in the past. The new species differs from the other species of the genus Pholoe in having elytra with radiating rows of small surface papillae.
1994, (1): 133-142.
Abstract:
Using electron microscopic technique, ultrastructural characters of the oogonia and oocyte at the different phases of amphioxus are observed in detail in the present study. The squeezed out nucleolus, nucleolus-like bodies and yolk nucleus at the side of nucleus are the characters in the early egg cells of the first and secondary phase. The nucleus and cytoplasm of oocyte change obviously their morphology and structure from large growth stage to mature stage (from Stage Ⅲ to Stage Ⅴ).As a result, the dense distribution of nuclear pore and the extension and depression of nuclear envelope are observable. Mitochondria, Golgi complex, rough endoplasm reticular and annulate lamellae, and others in the cytoplasm join in the formation of yolk granular. Their morphology and number also change correspondingly with the development and maturation of the oocyte. These results will provide a whole base for the reproductive physiology and artificial propagation as well as the resource management of amphioxus.
Using electron microscopic technique, ultrastructural characters of the oogonia and oocyte at the different phases of amphioxus are observed in detail in the present study. The squeezed out nucleolus, nucleolus-like bodies and yolk nucleus at the side of nucleus are the characters in the early egg cells of the first and secondary phase. The nucleus and cytoplasm of oocyte change obviously their morphology and structure from large growth stage to mature stage (from Stage Ⅲ to Stage Ⅴ).As a result, the dense distribution of nuclear pore and the extension and depression of nuclear envelope are observable. Mitochondria, Golgi complex, rough endoplasm reticular and annulate lamellae, and others in the cytoplasm join in the formation of yolk granular. Their morphology and number also change correspondingly with the development and maturation of the oocyte. These results will provide a whole base for the reproductive physiology and artificial propagation as well as the resource management of amphioxus.
1994, (1): 143-154.
Abstract:
The offshore reinforced concrete structures are always subject to cyclic load,such as wave load. In this paper a new finite element analysis model is developed to analyze the stress and strain state of reinforced concrete structures including offshore concrete structures, subject to any number of the cyclic load. On the basis of the analysis of the experimental data, this model simplifies the number of cycles-total cyclic strain curve of concrete as three straight line segments, and it is assumed that the stress-strain curves of different cycles in each segment are the same, thus the elastoplastic analysis is only needed for the first cycle of each segment, and the stress or strain corresponding to any number of cycles can be obtained by superposition of stress or strain obtained by the above elastoplastic analysis based on the cyclic numbers in each segment. This model spends less computer time, and can obtain the stress and strain states of the structures after any number of cycles. The endochronic-damage and ideal elastoplastic constitutive models are used for concrete and steel bars respectively. The reinforced concrete slabs of offshore concrete platform subject to cyclic loading are experimented and analyzed by the finite element method based on the model proposed in this paper. The results between the experiment and the finite element analysis are in good agreement, which demonstrates the validity and accuracy of the proposed model.
The offshore reinforced concrete structures are always subject to cyclic load,such as wave load. In this paper a new finite element analysis model is developed to analyze the stress and strain state of reinforced concrete structures including offshore concrete structures, subject to any number of the cyclic load. On the basis of the analysis of the experimental data, this model simplifies the number of cycles-total cyclic strain curve of concrete as three straight line segments, and it is assumed that the stress-strain curves of different cycles in each segment are the same, thus the elastoplastic analysis is only needed for the first cycle of each segment, and the stress or strain corresponding to any number of cycles can be obtained by superposition of stress or strain obtained by the above elastoplastic analysis based on the cyclic numbers in each segment. This model spends less computer time, and can obtain the stress and strain states of the structures after any number of cycles. The endochronic-damage and ideal elastoplastic constitutive models are used for concrete and steel bars respectively. The reinforced concrete slabs of offshore concrete platform subject to cyclic loading are experimented and analyzed by the finite element method based on the model proposed in this paper. The results between the experiment and the finite element analysis are in good agreement, which demonstrates the validity and accuracy of the proposed model.
