1993 Vol. 12, No. 3
Display Method:
1993, (3): 323-334.
Abstract:
A three-layer model of the thermohaline structure is developed on the basis of the two-layer model of thermocline.The model is able to simulate the depth,thickness and intensity of both thermocline and halocline, and the temperature and salinity of both upper layer and lower layer in the shallow seas.
Camparison of simulation with data is favorable.
Detailed analysis is made on a variety of factors affecting the intensity of the thermocline.
A three-layer model of the thermohaline structure is developed on the basis of the two-layer model of thermocline.The model is able to simulate the depth,thickness and intensity of both thermocline and halocline, and the temperature and salinity of both upper layer and lower layer in the shallow seas.
Camparison of simulation with data is favorable.
Detailed analysis is made on a variety of factors affecting the intensity of the thermocline.
1993, (3): 335-345.
Abstract:
Ocean current forecasting is still in explorative stage of study.In the study, we face some problems that have not been met before.The solving of these problems has become fundamental premise for realizing the ocean current forecasting.In the present paper are discussed in depth the physical essence for such basic problems as the predictability of ocean current, the predictable currents, the dynamical basis for studying respectively the tidal current and circulation, the necessity of boundary model, the models on regions with different scales and their link.The foundations and plans to solve the problems are demonstrated.Finally a set of operational numerical forecasting system for ocean current is proposed.
Ocean current forecasting is still in explorative stage of study.In the study, we face some problems that have not been met before.The solving of these problems has become fundamental premise for realizing the ocean current forecasting.In the present paper are discussed in depth the physical essence for such basic problems as the predictability of ocean current, the predictable currents, the dynamical basis for studying respectively the tidal current and circulation, the necessity of boundary model, the models on regions with different scales and their link.The foundations and plans to solve the problems are demonstrated.Finally a set of operational numerical forecasting system for ocean current is proposed.
1993, (3): 347-357.
Abstract:
Besides seasonal variation, instantaneous variation of thermal layer will occur under the effects of tide, tidal current and wind disturbance.In this study the numerical simulation has been first carried out on fluctuation and undulation of thermal layer under influence of tide (simultaneous input of 8 tidal components).The study reveals the geographic distribution of thermal layer fluctuation in the entire study region and temporal and spatial variations of the undulation in tidal period superposing on the fluctuation.Especially, the wave with large amplitude simulated is consistent with observation in the channal and the sea areas with a convex coastline and complex variation of depth, internal relations of tide, tidal current, residual current as well as the factors such as geography, and the fluctuation of thermal layer is induced by residual current due to unsymmetry which occurs as a result of the tidal movement in lower layer influenced by friction and geography, meanwhile, analysis indicates that the fluctuation of thermal layer and tidal oscillation are different undulations in character.
Besides seasonal variation, instantaneous variation of thermal layer will occur under the effects of tide, tidal current and wind disturbance.In this study the numerical simulation has been first carried out on fluctuation and undulation of thermal layer under influence of tide (simultaneous input of 8 tidal components).The study reveals the geographic distribution of thermal layer fluctuation in the entire study region and temporal and spatial variations of the undulation in tidal period superposing on the fluctuation.Especially, the wave with large amplitude simulated is consistent with observation in the channal and the sea areas with a convex coastline and complex variation of depth, internal relations of tide, tidal current, residual current as well as the factors such as geography, and the fluctuation of thermal layer is induced by residual current due to unsymmetry which occurs as a result of the tidal movement in lower layer influenced by friction and geography, meanwhile, analysis indicates that the fluctuation of thermal layer and tidal oscillation are different undulations in character.
1993, (3): 359-377.
Abstract:
The aim of this paper is to study whether the features of perennial summer over the South China Sea remain constant all the year round or not, and whether there are any seasonal differences throughout the year or not.According to the characteristics of remarkable monsoon and frequent typhoon, the influences of monsoon and tropical cyclone on the hydrological features and the seasonal structure over the South China Sea1) are analysed by using examples.It may be considered that in the perennial summer area over the South China Sea, it is summer all the year round, but it does not remain constant throughout the year.On the basis of index dates of developing stages for winter and summer monsoons as well as the seasonal characteristics of typhoon frequency,the perennial summer season over the South China Sea may be divided into four periods, namely, early summer, midsummer, sweltering summer and late summer.The concrete classification and the hydrological seasonal feature of each period are discussed.
