2003 Vol. 25, No. 3
Display Method:
2003, 25(3): 1-7.
Abstract:
The effect of long-term variation in mean sea-level on extreme water levels of multiyear return periods was analyzed and discussed on the basis of data of the yearly extreme high(low) water levels and yearly mean sea-levels obtained through observation at Rushankou in a period of 24 a.And also approaches for eliminating the yearly mean sea-level long-term variation were discussed.Through the comparison between the extreme water levels of multiyear return periods in the case of yearly mean sea-level long-term variation being eliminated and those in the case of the long-term variation being retained,one can find that for the extreme high water levels,the results with the longterm variation being retained are higher than those with the long-term variation being eliminated,as for the extreme low water levels,the situation is just the oposite.
The effect of long-term variation in mean sea-level on extreme water levels of multiyear return periods was analyzed and discussed on the basis of data of the yearly extreme high(low) water levels and yearly mean sea-levels obtained through observation at Rushankou in a period of 24 a.And also approaches for eliminating the yearly mean sea-level long-term variation were discussed.Through the comparison between the extreme water levels of multiyear return periods in the case of yearly mean sea-level long-term variation being eliminated and those in the case of the long-term variation being retained,one can find that for the extreme high water levels,the results with the longterm variation being retained are higher than those with the long-term variation being eliminated,as for the extreme low water levels,the situation is just the oposite.
2003, 25(3): 8-19.
Abstract:
An investigation for understanding relative contributions of the surface wind stress forcing and the heat flux forcing to the upper ocean variability in the tropical Atlantic is presented,with an intermediate ocean model(IOM) developed in Hawaii University.The model was integrated for 41 a as a control experiment with both anomalous wind stresses and anomalous heat fluxes.Two parallel sensitive experiments without forcing of either the wind stress anomalies or the surface heat flux anomalies were conducted.The relative importance of the two forcing factors in generating the upper ocean variabilities for the sea surface temperature(SST) and the thermocline depth was examined.This model successfully simulates the SST variations in the tropical Atlantic with a weak ENSO-like mode on the interannual time scale and a north-south dipole mode on the interdecadal time scale.The interannual SST variability is determined by both forcing factors.The heat flux forcing has more contribution outside the equator while the wind stress forcing has contribution mainly near the equator.The interdecadal dipole mode is largely controlled by the heat flux forcing.Variations of the thermocline depth in the Atlantic are dominated by the wind stress anomalies,and the heat flux forcing has nearly no contribution.
An investigation for understanding relative contributions of the surface wind stress forcing and the heat flux forcing to the upper ocean variability in the tropical Atlantic is presented,with an intermediate ocean model(IOM) developed in Hawaii University.The model was integrated for 41 a as a control experiment with both anomalous wind stresses and anomalous heat fluxes.Two parallel sensitive experiments without forcing of either the wind stress anomalies or the surface heat flux anomalies were conducted.The relative importance of the two forcing factors in generating the upper ocean variabilities for the sea surface temperature(SST) and the thermocline depth was examined.This model successfully simulates the SST variations in the tropical Atlantic with a weak ENSO-like mode on the interannual time scale and a north-south dipole mode on the interdecadal time scale.The interannual SST variability is determined by both forcing factors.The heat flux forcing has more contribution outside the equator while the wind stress forcing has contribution mainly near the equator.The interdecadal dipole mode is largely controlled by the heat flux forcing.Variations of the thermocline depth in the Atlantic are dominated by the wind stress anomalies,and the heat flux forcing has nearly no contribution.
2003, 25(3): 20-31.
