2004 Vol. 26, No. 6
Display Method:
2004, 26(6): 1-12.
Abstract:
The monthly variation of surface currents in the tropical Atlantic is studied by using the TOPEX/Poseidon altimeter data from April 1993 to March 2001.The results are as follow:The current is stronger in the low latitude of the tropical Atlantic Ocean than that in the high latitude of the tropical Atlantic Ocean.Although there are regions with a strong monthly variation of the tropical surface circulation,large regions of the tropics do not show a significant monthly variation.The zonal current in the North Equatorial Current region in July-December is greater than that in January-June.From May to November,the African Coastal Current is northeastward,while during the other months the velocity is southeastward.The North Equatorial Counter current is divided into two parts:East of 25°W the countercurrent continued throughout the year,and the maximum average velocity is about 25 cm/s in September.West of 25°W,from February to June the counter current diminishes and westward currents are observed,while during the other months,the countercurrent is eastward.
The monthly variation of surface currents in the tropical Atlantic is studied by using the TOPEX/Poseidon altimeter data from April 1993 to March 2001.The results are as follow:The current is stronger in the low latitude of the tropical Atlantic Ocean than that in the high latitude of the tropical Atlantic Ocean.Although there are regions with a strong monthly variation of the tropical surface circulation,large regions of the tropics do not show a significant monthly variation.The zonal current in the North Equatorial Current region in July-December is greater than that in January-June.From May to November,the African Coastal Current is northeastward,while during the other months the velocity is southeastward.The North Equatorial Counter current is divided into two parts:East of 25°W the countercurrent continued throughout the year,and the maximum average velocity is about 25 cm/s in September.West of 25°W,from February to June the counter current diminishes and westward currents are observed,while during the other months,the countercurrent is eastward.
2004, 26(6): 13-21.
Abstract:
Thermodynamic coupling plays an important role in the simulation of sea ice and general oceanic circulation.It is an important factor to represent the ice-ocean interaction.It is necessary to copy with such a process with detailed tur bulence model,however,this treatment is limited by computation especially for the climate model. And the temper ature of the upper oceanic mixed layer in ice zone was assumed at the freezing point of seawater, which is often set to a constant,in most of the ice models and coupled ice-ocean models.Such an assumption is exact enough for the inner ice zone.But there exist exceptions when ice floe advects to a warmer waters in the marginal ice zone or when the freezing point varies with the salinity of seawater under ice bottom for salt rejection while freezing or for freshening while melting.A new thermody namic coupling scheme is presented according to the energy balances between the coupled ice-ocean system.The scheme neither keep the temperature of the mixed layer at the freezing point of seawater nor consider the detailed turbulent processes at the ice-ocean interface.
Thermodynamic coupling plays an important role in the simulation of sea ice and general oceanic circulation.It is an important factor to represent the ice-ocean interaction.It is necessary to copy with such a process with detailed tur bulence model,however,this treatment is limited by computation especially for the climate model. And the temper ature of the upper oceanic mixed layer in ice zone was assumed at the freezing point of seawater, which is often set to a constant,in most of the ice models and coupled ice-ocean models.Such an assumption is exact enough for the inner ice zone.But there exist exceptions when ice floe advects to a warmer waters in the marginal ice zone or when the freezing point varies with the salinity of seawater under ice bottom for salt rejection while freezing or for freshening while melting.A new thermody namic coupling scheme is presented according to the energy balances between the coupled ice-ocean system.The scheme neither keep the temperature of the mixed layer at the freezing point of seawater nor consider the detailed turbulent processes at the ice-ocean interface.
2004, 26(6): 22-28.
Abstract:
Marine geographic information system(MGIS)has great ability to deal with the spatio temporal problem and has potential superiority in the applications for ocean research inrecent years.Taking extracting the features of oceanic phenomena as a case to analyse the function of M GI S,the presentation defines the position of MGIS in the oceanography.Comparing the requirement difference between MGIS and the traditional GIS,of which the latter has developed in the terrestrial applications.According to the established MGIS,some key technologies for MGIS are discussed in detail and the speciality is emphasized on when comparing with that in the traditional GIS.
