2010 Vol. 32, No. 6
Display Method:
2010, 32(6): 1-10.
Abstract:
The mechanism of the westward shifting of the Huanghai Sea(Yellow Sea) Warm Current (HSWC) is studied through a group of numerical experiments using MIT General Circulation Model (MITgcm). The simulated wintertime Huanghai Sea circulation indicates that after the HSWC enters the Huanghai Sea domain around 32.5°N, 125°E to the west of the Cheju Island, it heads northwestward along the 70 m isobaths to the west of the Huanghai Sea trough. The sea surface height distribution also shows that along the path of the HSWC the sea surface height gradient is greater than the adjacent areas. The northward volume transport induced by the geostrophic current explains 78% of the total northward volume transport, the adjustment of the sea surface height is important to the path the HSWC. The topography control experiments conducted under the elongated semi-enclosed basin show the upwind flow goes along the deep trough regardless of the location of the deep trough, in the central of the basin or sideways. This means the deviation of the Huanghai Sea trough is not sufficient to make the HSWC shift to the west.The experiments performed with the topography of the typical section chosen in the Huanghai Sea tell the position where the HSWC enters the Huanghai Sea is crucial. The HSWC enters the Huanghai Sea domain along 50~70 m isobaths where the topography gradient is greater than adjacent areas. The topography gradient then traps the HSWC to flow along these isobaths. The position where the HSWC enters the Huanghai Sea domain is also related to the sharper topography gradient of the northern East China Sea.The site specific sharper topography gradient influences also the shelf circulation of the northern East China Sea. Under the strong winter monsoon, a part of the East China Sea shelf circulation enters the Huanghai Sea and becomes the HSWC. Therefore, the adjustment of the circulation in the East China Sea and Huanghai Sea under the winter monsoon together with the topography leads to the westward shifting of the HSWC which is trapped along the sharper topography gradient under the constrain of the conservation of the potential vorticity.
The mechanism of the westward shifting of the Huanghai Sea(Yellow Sea) Warm Current (HSWC) is studied through a group of numerical experiments using MIT General Circulation Model (MITgcm). The simulated wintertime Huanghai Sea circulation indicates that after the HSWC enters the Huanghai Sea domain around 32.5°N, 125°E to the west of the Cheju Island, it heads northwestward along the 70 m isobaths to the west of the Huanghai Sea trough. The sea surface height distribution also shows that along the path of the HSWC the sea surface height gradient is greater than the adjacent areas. The northward volume transport induced by the geostrophic current explains 78% of the total northward volume transport, the adjustment of the sea surface height is important to the path the HSWC. The topography control experiments conducted under the elongated semi-enclosed basin show the upwind flow goes along the deep trough regardless of the location of the deep trough, in the central of the basin or sideways. This means the deviation of the Huanghai Sea trough is not sufficient to make the HSWC shift to the west.The experiments performed with the topography of the typical section chosen in the Huanghai Sea tell the position where the HSWC enters the Huanghai Sea is crucial. The HSWC enters the Huanghai Sea domain along 50~70 m isobaths where the topography gradient is greater than adjacent areas. The topography gradient then traps the HSWC to flow along these isobaths. The position where the HSWC enters the Huanghai Sea domain is also related to the sharper topography gradient of the northern East China Sea.The site specific sharper topography gradient influences also the shelf circulation of the northern East China Sea. Under the strong winter monsoon, a part of the East China Sea shelf circulation enters the Huanghai Sea and becomes the HSWC. Therefore, the adjustment of the circulation in the East China Sea and Huanghai Sea under the winter monsoon together with the topography leads to the westward shifting of the HSWC which is trapped along the sharper topography gradient under the constrain of the conservation of the potential vorticity.
2010, 32(6): 25-34.
Abstract:
Internal waves in the steady stratified fluid propagate along the characteristic, whose angle with the vertical direction is determined by the wave frequency, float frequency and some other factors. The characteristics being reflected at boundaries keep the wave frequency as well as the angle with the vertical direction. In a closed container with one oblique boundary, the energy of the internal waves concentrate or diverse due to the reflections of characteristic by the boundaries. A limited circle, which is called internal wave attractor, might be formed in the concentrating case. This phenomenon has been observed in the water tank experiment, and verified by linear theory and numerical simulation. In this paper, we simulate the (1, 1) and (2, 1)-attractors using a nonlinear non-hydrostatic circulation model, MITgcm, and discuss the dependence of their characteristics on initial conditions. For a stable (1, 1)-attractor, strong shear current was generated around the limit circle. When reducing the slop of oblique boundary in a range, the structure of the attractor will not change greatly, but induce a quicker shrinkage of phase space due to the increase of linearity. For a (2, 1)-attractor, a part of the wave energy dissipated at the node between the two circuits and thus convergence of it needs more time. At the position of the node, current velocity is always zero. But the mixing is strong, and the buoyancy oscillates periodically with large amplitude.