Abstract:
Multi-year JEDAC data of heat content in upper ocean and NCEP/NCAR reanalysis data were used to analyse the relationship between the heat content anomalies in the warm pool(WP) area of the western Pacific and onset of South China Sea summer monsoon(SCSM).The results show that the warm pool area is the place where heat content in the tropical upper layer changes with maximum range and which is most obviously influential on the SCSM.Compared with the central and eastern equatorial Pacific,the thermal state change in the WP aerea has more direct influence on Asian monsoon.Onset of the SCSM is very closely related to the heat content anomaly during the previous period(previous winter and spring) of the WP so that the heat content of March to April in the WP area is very good predictor for the onset of the SCSM.When the heat content of the WP area is positive convection center will be located in the South Chine Sea-West Pacific with strong convection,a positive anomaly of monsoon circulation and Walker circulation will take place and the subtropical high will be weaker and farther east.Positive anomalous monsoon circulation and Walker circulation will be favorable for westerly and southwesterly flow——the SCSM breaks off earlier than normal.Otherwise,the SCSM comes later than usual.Large-scale anomalous change of monsoon circulation and Walker circulation seems one of the important mechanisms to influence the SCSM.
Multi-year JEDAC data of heat content in upper ocean and NCEP/NCAR reanalysis data were used to analyse the relationship between the heat content anomalies in the warm pool(WP) area of the western Pacific and onset of South China Sea summer monsoon(SCSM).The results show that the warm pool area is the place where heat content in the tropical upper layer changes with maximum range and which is most obviously influential on the SCSM.Compared with the central and eastern equatorial Pacific,the thermal state change in the WP aerea has more direct influence on Asian monsoon.Onset of the SCSM is very closely related to the heat content anomaly during the previous period(previous winter and spring) of the WP so that the heat content of March to April in the WP area is very good predictor for the onset of the SCSM.When the heat content of the WP area is positive convection center will be located in the South Chine Sea-West Pacific with strong convection,a positive anomaly of monsoon circulation and Walker circulation will take place and the subtropical high will be weaker and farther east.Positive anomalous monsoon circulation and Walker circulation will be favorable for westerly and southwesterly flow——the SCSM breaks off earlier than normal.Otherwise,the SCSM comes later than usual.Large-scale anomalous change of monsoon circulation and Walker circulation seems one of the important mechanisms to influence the SCSM.
2003, 25(3): 32-46.
Abstract:
Sea ice data provided by Ice and Snow Center,USA and field observed sea ice data with assimilation processed are used to study the dynamic change and long-term change trend of the Antarctic sea ice.The study shows that,there was more ice period in the later stage of the 1970s,less ice period in the 1980s.While in the 1990s,the Antarctic sea ice was in raising trend,and more ice in later stage.Regional variation difference was very large with more ice in the eastern Antarctic,obviously less ice in the west Antarctic,both sides of the Antarctic Peninsula,especially in the Weddell Sea and the Bellingshausen Sea.The sea ice variation trend in the eastern and western Antarctic is always in opposite phase.In the later 1990s,sea ice in the Prydz Bay was obviously more.The outer periphery line of sea ice of the Antarctic Continent shelf,on the wholle,wasn't any evident retreat,it was in natural variation trend with collapse and also renascence.While in the western Antarctic,the Ronne ice shelf of the Weddell Sea and the eastern part of Ross Sea ice shelf,collapse and retreat trend was evident.The collapse and retreat of ice shelf in the eastern Antarctic also existed,but not as evident as in the western Antarctic.Iceberg transferred from shelf ice collapse to ocean gives a certain impact on global sea level raising.In a word,the Antarctic sea ice had not obviously decreased with global climate warming,but periodically changes,adjusts and restricts according to opposite phase variation rule in the eastern and western Antarctic.