The aim of this paper is to study whether the features of perennial summer over the South China Sea remain constant all the year round or not, and whether there are any seasonal differences throughout the year or not.According to the characteristics of remarkable monsoon and frequent typhoon, the influences of monsoon and tropical cyclone on the hydrological features and the seasonal structure over the South China Sea1) are analysed by using examples.It may be considered that in the perennial summer area over the South China Sea, it is summer all the year round, but it does not remain constant throughout the year.On the basis of index dates of developing stages for winter and summer monsoons as well as the seasonal characteristics of typhoon frequency,the perennial summer season over the South China Sea may be divided into four periods, namely, early summer, midsummer, sweltering summer and late summer.The concrete classification and the hydrological seasonal feature of each period are discussed.
1993, (3): 379-393.
Abstract:
The dynamical features of air-sea coupling waves and their stabilities in a simple coupled air-sea model in the tropics have been studied with respect to interaction occurring among different types of the free waves in the ocean and in the atmosphere.It is pointed out that there exist a stable and an unstable air-sea interaction modes in the tropical coupled system, respectively.The propagation of the unstable mode relies greatly on the zonal space scale, i.e.only for wave length ranging from 5 000 km to 10 000 km can the disturbance unstably move slowly eastward.The waves that slowly propagate unstably eastward agree well with the observational facts.Finally,it is also proposed that the interaction between Kelvin wave in one medium and Rossby wave in another medium is a necessary condition for the occurrence of destabilization of the coupled air-sea system in the tropics.
The dynamical features of air-sea coupling waves and their stabilities in a simple coupled air-sea model in the tropics have been studied with respect to interaction occurring among different types of the free waves in the ocean and in the atmosphere.It is pointed out that there exist a stable and an unstable air-sea interaction modes in the tropical coupled system, respectively.The propagation of the unstable mode relies greatly on the zonal space scale, i.e.only for wave length ranging from 5 000 km to 10 000 km can the disturbance unstably move slowly eastward.The waves that slowly propagate unstably eastward agree well with the observational facts.Finally,it is also proposed that the interaction between Kelvin wave in one medium and Rossby wave in another medium is a necessary condition for the occurrence of destabilization of the coupled air-sea system in the tropics.
1993, (3): 395-404.
Abstract:
A five-level oceanic primitive equation model has been developed.This model is integrated numerically with annual mean wind stress and heat flux at sea surface for 30 a.The ocean circulations tend to quasi-stability.The simulated results show that the computed annual mean currents and sea surface temperature agree well with the observations.
A five-level oceanic primitive equation model has been developed.This model is integrated numerically with annual mean wind stress and heat flux at sea surface for 30 a.The ocean circulations tend to quasi-stability.The simulated results show that the computed annual mean currents and sea surface temperature agree well with the observations.
1993, (3): 405-415.
Abstract:
The species of iodine in the water samples collected from the west Pacific Ocean and its adjacent seas were analysed.Results show that the concentration of total inorganic iodine appears higher in the south than that in the north of the Equator.The iodide concentration is distributed symmetrically on both sides of the Equator in tropic and subtropic zones and it decreases away from the Equator.Around the Antarctic Divergence iodide concentration approaches its minimum in the surface waters.which only accounts for 10% of the total iodine.The dissolved organic iodine concentration keeps constant generally either in horizontal or in vertical.Discussions on the relationships of iodine with chemical, biological and hydrological factors reveal that iodine has a transitional behavior between conservative and biodepleting elements; I/S ratio is of a certain stability on a vast scale, however, it may be largely affected by organism activity in some zones.Besides, evidence shows that iodine is adsorbed by organic particle, in surface water but released as the remineral izatiun of the organic particles occurs near the bottom of euphotic layer, which makes iodine look as if it is depleted by organisms like the nutrients.
The species of iodine in the water samples collected from the west Pacific Ocean and its adjacent seas were analysed.Results show that the concentration of total inorganic iodine appears higher in the south than that in the north of the Equator.The iodide concentration is distributed symmetrically on both sides of the Equator in tropic and subtropic zones and it decreases away from the Equator.Around the Antarctic Divergence iodide concentration approaches its minimum in the surface waters.which only accounts for 10% of the total iodine.The dissolved organic iodine concentration keeps constant generally either in horizontal or in vertical.Discussions on the relationships of iodine with chemical, biological and hydrological factors reveal that iodine has a transitional behavior between conservative and biodepleting elements; I/S ratio is of a certain stability on a vast scale, however, it may be largely affected by organism activity in some zones.Besides, evidence shows that iodine is adsorbed by organic particle, in surface water but released as the remineral izatiun of the organic particles occurs near the bottom of euphotic layer, which makes iodine look as if it is depleted by organisms like the nutrients.