Internal waves in the steady stratified fluid propagate along the characteristic, whose angle with the vertical direction is determined by the wave frequency, float frequency and some other factors. The characteristics being reflected at boundaries keep the wave frequency as well as the angle with the vertical direction. In a closed container with one oblique boundary, the energy of the internal waves concentrate or diverse due to the reflections of characteristic by the boundaries. A limited circle, which is called internal wave attractor, might be formed in the concentrating case. This phenomenon has been observed in the water tank experiment, and verified by linear theory and numerical simulation. In this paper, we simulate the (1, 1) and (2, 1)-attractors using a nonlinear non-hydrostatic circulation model, MITgcm, and discuss the dependence of their characteristics on initial conditions. For a stable (1, 1)-attractor, strong shear current was generated around the limit circle. When reducing the slop of oblique boundary in a range, the structure of the attractor will not change greatly, but induce a quicker shrinkage of phase space due to the increase of linearity. For a (2, 1)-attractor, a part of the wave energy dissipated at the node between the two circuits and thus convergence of it needs more time. At the position of the node, current velocity is always zero. But the mixing is strong, and the buoyancy oscillates periodically with large amplitude.
2010, 32(6): 35-40.
Abstract:
Based on the original Boltzmann integration, a new model for exact computation of the non-linear energy transfer between wind waves has been set up and its results coincide with the other authors’. The new model also can present the contribution of different configurations to the total energy transfer and the structure of each configuration is illustrated directly and clearly. Advanced studies can be carried out based on this model, such like the study of the structure in most-contribution configurations and the study of improving approximation computation methods.
Based on the original Boltzmann integration, a new model for exact computation of the non-linear energy transfer between wind waves has been set up and its results coincide with the other authors’. The new model also can present the contribution of different configurations to the total energy transfer and the structure of each configuration is illustrated directly and clearly. Advanced studies can be carried out based on this model, such like the study of the structure in most-contribution configurations and the study of improving approximation computation methods.
2010, 32(6): 41-46.
Abstract:
The breaking wave induced near-shore current is crucial hydrodynamics in near-shore zone.Based on the elliptic mild-slope equation for surface water waves and the 2D wave-induced current equation, the numerical model for near-shore breaking-wave-induced current was developed on unstructured grid.In the model, the spatial dispersion was made by finite volume method, and the time dispersion was made by Euler forward schemes.It was shown by numerical results that the model was effective in modeling near-shore wave-induced currents.
The breaking wave induced near-shore current is crucial hydrodynamics in near-shore zone.Based on the elliptic mild-slope equation for surface water waves and the 2D wave-induced current equation, the numerical model for near-shore breaking-wave-induced current was developed on unstructured grid.In the model, the spatial dispersion was made by finite volume method, and the time dispersion was made by Euler forward schemes.It was shown by numerical results that the model was effective in modeling near-shore wave-induced currents.
2010, 32(6): 47-55.
Abstract:
This study evaluated the microwave remote sensing SST derived from AMSR-E (Advanced Microwave Scanning Radiometer for the Earth Observing System) using AOML (Atlantic Oceanographical and Meteorological Laboratory) SVP drifting buoy data, focusing on the Southern Ocean (south of 30°S). Compared to the buoy data, AMSR-E has a mean bias of -0.01 ℃ (0.004 ℃ for summer and -0.06 ℃ for winter) and standard deviation (STD) of 0.70 ℃(0.64 ℃ for summer, and 0.75 ℃ for winter). The biases of AMSR-E SST (ΔT) are influenced by ocean surface velocity, particularly decreasing with the increasing velocity in summer. The drogued data shows similar results to that of all data, but the undrogued data is more significantly influenced by the velocity. Also, the biases of AMSR-E SST are influenced by water vapor, particularly decreasing with the increasing water vapor in winter. Further analyses of tracing four buoys crossing or following the Antarctic circumpolar current suggest that the SST bias is influenced by the ocean current systems. The SST uncertainty is much larger than that of overall circumstances.
This study evaluated the microwave remote sensing SST derived from AMSR-E (Advanced Microwave Scanning Radiometer for the Earth Observing System) using AOML (Atlantic Oceanographical and Meteorological Laboratory) SVP drifting buoy data, focusing on the Southern Ocean (south of 30°S). Compared to the buoy data, AMSR-E has a mean bias of -0.01 ℃ (0.004 ℃ for summer and -0.06 ℃ for winter) and standard deviation (STD) of 0.70 ℃(0.64 ℃ for summer, and 0.75 ℃ for winter). The biases of AMSR-E SST (ΔT) are influenced by ocean surface velocity, particularly decreasing with the increasing velocity in summer. The drogued data shows similar results to that of all data, but the undrogued data is more significantly influenced by the velocity. Also, the biases of AMSR-E SST are influenced by water vapor, particularly decreasing with the increasing water vapor in winter. Further analyses of tracing four buoys crossing or following the Antarctic circumpolar current suggest that the SST bias is influenced by the ocean current systems. The SST uncertainty is much larger than that of overall circumstances.