Marine geographic information system(MGIS)has great ability to deal with the spatio temporal problem and has potential superiority in the applications for ocean research inrecent years.Taking extracting the features of oceanic phenomena as a case to analyse the function of M GI S,the presentation defines the position of MGIS in the oceanography.Comparing the requirement difference between MGIS and the traditional GIS,of which the latter has developed in the terrestrial applications.According to the established MGIS,some key technologies for MGIS are discussed in detail and the speciality is emphasized on when comparing with that in the traditional GIS.
2004, 26(6): 29-36.
Abstract:
The data loading and organizing of China coast and the offshore comprehensive data platform are implemented by using the currently advanced spatial database management——Oracle9i ArcSDE with a full consideration of the variety and the complexity of the marine dataset.Meanwhile,a client management system with the functions of remote sensing data seamless merging oriented for this data platform,multi-data source quick querying,data extraction,image data loading and meta-data management was developed based on ArcObject COM.The main serving client is supposed to be the department of scientific researching that charges the affairs of national coastal and off-shore.This system has been applied to some routine service and is proved to be a qualified tool.
The data loading and organizing of China coast and the offshore comprehensive data platform are implemented by using the currently advanced spatial database management——Oracle9i ArcSDE with a full consideration of the variety and the complexity of the marine dataset.Meanwhile,a client management system with the functions of remote sensing data seamless merging oriented for this data platform,multi-data source quick querying,data extraction,image data loading and meta-data management was developed based on ArcObject COM.The main serving client is supposed to be the department of scientific researching that charges the affairs of national coastal and off-shore.This system has been applied to some routine service and is proved to be a qualified tool.
2004, 26(6): 37-48.
Abstract:
Six surface water samples from the Humen tidal channel were collected in 2001 and filtered by GF/F glass fiber filter.Polycyclic aromatic hydrocarbons(PAHs),including parent,alkylated and sulfur/oxygenated PAHs were identified and measured based on USEPA 8000 series methods and under quality assurance and quality control (QA/QC).The spatial and temporal distribution of particulate and dissolved PAHs during both low flow and high flow seasons was investigated.Total PAHs concentrations vary from 11 360 to 34 338 ng/dm3 and 786~2 098 ng/dm3 in low flow season and high flow season respectively,and the 16 PAHs concetrations vary from 6 559 to 20 031 ng/dm3 and 223 to 614 ng/dm3 in low flow season and high flow season respectively.The dominated compounds are 2-ring PAHs,which are up to 95% and exist mainly in dissolved phase in low flow season.PAH concentrations in low flow season are one order of magnitude higher than those in high flow season.The increase of high molecular weight PAHs and elevated concentrations of particulate phase PAHs were found in the high flow season.
Six surface water samples from the Humen tidal channel were collected in 2001 and filtered by GF/F glass fiber filter.Polycyclic aromatic hydrocarbons(PAHs),including parent,alkylated and sulfur/oxygenated PAHs were identified and measured based on USEPA 8000 series methods and under quality assurance and quality control (QA/QC).The spatial and temporal distribution of particulate and dissolved PAHs during both low flow and high flow seasons was investigated.Total PAHs concentrations vary from 11 360 to 34 338 ng/dm3 and 786~2 098 ng/dm3 in low flow season and high flow season respectively,and the 16 PAHs concetrations vary from 6 559 to 20 031 ng/dm3 and 223 to 614 ng/dm3 in low flow season and high flow season respectively.The dominated compounds are 2-ring PAHs,which are up to 95% and exist mainly in dissolved phase in low flow season.PAH concentrations in low flow season are one order of magnitude higher than those in high flow season.The increase of high molecular weight PAHs and elevated concentrations of particulate phase PAHs were found in the high flow season.
2004, 26(6): 49-57.
Abstract:
By the study of the geochemistry characteristics of trace elements for the sediments of Core E2 from the southern Huanghai Sea,combining with characteristics of environment and climate changes in the last 100~200 a, the results exhibit that Pb and Au,and Pt family showing the influence of modern moving of industry and agriculture on environment have been recorded in the sediments of the southern Huanghai Sea;inactive trace elements and transitive metals elements showing the rising of temperature after the ended modern small ice age had great influenced the condition of oxidation-reduction of sediment zone and the efflorescence of the Huanghe River valley;the changed its course of the Huanghe River had been influenced on the terrestrial input of the sediment for the southern Huanghai Sea.