1993, (3): 417-423.
Abstract:
After the oxidation of river and marine sediments with CuO under alkaline conditions, the phenolic compounds in the oxidation products are determined gas chromatographically and compared to that of lignin oxidation products.The method of CuO oxidation is compared to that of nitrobenzen.The quantitative determination of produced phenolic compounds by capillary gas chromatography is examined and the blank and repetibility of the method are tested.
After the oxidation of river and marine sediments with CuO under alkaline conditions, the phenolic compounds in the oxidation products are determined gas chromatographically and compared to that of lignin oxidation products.The method of CuO oxidation is compared to that of nitrobenzen.The quantitative determination of produced phenolic compounds by capillary gas chromatography is examined and the blank and repetibility of the method are tested.
1993, (3): 425-429.
Abstract:
Analysis of gravity data based on the Airy isostasy, magnetic depth estimates and few seismic refraction data taken together indicates a thinning of the crust between the Antarctic Peninsula and the East Antarctic craton below the Filchner and Ronne ice shelves.
Analysis of gravity data based on the Airy isostasy, magnetic depth estimates and few seismic refraction data taken together indicates a thinning of the crust between the Antarctic Peninsula and the East Antarctic craton below the Filchner and Ronne ice shelves.
1993, (3): 431-443.
Abstract:
Through the analysis of foraminiferal fossils in the cores and the combination with the data of paleomag-netism and 1C ages, seven transgressive strata are recognized in the plains of coastal areas of Zhejiang Province.Among them the upper five ones are compared with the results of the previous study, and the lower two ones are discovered for the first time.The sixth stratum is formed in the shallow-sea environment with a warm climate and water depth of 20~30 m.and the seventh one is formed in the nearshore environment with a warm climate and water depth of less than 20 m.The distribution, age and paleoenvironment of every transgressive stratum is discussed in this paper.
Through the analysis of foraminiferal fossils in the cores and the combination with the data of paleomag-netism and 1C ages, seven transgressive strata are recognized in the plains of coastal areas of Zhejiang Province.Among them the upper five ones are compared with the results of the previous study, and the lower two ones are discovered for the first time.The sixth stratum is formed in the shallow-sea environment with a warm climate and water depth of 20~30 m.and the seventh one is formed in the nearshore environment with a warm climate and water depth of less than 20 m.The distribution, age and paleoenvironment of every transgressive stratum is discussed in this paper.
1993, (3): 445-456.
Abstract:
The materials were obtained from the survey conducted in the Kuroshio area of the East China Sea to the Southwest of Kyushu in Japan (29°30'-32°00', 128°00'-130°00'E) on board the R.V.Yoko Maru of Seikai Regional Fisheries Lab, Fisheries Agency, Japan in June 15~28, 1988 during China-Japan Joint Research on the Kuroshio.Zooplankton was collected by means of the North Pacific Net with model TSK flowmeter through vertical haul from 50-0m.Temperature and salinity were measured with CTD.134 species (including 4 spp.) of planktonic copepods were preliminarily identified in the survey area.Most of them belonged to the tropical and subtropical species and a few of them were the warm-temperate species and eurytopic species.The main dominant species vteie Oncaea venusta, Oithona plumifera, Clausocalanus furcatus, C.Arcuicornis, Paracaianus dculeatus, Oithona similis, Temara turbinata, Oncaea media, Undinula danvinii, Acartia negligent, Corycaeus speciosus, Scolecithrix danae, etc.The total number of individuals of planktonic copepods were about 367.6 ind./m3 on an average.The horizontal distribution of planktonic copepods was less in number but more in species in the main current area of the Kuroshio.The variations of growth and decline of the warm Kuroshio and the coastal current along China coast influenced the community structure and the distribution of planktonic copepods.Water temperature was one of principal controlling factors affecting the species composition and the quantitative distribution of planktonic copepods.