2010, 32(6): 56-63.
Abstract:
This paper describes a coupling model that simulates storm tide and waves induced by typhoon in Shenzhen and Hong Kong waters. The coupling model is based on the nonlinear long-wave model ECOM and the third wave model SWAN driven by the parametric typhoon model and the global tide model TPXO6.2 for three levels of nested geographic domains, ocean, continental and coastal. No.0814 typhoon "Hagupit" was chosen for case study to test the coupling model, and the computed results show the good agreement with the observed data for the astronomical tide, significant wave height, and storm tide level. And also the interaction is analyzed between the storm tide and wave, and the distribution of the wave height is given in Shenzhen and Hong Kong waters.
2010, 32(6): 64-71.
Abstract:
By using the western North Pacific tropical cyclone(TC)data and the NCEP/DOE AMIP-Ⅱ reanalysis daily data during 1979-2005, the features of TCs in the South China Sea(SCS)-western North Pacific monsoon trough (MTTC) and the cluster of tropical cyclogensis (CTC) are analysed. The main results are shown as follows: (1)The average frequency of the CTC is 3~4 times per year. In August, the number of the CTC is maximum, occupying 30%, followed by September, and it is minimum in May, only accounting for 4%. (2) The MTTCs genesis area is smaller (bigger), located more south-(north-) and west-(eastward) than normal in inactive (active) years.(3)CTC mainly formed in four monsoon trough (MT) patterns: eastward extend MT, reverse-oriented MT, the three streams MT and western Pacific MT, of which the first pattern is the chief, in which 60.0% of MTTC form, the last one is the least, only accounting for 4.8%. (4) Anomalies in the intensity and pattern of monsoon trough lead to the abnormal CTCs which result in the abnormal frequency of MTTCs.
By using the western North Pacific tropical cyclone(TC)data and the NCEP/DOE AMIP-Ⅱ reanalysis daily data during 1979-2005, the features of TCs in the South China Sea(SCS)-western North Pacific monsoon trough (MTTC) and the cluster of tropical cyclogensis (CTC) are analysed. The main results are shown as follows: (1)The average frequency of the CTC is 3~4 times per year. In August, the number of the CTC is maximum, occupying 30%, followed by September, and it is minimum in May, only accounting for 4%. (2) The MTTCs genesis area is smaller (bigger), located more south-(north-) and west-(eastward) than normal in inactive (active) years.(3)CTC mainly formed in four monsoon trough (MT) patterns: eastward extend MT, reverse-oriented MT, the three streams MT and western Pacific MT, of which the first pattern is the chief, in which 60.0% of MTTC form, the last one is the least, only accounting for 4.8%. (4) Anomalies in the intensity and pattern of monsoon trough lead to the abnormal CTCs which result in the abnormal frequency of MTTCs.
2010, 32(6): 72-82.
Abstract:
A new turbulent flux parameterization scheme has been incorporated into the Community Atmosphere Model version3 (CAM3). The global distribution of turbulent fluxes and precipitation, and the zonal means of latent heat flux and precipitation simulated by CAM3 coupled with the new scheme are compared to the counterparts simulated by the original CAM3. The results show that the outputs of the improved model are much more closely to ERS, ERA40 turbulent data and CMAP data than those of the original CAM3 model, especially the wind stress in the Northern Hemisphere trade wind region, and the latent heat flux and precipitation in Asia monsoon. Because the Obukhov stability parameter is parameterized directly by using bulk Richardson number, aerodynamic roughness length, and heat roughness length, the calculate efficiency increased.
A new turbulent flux parameterization scheme has been incorporated into the Community Atmosphere Model version3 (CAM3). The global distribution of turbulent fluxes and precipitation, and the zonal means of latent heat flux and precipitation simulated by CAM3 coupled with the new scheme are compared to the counterparts simulated by the original CAM3. The results show that the outputs of the improved model are much more closely to ERS, ERA40 turbulent data and CMAP data than those of the original CAM3 model, especially the wind stress in the Northern Hemisphere trade wind region, and the latent heat flux and precipitation in Asia monsoon. Because the Obukhov stability parameter is parameterized directly by using bulk Richardson number, aerodynamic roughness length, and heat roughness length, the calculate efficiency increased.
2010, 32(6): 83-90.