By the study of the geochemistry characteristics of trace elements for the sediments of Core E2 from the southern Huanghai Sea,combining with characteristics of environment and climate changes in the last 100~200 a, the results exhibit that Pb and Au,and Pt family showing the influence of modern moving of industry and agriculture on environment have been recorded in the sediments of the southern Huanghai Sea;inactive trace elements and transitive metals elements showing the rising of temperature after the ended modern small ice age had great influenced the condition of oxidation-reduction of sediment zone and the efflorescence of the Huanghe River valley;the changed its course of the Huanghe River had been influenced on the terrestrial input of the sediment for the southern Huanghai Sea.
2004, 26(6): 58-64.
Abstract:
The carbon and hydrogen isotopic compositions of CO2 and H2O in the gas releasing from the pumice samples in the Okinawa Trough by stepped heating are determined by the mass spectrometer.The primary CO2 and H2O are mainly released between 400 and 1 000.The carbon isotopic compositions of CO2 vary between-6.7×10-3 and-22.7×10-3,and hydrogen isotopic compositions of H2 Ovary from-45×10-3 to-71×10-3,which indicate the mantle source of the primary magma of pumices.Also,the hydrogen isotopic compositions of pumices are almost as same as those of basalts.This infers the close petrogenic relationship between them and pumices might have common magma sources with the basalts in the trough,but only they experienced different evolving processes.However,the carbon isotopic compositions are systematically lighter than those of mid-ocean ridge basalts,and tend to gather those of island arc rocks.Hydrogen isotopic compositions are heaver than those of mid-ocean ridge basalts,and also run to those of island arc rocks.These features suggest the influence of the fluid derived from the subducting slab on the magma during its forming and ascending process.
The carbon and hydrogen isotopic compositions of CO2 and H2O in the gas releasing from the pumice samples in the Okinawa Trough by stepped heating are determined by the mass spectrometer.The primary CO2 and H2O are mainly released between 400 and 1 000.The carbon isotopic compositions of CO2 vary between-6.7×10-3 and-22.7×10-3,and hydrogen isotopic compositions of H2 Ovary from-45×10-3 to-71×10-3,which indicate the mantle source of the primary magma of pumices.Also,the hydrogen isotopic compositions of pumices are almost as same as those of basalts.This infers the close petrogenic relationship between them and pumices might have common magma sources with the basalts in the trough,but only they experienced different evolving processes.However,the carbon isotopic compositions are systematically lighter than those of mid-ocean ridge basalts,and tend to gather those of island arc rocks.Hydrogen isotopic compositions are heaver than those of mid-ocean ridge basalts,and also run to those of island arc rocks.These features suggest the influence of the fluid derived from the subducting slab on the magma during its forming and ascending process.
2004, 26(6): 65-73.
Abstract:
The Deng zhou Shoal shaped in a stripped sub-water sandbar is located in south of the Miaodao Channel. Comparing the charts of 1974 with 1959,there is little change on the shoal with its to pography and water depth.It shows that the shoal had been in a state of dynamical equilibrium.Detailecl analysis on the sub-water geomorphology,sediments composition and environmental conditions,it can be deduced that the Dengzhou Shoal is one part of the ebb-tidal sand ridges formed after the period of Holocene.It is like a submerged barrier preserved the Penglai northeastern coast from wave incursion.But since 1985,some companies have begun to dredge on the shoal and caused the huge sand lost.Till 1990,the resident area surrounded by the-5 misobath line was changed from the original 3.96 km2 to 0.5 km2.Estimated by the reservoir model,the shoal can be recovered but cannot returned to the original scale.
The Deng zhou Shoal shaped in a stripped sub-water sandbar is located in south of the Miaodao Channel. Comparing the charts of 1974 with 1959,there is little change on the shoal with its to pography and water depth.It shows that the shoal had been in a state of dynamical equilibrium.Detailecl analysis on the sub-water geomorphology,sediments composition and environmental conditions,it can be deduced that the Dengzhou Shoal is one part of the ebb-tidal sand ridges formed after the period of Holocene.It is like a submerged barrier preserved the Penglai northeastern coast from wave incursion.But since 1985,some companies have begun to dredge on the shoal and caused the huge sand lost.Till 1990,the resident area surrounded by the-5 misobath line was changed from the original 3.96 km2 to 0.5 km2.Estimated by the reservoir model,the shoal can be recovered but cannot returned to the original scale.
2004, 26(6): 74-88.