Sea ice data provided by Ice and Snow Center,USA and field observed sea ice data with assimilation processed are used to study the dynamic change and long-term change trend of the Antarctic sea ice.The study shows that,there was more ice period in the later stage of the 1970s,less ice period in the 1980s.While in the 1990s,the Antarctic sea ice was in raising trend,and more ice in later stage.Regional variation difference was very large with more ice in the eastern Antarctic,obviously less ice in the west Antarctic,both sides of the Antarctic Peninsula,especially in the Weddell Sea and the Bellingshausen Sea.The sea ice variation trend in the eastern and western Antarctic is always in opposite phase.In the later 1990s,sea ice in the Prydz Bay was obviously more.The outer periphery line of sea ice of the Antarctic Continent shelf,on the wholle,wasn't any evident retreat,it was in natural variation trend with collapse and also renascence.While in the western Antarctic,the Ronne ice shelf of the Weddell Sea and the eastern part of Ross Sea ice shelf,collapse and retreat trend was evident.The collapse and retreat of ice shelf in the eastern Antarctic also existed,but not as evident as in the western Antarctic.Iceberg transferred from shelf ice collapse to ocean gives a certain impact on global sea level raising.In a word,the Antarctic sea ice had not obviously decreased with global climate warming,but periodically changes,adjusts and restricts according to opposite phase variation rule in the eastern and western Antarctic.
2003, 25(3): 47-52.
Abstract:
Based on the seawater samples collected from the Xihu Harbour of Zhejiang,China on June 10-14,2000,AA-800 graphite furnace atomic absorption spectrophotometer(AAS) and anodic stripping voltammetry(ASV) were used to determine the content of heavy metal copper in the samples and acquire that copper in seawater is controlled by different organic complexes.Compared with different particle sizes(1.00,0.40,0.20 pm),the apparent copper complexation capacity(ACuCC) is respectively 144.4,103.0 and 102.0 nmol/dm3;the conditional stability constants logarithm of copper organic ligand is respectively 9.14,8.66 and 7.25.Total nipper(21.72 nmol/dm3)in the Xihu Harbour is higher.Copper all is steady dissolved,including pH2 acid dissolved nipper 95.0% and organic high complexing copper 5.0%.Dissolved organic complexing copper accounts for 61.6% of total copper in filtered seawater.
Based on the seawater samples collected from the Xihu Harbour of Zhejiang,China on June 10-14,2000,AA-800 graphite furnace atomic absorption spectrophotometer(AAS) and anodic stripping voltammetry(ASV) were used to determine the content of heavy metal copper in the samples and acquire that copper in seawater is controlled by different organic complexes.Compared with different particle sizes(1.00,0.40,0.20 pm),the apparent copper complexation capacity(ACuCC) is respectively 144.4,103.0 and 102.0 nmol/dm3;the conditional stability constants logarithm of copper organic ligand is respectively 9.14,8.66 and 7.25.Total nipper(21.72 nmol/dm3)in the Xihu Harbour is higher.Copper all is steady dissolved,including pH2 acid dissolved nipper 95.0% and organic high complexing copper 5.0%.Dissolved organic complexing copper accounts for 61.6% of total copper in filtered seawater.
2003, 25(3): 53-58.
Abstract:
Origination of flints is rather complicated.The macro-feature and micro-texture of flints and their component characteristics of chemistry,minerals,and the silicon and oxygen isotope are studied.It is considered that the formation mechanism of flints from the central Pacific Ocean mountains is that foraminiferal limestone is substituted with the silica.The main characteristics of flints and analytic results are:there are white silicared stripes in flints.The same foraminiferal fossils can be found in the thin sections of flints.The remnants of foraminiferal limestone can be seen with the naked eyes in the part place of the same flints.The living environment of foraminifera is a normal marine(water depth 1000-3000 m).The composition of mineral is quartz,and the content of SiO2 is over 96% in flints,and it has rather high value of δ18O(0.032) and lower value of δ30SiO2(0.000 4).Two groups of faults of NW and EW directions suffered by volcanic eruption many times are main features of geological structure in this area.The geochron of these mountains is from Cretaceous period to early Tertiary period,and they underwent a subsidence process because of the"crustal movement.Flints are formed in the environment of semi-deep sea.Volcanogene hydrothermal activity might be main sources of silica.