Abstract:
A climatology of surface wind speed, wind stress and wind stress curl fields on a global 0.25°×0.25° grid (named SCAT) is constructed using 11.5 a surface wind observations from scatterometers NSCAT, QuikSCAT and SeaWinds on ADEOS-II. The L2B swath observations from each sensor were processed with quality control procedure, spatially low-pass filtered to remove spurious points, and then averaged as monthly fields.The SCAT is entirely based on satellite observations with the highest temporal and spatial sampling frequencies to date. The SCAT stress and stress curl fields reveal many mesoscale and small-scale features near the coastal regions of China that are of great importance to oceanography, climate studies, marine meteorology, fishery and ocean engineering. As a preliminary study of China’s ocean satellite mission "HY-2",The SCAT data can be obtained from the National Satellite Ocean Applications Service,the State Oceanic Administration.
A climatology of surface wind speed, wind stress and wind stress curl fields on a global 0.25°×0.25° grid (named SCAT) is constructed using 11.5 a surface wind observations from scatterometers NSCAT, QuikSCAT and SeaWinds on ADEOS-II. The L2B swath observations from each sensor were processed with quality control procedure, spatially low-pass filtered to remove spurious points, and then averaged as monthly fields.The SCAT is entirely based on satellite observations with the highest temporal and spatial sampling frequencies to date. The SCAT stress and stress curl fields reveal many mesoscale and small-scale features near the coastal regions of China that are of great importance to oceanography, climate studies, marine meteorology, fishery and ocean engineering. As a preliminary study of China’s ocean satellite mission "HY-2",The SCAT data can be obtained from the National Satellite Ocean Applications Service,the State Oceanic Administration.
2010, 32(6): 91-101.
Abstract:
The satellite altimetry products are widely used by researchers and operational users. However, altimeter measurements over coastal waters are unavailable because of land contamination of the altimeter return waveforms and inappropriate geophysical corrections, such as the atmospheric wet troposphere correction, the ocean tide correction and the high-frequency factor correction. To shorten the unavailable distance offshore, four waveform retracking algorithms (ocean, offset centre of gravity, Ice-2, and threshold retracking algorithms) are compared using the JASON-1 altimeter measurements over China’s seas. Results, which are validated using crossover analysis and in situ sea surface height data show that the OCOG algorithm is more suitable than the other three algorithms for China’s offshore altimeter waveform retracking.
The satellite altimetry products are widely used by researchers and operational users. However, altimeter measurements over coastal waters are unavailable because of land contamination of the altimeter return waveforms and inappropriate geophysical corrections, such as the atmospheric wet troposphere correction, the ocean tide correction and the high-frequency factor correction. To shorten the unavailable distance offshore, four waveform retracking algorithms (ocean, offset centre of gravity, Ice-2, and threshold retracking algorithms) are compared using the JASON-1 altimeter measurements over China’s seas. Results, which are validated using crossover analysis and in situ sea surface height data show that the OCOG algorithm is more suitable than the other three algorithms for China’s offshore altimeter waveform retracking.
2010, 32(6): 102-107.
Abstract:
Based on the in situ continuous profiling data of chlorophyll a concentration acquired by the ship-board multi-parameter towed profiling system in the southeast of Taiwan Island, ENVISAT MERIS product was validated. MERIS product overestimates the in situ chlorophyll a concentration by less than 30%. It is manifested that towed profiling system can provide high-quality in situ data for satellite product assessment and has the obvious advantage of high efficiency over traditional stationary platforms.
Based on the in situ continuous profiling data of chlorophyll a concentration acquired by the ship-board multi-parameter towed profiling system in the southeast of Taiwan Island, ENVISAT MERIS product was validated. MERIS product overestimates the in situ chlorophyll a concentration by less than 30%. It is manifested that towed profiling system can provide high-quality in situ data for satellite product assessment and has the obvious advantage of high efficiency over traditional stationary platforms.
2010, 32(6): 108-117.
Abstract:
Four cruises are conducted in the Sanggou Bay in April, July, November 2006 and January 2007, nutrient distributions, structure features, primary control processes and exchange fluxes across the sediment-water interface are dscussed.The results indicate that nutrient concentrations show obvious seasonal changes. The concentrations of NO-3, NO-2, PO3-4, DOP, TDP and SiO2-3are the highest in autumn, while the concentrations of NH+4-N, DON and TDN show the highest in summer. The concentrations of nutrients are the lowest in spring except DON. In spring, the water exchange between the Sanggou Bay and the Huanghai Sea and the uptake by large phytoplankton result in the concentrations of nutrients at lower level in the bay. In summer and autumn, the riverine input affects the nutrient levels. In winter, the nutrient levels are affected by coastal waters . The structure of P shows a more obvious change and DOP is the major component in summer which can be 81%. The structure of N transforms from DON to DIN domination. The atom ratio of Si to N changes slightly in the whole year, while the atom ratios of Si to N and N to P in spring and summer are higher those that in autumn and winter. Based on the analysis of nutrient limiting criterion and the lowest threshold values of the phytoplankton growth, P is the limiting factor for the phytoplankton growth in spring and summer in the Sanggou Bay. Si is also a potential limiting factor in spring with the concentration lower than the threshold value of the phytoplankton growth, which shows that the contributions of NH+4, PO3-4 and SiO2-3fluxes released from the sediment to primary production is quite limited. Comparing to other shallow sea environments, the benthic nutrient fluxes in the Sanggou Bay are ranked at the lower level.
