2003 Vol. 25, No. 6
Display Method:
2003, 25(6): 1-8.
Abstract:
Based on data of tracts of drifting bottles, current at continuous stations, temperature and salinity in some cruise investigations, ADCP (current) and AVHRR(SST) in the west coast of Guangdong Province, the synthetic analysis results show that the coastal currents in the west of the mouth of Zhujiang River flow mainly westward in summer, composing the north branch of cyclonic gyre in the east of Qiongzhou Strait, and partially water flows westward into the Beibu Gulf through the Qiongzhou Strait.The coastal current pattern is no tidentical with the traditional current system, which is that the residual current flows westward in the Qiongzhou Strait in winter and eastward in summer.The coastal current, which is westward, maybe temporarily turn to northeast only if the southwestern wind is strong.The important characteristics of coastal current in the west coast of Guangdong Province, in the Qiongzhou Strait and in the north of Beibuwan Gulf are analyzed and their mechanism are explained.
Based on data of tracts of drifting bottles, current at continuous stations, temperature and salinity in some cruise investigations, ADCP (current) and AVHRR(SST) in the west coast of Guangdong Province, the synthetic analysis results show that the coastal currents in the west of the mouth of Zhujiang River flow mainly westward in summer, composing the north branch of cyclonic gyre in the east of Qiongzhou Strait, and partially water flows westward into the Beibu Gulf through the Qiongzhou Strait.The coastal current pattern is no tidentical with the traditional current system, which is that the residual current flows westward in the Qiongzhou Strait in winter and eastward in summer.The coastal current, which is westward, maybe temporarily turn to northeast only if the southwestern wind is strong.The important characteristics of coastal current in the west coast of Guangdong Province, in the Qiongzhou Strait and in the north of Beibuwan Gulf are analyzed and their mechanism are explained.
2003, 25(6): 9-19.
Abstract:
Structure and variability of the fronts along the sections from Zhongshan Station to Fremantle, Australia in the South Indian Ocean are analyzed with XBT/XCTD data and CTD data obtained by CHINARE in 1998, 1999, 2000 and 2002.(1) The Antarctic Slope Front at 75°~78°E is bordered between 64.5° and 65.5°S, the Polar Front at 84°~100°E varies closed to 53.5°~54.3°S, the Subtropical Front at 96°~103°E varies between 46°~47.0°S, the Subtropical Front at 110°E is located on 37.2~38.0°S; (2) in the Polar Front Zone, the isolines fluctuate strongly in temperature and salinity sections and are effected possibly by eddies; (3) north to the Subantarctic Front, the distribution of temperature salinity is homogenous in vertical direction; (4) the Polar Front retreats about one degree southward in latitude in recent four years, compared with that in 1979, 1991 and 1992 in the same area and season.
Structure and variability of the fronts along the sections from Zhongshan Station to Fremantle, Australia in the South Indian Ocean are analyzed with XBT/XCTD data and CTD data obtained by CHINARE in 1998, 1999, 2000 and 2002.(1) The Antarctic Slope Front at 75°~78°E is bordered between 64.5° and 65.5°S, the Polar Front at 84°~100°E varies closed to 53.5°~54.3°S, the Subtropical Front at 96°~103°E varies between 46°~47.0°S, the Subtropical Front at 110°E is located on 37.2~38.0°S; (2) in the Polar Front Zone, the isolines fluctuate strongly in temperature and salinity sections and are effected possibly by eddies; (3) north to the Subantarctic Front, the distribution of temperature salinity is homogenous in vertical direction; (4) the Polar Front retreats about one degree southward in latitude in recent four years, compared with that in 1979, 1991 and 1992 in the same area and season.
2003, 25(6): 20-30.
