2009 Vol. 31, No. 4
Display Method:
2009, 31(4): 1-12.
Abstract:
A large area hypoxia has been already reported respectively by two interdisciplinary surveys off the Chang jiang Estuary since summer of 1999 and 2006.The hypoxic zone shows distinct year-to-year variations.Observed oceanographic data are first analysized and reveals a big difference for the Chang jiang Diluted Water (CDW) between these two periods,either.These great changes are related to the tremendous reduction of the freshwater discharge and variations of wind fields between these two years.It is also found that the monthly mean intrusion of Kuroshio and its branches has increased in the north of East China Sea(ECS),but decreased in the south of ECS in August 2006 comparing with 1999 on the base of general circulation models.Then,the Regional Ocean Modelling Systems is applied to the ECS to evaluate the contributions and relative importance of impacts from the river discharge,wind forcing and open boundary data.Our simulations reproduce the phenomena that more fresh water extends northeastward in 2006 and forms a negative SSS anomaly to the northeast of the river mouth comparing with 1999,which is consistent with observations.The five group numerical tests suggest that the wind forcing dominates the CDW variations followed by the Kuroshio and its branches.
A large area hypoxia has been already reported respectively by two interdisciplinary surveys off the Chang jiang Estuary since summer of 1999 and 2006.The hypoxic zone shows distinct year-to-year variations.Observed oceanographic data are first analysized and reveals a big difference for the Chang jiang Diluted Water (CDW) between these two periods,either.These great changes are related to the tremendous reduction of the freshwater discharge and variations of wind fields between these two years.It is also found that the monthly mean intrusion of Kuroshio and its branches has increased in the north of East China Sea(ECS),but decreased in the south of ECS in August 2006 comparing with 1999 on the base of general circulation models.Then,the Regional Ocean Modelling Systems is applied to the ECS to evaluate the contributions and relative importance of impacts from the river discharge,wind forcing and open boundary data.Our simulations reproduce the phenomena that more fresh water extends northeastward in 2006 and forms a negative SSS anomaly to the northeast of the river mouth comparing with 1999,which is consistent with observations.The five group numerical tests suggest that the wind forcing dominates the CDW variations followed by the Kuroshio and its branches.
2009, 31(4): 13-21.
Abstract:
A typical double-peaked wave spectrum data,collected at the A merican National Data Buoy 44008 from June,2002.Using WAFO (Wave A nalysis for Fatigue and Oceanog raphy) method,it represents the latest developments.Taking the measured spectrum as the target spectrum,fast and exact simulate stationary Gaussian process through circulate embedding of the Covariance matrix.We find the estimate spectrum is very closing the measured spectrum,and peak frequency almost same.It is a feasible method based on simulated wave surface,which can reflect the wave charact eristics.Using observed wave spectrum data,we analyze sea wave characteristics.We can sea that the theoretical density and the estimated density are in good agreement with the original spectrum.Using Longuet-Higgins(1983) model,we calculate joint pdf of crest height and crest period.We conclude that joint probability density function of crest height and crest period calculated on the transform Gaussian sea is very closing the joint pdf of crest height and crest period derived by the measured data.
A typical double-peaked wave spectrum data,collected at the A merican National Data Buoy 44008 from June,2002.Using WAFO (Wave A nalysis for Fatigue and Oceanog raphy) method,it represents the latest developments.Taking the measured spectrum as the target spectrum,fast and exact simulate stationary Gaussian process through circulate embedding of the Covariance matrix.We find the estimate spectrum is very closing the measured spectrum,and peak frequency almost same.It is a feasible method based on simulated wave surface,which can reflect the wave charact eristics.Using observed wave spectrum data,we analyze sea wave characteristics.We can sea that the theoretical density and the estimated density are in good agreement with the original spectrum.Using Longuet-Higgins(1983) model,we calculate joint pdf of crest height and crest period.We conclude that joint probability density function of crest height and crest period calculated on the transform Gaussian sea is very closing the joint pdf of crest height and crest period derived by the measured data.
2009, 31(4): 22-28.
Abstract:
With 2-D water and substance's long-term transport velocities and their decomposed items,the observation data is analyzed on 1997 flood season in the Changjiang Estuary to give the separation character of suspended sediment,salinity and water's long-term transport.In the turbidity maximum,the average value of the angle between 2-D suspended sediment's long-term transport velocity and 2-D water's longterm transport velocity is 36.0°,and the average discrepant value of their speeds is 29.9%,so there is obvious separation character of suspended sediment and water's long-term transport.In the salinity front,the average value of the angle between 2-D salinityps long-term transport velocity and 2-D water's longterm transport velocity is 43.6°,and the average discrepant value of their speeds is 27.8%,so there is also obvious separation character of salinity and water's long-term transport.