Origination of flints is rather complicated.The macro-feature and micro-texture of flints and their component characteristics of chemistry,minerals,and the silicon and oxygen isotope are studied.It is considered that the formation mechanism of flints from the central Pacific Ocean mountains is that foraminiferal limestone is substituted with the silica.The main characteristics of flints and analytic results are:there are white silicared stripes in flints.The same foraminiferal fossils can be found in the thin sections of flints.The remnants of foraminiferal limestone can be seen with the naked eyes in the part place of the same flints.The living environment of foraminifera is a normal marine(water depth 1000-3000 m).The composition of mineral is quartz,and the content of SiO2 is over 96% in flints,and it has rather high value of δ18O(0.032) and lower value of δ30SiO2(0.000 4).Two groups of faults of NW and EW directions suffered by volcanic eruption many times are main features of geological structure in this area.The geochron of these mountains is from Cretaceous period to early Tertiary period,and they underwent a subsidence process because of the"crustal movement.Flints are formed in the environment of semi-deep sea.Volcanogene hydrothermal activity might be main sources of silica.
2003, 25(3): 59-67.
Abstract:
The research area lies in the subaqueous delta that the Huanghe River entering the sea is formed vis Diaokou between 1964 and 1976.One well field road was built for exploring petroleum which formed a seawall favorably obstructing waves.The hydrodynamic conditions of the north side of the road are relatively violent,on the contrary,that of the south side of the road is nearly placid,which makes the research area a natural laboratory fog studying the influence of the hydrodynamic conditions on the fractal characteristics of the tidal flat.Selecting a area named Case 1 on the side of strong hydrodynamic conditions,and a area named Case 2 on the other side.Measuring the topography and sampling,and analyzing the granulometric compositions,it is found that the hydrodynamic conditions have fatal influence on the surface fractal dimensions and the granulometric fractal dimensions of the research area.In Case 1,which has the strong hydrodynamic conditions,the surface fractal dimensions are obviously larger than those of Case 2 and the granulometric fractal dimensions are relatively smaller than those of Case 2,the surface fractal dimensions of Case 1 decrease quickly with the increase of grid size; the granulometric fractal dimensions are disperse,while the conditions of Case 2 are just reverse.A sampling line and a sampling point in depth on each side of the road are selected.It is found that in the south side of the road the granulometric fractal dimensions change regularly in the line and in depth,the more far from the road the smaller the fractal dimensions,and the more deep the sampling position is the larger the fractal dimensions.While the north side of the road has no this orderliness.The mechanism of the influence of hydrodynamic conditions on the fractal charateristics is discussed.
The research area lies in the subaqueous delta that the Huanghe River entering the sea is formed vis Diaokou between 1964 and 1976.One well field road was built for exploring petroleum which formed a seawall favorably obstructing waves.The hydrodynamic conditions of the north side of the road are relatively violent,on the contrary,that of the south side of the road is nearly placid,which makes the research area a natural laboratory fog studying the influence of the hydrodynamic conditions on the fractal characteristics of the tidal flat.Selecting a area named Case 1 on the side of strong hydrodynamic conditions,and a area named Case 2 on the other side.Measuring the topography and sampling,and analyzing the granulometric compositions,it is found that the hydrodynamic conditions have fatal influence on the surface fractal dimensions and the granulometric fractal dimensions of the research area.In Case 1,which has the strong hydrodynamic conditions,the surface fractal dimensions are obviously larger than those of Case 2 and the granulometric fractal dimensions are relatively smaller than those of Case 2,the surface fractal dimensions of Case 1 decrease quickly with the increase of grid size; the granulometric fractal dimensions are disperse,while the conditions of Case 2 are just reverse.A sampling line and a sampling point in depth on each side of the road are selected.It is found that in the south side of the road the granulometric fractal dimensions change regularly in the line and in depth,the more far from the road the smaller the fractal dimensions,and the more deep the sampling position is the larger the fractal dimensions.While the north side of the road has no this orderliness.The mechanism of the influence of hydrodynamic conditions on the fractal charateristics is discussed.
