1997 Vol. 16, No. 4
Display Method:
1997, (4): 429-439.
Abstract:
This paper is concerned with the physical interpretations for the statistical uncertainty of the spectral peak energy and peak frequency of the Fourier frequency spectrum.The local wavelet energy spectrum, based on the wavelet transform, is introduced to analyze the wind wave data obtained in a wind wave channel.It is shown that wave energy exhibits localizations both in scale (frequency) and in physical space (time), which implies energy intermittency——the energy at a given frequency may not be evenly distributed in the whole time.Especially, the peak energy and the corre-sponding peak frequency of a local wavelet energy spectrum have significant fluctuations as time evolves.Such intermittency and fluctuations give appropriate interpretations for the above mentioned statistical uncertainty.
This paper is concerned with the physical interpretations for the statistical uncertainty of the spectral peak energy and peak frequency of the Fourier frequency spectrum.The local wavelet energy spectrum, based on the wavelet transform, is introduced to analyze the wind wave data obtained in a wind wave channel.It is shown that wave energy exhibits localizations both in scale (frequency) and in physical space (time), which implies energy intermittency——the energy at a given frequency may not be evenly distributed in the whole time.Especially, the peak energy and the corre-sponding peak frequency of a local wavelet energy spectrum have significant fluctuations as time evolves.Such intermittency and fluctuations give appropriate interpretations for the above mentioned statistical uncertainty.
1997, (4): 441-457.
Abstract:
A three-dimensional nonlinear model in a coordinate is set up and used to calculate the currents in the Taiwan Strait (TS) with hydrographic data collected during summer of 1984 end 1988.It is shown that there is a persistent northward current with the volume transport(VT) of 0.83×106 m3/s through the TS during summer.Among them, the VT through the eastern and western part of the southern boundary of the strait is 0.58×106 m3/s and 0.25×106 m3/s, respectively.The velocity is the strongest in the eastern part of the TS and comes sernnd in the western part of the TS.The upwelling generally occurs near Fujian coast.On the current features in the TS during summer, the density current is primary and the wind-driven current is of secondary importance.
A three-dimensional nonlinear model in a coordinate is set up and used to calculate the currents in the Taiwan Strait (TS) with hydrographic data collected during summer of 1984 end 1988.It is shown that there is a persistent northward current with the volume transport(VT) of 0.83×106 m3/s through the TS during summer.Among them, the VT through the eastern and western part of the southern boundary of the strait is 0.58×106 m3/s and 0.25×106 m3/s, respectively.The velocity is the strongest in the eastern part of the TS and comes sernnd in the western part of the TS.The upwelling generally occurs near Fujian coast.On the current features in the TS during summer, the density current is primary and the wind-driven current is of secondary importance.
1997, (4): 459-473.
Abstract:
Wind and wave fields are hindcasted for Typhoon Betty (8710), using LAGFD-WIN dynamical wind model end LAGFD-NWM third genezation wave model.The results are satisfying, which validates the models and shows their reliability for strong sea state.An idea is brought out that wind input source function should be improved, including the effects of wind guatness and wave age factor.The present work makes preliminary preparations for the regional oceanography study of the South China Sea, also provides the technical supports for ocean engineering design.
Wind and wave fields are hindcasted for Typhoon Betty (8710), using LAGFD-WIN dynamical wind model end LAGFD-NWM third genezation wave model.The results are satisfying, which validates the models and shows their reliability for strong sea state.An idea is brought out that wind input source function should be improved, including the effects of wind guatness and wave age factor.The present work makes preliminary preparations for the regional oceanography study of the South China Sea, also provides the technical supports for ocean engineering design.
1997, (4): 475-490.
Abstract:
In the summer of 1991 studies of sound propagation and reverberation were carried out in the Huanghai (Yellow) Sea with a strong thermocline by using explosive sound sources.Experimental results of both the sound trans-mission loss along a certain course and the average reverberation intensity showed an abnormally large attenuation over a frequency range from 1 000 to 2 000 Hz when both the source and the receiver were located above the thermocline.An interesting point is that the anomalous attenuation of the average reverberation intensity obtained by using omnidirectional source and receiver and that of the transmission loss along the certain course exhibit a resonance-like or frequency-selective characteristic with the same centre frequency, similar bandwidth and wmparable extra attenuation values.Obviously, this anomalous attenuation cannot be explained by any anisotropic mechanism (e.g.,internal waves, regular fluctuations of sea surface or bottom, etc.).On the basis of the depth dependences of the transmission loss and reverberation intensity obtained by the authors and some indirect evidences, it is believed that the observed frequency-selective attenuation is due to fish with swim-bladders (probably, anchovies) living dispersedly above the thermocline.
In the summer of 1991 studies of sound propagation and reverberation were carried out in the Huanghai (Yellow) Sea with a strong thermocline by using explosive sound sources.Experimental results of both the sound trans-mission loss along a certain course and the average reverberation intensity showed an abnormally large attenuation over a frequency range from 1 000 to 2 000 Hz when both the source and the receiver were located above the thermocline.An interesting point is that the anomalous attenuation of the average reverberation intensity obtained by using omnidirectional source and receiver and that of the transmission loss along the certain course exhibit a resonance-like or frequency-selective characteristic with the same centre frequency, similar bandwidth and wmparable extra attenuation values.Obviously, this anomalous attenuation cannot be explained by any anisotropic mechanism (e.g.,internal waves, regular fluctuations of sea surface or bottom, etc.).On the basis of the depth dependences of the transmission loss and reverberation intensity obtained by the authors and some indirect evidences, it is believed that the observed frequency-selective attenuation is due to fish with swim-bladders (probably, anchovies) living dispersedly above the thermocline.