With 2-D water and substance's long-term transport velocities and their decomposed items,the observation data is analyzed on 1997 flood season in the Changjiang Estuary to give the separation character of suspended sediment,salinity and water's long-term transport.In the turbidity maximum,the average value of the angle between 2-D suspended sediment's long-term transport velocity and 2-D water's longterm transport velocity is 36.0°,and the average discrepant value of their speeds is 29.9%,so there is obvious separation character of suspended sediment and water's long-term transport.In the salinity front,the average value of the angle between 2-D salinityps long-term transport velocity and 2-D water's longterm transport velocity is 43.6°,and the average discrepant value of their speeds is 27.8%,so there is also obvious separation character of salinity and water's long-term transport.
2009, 31(4): 29-38.
Abstract:
Based on the lightning data explored by the lightning imaging sensor carrying on TRMM during 1998-2005,combined with the characteristics of tropical cyclone(TC),a method to identify the TC's lightning has established.On this basis,this study separated and obtained the lightning information of TC in the northwest Pacific during 1998-2005,and the characteristics of TC's lightning were analyzed.The results show that(1) in Northwest Pacific,the lightning phenomenon are widespread in the TC's out side rain bands(away from TC center about 130-610 km),inside rain bands(away from TC center about 60-100 km) and near the eye wall(away from TC center about 30-50 km).The TC's lightning can occurred in each month,but more frequent in July to August.(2) Two regions are most prone to the TC's lightning occurred,one is the Taiwan Island-the Taiwan Strait-the coastal areas of Fijian Province,and other is the coastal area of the Zhujiang River Delta.And the vastsea area south-east erly of Japanese Island,while less TC's lightning occurred.(3) In addition,TC's lightning and its intensity have a certain relationship,and based on the relationship between lightning and intensity,the information of lightning occurring in different regions of TC can using to estimate the TC's intensity and its change.The error is closed with the current operational.
Based on the lightning data explored by the lightning imaging sensor carrying on TRMM during 1998-2005,combined with the characteristics of tropical cyclone(TC),a method to identify the TC's lightning has established.On this basis,this study separated and obtained the lightning information of TC in the northwest Pacific during 1998-2005,and the characteristics of TC's lightning were analyzed.The results show that(1) in Northwest Pacific,the lightning phenomenon are widespread in the TC's out side rain bands(away from TC center about 130-610 km),inside rain bands(away from TC center about 60-100 km) and near the eye wall(away from TC center about 30-50 km).The TC's lightning can occurred in each month,but more frequent in July to August.(2) Two regions are most prone to the TC's lightning occurred,one is the Taiwan Island-the Taiwan Strait-the coastal areas of Fijian Province,and other is the coastal area of the Zhujiang River Delta.And the vastsea area south-east erly of Japanese Island,while less TC's lightning occurred.(3) In addition,TC's lightning and its intensity have a certain relationship,and based on the relationship between lightning and intensity,the information of lightning occurring in different regions of TC can using to estimate the TC's intensity and its change.The error is closed with the current operational.
2009, 31(4): 39-50.
Abstract:
In this study,a dense fog event occurred around the coastal of Bohai Sea and Huanghai Sea from 23th to 24th in Dec.2003,is analyzed with observational data and investigated with numerical model.During the fog days,about 100 thousands of square kilometers of area from of fing to inland was covered,partly with visibility less than 200 m,which led to a great influence for the traffic both on sea,land and in air.So almost all available observational data are used to analyze the evolutionary process of the fog from it's formation to dissipation,and it's concluded that it's a typical advection-radiation fog occurred over the sea-land int erface in winter.Then fog event is simulated with the RAMS(Regional At mospheric Modeling System) model.The horzontal visibility distribution of lower at mosphere and the vertical distribution of the cloud mixing ratio are calculated based upon the model out puts,the results indicates that,the shape of fog area,the time when fog formed and dissipated,as well as the thickness of the fog which derived from the simulation agrees with the observation data well.
In this study,a dense fog event occurred around the coastal of Bohai Sea and Huanghai Sea from 23th to 24th in Dec.2003,is analyzed with observational data and investigated with numerical model.During the fog days,about 100 thousands of square kilometers of area from of fing to inland was covered,partly with visibility less than 200 m,which led to a great influence for the traffic both on sea,land and in air.So almost all available observational data are used to analyze the evolutionary process of the fog from it's formation to dissipation,and it's concluded that it's a typical advection-radiation fog occurred over the sea-land int erface in winter.Then fog event is simulated with the RAMS(Regional At mospheric Modeling System) model.The horzontal visibility distribution of lower at mosphere and the vertical distribution of the cloud mixing ratio are calculated based upon the model out puts,the results indicates that,the shape of fog area,the time when fog formed and dissipated,as well as the thickness of the fog which derived from the simulation agrees with the observation data well.
2009, 31(4): 51-57.
Abstract:
Significant wave height(SWH) data from multisatellite altimeters are merged to overcome the problem of insufficient temporal and spatial resolutions of single satellite altimeter data.The fusion data are more accurate for various marine applications.Data fusion methods,such as inverse distance to a power,Kriging and successive correction,are studied in order to find the suitable models and parameters for fusion of SWH data.Using the SWH data from GFO,Jason-1 and Envisat in China's seas and their adjacent seas,some factors which influence the fusion result are analyzed.These factors include different fusion methods,size of filter window and number of satellites.It is shown that(1) after the effective fusion,the distribution of SWH is almost the same as previous statistical analysis;(2) there is little difference among the results by different methods in case the distribution of altimeter data is sparse;(3) the filter window needs to be approx imately 2.5°×2.5°~3°×3° for reasonable results when the temporal resolution is 10 d;(4) at least three satellites are needed.