Abstract:
Based on the hydrographic data obtained by the cruise in August 2000 in the South China Sea (SCS), the revised Princeton Ocean Model (POM) with a generalized terrain-following coordinate system, i.e., the -T-F ocean model (GTFOM) was firstly adopted to study the circulation in the SCS during summer.The observational area is covered well by an orthogonal curvilinear grid in the horizontal, while in the vertical a generalized terrain following grid is set up which is similar to a z-level grid in most part of z-direction, but departs from the z level constraint near the bottom boundary, such that the lowest layer follows the bottom topography.With the actual topography and horizontally uniform, vertically varying buoyancy field, the comparison between the two numerical experiments shows that the adopted vertical grid scheme of GTFOM is better than the traditional sigma coordinate scheme, and the systematic error produced by the horizontal pressure gradient calculation near steep topography be comes much smaller when the scheme GTFOM is used.For the calculation of circulation in the SCS during the summer of 2000, there are two computed methods, i.e., the diagnostic and semidiagnostic calculations.The horizontal mixing coefficients for viscosity and diffusivity are calculated by two Smagorinsky-type for mulations.It is found by several numerical experiments that the computational results are sensitive to the taken values of their parameters.Comparisons between the diagnostic and semi diagnostic results indicate that they agree qualitatively, but there are some differences between them in quantity.In the semi diagnostic calculation, the flow field is hy drodynamically adjusted with the density field, wind stress and bottom topography, moreover, the small scale noises are removed.The main feature of circulation over the computational domain of SCS during August 2000 is as follows: There exists many warm and cold eddies, and among them the most notable eddy is the anticyclonic warm eddy southeast off Vietnam, and its center is located at 11°51'N, 112°11'E and its horizontal scale is about 300 km.East off this warm eddy there is a cyclonic cold eddy.The existence of such two cold and warm eddies is one of important circulation char acteristics in the SCS during the summer of 2000.The northeast part of SCS is dominated mainly by an anticyclonic circulation system, while it becomes cyclonic circulation system in the southeast part of SCS.Additionally, a western intensification phenomenon obviously occurs in the distribution of circulation in the SCS.
Based on the hydrographic data obtained by the cruise in August 2000 in the South China Sea (SCS), the revised Princeton Ocean Model (POM) with a generalized terrain-following coordinate system, i.e., the -T-F ocean model (GTFOM) was firstly adopted to study the circulation in the SCS during summer.The observational area is covered well by an orthogonal curvilinear grid in the horizontal, while in the vertical a generalized terrain following grid is set up which is similar to a z-level grid in most part of z-direction, but departs from the z level constraint near the bottom boundary, such that the lowest layer follows the bottom topography.With the actual topography and horizontally uniform, vertically varying buoyancy field, the comparison between the two numerical experiments shows that the adopted vertical grid scheme of GTFOM is better than the traditional sigma coordinate scheme, and the systematic error produced by the horizontal pressure gradient calculation near steep topography be comes much smaller when the scheme GTFOM is used.For the calculation of circulation in the SCS during the summer of 2000, there are two computed methods, i.e., the diagnostic and semidiagnostic calculations.The horizontal mixing coefficients for viscosity and diffusivity are calculated by two Smagorinsky-type for mulations.It is found by several numerical experiments that the computational results are sensitive to the taken values of their parameters.Comparisons between the diagnostic and semi diagnostic results indicate that they agree qualitatively, but there are some differences between them in quantity.In the semi diagnostic calculation, the flow field is hy drodynamically adjusted with the density field, wind stress and bottom topography, moreover, the small scale noises are removed.The main feature of circulation over the computational domain of SCS during August 2000 is as follows: There exists many warm and cold eddies, and among them the most notable eddy is the anticyclonic warm eddy southeast off Vietnam, and its center is located at 11°51'N, 112°11'E and its horizontal scale is about 300 km.East off this warm eddy there is a cyclonic cold eddy.The existence of such two cold and warm eddies is one of important circulation char acteristics in the SCS during the summer of 2000.The northeast part of SCS is dominated mainly by an anticyclonic circulation system, while it becomes cyclonic circulation system in the southeast part of SCS.Additionally, a western intensification phenomenon obviously occurs in the distribution of circulation in the SCS.
2003, 25(6): 31-38.
Abstract:
Based on several methods of geostrophic velocity calculation, nonlinear conjugate gradient method is introduced.Sharing the same dynamical characteristics and inherent hypotheses with PV method, this approach is simple, effective, easy-expanded and wide-applicable.By using of this method, geostrophic velocity of Kuroshio in the East China Sea is studied using the CTD data of six cruises gained in the Sino-Japan joint investigation and the study on the Kuroshio since April 1989.Compared with observation data of shipbroad ADCP, the nonlinear conjugate gradient method has been proved feasible.