2003, 25(3): 68-76.
Abstract:
The Yuehu is a small tidal inlet system located in the eastern Shandong Peninsula,China.In order to investigate the time-velocity asymmetric patterns of the system,hydrodynamic observations and bathymetric surveys were undertaken in the winter of 1998 and the summer of 1999.Based upon the measured tidal water levels and the calculated tidal currents,two types of additional time-velocity asymmetric patterns,other than the "flood-dominated" and "ebb-dominated" patterns,are identified:the duration of flood tide is longer(or shorter) than that of ebb tide,while the flood currents are stronger(or weaker) than the ebb currents.These patterns have been shown to be associated with the mixed and semi-diurnal dominated tides,the timing of the current velocity and water level at the entrance,the cross-section shape of the entrance channel,and the flow and circulation structures within the entrance channel.An understanding of such time-velocity asymmetric patterns is important in terms of the sediment dynamic behaviours and the artificial utilization of tidal inlets.
The Yuehu is a small tidal inlet system located in the eastern Shandong Peninsula,China.In order to investigate the time-velocity asymmetric patterns of the system,hydrodynamic observations and bathymetric surveys were undertaken in the winter of 1998 and the summer of 1999.Based upon the measured tidal water levels and the calculated tidal currents,two types of additional time-velocity asymmetric patterns,other than the "flood-dominated" and "ebb-dominated" patterns,are identified:the duration of flood tide is longer(or shorter) than that of ebb tide,while the flood currents are stronger(or weaker) than the ebb currents.These patterns have been shown to be associated with the mixed and semi-diurnal dominated tides,the timing of the current velocity and water level at the entrance,the cross-section shape of the entrance channel,and the flow and circulation structures within the entrance channel.An understanding of such time-velocity asymmetric patterns is important in terms of the sediment dynamic behaviours and the artificial utilization of tidal inlets.
2003, 25(3): 77-82.
Abstract:
The effects of No.0 diesel oil,dimethyl benzene,and Cd2+ in sea on the activity of superoxide dismutase(SOD) of Scapharca subcrertata muscle were discussed by inside and outside body contamination.The results indicate that within the dose range inductions of the above three kinds of contaminants to SOD in Scapharca subcrenataare different.The effects of No.0 diesel oil and dimethyl benzene on the activity of SOD of Scapharca subcrertata are basically identical and the dose-effect curves of the two contaminants on the activity of S0D show parabola,while the dose-effect curve of contamination with neither inside body nor outside body display parabola,and significant induction of low concentration of Cd2+to SOD exists,and afterwards the curve shows a steep descent,which suggests that Scapharca subcrenata is sensitive to Cd2+contamination,and toxicity of Cd2+ to Scapharca subcrenata is relatively obvious.The sequence of toxicity of the three kinds of contaminants is as follows:cadmium larger than No.0 diesel oil larger than dimethyl benzene.
The effects of No.0 diesel oil,dimethyl benzene,and Cd2+ in sea on the activity of superoxide dismutase(SOD) of Scapharca subcrertata muscle were discussed by inside and outside body contamination.The results indicate that within the dose range inductions of the above three kinds of contaminants to SOD in Scapharca subcrenataare different.The effects of No.0 diesel oil and dimethyl benzene on the activity of SOD of Scapharca subcrertata are basically identical and the dose-effect curves of the two contaminants on the activity of S0D show parabola,while the dose-effect curve of contamination with neither inside body nor outside body display parabola,and significant induction of low concentration of Cd2+to SOD exists,and afterwards the curve shows a steep descent,which suggests that Scapharca subcrenata is sensitive to Cd2+contamination,and toxicity of Cd2+ to Scapharca subcrenata is relatively obvious.The sequence of toxicity of the three kinds of contaminants is as follows:cadmium larger than No.0 diesel oil larger than dimethyl benzene.