Four cruises are conducted in the Sanggou Bay in April, July, November 2006 and January 2007, nutrient distributions, structure features, primary control processes and exchange fluxes across the sediment-water interface are dscussed.The results indicate that nutrient concentrations show obvious seasonal changes. The concentrations of NO-3, NO-2, PO3-4, DOP, TDP and SiO2-3are the highest in autumn, while the concentrations of NH+4-N, DON and TDN show the highest in summer. The concentrations of nutrients are the lowest in spring except DON. In spring, the water exchange between the Sanggou Bay and the Huanghai Sea and the uptake by large phytoplankton result in the concentrations of nutrients at lower level in the bay. In summer and autumn, the riverine input affects the nutrient levels. In winter, the nutrient levels are affected by coastal waters . The structure of P shows a more obvious change and DOP is the major component in summer which can be 81%. The structure of N transforms from DON to DIN domination. The atom ratio of Si to N changes slightly in the whole year, while the atom ratios of Si to N and N to P in spring and summer are higher those that in autumn and winter. Based on the analysis of nutrient limiting criterion and the lowest threshold values of the phytoplankton growth, P is the limiting factor for the phytoplankton growth in spring and summer in the Sanggou Bay. Si is also a potential limiting factor in spring with the concentration lower than the threshold value of the phytoplankton growth, which shows that the contributions of NH+4, PO3-4 and SiO2-3fluxes released from the sediment to primary production is quite limited. Comparing to other shallow sea environments, the benthic nutrient fluxes in the Sanggou Bay are ranked at the lower level.
2010, 32(6): 118-129.
Abstract:
The grain size and content of clay from surface sediments in accordance with water depth of less than 200 m, 200~2 000 m and more than 2 000 m in the central South China Sea (118 surface sediment samples with water depth from 82 to 4 420 m) and eastern South China Sea (106 surface sediment samples with water depth from 700 to 4508m) were statistically analyzed. The results indicate that the average grain size and content of clay have distinctly regular changes with water depth; furthermore, no remarkable change with water depth is found when the water depth over 2 000 m is further subdivided into over 2 500 m, over 3 000 m and over 3 500 m. For the depth range of water over 2 000 m, the average grain size and content of clay in the sediment samples from the central South China Sea are 3.39~3.54 μm and 54.91%~55.47% respectively, which are slightly higher than those from the eastern South China Sea (3.25~3.37 μm and 53.91%~54.56%). As a result, the water depth of 2 000 m has a significant indicator to classify deep sea sediment. The average content and grain size of clay for sediments in the central South China Sea in the depth range of water over 2 000 m are 55.19% and 3.39 μm, respectively. In the eastern South China Sea with water depth over 2 000 m, the content of clay is 53.91%, and the average grain size is 3.37 μm. In general, the average grain size of surface sediments is less than 4 μm, while the average content of clay is higher than 50% in both central and eastern South China Sea with water depth over 2 000 m.The clay content is an independent index representative for abiotic components, and has been adopted to classify deep-sea sediment combined with calcareous and siliceous components. 55 elements in the sediment samples from the eastern South China Sea were also detected, accounting for about 47.50% of the total content. Among them, the content for the main elements of silicon,aluminium,titanium,sodium, potassium,phosphorus,calcium,magnesium,iron and manganese is 47.03%, while only 0.47% is measured in association with other trace 45 elements. Although the sediments were originated from various sources through different causes, their chemical compositions were quite simple, mainly composed of the 10 major elements, together with oxygen. Moreover, aluminium,calcium and silicon were found to be separately accumulated in clay and calcareous and siliceous sediments. Besides, CaCO3 and SiO2 may be considered as alternative indices for calcareous and siliceous organisms through establishing the quantitative relationship between biogenic components and the content of CaCO3,Al2O3and SiO2 in surface sediments.