Based on several methods of geostrophic velocity calculation, nonlinear conjugate gradient method is introduced.Sharing the same dynamical characteristics and inherent hypotheses with PV method, this approach is simple, effective, easy-expanded and wide-applicable.By using of this method, geostrophic velocity of Kuroshio in the East China Sea is studied using the CTD data of six cruises gained in the Sino-Japan joint investigation and the study on the Kuroshio since April 1989.Compared with observation data of shipbroad ADCP, the nonlinear conjugate gradient method has been proved feasible.
2003, 25(6): 39-47.
Abstract:
Spatio-temporal characteristics of antarctic temperature and sea ice from 1973 to 2000 have been statistically analyzed.Result shows that: the lowest temperature center in Antarctica lies in Southeast Antarctic Mainland, and the distribution characteristic corresponds with the antarctic topography; the annual temperature of Vostok station is -55.3.The highest temperature is -32.1℃ between December and January next year, and the lowest is - 68.2 in August.The surface temperature of different sectors in Antarctica shows different characteristics.According to their variable characteristics, the climate of Antarctica can be divided into four types: Antarctic Continent type, Antarctic Peninsula type, southeast pole coast type and gulf type.In recent years, there is an obvious warming trend in the Antarctic Peninsula, however an obvious colding trend in the southeast pole coast, and their variation shows obvious anti-phase.There is a close response relationship between the sea ice and the temperature in Antarctica, the sea ice becomes least where it becomes warmer in the Antarctic Peninsula, however the sea ice becomes more where it becomes colder in southeast pole.It is difficult to explain such result by the effect of green-house.The anomalous variation of the antarctic sea ice extent has an influence on the warmer and cooler structure of the Antarctic Circumpolar Current and on the long itudinal transportation of ano malous warmer and cooler water, and then leads to the anomalous variation of upper ocean in the tropical and subtropical Pacific.
Spatio-temporal characteristics of antarctic temperature and sea ice from 1973 to 2000 have been statistically analyzed.Result shows that: the lowest temperature center in Antarctica lies in Southeast Antarctic Mainland, and the distribution characteristic corresponds with the antarctic topography; the annual temperature of Vostok station is -55.3.The highest temperature is -32.1℃ between December and January next year, and the lowest is - 68.2 in August.The surface temperature of different sectors in Antarctica shows different characteristics.According to their variable characteristics, the climate of Antarctica can be divided into four types: Antarctic Continent type, Antarctic Peninsula type, southeast pole coast type and gulf type.In recent years, there is an obvious warming trend in the Antarctic Peninsula, however an obvious colding trend in the southeast pole coast, and their variation shows obvious anti-phase.There is a close response relationship between the sea ice and the temperature in Antarctica, the sea ice becomes least where it becomes warmer in the Antarctic Peninsula, however the sea ice becomes more where it becomes colder in southeast pole.It is difficult to explain such result by the effect of green-house.The anomalous variation of the antarctic sea ice extent has an influence on the warmer and cooler structure of the Antarctic Circumpolar Current and on the long itudinal transportation of ano malous warmer and cooler water, and then leads to the anomalous variation of upper ocean in the tropical and subtropical Pacific.
2003, 25(6): 48-53.
Abstract:
The fabrics and crystals of one year ice in the Bohai Sea show that the noncontiguous ice growth rate makes an ice sheet have level layers with different amount of air bubbles in lower part of the ice sheet; typical grain ice and columnar ice occur in the gray ice which grows in stable water; thaw-refrozen ice and rafted ice have their crystal characteristics.On the Arctic sea ice, the 2.2 m long ice core located at 72°24.037'N, 153°33.994'W is a three year ice floe, and a new sort of crystal is found, which is defined as refrozen clastic pieces.The crystal profile of the ice core (its length is 4.86 m) located at 74°58.614'N, 160°31.830'W shows the evidence of an ice ridge changed into hummock.