Significant wave height(SWH) data from multisatellite altimeters are merged to overcome the problem of insufficient temporal and spatial resolutions of single satellite altimeter data.The fusion data are more accurate for various marine applications.Data fusion methods,such as inverse distance to a power,Kriging and successive correction,are studied in order to find the suitable models and parameters for fusion of SWH data.Using the SWH data from GFO,Jason-1 and Envisat in China's seas and their adjacent seas,some factors which influence the fusion result are analyzed.These factors include different fusion methods,size of filter window and number of satellites.It is shown that(1) after the effective fusion,the distribution of SWH is almost the same as previous statistical analysis;(2) there is little difference among the results by different methods in case the distribution of altimeter data is sparse;(3) the filter window needs to be approx imately 2.5°×2.5°~3°×3° for reasonable results when the temporal resolution is 10 d;(4) at least three satellites are needed.
2009, 31(4): 58-68.
Abstract:
The method of estimating anthropogenic and dust aerosol components directly from satellite data is given.The method uses the relationship between the fine mode fraction and the aerosol optical thickness in MODIS data to respectively compute anthropogenic and dust aerosoloptical thicknesses in China for the first time.The result shows that the result obtained with the method is good over the China's seas,and the anthropogenic and dustoptical thicknesses have marked season variation and spatial distribution.In different seasons,the anthropog enic aerosol optical thickness is the largest in spring and summer and it is the smallest in fall and winter.Nevert heless,the dust aerosol optical thickness is the largest in winter and spring and it is the least in summer and fall.They show marked variation along the longitude and obvious variation along the latitude.In the long it udinal direction,the anthropogenic aero so loptical thickness appears to be the maximum value between 30° and 45°N and decreases northwards and southwards,which suggests that human influence is the most serious in this region.Meanwhile,the dustaerosol optical thickness appears to be the maximum value between 33° and 40°N and it is too small at other latitudes,which suggests that the region influenced by dustis limited.In the meridional direction,the anthropogenic aeroso loptical thickness has excellent relationship with the distance far from the coast.The anthropog enic aeroso loptical thickness reaches the maximum value round 120°E which is near the coast and it gradually decreases with the longitude increasing,which is caused by anthropog enic influence.On the other hand,as big particles,dustaerosol is difficult to be transported to remote region,so dustaerosol only affects a small meridional area.The dust aerosol optical thickness appears to be the maximum value between 120° and 123°E and it is too small at other long itudes.
The method of estimating anthropogenic and dust aerosol components directly from satellite data is given.The method uses the relationship between the fine mode fraction and the aerosol optical thickness in MODIS data to respectively compute anthropogenic and dust aerosoloptical thicknesses in China for the first time.The result shows that the result obtained with the method is good over the China's seas,and the anthropogenic and dustoptical thicknesses have marked season variation and spatial distribution.In different seasons,the anthropog enic aerosol optical thickness is the largest in spring and summer and it is the smallest in fall and winter.Nevert heless,the dust aerosol optical thickness is the largest in winter and spring and it is the least in summer and fall.They show marked variation along the longitude and obvious variation along the latitude.In the long it udinal direction,the anthropogenic aero so loptical thickness appears to be the maximum value between 30° and 45°N and decreases northwards and southwards,which suggests that human influence is the most serious in this region.Meanwhile,the dustaerosol optical thickness appears to be the maximum value between 33° and 40°N and it is too small at other latitudes,which suggests that the region influenced by dustis limited.In the meridional direction,the anthropogenic aeroso loptical thickness has excellent relationship with the distance far from the coast.The anthropog enic aeroso loptical thickness reaches the maximum value round 120°E which is near the coast and it gradually decreases with the longitude increasing,which is caused by anthropog enic influence.On the other hand,as big particles,dustaerosol is difficult to be transported to remote region,so dustaerosol only affects a small meridional area.The dust aerosol optical thickness appears to be the maximum value between 120° and 123°E and it is too small at other long itudes.
2009, 31(4): 69-77.