The grain size and content of clay from surface sediments in accordance with water depth of less than 200 m, 200~2 000 m and more than 2 000 m in the central South China Sea (118 surface sediment samples with water depth from 82 to 4 420 m) and eastern South China Sea (106 surface sediment samples with water depth from 700 to 4508m) were statistically analyzed. The results indicate that the average grain size and content of clay have distinctly regular changes with water depth; furthermore, no remarkable change with water depth is found when the water depth over 2 000 m is further subdivided into over 2 500 m, over 3 000 m and over 3 500 m. For the depth range of water over 2 000 m, the average grain size and content of clay in the sediment samples from the central South China Sea are 3.39~3.54 μm and 54.91%~55.47% respectively, which are slightly higher than those from the eastern South China Sea (3.25~3.37 μm and 53.91%~54.56%). As a result, the water depth of 2 000 m has a significant indicator to classify deep sea sediment. The average content and grain size of clay for sediments in the central South China Sea in the depth range of water over 2 000 m are 55.19% and 3.39 μm, respectively. In the eastern South China Sea with water depth over 2 000 m, the content of clay is 53.91%, and the average grain size is 3.37 μm. In general, the average grain size of surface sediments is less than 4 μm, while the average content of clay is higher than 50% in both central and eastern South China Sea with water depth over 2 000 m.The clay content is an independent index representative for abiotic components, and has been adopted to classify deep-sea sediment combined with calcareous and siliceous components. 55 elements in the sediment samples from the eastern South China Sea were also detected, accounting for about 47.50% of the total content. Among them, the content for the main elements of silicon,aluminium,titanium,sodium, potassium,phosphorus,calcium,magnesium,iron and manganese is 47.03%, while only 0.47% is measured in association with other trace 45 elements. Although the sediments were originated from various sources through different causes, their chemical compositions were quite simple, mainly composed of the 10 major elements, together with oxygen. Moreover, aluminium,calcium and silicon were found to be separately accumulated in clay and calcareous and siliceous sediments. Besides, CaCO3 and SiO2 may be considered as alternative indices for calcareous and siliceous organisms through establishing the quantitative relationship between biogenic components and the content of CaCO3,Al2O3and SiO2 in surface sediments.
2010, 32(6): 130-143.
Abstract:
The Taiwan Strait is a narrow passage connecting the broad and shallow East China Sea to the deep South China Sea, with multiple sources and various transport patterns of sediments (including suspended matter and bedload). A comprehensive investigation has been carried out in the southwest Taiwan Strait in April and May 2005, at 627 stations with SD204 CTD, Seapoint turbidity and fluorescence profiling and collected surfacial sediment. Sediment samples were analyzed by using Mastersizer 2000 laser particle size analyzer (a product of Malvern, UK), and ELEMENTOR varioEL III element analyzer (a product of ELEMENTOR). Then sediment grain sizes, carbon and nitrogen contents were obtained. The results show that the southwest Taiwan Strait water is affected by the coastal currents along Guangdong, the diluted water from the Hanjiang River and Jiulong River and the mixed water of the Taiwan Strait. The coastal currents along Guangdong coasts decrease northward. The diluted water from Hanjiang River transports towards the northeast, which is controlled by seasonal southwest winds. The sediment transports offshore from coasts but onshore from the deep continental area. Thus, a sediment sink center is observed between the southern Shanwei coast and the southeastern Nan'ao Island, in which the terrestrial source dominates. The bedload transport pattern is controlled by the local hydrodynamics and suspended matter settling. The fluorescence of suspended sediment is low at early stage of the upwelling formation in spring. However, the upwelling plays an important role in the sediment transport processes.
The Taiwan Strait is a narrow passage connecting the broad and shallow East China Sea to the deep South China Sea, with multiple sources and various transport patterns of sediments (including suspended matter and bedload). A comprehensive investigation has been carried out in the southwest Taiwan Strait in April and May 2005, at 627 stations with SD204 CTD, Seapoint turbidity and fluorescence profiling and collected surfacial sediment. Sediment samples were analyzed by using Mastersizer 2000 laser particle size analyzer (a product of Malvern, UK), and ELEMENTOR varioEL III element analyzer (a product of ELEMENTOR). Then sediment grain sizes, carbon and nitrogen contents were obtained. The results show that the southwest Taiwan Strait water is affected by the coastal currents along Guangdong, the diluted water from the Hanjiang River and Jiulong River and the mixed water of the Taiwan Strait. The coastal currents along Guangdong coasts decrease northward. The diluted water from Hanjiang River transports towards the northeast, which is controlled by seasonal southwest winds. The sediment transports offshore from coasts but onshore from the deep continental area. Thus, a sediment sink center is observed between the southern Shanwei coast and the southeastern Nan'ao Island, in which the terrestrial source dominates. The bedload transport pattern is controlled by the local hydrodynamics and suspended matter settling. The fluorescence of suspended sediment is low at early stage of the upwelling formation in spring. However, the upwelling plays an important role in the sediment transport processes.