Abstract:
The annual cycle of phy to plankton dynamics in the southern Huanghai Sea is studied by a three-dimensional physical-biological model.The physical model is Princeton ocean model(POM),the biological model involves interactions between the inorganic nutrients(nitrogen,phosphate,silicate),phytoplankton and herbivorous zooplankton biomass,and detritus.Given a know ledge of physical forcing,the model simulates main observed seasonal characteristic features,in particular,the annual cycle of phytoplankton with the spring and fall blooms,and the subsurface phytoplankton maximum layer in summer.Initiation of the spring bloom is shown to be critically dependent on the water column stability.It commences as soon as the convective mixing process weakens and before the seasonal stratification of surface begins to develop(in earlier April).At the time of establishment of the seasonal thermocline from May to October,the nutrient concentrations in the mixed layer are low enough to limit production in the center of the South Huanghai Sea,the layer between the thermocline and the base of the euphotic zone provides sufficient light and nutrients to support subsurface phytoplankton development.The fall bloom takes place sometime between September and November depending on environmental conditions.
The annual cycle of phy to plankton dynamics in the southern Huanghai Sea is studied by a three-dimensional physical-biological model.The physical model is Princeton ocean model(POM),the biological model involves interactions between the inorganic nutrients(nitrogen,phosphate,silicate),phytoplankton and herbivorous zooplankton biomass,and detritus.Given a know ledge of physical forcing,the model simulates main observed seasonal characteristic features,in particular,the annual cycle of phytoplankton with the spring and fall blooms,and the subsurface phytoplankton maximum layer in summer.Initiation of the spring bloom is shown to be critically dependent on the water column stability.It commences as soon as the convective mixing process weakens and before the seasonal stratification of surface begins to develop(in earlier April).At the time of establishment of the seasonal thermocline from May to October,the nutrient concentrations in the mixed layer are low enough to limit production in the center of the South Huanghai Sea,the layer between the thermocline and the base of the euphotic zone provides sufficient light and nutrients to support subsurface phytoplankton development.The fall bloom takes place sometime between September and November depending on environmental conditions.
2004, 26(6): 89-95.
Abstract:
RAPD detection and IT S1,5.8 s rDNA sequencing analysis were conducted to study the genetic variation and phylogenesis of Gracilaria tenuistipitata and G.tenuistipitata var.liui.The proportion of polymorphic,average heterozygosity and genetic distance were compared,a cluster tree was constructed by UPGMA from TFPGA. The results show that the genetic diversity of G.tenuistipitata is higher than G.tenuistipiitata var.liui.Eight RAPD primers were selected through the screening from the 300 primers,and its yielded specific markers for verification of G.tenuistipitata and G.tenuistipitatavar.liui.Only one base difference was found from the IT S1 and 5.8srDNA sequences analysis between G.tenuistipitata and G.tenuistipitata var.liui.it is indicated that RAPD method can be used for Gracilaria germplasm verification and genetic analysis,and it is confirmed that G.tenuistipitata and G.tenuistipitata var.liui belong to the same species,which meant that G.tenuistipitata var. liui is the morphological variant of G.tenuistipitata.
RAPD detection and IT S1,5.8 s rDNA sequencing analysis were conducted to study the genetic variation and phylogenesis of Gracilaria tenuistipitata and G.tenuistipitata var.liui.The proportion of polymorphic,average heterozygosity and genetic distance were compared,a cluster tree was constructed by UPGMA from TFPGA. The results show that the genetic diversity of G.tenuistipitata is higher than G.tenuistipiitata var.liui.Eight RAPD primers were selected through the screening from the 300 primers,and its yielded specific markers for verification of G.tenuistipitata and G.tenuistipitatavar.liui.Only one base difference was found from the IT S1 and 5.8srDNA sequences analysis between G.tenuistipitata and G.tenuistipitata var.liui.it is indicated that RAPD method can be used for Gracilaria germplasm verification and genetic analysis,and it is confirmed that G.tenuistipitata and G.tenuistipitata var.liui belong to the same species,which meant that G.tenuistipitata var. liui is the morphological variant of G.tenuistipitata.
2004, 26(6): 96-106.