2003, 25(3): 83-97.
Abstract:
During summer of 1999,the investigations of abundance and distribution of the three photosynthetic picoplankton-Synechococcus(Syn),Prochlorococcus(Pro) and Picoeukaryotes(Euk) and their environmentally regulating mechanisms were firstly carried out in the northern South China Sea.The results show that the average values of Syn,Pro and Euk abundances are(5.0±7.6)×104 cell/cm3,(4.6±4.2)×104 cell/cm3 and(1.8±1.1)×103 cell/cm3,respectively.The most of high values of Syn population abundance appeared in the estuaries,coast and continental shelf in the sea area to the east of Leizhou Peninsula and Hainan Island,where nutrients were rich,and those appeared in the Beibu Gulf were secondary,while those appeared in continental slope and open sea were one tenths of the above those.Its distribution in water column was mainly above the thermocline and the value below it sharply lowered.The distribution pattern of Pro was markedly different from that of Syn; its abundance of communities at deep layers markedly increased towards outer sea,continental slope and open sea where nutrients were poor; the high values mainly occurred at the bottom of euphotic depth and above the nitrate-cline.The distribution difference of Euk in different sea areas is less than those of Syn and Pro,but it was higher in coast and continental shelf and lower in continental slope and open sea.The high values of Euk in the water column mostly appeared at the bottom of euphotic depth and it made a major contribution to subsurface chlorophyll maximum(SCM).These different distribution patterns depend on environmental regulation and difference of the ecological and physiological adaptation.In addition,in this study,it was discovered that two different populations of Pro at the surface and deep layer existed in the northern South China Sea and often vigorously grew above the nitrate-cline.The contributions of Syn,Pro and Euk,the three photosynthetic picoplankton,to total abundance of photosynthetic picoplankton in the studiy sea area were 50.9%,47.3%and 1.8% respectively.
During summer of 1999,the investigations of abundance and distribution of the three photosynthetic picoplankton-Synechococcus(Syn),Prochlorococcus(Pro) and Picoeukaryotes(Euk) and their environmentally regulating mechanisms were firstly carried out in the northern South China Sea.The results show that the average values of Syn,Pro and Euk abundances are(5.0±7.6)×104 cell/cm3,(4.6±4.2)×104 cell/cm3 and(1.8±1.1)×103 cell/cm3,respectively.The most of high values of Syn population abundance appeared in the estuaries,coast and continental shelf in the sea area to the east of Leizhou Peninsula and Hainan Island,where nutrients were rich,and those appeared in the Beibu Gulf were secondary,while those appeared in continental slope and open sea were one tenths of the above those.Its distribution in water column was mainly above the thermocline and the value below it sharply lowered.The distribution pattern of Pro was markedly different from that of Syn; its abundance of communities at deep layers markedly increased towards outer sea,continental slope and open sea where nutrients were poor; the high values mainly occurred at the bottom of euphotic depth and above the nitrate-cline.The distribution difference of Euk in different sea areas is less than those of Syn and Pro,but it was higher in coast and continental shelf and lower in continental slope and open sea.The high values of Euk in the water column mostly appeared at the bottom of euphotic depth and it made a major contribution to subsurface chlorophyll maximum(SCM).These different distribution patterns depend on environmental regulation and difference of the ecological and physiological adaptation.In addition,in this study,it was discovered that two different populations of Pro at the surface and deep layer existed in the northern South China Sea and often vigorously grew above the nitrate-cline.The contributions of Syn,Pro and Euk,the three photosynthetic picoplankton,to total abundance of photosynthetic picoplankton in the studiy sea area were 50.9%,47.3%and 1.8% respectively.
2003, 25(3): 98-103.