2010, 32(6): 144-151.
Abstract:
Based on measured data in storm waves, the suspended sediment content of silty coast water is uniform at the upper layer, with a sudden increase near the bottom, and is named as L-shaped vertical distribution. Flume experiments were carried out to study the characteristics of vertical suspended sediment content on the liquefied silty soil bed, which is made using Huanghe River Delta silty soil. It is revealed that the vertical suspended sediment content on the liquefied silty soil bed under wave action is L-shaped.According to the variation of the particle size and the experiment phenomena, the formation of the high content layer at the bottom was affected by the fine sediments entering into the water when the silty soil liquefied, and the suspended sediments in the upper water was kept by turbulent fluctuation.The dramatic increase of the water-sediment on the silty soil coast during stormy weather is preliminarily explained using wave-induced soil liquefaction point of view.
Based on measured data in storm waves, the suspended sediment content of silty coast water is uniform at the upper layer, with a sudden increase near the bottom, and is named as L-shaped vertical distribution. Flume experiments were carried out to study the characteristics of vertical suspended sediment content on the liquefied silty soil bed, which is made using Huanghe River Delta silty soil. It is revealed that the vertical suspended sediment content on the liquefied silty soil bed under wave action is L-shaped.According to the variation of the particle size and the experiment phenomena, the formation of the high content layer at the bottom was affected by the fine sediments entering into the water when the silty soil liquefied, and the suspended sediments in the upper water was kept by turbulent fluctuation.The dramatic increase of the water-sediment on the silty soil coast during stormy weather is preliminarily explained using wave-induced soil liquefaction point of view.
2010, 32(6): 152-156.
Abstract:
In order to selecting the best applied blocks of cobalt-rich crust, the fuzzy method was used. The average thick, the average percent of cobalt, the ore field area, the average slope, the average water depth and the number of valid stations were selected as the indexes for deciding the quality of the applied blocks of cobalt-rich crust, and the quality of the applied blocks of cobalt-rich crust was divided into three classes, and the fuzzy evaluation model was setting, then an instance was done. The result could be fundamental for selecting the best applied blocks of cobalt-rich crust. The fuzzy evaluation results were inconsistent with the resource quantities for some applied blocks of cobalt-rich crust, so both of them should be considered when the applied blocks of cobalt-rich crust were selected.The result would benefit the selection of the applied blocks of cobalt-rich crust in the future.
In order to selecting the best applied blocks of cobalt-rich crust, the fuzzy method was used. The average thick, the average percent of cobalt, the ore field area, the average slope, the average water depth and the number of valid stations were selected as the indexes for deciding the quality of the applied blocks of cobalt-rich crust, and the quality of the applied blocks of cobalt-rich crust was divided into three classes, and the fuzzy evaluation model was setting, then an instance was done. The result could be fundamental for selecting the best applied blocks of cobalt-rich crust. The fuzzy evaluation results were inconsistent with the resource quantities for some applied blocks of cobalt-rich crust, so both of them should be considered when the applied blocks of cobalt-rich crust were selected.The result would benefit the selection of the applied blocks of cobalt-rich crust in the future.
2010, 32(6): 157-166.
Abstract:
Three lines (Line XC-03 of Kappaphycus alvarezii from Lingshui coast, Line LD-02 and Line LD-06 from Sanya coast) of eucheumatoids algae with different shapes cultivated in Hainan Province, China were identified by morphological characteristics and molecular phylogenetic analysis, and were compared with Line TSNY-05 of Eucheuma denticulatum from Tanzania. There were differences in the branch shapes, length and distributing and tuber numbers, the cell sizes of epidermis, cortex and medulla part, the counts of cortex and the thickness of the colloid among three lines (Line XC-03, Line LD-02 and Line LD-06). But molecular identification indicated that Line XC-03, Line LD-02 and Line LD-06 were same species, K. alvarezii. The genome DNA was extracted from four lines by CTAB method. 5 polymorphic primers were screened out of 30 primers for random amplified polymorphic DNA (RAPD) analyses and 39 primers for inter-simple sequence repeat (ISSR) analyses, respectively. 12 individuals were used for molecular analysis respectively, and 39 loci (RAPD) and 49 loci (ISSR) were obtained. The fragments for RAPD and ISSR markers were from 300 to 3 000 bp or from 400 to 3 000 bp, respectively. The PCR amplified products of the internal transcribed spacer (ITS) were sequenced by the ABI PRISM 3730 genetic analyzer. The sequence data were blasted and aligned, and phylogeny trees were constructed by neighbour-joining and UPGMA analyses using MEGA 4.0. The results showed that the similarity of the ITS sequence was 99.69%~99.85% among Line XC-03, Line LD-02 and Line LD-06. There was one base transition and one base transversion between Line XC-03 and Line LD-02, and there was only one base transition between Line XC-03 and Line LD-06 and one base transversion between Line LD-02 and Line LD-06. While the similarity of the ITS sequence was 41.28% between K. alvarezii.and E. denticulatum. And RAPD, ISSR and ITS analysis further indicated that the pairwise genetic distance between Line XC-03, Line LD-02 and Line LD-06 was from 0.122 9 to 0.153 5 (RAPD), from 0.068 8 to 0.112 4(ISSR) and from 0.002 to 0.005 (ITS), respectively, with software Popgen 32 and MEGA 4.0. With Neighbor-Joining and UPGMA analyses, it indicated that the relationship between Line XC-03 and LD-06 was closer than that between Line XC-03 and Line LD-02. However, the pairwise genetic distance was above 0.9 between E. denticulatum and K. alvarezii, and it showed that the relationship was very far between E. denticulatum.and K. alvarezii. These results provide a basis for the species identification and genetics breeding in K. alvarezii cultivation.