Abstract:
Based on the data of dissolved oxygen(DO) collected from Southern Huanghai Sea investigation during July,2006,this paper focused on an analysis of the maximum value phenomenon of DO vertical distribution in the Cold Water Mass of the western Southern Huanghai Sea,and the relationship of DO concent ration between the main environmental factors was also studied.The results showed that the maximum value phenomenon was the dominant feature of DO vertical distribution in the Cold Water Mass of the western Southern Huanghai Sea,which was also accom panied with SCM;The depth and value of the DO maximum had obvious regional differences;The temperature and salinity was the main controlling factors of DO in the water volume above DO maximum layer;After the form ation of the therm ocline with a certain streng th,the DO maximum layer appeared in the vicinity of the lower bound of the therm ocline,DO maximun value was contr olled by the thickness of the thermo cline and the biochemical activity,besides,the study also found that the thickness of the therm ocline layer and the DO maximum value were positively correlated;DO concentration was low in bottom water,which was caused by the decomposition of organic matter.Simult aneously,successfully giving the explaination that the location was not match and the value was not related of the DO maximum layer and the subsur face chlor ophyll maximum layer,in addition,a perspective named "DO net cumulative effect" was put forward,not only the formation mechanism of DO maximum value was analyzed from time scale and dynamic angle,but also the constitution of DO value or source in the DO maximum layer was discussed theoretically,and pointing that since the beginning of DO maximum layer to the time of observation,the biochemical activity(or Ch-latotal output) in the water volume under the DO maximum layer and in the euphotic zone was closely related to the DO maximum value.Overall,The water column stratification and biochemistry significantly affected the vertical distribution of DO in the Cold Water Mass of the western Southern Huang hai Sea in summer.
Based on the data of dissolved oxygen(DO) collected from Southern Huanghai Sea investigation during July,2006,this paper focused on an analysis of the maximum value phenomenon of DO vertical distribution in the Cold Water Mass of the western Southern Huanghai Sea,and the relationship of DO concent ration between the main environmental factors was also studied.The results showed that the maximum value phenomenon was the dominant feature of DO vertical distribution in the Cold Water Mass of the western Southern Huanghai Sea,which was also accom panied with SCM;The depth and value of the DO maximum had obvious regional differences;The temperature and salinity was the main controlling factors of DO in the water volume above DO maximum layer;After the form ation of the therm ocline with a certain streng th,the DO maximum layer appeared in the vicinity of the lower bound of the therm ocline,DO maximun value was contr olled by the thickness of the thermo cline and the biochemical activity,besides,the study also found that the thickness of the therm ocline layer and the DO maximum value were positively correlated;DO concentration was low in bottom water,which was caused by the decomposition of organic matter.Simult aneously,successfully giving the explaination that the location was not match and the value was not related of the DO maximum layer and the subsur face chlor ophyll maximum layer,in addition,a perspective named "DO net cumulative effect" was put forward,not only the formation mechanism of DO maximum value was analyzed from time scale and dynamic angle,but also the constitution of DO value or source in the DO maximum layer was discussed theoretically,and pointing that since the beginning of DO maximum layer to the time of observation,the biochemical activity(or Ch-latotal output) in the water volume under the DO maximum layer and in the euphotic zone was closely related to the DO maximum value.Overall,The water column stratification and biochemistry significantly affected the vertical distribution of DO in the Cold Water Mass of the western Southern Huang hai Sea in summer.
2009, 31(4): 78-86.
Abstract:
The diversities of genes specific for dissimilatory sulfite reductase(DSR) and methyl coenzyme Mreductase MCR in metagenomic DNA of deep sediment of the West Pacific warm pool were studied by PCR RFLP using primers specific for dsrAB and mcr A,respectively.The results showed that the dsrA B in the sample were come from 6 genus of δ-Proteobacteria,mainly Desulfovibrio and Desulf obacter.All of the mcrA in the sample were come from archaeal methanogens,mainly Met hanomicrobia.These genes were tend to clustered within independent clades on phylogenetic tree respectively.Fur thermore,many dsr AB and mcr A genes showed high similarity to those from unknown or new species.These results indicated that the microbial metabolisms,which may include some new metabolic pathway,were active in the Sand CH4 cycles in deep sediment of "warm pool".
The diversities of genes specific for dissimilatory sulfite reductase(DSR) and methyl coenzyme Mreductase MCR in metagenomic DNA of deep sediment of the West Pacific warm pool were studied by PCR RFLP using primers specific for dsrAB and mcr A,respectively.The results showed that the dsrA B in the sample were come from 6 genus of δ-Proteobacteria,mainly Desulfovibrio and Desulf obacter.All of the mcrA in the sample were come from archaeal methanogens,mainly Met hanomicrobia.These genes were tend to clustered within independent clades on phylogenetic tree respectively.Fur thermore,many dsr AB and mcr A genes showed high similarity to those from unknown or new species.These results indicated that the microbial metabolisms,which may include some new metabolic pathway,were active in the Sand CH4 cycles in deep sediment of "warm pool".
2009, 31(4): 87-92.
Abstract:
Geomagnetic secular variation and short-term disturbance need to be reliably separated from the geomagnetic diurnal observation.In this wise,it will provide a definite datum for correction to geomagnetic data,and guarantee accuracy of data fusion for different cruises.In the case of good coverage of the geomagnetic diurnal observatory for marine geomagnetic survey,for the secular variation at the survey area to be corrected by that at the geomagnetic diurnal observatory,the geomagnetic normal field fixed at anuni form time would be adopted to become a datum for geomagnetic anomalies at both the geomagnetic diurnal observatory and the survey area.Otherwise,for the secular variation at the survey area to be corrected by the geomagnetic normal field,the geom agnetic normal field changing with time would be adopted to become a datum for geomagnetic anomaly at both the geomagnetic diurnal observatory and the surveyarea.Thus,the base value for geo magnetic diurnal variation correction maybe explicitly defined to be a sum of the geomagnetic normal field and geomagnetic anomaly.Geomagnetic anomaly at the diurnal observatory can be obtained to average the deviation of the geomagnetic total field obser vation from the geomag netic normal field at some way.Geomagnetic disturbance may be at tentively separated to maintain continuous transition to the disturbance beginning and end.The comprehensive model can be adopted to unitedly perform corrections for diurnal variation,normal field and its secular variation,which will preferably solve problems arisen in diurnal variation correction.