The fabrics and crystals of one year ice in the Bohai Sea show that the noncontiguous ice growth rate makes an ice sheet have level layers with different amount of air bubbles in lower part of the ice sheet; typical grain ice and columnar ice occur in the gray ice which grows in stable water; thaw-refrozen ice and rafted ice have their crystal characteristics.On the Arctic sea ice, the 2.2 m long ice core located at 72°24.037'N, 153°33.994'W is a three year ice floe, and a new sort of crystal is found, which is defined as refrozen clastic pieces.The crystal profile of the ice core (its length is 4.86 m) located at 74°58.614'N, 160°31.830'W shows the evidence of an ice ridge changed into hummock.
2003, 25(6): 54-60.
Abstract:
Based on theoretical and experimental studies of acoustic attenuation in thick suspended sediments, two types of acoustic observation instruments for real-time measurements of the bulk-density profile of suspended-sediments (UBD-500/1500 ultrasonic bulk-density meter) have been developed and applied to surveying the fluidmud in the Changjiang waterway and to the observations of mud and sand in the Xiaolangdi Reservoir of the Huanghe River.The principle of measurement and design and calibration of the instrument are discussed in detail.The specifications of the instruments are as follows: the range of measurement is 800 kg/m3 (for UBD-500) and 50 kg/m3 (for UBD-1500), the error of measurement is ±5% (F.S.).Comparing with other kinds of instruments for measuring suspended sediments (OBS, ABS, infr ared or γ-ray meter), the main advantage of the ultrasonic bulk density meter by way of acoustic attenuation measurement is that the calibration to the instrument is relatively more stable and easier.
Based on theoretical and experimental studies of acoustic attenuation in thick suspended sediments, two types of acoustic observation instruments for real-time measurements of the bulk-density profile of suspended-sediments (UBD-500/1500 ultrasonic bulk-density meter) have been developed and applied to surveying the fluidmud in the Changjiang waterway and to the observations of mud and sand in the Xiaolangdi Reservoir of the Huanghe River.The principle of measurement and design and calibration of the instrument are discussed in detail.The specifications of the instruments are as follows: the range of measurement is 800 kg/m3 (for UBD-500) and 50 kg/m3 (for UBD-1500), the error of measurement is ±5% (F.S.).Comparing with other kinds of instruments for measuring suspended sediments (OBS, ABS, infr ared or γ-ray meter), the main advantage of the ultrasonic bulk density meter by way of acoustic attenuation measurement is that the calibration to the instrument is relatively more stable and easier.
2003, 25(6): 61-68.
Abstract:
Because of highly-developed economic region, traditional coastal zone surveying in China can't meet thebasic demands of economic development and modern management in coastal zone. The organization and management of great numerous high-resolution remote sensing data, the realization of fast and accurate spatial position system, and the development of image fusion based on feature and algorithms for feature extraction of coastal zone objects are focused on. All these construct technological basis for processing and analysis methods of high2resolution remote sensing data in coastal zone. Meanwhile, through the method researches suitable remote sensing classification system for coastal zone and integrated surveying and mapping are studied, advanced technological construction for remote sensing resource surveying in coastal zone is sustained. It is the theoretical and technological basis to realize modern management in China's coastal zone.
Because of highly-developed economic region, traditional coastal zone surveying in China can't meet thebasic demands of economic development and modern management in coastal zone. The organization and management of great numerous high-resolution remote sensing data, the realization of fast and accurate spatial position system, and the development of image fusion based on feature and algorithms for feature extraction of coastal zone objects are focused on. All these construct technological basis for processing and analysis methods of high2resolution remote sensing data in coastal zone. Meanwhile, through the method researches suitable remote sensing classification system for coastal zone and integrated surveying and mapping are studied, advanced technological construction for remote sensing resource surveying in coastal zone is sustained. It is the theoretical and technological basis to realize modern management in China's coastal zone.
2003, 25(6): 69-78.