Abstract:
In order to get high EPA content strains from microalgae Ellipsoidion sp.,the algae were treated by herbicide San9785 which was reported as one of the most effective inhibitors of EPA synthesis,especially in the pathway from C18:2ω-6 to C18:3ω-3.Alga cells were spread on the selective plates which contained San 9785 at the concentration of 0.1 mmol/dm3,after radiated by U.V.light,plates were cultured under optimal conditions.One month later,a few microalgal colonies appeared and were transferred into liquid medium individually.Fourteen strains were selected.The growth rate,total lipids content and fatty acids were compared among these strains vs the initial strain.Results show that EPA content of the selected strains increased as well as the ratio of ω-3 to ω-6 polyunsaturated fatty acids.The highest EPA content in strain E-14 is 26.2% in total fatty acids,212% higher than that of the initial strain,suggesting that herbicide San 9785 is an efficitive and practical chemical compound in selection of high EPA content in microalgae Ellipsoidion sp.
In order to get high EPA content strains from microalgae Ellipsoidion sp.,the algae were treated by herbicide San9785 which was reported as one of the most effective inhibitors of EPA synthesis,especially in the pathway from C18:2ω-6 to C18:3ω-3.Alga cells were spread on the selective plates which contained San 9785 at the concentration of 0.1 mmol/dm3,after radiated by U.V.light,plates were cultured under optimal conditions.One month later,a few microalgal colonies appeared and were transferred into liquid medium individually.Fourteen strains were selected.The growth rate,total lipids content and fatty acids were compared among these strains vs the initial strain.Results show that EPA content of the selected strains increased as well as the ratio of ω-3 to ω-6 polyunsaturated fatty acids.The highest EPA content in strain E-14 is 26.2% in total fatty acids,212% higher than that of the initial strain,suggesting that herbicide San 9785 is an efficitive and practical chemical compound in selection of high EPA content in microalgae Ellipsoidion sp.
2003, 25(3): 104-112.
Abstract:
Wave-induced longshore current is an important flow in the nearshore zone.It is very important to understanding and predicting pollutant dispersion under the wave-induced longshore current especially on mild slope.The model simulating pollutant dispersion under waves is proposed.Wave transformation is simulated based on the higher-order approximate parabolic mild-slope equation.Model tests of different incident waves acting on two plane beaches with different slopes are conducted.The numerical results are compared with the experimental data.The result of analysis indicates that the effect of the slope and the greater than others based on the comparison between the incident wave height on the pollutant dispersion is different cases.Pollutant transport is parallel approxirnately to the shoreline on the effect of waves for a mild-slope beach.
Wave-induced longshore current is an important flow in the nearshore zone.It is very important to understanding and predicting pollutant dispersion under the wave-induced longshore current especially on mild slope.The model simulating pollutant dispersion under waves is proposed.Wave transformation is simulated based on the higher-order approximate parabolic mild-slope equation.Model tests of different incident waves acting on two plane beaches with different slopes are conducted.The numerical results are compared with the experimental data.The result of analysis indicates that the effect of the slope and the greater than others based on the comparison between the incident wave height on the pollutant dispersion is different cases.Pollutant transport is parallel approxirnately to the shoreline on the effect of waves for a mild-slope beach.
2003, 25(3): 113-119.
Abstract:
Bed shear stress and friction coefficient have been studied.Based on the critical condition for the initiation of sediment movement by means of a lot of test data for a wave-current coexistent system,formulas of sediment initial movement for both laminar and turbulent have been set up,and wave height and water depth for initiation of sediment movement are given as well.
Bed shear stress and friction coefficient have been studied.Based on the critical condition for the initiation of sediment movement by means of a lot of test data for a wave-current coexistent system,formulas of sediment initial movement for both laminar and turbulent have been set up,and wave height and water depth for initiation of sediment movement are given as well.
2003, 25(3): 120-128.
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2003, 25(3): 129-137.
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2003, 25(3): 138-142.
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2003, 25(3): 143-148.
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