Abstract:
Through analyzing of multidisciplinary oceanography data of a clear spatial zonation of the parameters and a primary productivity front are found in the study areas.In the turbid river mouth phytoplankton biomass and productivity are low,although the concentrations of nutrients,e.g,NO3-,PO43-,etc.are high,but bacteria are active.On offshore ward,phytoplankton biomass and productivity increase gradually with suspended solids(SS)settling out.The maxima of phytoplankton parameters occur at about 100 km away from the river mouth and the east side of Zhoushan Archipelago,where SSconcentration is less than 5 mg/dm3 and salinity 25~30,which results in high concentration of dissolved oxygen,depletion of nutrients,particularly PO43- in the upper layer and the dominance of young Synechococcus cells with smaller size,due to their fast growth there.The front of zooplankton biomaas is resulted from the abundant phytoplankton,as its food.
Through analyzing of multidisciplinary oceanography data of a clear spatial zonation of the parameters and a primary productivity front are found in the study areas.In the turbid river mouth phytoplankton biomass and productivity are low,although the concentrations of nutrients,e.g,NO3-,PO43-,etc.are high,but bacteria are active.On offshore ward,phytoplankton biomass and productivity increase gradually with suspended solids(SS)settling out.The maxima of phytoplankton parameters occur at about 100 km away from the river mouth and the east side of Zhoushan Archipelago,where SSconcentration is less than 5 mg/dm3 and salinity 25~30,which results in high concentration of dissolved oxygen,depletion of nutrients,particularly PO43- in the upper layer and the dominance of young Synechococcus cells with smaller size,due to their fast growth there.The front of zooplankton biomaas is resulted from the abundant phytoplankton,as its food.
2004, 26(6): 107-117.
Abstract:
The composition of dominant species,the cell abundance,size fractionated biomass and productivity,and the new prodution of phytoplankton are studied in the Prydz Bay and its adjacent sea area during the 18th CHINA RE cruise.The results show that there is marked feature of spatial zonation in the sea areas investigated.In the Prydz Bay and its adjacent continental shelf,the standing stock,and produtivity and new production are much higher than those of continental slope and deep-sea area.The results of size-frationed producitvity show that the contribution of net plankton to the total productivity(49.6% and 46.2% respectively)is the largest in the continental slope and deep-sea area,and the productivity of picoplankton is the dominant composition of total productivity(66.2%)in the bay and continental shelf area.
The composition of dominant species,the cell abundance,size fractionated biomass and productivity,and the new prodution of phytoplankton are studied in the Prydz Bay and its adjacent sea area during the 18th CHINA RE cruise.The results show that there is marked feature of spatial zonation in the sea areas investigated.In the Prydz Bay and its adjacent continental shelf,the standing stock,and produtivity and new production are much higher than those of continental slope and deep-sea area.The results of size-frationed producitvity show that the contribution of net plankton to the total productivity(49.6% and 46.2% respectively)is the largest in the continental slope and deep-sea area,and the productivity of picoplankton is the dominant composition of total productivity(66.2%)in the bay and continental shelf area.
2004, 26(6): 118-123.
Abstract:
On the basis of the investigating results of chlorophylla,water temperature,salinity,phytoplankton and squid fishing in the squid fishing ground(39°~43°N,152°E~171°W)of the northern Pacific Ocean during June to August of 2001,The distributional characteristics of surface chlorophylla and relation to the environmental factors and squid fishing ground were mainly analyzed.The analyzing results show that the content of surface chlorophylla in the investigating area is between 0.03 and 0.32 mg/m3,mean value is 0.13 mg/m3.Among them,the content of surface chlorophylla in the middle part fishing ground is the biggest,the second is the in the eastern-part and the lowest is in the western-part.There is a good relationship of the distributions of surface chlorophylla contents with water temperature and salinity in the survey area.The high chlorophylla content is located in the region with high temperature,the content is the lowest in the cold eddy and the highest in the warm eddy.The chlorophylla content increases with increasing of salinity.The surface chlorophylla content has a positive relationship with the phytoplankton in the west,middle and east fishing grounds.The distribution of surface chlorophylla also exits a better relation with the middle part fishing ground of squid which mainly is located in the tongue part of 0.1 mg/m3 of isopleth and the maximum gradient belt.The values of the surface chlorophylla in the middle part fishing ground were more than 0.1 mg/m3.The relative analyses of distributional of chlorophylla with the environmental factors and fishing ground indicate that it may be as an important reference index in the study of squid fishing grounds.