Abstract:
It is a valid route for quantitatively remote sensing on water pollution to build model according to the physical mechanisms of scattering and absorption of suspended substance, pollutant and molecules of water.Remote sensing model for water pollution based on single scatter ing is simple and easy to be used, but the precision is affected by the turbidity of water.The char acteristics of the energy composition of multiple scatter ing are analyzed, and it is proposed that, based on the model of single scattering, if the flux of the second scattering is consider ed additionally, the precision of the model will be remarkably raised, and the calculation is still very simple.The factor of the second scattering is deduced to build a double scattering model, and the practical arithmetic for the calculation of the model is put for ward.The result of applying this model on the water area around the Zhujiang River Estuary shows that the precison of the model basing on double scattering is obviously improved.The result also shows that the seriously polluted water area was distributed on the north of Lingding Sea, the Victoria Bay of Hong Kong and the Shenzhen Bay.
It is a valid route for quantitatively remote sensing on water pollution to build model according to the physical mechanisms of scattering and absorption of suspended substance, pollutant and molecules of water.Remote sensing model for water pollution based on single scatter ing is simple and easy to be used, but the precision is affected by the turbidity of water.The char acteristics of the energy composition of multiple scatter ing are analyzed, and it is proposed that, based on the model of single scattering, if the flux of the second scattering is consider ed additionally, the precision of the model will be remarkably raised, and the calculation is still very simple.The factor of the second scattering is deduced to build a double scattering model, and the practical arithmetic for the calculation of the model is put for ward.The result of applying this model on the water area around the Zhujiang River Estuary shows that the precison of the model basing on double scattering is obviously improved.The result also shows that the seriously polluted water area was distributed on the north of Lingding Sea, the Victoria Bay of Hong Kong and the Shenzhen Bay.
2003, 25(6): 79-88.
Abstract:
Based on the result of the investigation on hydrocarbon in the surface sediments, the content distribution and composite characteristic of various components of acidolytical hydrocarbon in surface sediments in the east area of the South China sea are discussed and compared with other areas of our country.By Bernard and Faber's method concerning the cause of formation of acidolytical hydrocarbon in ocean sediments, the types of formation cause in this area are approached.The result of statistical analysis shows that it is in correspondence with value of acidolytical hydrocarbon.
Based on the result of the investigation on hydrocarbon in the surface sediments, the content distribution and composite characteristic of various components of acidolytical hydrocarbon in surface sediments in the east area of the South China sea are discussed and compared with other areas of our country.By Bernard and Faber's method concerning the cause of formation of acidolytical hydrocarbon in ocean sediments, the types of formation cause in this area are approached.The result of statistical analysis shows that it is in correspondence with value of acidolytical hydrocarbon.
2003, 25(6): 89-98.
Abstract:
The species composition and cell density of nanodiatoms(cell size smaller than 20 μm) were investigated with TEM for the sedimental samples from different sedimental sections at modern intertidal zones and Middle Holocene in the Jiulong River, and in Dongyu Island in late Middle Holocene and Late Holocene.In total, 26 diatom species (including varieties) belonging to 12 genus of Bacillariophyta were found.The ecological distribution of each species was described to gether with TEM photographs.The dominant species at the modern intertidal zones in the estuary of Jiulong River is Thalassionema nitzschioides, and that in Middle Holocene is Navicula climacospheniae and Thalassionema nitzschioides; in Dongyu Island in late Middle Holocene and Late Holocene the dominant species is Cyclotella striata and Thalassionema nitzschioides.The percentage contribution of nanodiatoms to total diatom assemblages in sedimental sections is relatively high which can be up to 86.7%, showing the importance of nanodiatoms in diatom assemblages in sediments.
The species composition and cell density of nanodiatoms(cell size smaller than 20 μm) were investigated with TEM for the sedimental samples from different sedimental sections at modern intertidal zones and Middle Holocene in the Jiulong River, and in Dongyu Island in late Middle Holocene and Late Holocene.In total, 26 diatom species (including varieties) belonging to 12 genus of Bacillariophyta were found.The ecological distribution of each species was described to gether with TEM photographs.The dominant species at the modern intertidal zones in the estuary of Jiulong River is Thalassionema nitzschioides, and that in Middle Holocene is Navicula climacospheniae and Thalassionema nitzschioides; in Dongyu Island in late Middle Holocene and Late Holocene the dominant species is Cyclotella striata and Thalassionema nitzschioides.The percentage contribution of nanodiatoms to total diatom assemblages in sedimental sections is relatively high which can be up to 86.7%, showing the importance of nanodiatoms in diatom assemblages in sediments.