Three lines (Line XC-03 of Kappaphycus alvarezii from Lingshui coast, Line LD-02 and Line LD-06 from Sanya coast) of eucheumatoids algae with different shapes cultivated in Hainan Province, China were identified by morphological characteristics and molecular phylogenetic analysis, and were compared with Line TSNY-05 of Eucheuma denticulatum from Tanzania. There were differences in the branch shapes, length and distributing and tuber numbers, the cell sizes of epidermis, cortex and medulla part, the counts of cortex and the thickness of the colloid among three lines (Line XC-03, Line LD-02 and Line LD-06). But molecular identification indicated that Line XC-03, Line LD-02 and Line LD-06 were same species, K. alvarezii. The genome DNA was extracted from four lines by CTAB method. 5 polymorphic primers were screened out of 30 primers for random amplified polymorphic DNA (RAPD) analyses and 39 primers for inter-simple sequence repeat (ISSR) analyses, respectively. 12 individuals were used for molecular analysis respectively, and 39 loci (RAPD) and 49 loci (ISSR) were obtained. The fragments for RAPD and ISSR markers were from 300 to 3 000 bp or from 400 to 3 000 bp, respectively. The PCR amplified products of the internal transcribed spacer (ITS) were sequenced by the ABI PRISM 3730 genetic analyzer. The sequence data were blasted and aligned, and phylogeny trees were constructed by neighbour-joining and UPGMA analyses using MEGA 4.0. The results showed that the similarity of the ITS sequence was 99.69%~99.85% among Line XC-03, Line LD-02 and Line LD-06. There was one base transition and one base transversion between Line XC-03 and Line LD-02, and there was only one base transition between Line XC-03 and Line LD-06 and one base transversion between Line LD-02 and Line LD-06. While the similarity of the ITS sequence was 41.28% between K. alvarezii.and E. denticulatum. And RAPD, ISSR and ITS analysis further indicated that the pairwise genetic distance between Line XC-03, Line LD-02 and Line LD-06 was from 0.122 9 to 0.153 5 (RAPD), from 0.068 8 to 0.112 4(ISSR) and from 0.002 to 0.005 (ITS), respectively, with software Popgen 32 and MEGA 4.0. With Neighbor-Joining and UPGMA analyses, it indicated that the relationship between Line XC-03 and LD-06 was closer than that between Line XC-03 and Line LD-02. However, the pairwise genetic distance was above 0.9 between E. denticulatum and K. alvarezii, and it showed that the relationship was very far between E. denticulatum.and K. alvarezii. These results provide a basis for the species identification and genetics breeding in K. alvarezii cultivation.
2010, 32(6): 167-173.
Abstract:
A new numerical model for three-dimensional flow is proposed, in which the Navier-Stokes (N-S) equations of incompressible fluid are solved as the governing equations for flow movement, and a fast particle level set method is adopted for free surface tracking. The N-S equations are solved only in the liquid phase for saving computational time. A ghost pressure method is utilized to close the Poisson equation on the free surface and the simple extrapolation of velocity is applied to obtaining the ghost velocity field out of the water domain. The flow model is verified by the modeled results of oscillatory flow, collapse of water column, impact of water drop and water infusion.
A new numerical model for three-dimensional flow is proposed, in which the Navier-Stokes (N-S) equations of incompressible fluid are solved as the governing equations for flow movement, and a fast particle level set method is adopted for free surface tracking. The N-S equations are solved only in the liquid phase for saving computational time. A ghost pressure method is utilized to close the Poisson equation on the free surface and the simple extrapolation of velocity is applied to obtaining the ghost velocity field out of the water domain. The flow model is verified by the modeled results of oscillatory flow, collapse of water column, impact of water drop and water infusion.
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