Geomagnetic secular variation and short-term disturbance need to be reliably separated from the geomagnetic diurnal observation.In this wise,it will provide a definite datum for correction to geomagnetic data,and guarantee accuracy of data fusion for different cruises.In the case of good coverage of the geomagnetic diurnal observatory for marine geomagnetic survey,for the secular variation at the survey area to be corrected by that at the geomagnetic diurnal observatory,the geomagnetic normal field fixed at anuni form time would be adopted to become a datum for geomagnetic anomalies at both the geomagnetic diurnal observatory and the survey area.Otherwise,for the secular variation at the survey area to be corrected by the geomagnetic normal field,the geom agnetic normal field changing with time would be adopted to become a datum for geomagnetic anomaly at both the geomagnetic diurnal observatory and the surveyarea.Thus,the base value for geo magnetic diurnal variation correction maybe explicitly defined to be a sum of the geomagnetic normal field and geomagnetic anomaly.Geomagnetic anomaly at the diurnal observatory can be obtained to average the deviation of the geomagnetic total field obser vation from the geomag netic normal field at some way.Geomagnetic disturbance may be at tentively separated to maintain continuous transition to the disturbance beginning and end.The comprehensive model can be adopted to unitedly perform corrections for diurnal variation,normal field and its secular variation,which will preferably solve problems arisen in diurnal variation correction.
2009, 31(4): 93-102.
Abstract:
E-W trending Zhenbei-Huangyan Seamount at about 15°N in the South China Sea Basin was considered to be ancient spreading axis.Two samples(9DG,9DG-2) were dredged from Huangyan Seamount in 2005 and detail petrological,geochemical and chronological analyses were conducted.The samples are characterized by high contents of silica,aluminium,potassium,sodium and the low content of titanium,with content of 60.3% and 63.6% for SiO2,17.56% and 17.55% for Al2O3,0.48% and 0.31% for TiO2,and the alkalinity ratios and 3.88 and 3.62.Based on petrological and petrochemical classification,the two samples are trachyte and belong to the alkaline series.Their REE and trace element distribution patterns are similar to oceanic island basalt(OIB),but with higher LREE content and lower contents of europium,srtontium,phosphorus and titanium.Strontium-neodymium-leadisotope analysis shows that the cotentratioes 87Sr/86Sr=0.704183,206Pb/204MPb=18.68668,207Pb/204Pb=39.00261,and 143Nd/144 Nd=0.512827,respectlvely,which indicates that magm as were derived from the mixture of DM (depleted mantle) and EM Ⅱ(enriched mant leⅡ).According to potassiumarg on dating,the samples were formed (7.77±0.49) Ma ago,a bit later than the basalts[(9.1±1.29)~(10.0±1.80) Ma]from Zhenbei Seamount.Compared with geochemical and isotopic features of the basalts from Zhenbei Seamount,it is concluded that trachyte from Huangyan Seamount was originated from the same mantle source of basalts from Zhenbei Seamount,but formed at the different evolution stages.It is suggested that during the late Miocene,there was mantle plume activity probably or athenosphere mantle upwelling along Zhengbei-Huang yan Seamount.
E-W trending Zhenbei-Huangyan Seamount at about 15°N in the South China Sea Basin was considered to be ancient spreading axis.Two samples(9DG,9DG-2) were dredged from Huangyan Seamount in 2005 and detail petrological,geochemical and chronological analyses were conducted.The samples are characterized by high contents of silica,aluminium,potassium,sodium and the low content of titanium,with content of 60.3% and 63.6% for SiO2,17.56% and 17.55% for Al2O3,0.48% and 0.31% for TiO2,and the alkalinity ratios and 3.88 and 3.62.Based on petrological and petrochemical classification,the two samples are trachyte and belong to the alkaline series.Their REE and trace element distribution patterns are similar to oceanic island basalt(OIB),but with higher LREE content and lower contents of europium,srtontium,phosphorus and titanium.Strontium-neodymium-leadisotope analysis shows that the cotentratioes 87Sr/86Sr=0.704183,206Pb/204MPb=18.68668,207Pb/204Pb=39.00261,and 143Nd/144 Nd=0.512827,respectlvely,which indicates that magm as were derived from the mixture of DM (depleted mantle) and EM Ⅱ(enriched mant leⅡ).According to potassiumarg on dating,the samples were formed (7.77±0.49) Ma ago,a bit later than the basalts[(9.1±1.29)~(10.0±1.80) Ma]from Zhenbei Seamount.Compared with geochemical and isotopic features of the basalts from Zhenbei Seamount,it is concluded that trachyte from Huangyan Seamount was originated from the same mantle source of basalts from Zhenbei Seamount,but formed at the different evolution stages.It is suggested that during the late Miocene,there was mantle plume activity probably or athenosphere mantle upwelling along Zhengbei-Huang yan Seamount.
2009, 31(4): 103-111.
Abstract:
To some extent,scouring and silting evolution of tidal flat may reflect the relationship and interaction between dynamic effect and geomorphologic characteristics.On the basis of Shanghai coastal zone investigation project,acontinuous observation was made at the intertidal zone of three sections on Nanhui Spit from June 2006 to June 2007,in order to research the properties of short-term scouring and silting changes as well as its influencing factors.The results show that(1) recently,the tidal flat of Nanhui Spit mostly has a scouring posture,and seasonal difference of flat variation in the year is relatively obvious;affected by it slocation,the respective section shows different developing properties,for example,scouring and silting changes of section one are the most obvious of all,the amount of which is both above 10cm; (2) acted by waves and tidal current,the surface sediment of this zone is easy to be stirred,and the existence of sediment circulation system is favorable for the suspended sediment to settle in shallow water area,which becomes the sediment source of tidal flat;(3) influenced by the storm surge caused by typhoon "Bilis",drastic scouring as well as silting happened in this zone.All of these have proved that the scouring and silting changes of tidal flat were affected by several kinds of dynamic conditions.
To some extent,scouring and silting evolution of tidal flat may reflect the relationship and interaction between dynamic effect and geomorphologic characteristics.On the basis of Shanghai coastal zone investigation project,acontinuous observation was made at the intertidal zone of three sections on Nanhui Spit from June 2006 to June 2007,in order to research the properties of short-term scouring and silting changes as well as its influencing factors.The results show that(1) recently,the tidal flat of Nanhui Spit mostly has a scouring posture,and seasonal difference of flat variation in the year is relatively obvious;affected by it slocation,the respective section shows different developing properties,for example,scouring and silting changes of section one are the most obvious of all,the amount of which is both above 10cm; (2) acted by waves and tidal current,the surface sediment of this zone is easy to be stirred,and the existence of sediment circulation system is favorable for the suspended sediment to settle in shallow water area,which becomes the sediment source of tidal flat;(3) influenced by the storm surge caused by typhoon "Bilis",drastic scouring as well as silting happened in this zone.All of these have proved that the scouring and silting changes of tidal flat were affected by several kinds of dynamic conditions.
2009, 31(4): 112-119.
Abstract:
In order to study the silty sediment erosion variety under the dynamic circulative loading,a series of indoor tests were processed.The rem oulded soil samples were prepared by the vacuum preloading.The dynamic loading,in different magnitudes and acting times,was exerted on the samples using the dynamic triaxial device.When the dynamic loading ended,the undrained shear strength and residual strength were continuo usly mensurated in the static test.The parallel samples were directly taken out from the dynamic triaxial device after dynamic loading for the penetration strength tested by the electronic digital display micropenet rometer.Then the scour experiments were carried out to mensurate the threshold velocity and the erosion rate.What is more,critical shear stress was calculated by the empirical equation.The results show that both an tierosio and strength of the silty soil are decreased after the dynamic loading action,and it is also found that the silty erosibility parameters of the threshold velocity and the erosion rate have a significant linear correlation with the dynamic loading conditions including the loading magnitude and acting times,and it is the same with the silty sediment strength parameters of the undrained shear strength,the residual strength and the penetration strength.
In order to study the silty sediment erosion variety under the dynamic circulative loading,a series of indoor tests were processed.The rem oulded soil samples were prepared by the vacuum preloading.The dynamic loading,in different magnitudes and acting times,was exerted on the samples using the dynamic triaxial device.When the dynamic loading ended,the undrained shear strength and residual strength were continuo usly mensurated in the static test.The parallel samples were directly taken out from the dynamic triaxial device after dynamic loading for the penetration strength tested by the electronic digital display micropenet rometer.Then the scour experiments were carried out to mensurate the threshold velocity and the erosion rate.What is more,critical shear stress was calculated by the empirical equation.The results show that both an tierosio and strength of the silty soil are decreased after the dynamic loading action,and it is also found that the silty erosibility parameters of the threshold velocity and the erosion rate have a significant linear correlation with the dynamic loading conditions including the loading magnitude and acting times,and it is the same with the silty sediment strength parameters of the undrained shear strength,the residual strength and the penetration strength.
2009, 31(4): 120-127.
Abstract:
Spatial distribution characteristics of grain-size being "fine in nearshore,but coarse in offshore" have been found along the Lianyungang coastal zone.For discussing this distribution,108 samples collected from this region were analyzed with the end-member analysis model and the multivariables analysis method.Results show that the sediment along the Lianyung ang coastal zone can be divided into three grain-size groups with certain dynamic significance,corresponding to the sediment of prodelta,the dynamo-reworking sediment,and the sediment of in situ deposited on sedentary beach,which deposit under different environments,i.e.,depositional environments of tidal current,wave and both of them.
Spatial distribution characteristics of grain-size being "fine in nearshore,but coarse in offshore" have been found along the Lianyungang coastal zone.For discussing this distribution,108 samples collected from this region were analyzed with the end-member analysis model and the multivariables analysis method.Results show that the sediment along the Lianyung ang coastal zone can be divided into three grain-size groups with certain dynamic significance,corresponding to the sediment of prodelta,the dynamo-reworking sediment,and the sediment of in situ deposited on sedentary beach,which deposit under different environments,i.e.,depositional environments of tidal current,wave and both of them.
2009, 31(4): 128-134.
Abstract:
Inter-simple sequence repeat(ISSR) was employed to detect the genetic diversity in three wild and one farmed stocks of stone flounder(Kareius bicoloratus).Of the 60 primers screened,eight were selected for their reproducibility,reliability and high poly morphism.Atotal of 183 loci were am plified from the investigated individuals of the 4 stocks.The percentage of polymorphic lociranged from 48.1% to 50.8% and the Shannon diversity indices were from 15.68 to 18.53 within the 4 stocks.The genetic similarities were 0.9053~0.9189 within stocks,and the genetic distances were 0.0055~0.0173 among stocks.Compared with other fish species,stocks of K.bicoloratus presented relatively low genetic diversity.The phylogenetic tree constructed through UPGMA method indicated that WH and LZ stocks were first clustered into one clade for the lowest genetic distance,and then clustered with YZ stock,at last with QD stock.The analysis of stock pairwise gene differentiation showed that 96.47% of the genetic variation was distributed within stocks,while only 3.53% among stocks,indicating that the genetic structures of different stocks were absolutely similar.
Inter-simple sequence repeat(ISSR) was employed to detect the genetic diversity in three wild and one farmed stocks of stone flounder(Kareius bicoloratus).Of the 60 primers screened,eight were selected for their reproducibility,reliability and high poly morphism.Atotal of 183 loci were am plified from the investigated individuals of the 4 stocks.The percentage of polymorphic lociranged from 48.1% to 50.8% and the Shannon diversity indices were from 15.68 to 18.53 within the 4 stocks.The genetic similarities were 0.9053~0.9189 within stocks,and the genetic distances were 0.0055~0.0173 among stocks.Compared with other fish species,stocks of K.bicoloratus presented relatively low genetic diversity.The phylogenetic tree constructed through UPGMA method indicated that WH and LZ stocks were first clustered into one clade for the lowest genetic distance,and then clustered with YZ stock,at last with QD stock.The analysis of stock pairwise gene differentiation showed that 96.47% of the genetic variation was distributed within stocks,while only 3.53% among stocks,indicating that the genetic structures of different stocks were absolutely similar.
2009, 31(4): 135-140.
Abstract:
The contents of N,P,heavy metal in the Jiaozhou Bay coast of Licun River and Haibo Riverestuaries sediment were measured using Shilaoren as control.Statistical analysis of contamination status and biodiversity of Deuteromycetes in these habitats were conducted.The results show that the heavy metal indexes of Licun River and Haibo River estuaries were 3.64 and 1.75,23.59 times and 10.58 times compared with control respectively.As for total N,P,the Licun Estuary was 1.73 and 1.33 higher than control and the Haibo Estuaries was 1.44 and 1.98 higher than control.Licun Estuary was more seriously polluted.The amount of culturable Deuteromy cetes decreased as the increase of pollution degree and this relevance was more relied on heavy metal index.Within a certain range,the biodiversity index of Deuteromy cetes increased as the increase of heavy metal index,however,it decreased rapidly when heavy metal in dexachieved certain value.The change of total N,Pcould only exert effect on some Deuteromy cetes populations and had little effect on the amount and biodiversity of the integrity Deuteromycetes.
The contents of N,P,heavy metal in the Jiaozhou Bay coast of Licun River and Haibo Riverestuaries sediment were measured using Shilaoren as control.Statistical analysis of contamination status and biodiversity of Deuteromycetes in these habitats were conducted.The results show that the heavy metal indexes of Licun River and Haibo River estuaries were 3.64 and 1.75,23.59 times and 10.58 times compared with control respectively.As for total N,P,the Licun Estuary was 1.73 and 1.33 higher than control and the Haibo Estuaries was 1.44 and 1.98 higher than control.Licun Estuary was more seriously polluted.The amount of culturable Deuteromy cetes decreased as the increase of pollution degree and this relevance was more relied on heavy metal index.Within a certain range,the biodiversity index of Deuteromy cetes increased as the increase of heavy metal index,however,it decreased rapidly when heavy metal in dexachieved certain value.The change of total N,Pcould only exert effect on some Deuteromy cetes populations and had little effect on the amount and biodiversity of the integrity Deuteromycetes.
2009, 31(4): 141-148.