2003, 25(6): 99-105.
Abstract:
The studies on the composition, growth rate and environmental controlling were car ried out during three cruises in the Taiwan Strait (August 1997, February-March 1998 and August 1998) using epifluorescence microscopy and 14C-radio tracer.The results show that phycoerythrin-rich cyanobacteria (PE) dominate in abundance (contributed 83%~93%), picoeukaryotes (EU) are second and phycocyanin-rich cyanobacteria (PC) are the least abundant.With carbon biomass, PE still predominates although the contribution goes down (52%~74%), EU's contribution increases up to 26%~44%.Growth rate of picophy toplankton varies from 0.52 to 2.25 d-1, which may be due to different environmental parameters (e.g., nutrients) in the study area.Prochlorococcus may occur in the Taiwan Strait by using chl.a evaluation, its abundance ranges between 107 and 108 cell/dm3, Prochlorococcus dominate the picophytoplankton both in abundance and biomass if included in picophytoplankton in the Taiwan Strait in August 1997, and February-March 1998, however, cyanobacteria dominate in carbon biomass in August 1998.
The studies on the composition, growth rate and environmental controlling were car ried out during three cruises in the Taiwan Strait (August 1997, February-March 1998 and August 1998) using epifluorescence microscopy and 14C-radio tracer.The results show that phycoerythrin-rich cyanobacteria (PE) dominate in abundance (contributed 83%~93%), picoeukaryotes (EU) are second and phycocyanin-rich cyanobacteria (PC) are the least abundant.With carbon biomass, PE still predominates although the contribution goes down (52%~74%), EU's contribution increases up to 26%~44%.Growth rate of picophy toplankton varies from 0.52 to 2.25 d-1, which may be due to different environmental parameters (e.g., nutrients) in the study area.Prochlorococcus may occur in the Taiwan Strait by using chl.a evaluation, its abundance ranges between 107 and 108 cell/dm3, Prochlorococcus dominate the picophytoplankton both in abundance and biomass if included in picophytoplankton in the Taiwan Strait in August 1997, and February-March 1998, however, cyanobacteria dominate in carbon biomass in August 1998.
2003, 25(6): 106-116.
Abstract:
The vertical distribution of bacterial abundance and biomass were investigated in relation to algal biomass in ice cores taken from drifting ice floes in two arctic shelf areas: the Barents Sea and the Laptev Sea.The individual size and carbon content of a single sea ice bacterium was determined by means of image analysis.Bacteria were not evenly distributed but occurred in dense layers.At least two different types of distribution patterns were found with either a single maximum inside or at the bottom of the ice floe or two maxima in different parts of the floes.Bacterial concentrations range from 0.4×105 to 36.7×105 cells/cm3.The individual cell size exhibits consider able variations between the ice floes.In a multi-year ice floe, the largest bacteria were observed in relation to an internal chlorophyll a maximum, while no vertical changes were found in first-year ice floe.Total bacterial biomass (C) for the entire ice cores ranges from 19.2 to 79.2 mg/cm2 and the ratio of bacterum to ice algal biomass from 0.43 to 10.00.A comparison with data collected from fast ice reveals large differences in cell size, abundance and biomass.Based on these comparisons limitations in the metho dological approaches used in current sea ice research are analyzed and a standardized sampling scheme for sea ice cores is proposed.
The vertical distribution of bacterial abundance and biomass were investigated in relation to algal biomass in ice cores taken from drifting ice floes in two arctic shelf areas: the Barents Sea and the Laptev Sea.The individual size and carbon content of a single sea ice bacterium was determined by means of image analysis.Bacteria were not evenly distributed but occurred in dense layers.At least two different types of distribution patterns were found with either a single maximum inside or at the bottom of the ice floe or two maxima in different parts of the floes.Bacterial concentrations range from 0.4×105 to 36.7×105 cells/cm3.The individual cell size exhibits consider able variations between the ice floes.In a multi-year ice floe, the largest bacteria were observed in relation to an internal chlorophyll a maximum, while no vertical changes were found in first-year ice floe.Total bacterial biomass (C) for the entire ice cores ranges from 19.2 to 79.2 mg/cm2 and the ratio of bacterum to ice algal biomass from 0.43 to 10.00.A comparison with data collected from fast ice reveals large differences in cell size, abundance and biomass.Based on these comparisons limitations in the metho dological approaches used in current sea ice research are analyzed and a standardized sampling scheme for sea ice cores is proposed.
Marine fouling in offshore areas southeast of the Zhujiang River mouth, the northern South China Sea
2003, 25(6): 117-125.
Abstract:
To understand the type and extent of marine fouling in offshore areas southeast of the Zhujiang (Pearl) river mouth, the northern South China Sea, an investigation project is conducted within the period from May 1986 to June 1987.Two biological investigation buoy stations were deployed in 95 and 113 m water depth, being 114 and 160 km away from southeast of Hong Kong, respectively.Moreover, the fouling community of a Marex hydrological buoy located in 115 m water depth, being about 172 km away frow Hong Kong Hong Kong was surveyed also.The results show that a total of 78 species were collected and identified.The 3-month panels were mainly occupied by pedunculate barnacles, hydroids and algae.Of them, the dominant species are Conchoderma hunteri, Lepas anatifera and Orthopyxis sp.Oysters, pearloysters, acorn barnacles and bryozoans are only found on the buoys, including the subsurface buoys, and their mooring systems, which had been exposed for 6 and 12 months, respectively.Fouling communities also exhibit a distinct shift of species composition with depth.
To understand the type and extent of marine fouling in offshore areas southeast of the Zhujiang (Pearl) river mouth, the northern South China Sea, an investigation project is conducted within the period from May 1986 to June 1987.Two biological investigation buoy stations were deployed in 95 and 113 m water depth, being 114 and 160 km away from southeast of Hong Kong, respectively.Moreover, the fouling community of a Marex hydrological buoy located in 115 m water depth, being about 172 km away frow Hong Kong Hong Kong was surveyed also.The results show that a total of 78 species were collected and identified.The 3-month panels were mainly occupied by pedunculate barnacles, hydroids and algae.Of them, the dominant species are Conchoderma hunteri, Lepas anatifera and Orthopyxis sp.Oysters, pearloysters, acorn barnacles and bryozoans are only found on the buoys, including the subsurface buoys, and their mooring systems, which had been exposed for 6 and 12 months, respectively.Fouling communities also exhibit a distinct shift of species composition with depth.
2003, 25(6): 126-134.
Abstract:
The state-space model is one of the effective mathematical models to study the interaction between ocean waves and the wave energy conversion system.One of the key aspects of the application of the model is how to efficiently obtain the matrix parameters of the model according to the experimental data or the computed values of the impulse response function.In combination with the simplex method, the least square method and a simplified method for the matrix exponential, an effectively numerical method is proposed to determine the parameters in the state space model.The numer ical tests show that the range for the initial values of matrix parameters is enlarged very much, the numerical simulation efficiency is increased effectively and the numerical results are high accuracy.The reason lies in that the present method over comes the shortcomings of local convergence and the requirement for solving the derivatives of matrix exponential relative to parameters of Gauss-Newton method.
The state-space model is one of the effective mathematical models to study the interaction between ocean waves and the wave energy conversion system.One of the key aspects of the application of the model is how to efficiently obtain the matrix parameters of the model according to the experimental data or the computed values of the impulse response function.In combination with the simplex method, the least square method and a simplified method for the matrix exponential, an effectively numerical method is proposed to determine the parameters in the state space model.The numer ical tests show that the range for the initial values of matrix parameters is enlarged very much, the numerical simulation efficiency is increased effectively and the numerical results are high accuracy.The reason lies in that the present method over comes the shortcomings of local convergence and the requirement for solving the derivatives of matrix exponential relative to parameters of Gauss-Newton method.
2003, 25(6): 135-141.
Abstract:
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