On the basis of the investigating results of chlorophylla,water temperature,salinity,phytoplankton and squid fishing in the squid fishing ground(39°~43°N,152°E~171°W)of the northern Pacific Ocean during June to August of 2001,The distributional characteristics of surface chlorophylla and relation to the environmental factors and squid fishing ground were mainly analyzed.The analyzing results show that the content of surface chlorophylla in the investigating area is between 0.03 and 0.32 mg/m3,mean value is 0.13 mg/m3.Among them,the content of surface chlorophylla in the middle part fishing ground is the biggest,the second is the in the eastern-part and the lowest is in the western-part.There is a good relationship of the distributions of surface chlorophylla contents with water temperature and salinity in the survey area.The high chlorophylla content is located in the region with high temperature,the content is the lowest in the cold eddy and the highest in the warm eddy.The chlorophylla content increases with increasing of salinity.The surface chlorophylla content has a positive relationship with the phytoplankton in the west,middle and east fishing grounds.The distribution of surface chlorophylla also exits a better relation with the middle part fishing ground of squid which mainly is located in the tongue part of 0.1 mg/m3 of isopleth and the maximum gradient belt.The values of the surface chlorophylla in the middle part fishing ground were more than 0.1 mg/m3.The relative analyses of distributional of chlorophylla with the environmental factors and fishing ground indicate that it may be as an important reference index in the study of squid fishing grounds.
2004, 26(6): 124-132.
Abstract:
The genetic structure and segregation of molecular markers in a F1 hybrid family of Pacific abalone(Haliotis discus hannai Ino)were studied using random amplified polymorphic DNA(RAPD)technology.This family's usefulness in linkage mapping of abalones was assessed.Seven primers yielded a total of 4.markers,of which 24 (58.5%)were polymorphic in this family,14 were informative and could be used for linkage mapping,and 7 (17.1%)markers were segregated in the expected Mendelian ratio which is very low compared with other species. Two markers show some association with JC-F1's phenotypes,and this relationship needs further study.The genetic distances between two parents,father and progeny,mother and progeny are 0.384 4,0.137 2,0.127 3 respectively.The frequency in JC-F1 population of RAPD markers from father and mother are 0.824 and 0.841, which are almost the same.High genetic distance between parents and high heterozygosity(0.2016)in JC-F1 population is also confirmd the feasibility of linkage mapping using these parents and progenies.
The genetic structure and segregation of molecular markers in a F1 hybrid family of Pacific abalone(Haliotis discus hannai Ino)were studied using random amplified polymorphic DNA(RAPD)technology.This family's usefulness in linkage mapping of abalones was assessed.Seven primers yielded a total of 4.markers,of which 24 (58.5%)were polymorphic in this family,14 were informative and could be used for linkage mapping,and 7 (17.1%)markers were segregated in the expected Mendelian ratio which is very low compared with other species. Two markers show some association with JC-F1's phenotypes,and this relationship needs further study.The genetic distances between two parents,father and progeny,mother and progeny are 0.384 4,0.137 2,0.127 3 respectively.The frequency in JC-F1 population of RAPD markers from father and mother are 0.824 and 0.841, which are almost the same.High genetic distance between parents and high heterozygosity(0.2016)in JC-F1 population is also confirmd the feasibility of linkage mapping using these parents and progenies.
2004, 26(6): 133-142.
Abstract:
Extreme breaking waves are one of the key factors causing the damage of ocean engineering structures.So it is very meaningful to develop the theory for generating the extreme waves and to investigate the extreme wave characteristics.The method for generating three dimensional focusing waves is proposed using the principal that waves propagate faster for longer waves and slower for shorter waves.Wave packet transformation is simulated by linear calculation and a numerical model based on the Boussinesq equations and the finite element method to verify the proposed method.The calculated results show that the proposed method can generate expected focusing waves. The effects of the associated wave parameters such as the center frequency,frequency width and the type of frequency spectrum on the focusing waves are also discussed.
Extreme breaking waves are one of the key factors causing the damage of ocean engineering structures.So it is very meaningful to develop the theory for generating the extreme waves and to investigate the extreme wave characteristics.The method for generating three dimensional focusing waves is proposed using the principal that waves propagate faster for longer waves and slower for shorter waves.Wave packet transformation is simulated by linear calculation and a numerical model based on the Boussinesq equations and the finite element method to verify the proposed method.The calculated results show that the proposed method can generate expected focusing waves. The effects of the associated wave parameters such as the center frequency,frequency width and the type of frequency spectrum on the focusing waves are also discussed.
2004, 26(6): 143-148.
Abstract:
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