The materials were obtained from the survey conducted in the Kuroshio area of the East China Sea to the Southwest of Kyushu in Japan (29°30'-32°00', 128°00'-130°00'E) on board the R.V.Yoko Maru of Seikai Regional Fisheries Lab, Fisheries Agency, Japan in June 15~28, 1988 during China-Japan Joint Research on the Kuroshio.Zooplankton was collected by means of the North Pacific Net with model TSK flowmeter through vertical haul from 50-0m.Temperature and salinity were measured with CTD.134 species (including 4 spp.) of planktonic copepods were preliminarily identified in the survey area.Most of them belonged to the tropical and subtropical species and a few of them were the warm-temperate species and eurytopic species.The main dominant species vteie Oncaea venusta, Oithona plumifera, Clausocalanus furcatus, C.Arcuicornis, Paracaianus dculeatus, Oithona similis, Temara turbinata, Oncaea media, Undinula danvinii, Acartia negligent, Corycaeus speciosus, Scolecithrix danae, etc.The total number of individuals of planktonic copepods were about 367.6 ind./m3 on an average.The horizontal distribution of planktonic copepods was less in number but more in species in the main current area of the Kuroshio.The variations of growth and decline of the warm Kuroshio and the coastal current along China coast influenced the community structure and the distribution of planktonic copepods.Water temperature was one of principal controlling factors affecting the species composition and the quantitative distribution of planktonic copepods.
1993, (3): 457-464.
Abstract:
The effects of light on the fluorescence characteristics and biochemical composition of a marine diatom Tha-lassiosira pseudonana in light and dark cycles were investigated with semi-continuous culture.The results indicate that, with the increase of growing light intensity, DCMU enhanced fluorescence yield (Fd/Chl), enhanced fluorescence ratio (Fd/F), cellular carbohydrate content.carbohydrate/chlorophyll a and carbohydrate/protein ratio increased, but the fluorescence yield and cellular chlorophyll a content decreased; The protein content declined with the increase of light intensity in the range of 10-100 μmol/(m2·s) and increased at higher than 100 μmol/(m2·s).Sampling time during the day had great effect on the relationships between growing light intensity and cellular chlorophyll a, carbohydrate content, carbohydrate/chlorophyll a and carbohydrate/protein ratio.
The effects of light on the fluorescence characteristics and biochemical composition of a marine diatom Tha-lassiosira pseudonana in light and dark cycles were investigated with semi-continuous culture.The results indicate that, with the increase of growing light intensity, DCMU enhanced fluorescence yield (Fd/Chl), enhanced fluorescence ratio (Fd/F), cellular carbohydrate content.carbohydrate/chlorophyll a and carbohydrate/protein ratio increased, but the fluorescence yield and cellular chlorophyll a content decreased; The protein content declined with the increase of light intensity in the range of 10-100 μmol/(m2·s) and increased at higher than 100 μmol/(m2·s).Sampling time during the day had great effect on the relationships between growing light intensity and cellular chlorophyll a, carbohydrate content, carbohydrate/chlorophyll a and carbohydrate/protein ratio.
1993, (3): 465-474.
Abstract:
With the development of ocean engineering, it is one of the most important factors which determine the structural safety, cost and suitable forms of engineerings to select the ocean environmental design criteria.Owing to the complexity, variation and randomness of ocean environmental conditions, the commonly used methods for determining design criteria cannot consider the joint occurring probabilities of several environmental factors,therefore, lead to overestimate design criteria of them and result in an unnecessary overspend invest in engineering.On the basis of the measured and hindcasting data and the multi-demension joint probability theory, this paper presented the study of the joint loads of wind, wave and current on the offshore structures and its responsible joint probability level with the application of random simulation techniques, and presented the joint design criteria of environmental loads for the realistic design of engineerings.
With the development of ocean engineering, it is one of the most important factors which determine the structural safety, cost and suitable forms of engineerings to select the ocean environmental design criteria.Owing to the complexity, variation and randomness of ocean environmental conditions, the commonly used methods for determining design criteria cannot consider the joint occurring probabilities of several environmental factors,therefore, lead to overestimate design criteria of them and result in an unnecessary overspend invest in engineering.On the basis of the measured and hindcasting data and the multi-demension joint probability theory, this paper presented the study of the joint loads of wind, wave and current on the offshore structures and its responsible joint probability level with the application of random simulation techniques, and presented the joint design criteria of environmental loads for the realistic design of engineerings.