Abstract:
Coral bleaching was one of the most important causes of decline of coral reef ecosystem globally.Field investigations on mass bleaching events have showed variation in bleaching susceptibility among different coral species.Comparisons were made for thermal stress suscepbility of symbiotic algae in two scleractinian corals Acropora millepora and Galaxea fascicularis.Present study demonstrated that the symbiotic algae in the two scleract inian corals belonged to two clades of the genus Symbiodinium.The scleractinian coral Galaxea fascicularis harbored Symbiodinium clade D,while the scleractinian coral A cropora millepora harbored Symbiodinium subclade C1.No marked reduction in phot ochemical efficiency(Fv/Fm) of photosystem Ⅱ(PSⅡ) was observed in two clades of the genus Symbiodinium while exposed to 30℃ condition However,when it clined to 34℃ significant reduction in photochemical efficiency(Fv/Fm) of PSⅡ occurred in two clades of the genus Symbiodinium.This research indicated that the differences in as sociation with distinct symbiotic algaes were the major causes behind coral bleaching sensit ivities for the two scleractinian coral A cropora millepora and Galaxea fascicularis.The scleractinian coral A cropora millepora associating with Symbiodinium subclade C1 is more sensitive to coral bleaching compared with coral Galaxea fascicularis associating with Sym biodinium Dunder high thermal stress.
Coral bleaching was one of the most important causes of decline of coral reef ecosystem globally.Field investigations on mass bleaching events have showed variation in bleaching susceptibility among different coral species.Comparisons were made for thermal stress suscepbility of symbiotic algae in two scleractinian corals Acropora millepora and Galaxea fascicularis.Present study demonstrated that the symbiotic algae in the two scleract inian corals belonged to two clades of the genus Symbiodinium.The scleractinian coral Galaxea fascicularis harbored Symbiodinium clade D,while the scleractinian coral A cropora millepora harbored Symbiodinium subclade C1.No marked reduction in phot ochemical efficiency(Fv/Fm) of photosystem Ⅱ(PSⅡ) was observed in two clades of the genus Symbiodinium while exposed to 30℃ condition However,when it clined to 34℃ significant reduction in photochemical efficiency(Fv/Fm) of PSⅡ occurred in two clades of the genus Symbiodinium.This research indicated that the differences in as sociation with distinct symbiotic algaes were the major causes behind coral bleaching sensit ivities for the two scleractinian coral A cropora millepora and Galaxea fascicularis.The scleractinian coral A cropora millepora associating with Symbiodinium subclade C1 is more sensitive to coral bleaching compared with coral Galaxea fascicularis associating with Sym biodinium Dunder high thermal stress.
2009, 31(4): 149-158.
Abstract:
The phytoplankton and Harmful Algal Bloom(HAB) and the current environmental quality of water and sediment in sea area near Qiqu Archipelago were investigated in February,April and July,2001.Phytoplankton cell density and environment quality standard index were adopted to assess environmental quality conditions in the sea area.90 that species belonged to 45 genera were identified in total,among which,80 algal rest stages and cysts and 31 HAB species.The mean algal rest stages and cysts in deposit was 68 cells/g(12~612 cells/g).The mean phytoplankt on density in Summer,and Autumn and Spring (4.25×104 cells/dm3,and 3.85×104cells/dm3 and 2.66×104个/dm3) were more than that in Winter(5.2×103cells/dm3).The main HAB species were Skeletonema costatum,Prorocentr umdent atum(P.onghaiense),Alexandrium catenella,Alexandrium tamarense,Alexandrium monilatum,Pseudo-nitzschia pungens,Noctiluca scintillans,Dinophysis caudate and Eutreptiellagy mnasticaetc.The results showed that COD,PO4-P,TIN severely exceed the standard.The water environmental quality was in severe eutrophication state.
2009, 31(4): 159-166.
Abstract:
The interaction of diagonal waves with perforated wall breakwater partially filled with rock fill is studied using t he linear po tential theory.By means of the matched eigenfunction expansion method,an analy tical method is presented to calculate the reflection coefficient and the wave force coefficient of the breakwater.The calculated results of the reflection coefficient for limiting cases are the same to the existing results.The main influencing factors of the reflection coefficient and the wave force coefficient are analyzed by numerical examples.With the increasing of thickness of rock fill,the wave force coefficient on the perforated wall generally decreases,while the reflection coefficient increases.With the increasing of the in cident angle of the wave,the reflection coefficient of the breakwater first decreases,reaches its minimum,and then increases monotonously.
The interaction of diagonal waves with perforated wall breakwater partially filled with rock fill is studied using t he linear po tential theory.By means of the matched eigenfunction expansion method,an analy tical method is presented to calculate the reflection coefficient and the wave force coefficient of the breakwater.The calculated results of the reflection coefficient for limiting cases are the same to the existing results.The main influencing factors of the reflection coefficient and the wave force coefficient are analyzed by numerical examples.With the increasing of thickness of rock fill,the wave force coefficient on the perforated wall generally decreases,while the reflection coefficient increases.With the increasing of the in cident angle of the wave,the reflection coefficient of the breakwater first decreases,reaches its minimum,and then increases monotonously.
2009, 31(4): 167-175.
Abstract:
Email alert
RSS