1997, (4): 491-504.
Abstract:
The outer margin upfold zone of the East Chine Sea Shelf is a submarine residual volcanic arc between the continent-side back-arc rift-subsidence basins (shelf basin and Okinawa Though) of the Philippine Sea Plate subduction zone.Its geophysical field features, stratigraphic composition, magmatic activity and geological structures are charec-terized by forming "zonation from west to east and blocks from north to south".The upfold zone developed from the beginning of Tertiary when it was continental margin island arc.After Miocence, because of the tension-fracture action of the Okinawa Trough behind the Ryūkyū Arc, it became the residual arc of the ancient Ryūkyū Arc.The formation mechanism was controlled by the tectonic framework of the East China Sea, and was related to the subduction of the Philippine Sea Plate and the eastward movement of the subduction zone.The formation of upfold zone of the East China Sea went through 4 stages:(1) fracture-uplift volcanic arc (E1-E2), (2) fold-uplift volcanic arc (E3), (3) fold-up-lift residual arc (N1) and (4) withered residual arc (N2-Q).In the last stage, the upfold zone and shelf basin were depressed in whole and deposited almost 1 500 m Pliocene-Quaternary sediments of shallow-sea facies.
The outer margin upfold zone of the East Chine Sea Shelf is a submarine residual volcanic arc between the continent-side back-arc rift-subsidence basins (shelf basin and Okinawa Though) of the Philippine Sea Plate subduction zone.Its geophysical field features, stratigraphic composition, magmatic activity and geological structures are charec-terized by forming "zonation from west to east and blocks from north to south".The upfold zone developed from the beginning of Tertiary when it was continental margin island arc.After Miocence, because of the tension-fracture action of the Okinawa Trough behind the Ryūkyū Arc, it became the residual arc of the ancient Ryūkyū Arc.The formation mechanism was controlled by the tectonic framework of the East China Sea, and was related to the subduction of the Philippine Sea Plate and the eastward movement of the subduction zone.The formation of upfold zone of the East China Sea went through 4 stages:(1) fracture-uplift volcanic arc (E1-E2), (2) fold-uplift volcanic arc (E3), (3) fold-up-lift residual arc (N1) and (4) withered residual arc (N2-Q).In the last stage, the upfold zone and shelf basin were depressed in whole and deposited almost 1 500 m Pliocene-Quaternary sediments of shallow-sea facies.
1997, (4): 505-515.
Abstract:
The erosion of Shandong sandy coast has become more serious since the end of the 1970s.By now nearly 80% of sandy coast was eroded.Studies of many years have revealed that the recent erosive velocity is 2-3 m/a.A series of human factors have played a decisive rold for the recent aggravated Erosion of Shandong sandy coast.The methods and ways of their action include reducing discharge flux into the ocean by building dams across the rivers and digging sand, etc.to break the energy balance of coastal material and building improper projects on coastline.
The erosion of Shandong sandy coast has become more serious since the end of the 1970s.By now nearly 80% of sandy coast was eroded.Studies of many years have revealed that the recent erosive velocity is 2-3 m/a.A series of human factors have played a decisive rold for the recent aggravated Erosion of Shandong sandy coast.The methods and ways of their action include reducing discharge flux into the ocean by building dams across the rivers and digging sand, etc.to break the energy balance of coastal material and building improper projects on coastline.
Correlation study on planktonic Ostracoda with water systems in the northern South China Sea contine
1997, (4): 517-526.
Abstract:
This paper expounds the quantitative distributional patterns, population structure, ecological groups and their seasonal variations of planktonic Ostracoda in the continental shelf waters of the northern South China Sea, with special reference to the correlation study on Ostracoda with the different coastal currents such as the coastal current, South China Sea Warm Current, the South China Sea upwelling, subsurface hyperhaline water and the Zhujiang River runoff.
This paper expounds the quantitative distributional patterns, population structure, ecological groups and their seasonal variations of planktonic Ostracoda in the continental shelf waters of the northern South China Sea, with special reference to the correlation study on Ostracoda with the different coastal currents such as the coastal current, South China Sea Warm Current, the South China Sea upwelling, subsurface hyperhaline water and the Zhujiang River runoff.
1997, (4): 527-535.
Abstract:
A reverse transcription PCR (RT-PCR) method was used to detect the Hepatitis A virus in clam tissues The RNA template for PCR was prepared by a modified described previously (Yang and Xu, 1993).Its recovery wes determined by DNA hybridization.The sensitivity of RT-PCR and the quantitation of HAV were determined by quantitative competitive PCR.
A reverse transcription PCR (RT-PCR) method was used to detect the Hepatitis A virus in clam tissues The RNA template for PCR was prepared by a modified described previously (Yang and Xu, 1993).Its recovery wes determined by DNA hybridization.The sensitivity of RT-PCR and the quantitation of HAV were determined by quantitative competitive PCR.
1997, (4): 537-551.
Abstract:
1997, (4): 557-562.
Abstract:
