1999 Vol. 18, No. 3
Display Method:
1999, (3): 293-310.
Abstract:
By using part of CTD data collected at 2°S,155°E during the fall cruise of TOGA project in 1992,the multifractal characters of temperature finestructures are investigated.The absolute temperature gradients are supposed to be multifractal and their moments are computed by conventional box-counting method.It is found that these momeets have power dependence on the box size.This power dependence has two different scaling regimes,called S regime and I-regime respectively,with different scaling exponents.This is consistent with the combined effects of internal waves and mixing.Accordingly,the generalized fractal dimensions (Renyi dimension) of temperature gradients are derived.A nonlinear curve of the scaling exponents suggest a possible multifractal apptnach of the temperature shear.In fact,both regimes can be approximated by Besicovitch-Cantor model,respectively,by suitably chosen model parameters.A phenomenological model is developed on the basis of this two-regime mechanism.The model is compared with field data and Qood agreement is achieved.
By using part of CTD data collected at 2°S,155°E during the fall cruise of TOGA project in 1992,the multifractal characters of temperature finestructures are investigated.The absolute temperature gradients are supposed to be multifractal and their moments are computed by conventional box-counting method.It is found that these momeets have power dependence on the box size.This power dependence has two different scaling regimes,called S regime and I-regime respectively,with different scaling exponents.This is consistent with the combined effects of internal waves and mixing.Accordingly,the generalized fractal dimensions (Renyi dimension) of temperature gradients are derived.A nonlinear curve of the scaling exponents suggest a possible multifractal apptnach of the temperature shear.In fact,both regimes can be approximated by Besicovitch-Cantor model,respectively,by suitably chosen model parameters.A phenomenological model is developed on the basis of this two-regime mechanism.The model is compared with field data and Qood agreement is achieved.
1999, (3): 311-324.
Abstract:
Direct current measurements at the mooring station M southwest of Yonakuni-jima are carried out from May 18 to June 1,1996.The observed Kuroshio Current at 290 and 594 m depths of the mooring station M is quite steady during the period of observation.The rotary spectral estimates of the current data by the maximum entropy method show that there are prominent diurnal and semidiumal spectral peaks.The semidiumal tide is predominant at 290 m depth while there is the current fluctuation with the inertial period except for the tidal oscillation at 594 m depth.There are also peaks at the period of 4-7 d.There is a significant coherence between two time series of currents at 290 and 594 m depths in the period range of 3-5 d.The Japan Meteorological Agency (JMA) wind data during the same period as the oceanic measurement are used in comparison with the current meter data.Rotary spectral estimates for the wind data show significant peaks at the period of 3-5 d.It is concluded from the cross spectra between the wind and the current that the current fluctuation of 3-5 d period at 290 m depth response to the wind fluctuation of the same periods with time lags smaller than 1 d.
Direct current measurements at the mooring station M southwest of Yonakuni-jima are carried out from May 18 to June 1,1996.The observed Kuroshio Current at 290 and 594 m depths of the mooring station M is quite steady during the period of observation.The rotary spectral estimates of the current data by the maximum entropy method show that there are prominent diurnal and semidiumal spectral peaks.The semidiumal tide is predominant at 290 m depth while there is the current fluctuation with the inertial period except for the tidal oscillation at 594 m depth.There are also peaks at the period of 4-7 d.There is a significant coherence between two time series of currents at 290 and 594 m depths in the period range of 3-5 d.The Japan Meteorological Agency (JMA) wind data during the same period as the oceanic measurement are used in comparison with the current meter data.Rotary spectral estimates for the wind data show significant peaks at the period of 3-5 d.It is concluded from the cross spectra between the wind and the current that the current fluctuation of 3-5 d period at 290 m depth response to the wind fluctuation of the same periods with time lags smaller than 1 d.
1999, (3): 325-335.
Abstract:
A grey model with periodic term for sea-level analysis is presented.The present model keeps some advanloges of the GM (1,1)model,which well reflects the trend of sea-level changes and gives out the change rate as well as the acceleration of sea level conveniently.In addition,the present model can reproduce the periodic phenomena of sea level,hence,it overcomes the shortcatnings of the GM(1,1) model that is unsuitable for forecasting monthly mean.level with apparent periodicity,and its prediction accuracy is improved.The present model is used to analyse Guangxi coast.level,the rasults show that the rise rates of relative,level at 13eihei,Weizhou and Bailongwei are 1.67,2.51 and 0.89 mm/a respectively,the relative sea level at Shitoubu has a falling trend with a rate of 0.5-1.0 mm/a,the rise rate of eustatic sea level along the Guangxi coast is 2.0 mm/a.In comparison with the model with a linear trend term plus a periodic term,the simulation accuracies of both models are about the same.
A grey model with periodic term for sea-level analysis is presented.The present model keeps some advanloges of the GM (1,1)model,which well reflects the trend of sea-level changes and gives out the change rate as well as the acceleration of sea level conveniently.In addition,the present model can reproduce the periodic phenomena of sea level,hence,it overcomes the shortcatnings of the GM(1,1) model that is unsuitable for forecasting monthly mean.level with apparent periodicity,and its prediction accuracy is improved.The present model is used to analyse Guangxi coast.level,the rasults show that the rise rates of relative,level at 13eihei,Weizhou and Bailongwei are 1.67,2.51 and 0.89 mm/a respectively,the relative sea level at Shitoubu has a falling trend with a rate of 0.5-1.0 mm/a,the rise rate of eustatic sea level along the Guangxi coast is 2.0 mm/a.In comparison with the model with a linear trend term plus a periodic term,the simulation accuracies of both models are about the same.
1999, (3): 337-353.
Abstract:
Monthly changes of sea level recorded on the seas adjacent to Korea (the Huanghai Sea,the East China Sea and the East Sea) are investigated.The major in(fuences on the spatial and temporal variation of mean sea level are quantitatively identified.A set of modes of monthly air pressure variation over the Huanghai Sea,East China Sea and East Sea for the period of 1978-1992 is obtained.Each monthly air pressure distribution can be precisely defined by linear c+nbination of these modes.Hence,the set of air pressure series can be replaced by a set of time varying coefficiertts,where each coefficient describes the contribution of a particular mode to a given air pressure distribution.A selected set of the modal coefficients is then added to a multiple regression model,consisting of a trend,monthly wind stress and tidal termt,in an attempt to represent the effect of meteorological variations on monthly mean sea level on the seas adjacent to Korea.It is found that although the model may account for over 90% of the observed mean sea level variance,there still remains a high correlation between the residuals,hence identifying a regional variation for further study.
Monthly changes of sea level recorded on the seas adjacent to Korea (the Huanghai Sea,the East China Sea and the East Sea) are investigated.The major in(fuences on the spatial and temporal variation of mean sea level are quantitatively identified.A set of modes of monthly air pressure variation over the Huanghai Sea,East China Sea and East Sea for the period of 1978-1992 is obtained.Each monthly air pressure distribution can be precisely defined by linear c+nbination of these modes.Hence,the set of air pressure series can be replaced by a set of time varying coefficiertts,where each coefficient describes the contribution of a particular mode to a given air pressure distribution.A selected set of the modal coefficients is then added to a multiple regression model,consisting of a trend,monthly wind stress and tidal termt,in an attempt to represent the effect of meteorological variations on monthly mean sea level on the seas adjacent to Korea.It is found that although the model may account for over 90% of the observed mean sea level variance,there still remains a high correlation between the residuals,hence identifying a regional variation for further study.
1999, (3): 355-373.
Abstract:
The Huanghai (Yellow) Sea circulations suggested in the past were constructed mostly based on hydrographic data or simple numerical models,and were not rigorously compared with direct current measurements.Our present understanding of the Huanghai Sea circulation is still very poor and superficial.To evaluate our present knowledge about the circulation and to sketch a more realistic circulation pattern,the previous studies on the circulation are briefly reviewed and directly measured current data collected in the past are revisited.The Huanghai Sea Watm Current and the northeastward extension in summer of the Changjiang diluted water are paid more attention to,which are the major currents of the basic circulation,and then attempted to sketch the Huanghai Sea circulation by synthesizing hydrography and current data.The Huanghai Sea circulation is not considered to be persistent since the thin water column,less than 100 m,responds quickly and sensitively to external driving forces.Directly measured current data show that saline water originating from the Kuroshio water turns clockwise around Cheju-do throughout the year and eventually joins the Tsushima Warm Current at the western channel of the Korea Strait.This clockwise curzent is called the Cheju Warm Curzent.The curzent data do not support the persistent existence of the Huanghai Sea Warm Curzent,which has been believed to supply heat and salt to the Huanghai Sea throughout the year.However,a northward flow is generated intermittently during the weakening phase of mld air outbreaks in winter.The northeast extension of the Changjiang diluted water in summer is evidenced by satellite-tracked surface drifters.
The Huanghai (Yellow) Sea circulations suggested in the past were constructed mostly based on hydrographic data or simple numerical models,and were not rigorously compared with direct current measurements.Our present understanding of the Huanghai Sea circulation is still very poor and superficial.To evaluate our present knowledge about the circulation and to sketch a more realistic circulation pattern,the previous studies on the circulation are briefly reviewed and directly measured current data collected in the past are revisited.The Huanghai Sea Watm Current and the northeastward extension in summer of the Changjiang diluted water are paid more attention to,which are the major currents of the basic circulation,and then attempted to sketch the Huanghai Sea circulation by synthesizing hydrography and current data.The Huanghai Sea circulation is not considered to be persistent since the thin water column,less than 100 m,responds quickly and sensitively to external driving forces.Directly measured current data show that saline water originating from the Kuroshio water turns clockwise around Cheju-do throughout the year and eventually joins the Tsushima Warm Current at the western channel of the Korea Strait.This clockwise curzent is called the Cheju Warm Curzent.The curzent data do not support the persistent existence of the Huanghai Sea Warm Curzent,which has been believed to supply heat and salt to the Huanghai Sea throughout the year.However,a northward flow is generated intermittently during the weakening phase of mld air outbreaks in winter.The northeast extension of the Changjiang diluted water in summer is evidenced by satellite-tracked surface drifters.
1999, (3): 375-388.
Abstract:
The seasonal circulation in the southeastern Huanghai Sea has been studied with hydrographic data,which were observed in February and June 1994 and bimonthly during 1970-1990,and numerical model results.Horiwntal distributions of temperature and salinity in 1994 are quite different due to strong tidal mixing so that we need a analysis to see the real distributions of water masses.The mixing ratio analysis with the data of 1970-1990 shows the connection of the waters in the west coasts of Kotea Peninsula with warm and saline waters from the south in summer,which means northward inflows along the west coasts of Korea Peninsula in summer.With this flow,the seasonal circulations,which are deduced from the seasonal change of water mass distributions in the lower layer,are warm inflows in winter and mld outflows in summer in the central Huanghai Sea,and cold outflows in winter and warm inflows in summer along the west coasts of Korea Peninsula.The seasonally changed inflows might be the Huanghai Sea Warm Current.The monsoon winds can drive such circulations.However,summer monsoon winds are weak and irregular.As one of other possible dynamics,the variation of Kuroshio transport is numerically studied with allowing sea level fluctuations.Although it should be studied more,it possibly drives the summer circulations.The real circulations seem to be driven by both of them.
The seasonal circulation in the southeastern Huanghai Sea has been studied with hydrographic data,which were observed in February and June 1994 and bimonthly during 1970-1990,and numerical model results.Horiwntal distributions of temperature and salinity in 1994 are quite different due to strong tidal mixing so that we need a analysis to see the real distributions of water masses.The mixing ratio analysis with the data of 1970-1990 shows the connection of the waters in the west coasts of Kotea Peninsula with warm and saline waters from the south in summer,which means northward inflows along the west coasts of Korea Peninsula in summer.With this flow,the seasonal circulations,which are deduced from the seasonal change of water mass distributions in the lower layer,are warm inflows in winter and mld outflows in summer in the central Huanghai Sea,and cold outflows in winter and warm inflows in summer along the west coasts of Korea Peninsula.The seasonally changed inflows might be the Huanghai Sea Warm Current.The monsoon winds can drive such circulations.However,summer monsoon winds are weak and irregular.As one of other possible dynamics,the variation of Kuroshio transport is numerically studied with allowing sea level fluctuations.Although it should be studied more,it possibly drives the summer circulations.The real circulations seem to be driven by both of them.
1999, (3): 389-400.
Abstract:
In the viewpoint that the coral reef atolls' growth index of the Nansha Islands is influenced by many factons,the measured remote sensing composite information including some mutually related factors is divided into 10 geographic events as N1,N2…,N10,and the analysis of the atolls' infomation entropy is made.From the value of the entropy,the closed related factors with the index of the emerged atolls are shown.In proper order,the factors are reef top's area(0.319),lagoon's area(0.324),open-degree of atoll(0.336),trend of atoll(0.551).On the basis of this work,a new description function of the emerged atoll growth index is proposed.This function can be used to identify the open type of Nansha atoll growth.
In the viewpoint that the coral reef atolls' growth index of the Nansha Islands is influenced by many factons,the measured remote sensing composite information including some mutually related factors is divided into 10 geographic events as N1,N2…,N10,and the analysis of the atolls' infomation entropy is made.From the value of the entropy,the closed related factors with the index of the emerged atolls are shown.In proper order,the factors are reef top's area(0.319),lagoon's area(0.324),open-degree of atoll(0.336),trend of atoll(0.551).On the basis of this work,a new description function of the emerged atoll growth index is proposed.This function can be used to identify the open type of Nansha atoll growth.
1999, (3): 401-411.
Abstract:
The sensible and latent heat fluxes over the ocean area near China were calculated and analyzed by using the (ioddard Earth Observing System (GE0S)-four-dimensional Data Assimilation System (DAS).The calculated resuits showed that the sensible heat flux had its large value in winter and autumn,small value in spring and summer over the ocean area near China.In winter,the sensible heat flux increased distinctly with latitude,and its isolines were very crowded.Over the ocean area east of Taiwan Province and south of Japan,the direction of isoline was from southwest to northeast.In the South China Sea the sensible heat flux was lower than that of surrounding ocean areas,and its isoline was distributed into a type of an inverted trough.In autumn and winter,the maximum center of latent heat flux appeered over the ocean area northeast of Taiwan Province and south and southeast of Jepan,meanwhile,the isoline was in the direction of southwest to northeast.In spring and summer,the latent heat flux had minimum value in the Huanghai Sea.At the same time,the maximum value center of latent heat flux appeared over the ocean area south of Japan in spring.
The sensible and latent heat fluxes over the ocean area near China were calculated and analyzed by using the (ioddard Earth Observing System (GE0S)-four-dimensional Data Assimilation System (DAS).The calculated resuits showed that the sensible heat flux had its large value in winter and autumn,small value in spring and summer over the ocean area near China.In winter,the sensible heat flux increased distinctly with latitude,and its isolines were very crowded.Over the ocean area east of Taiwan Province and south of Japan,the direction of isoline was from southwest to northeast.In the South China Sea the sensible heat flux was lower than that of surrounding ocean areas,and its isoline was distributed into a type of an inverted trough.In autumn and winter,the maximum center of latent heat flux appeered over the ocean area northeast of Taiwan Province and south and southeast of Jepan,meanwhile,the isoline was in the direction of southwest to northeast.In spring and summer,the latent heat flux had minimum value in the Huanghai Sea.At the same time,the maximum value center of latent heat flux appeared over the ocean area south of Japan in spring.
1999, (3): 413-422.
Abstract:
One hundred and eighty-one aerosol samples,and two cascade impactor samples were collected in the atmosphere over the western Taiwan Strait from 1991 to 1993.Concentrations of Al,Fe,Cu,Pb,Cd and Na were determined by an atomic absorption spectrophotometry.The contents of Fe,Cu,Pb and Cd in the atmosphere over the western Taiwan Strait were lower than those over inland cities in China,Europe or North America.Annual and seasonal variations of concentrations of the metals could be primarily attributed to washout or monsoon for non-sea-salt metals.Fe was presented in bimodel distributions with size around 3.6 and 0.52 μm,AI was chiefly distributed on the particles with being greater than 2.1 μm,Na on the particles with being greater or equal to 3.6 μm,and the size distributions of Cu,P6 and Cd were presented in small particles,chiefly on those with being smaller than or equal to 0.52 μm.
One hundred and eighty-one aerosol samples,and two cascade impactor samples were collected in the atmosphere over the western Taiwan Strait from 1991 to 1993.Concentrations of Al,Fe,Cu,Pb,Cd and Na were determined by an atomic absorption spectrophotometry.The contents of Fe,Cu,Pb and Cd in the atmosphere over the western Taiwan Strait were lower than those over inland cities in China,Europe or North America.Annual and seasonal variations of concentrations of the metals could be primarily attributed to washout or monsoon for non-sea-salt metals.Fe was presented in bimodel distributions with size around 3.6 and 0.52 μm,AI was chiefly distributed on the particles with being greater than 2.1 μm,Na on the particles with being greater or equal to 3.6 μm,and the size distributions of Cu,P6 and Cd were presented in small particles,chiefly on those with being smaller than or equal to 0.52 μm.
1999, (3): 423-433.
Abstract:
The abundance,diurnal variation features of phytoplankton biomass and the horizontal distribution patterns of Chl.a and primary productivity in the Taiwan Strait were investigated during a summer and a winter cruise in August 1994 and February 1995,respectively.Results show that the horizontal distribution of phytoplanktat bianass was quite similar to that of productivity.In summer,there was a relatively barren,low productive region in the central location of the northern Taiwan Strait (NTS),and high productive regions were located at the nearshore and to the north of Cape Fugui of Taiwan Island;meanwhile,high productivity regions were only located at coastal waters of the southern Taiwan Strait (STS).In winter,high productive regions of NTS occurred off northwestern coast of Taiwan Island,while that of STS was located along the southern edge of Minnan (South Fujian)-Taiwan Bank.Vertical patterns of the diurnal variation of Chl.a indicated that in non-stratified waters,phytoplankton biornass changed in tidal rhythm;as for the stratified waters,the depth at which the highest variation amplitude located coincided with the depth where the highest variation frequency occurred.The grazing pressure of zooplankton strongly influenced the diumal variation of size-ractionated structure of phytoplankton biomass.As a result of our investigations,we conclude that in the Taiwan Strait,biological pcncesses may be more important at smaller scales where behaviors such as vertical migration and predation may control the phytoplankton production,whereas physical processes may be more important at larger scales in structuring phytoplankton patchness.
The abundance,diurnal variation features of phytoplankton biomass and the horizontal distribution patterns of Chl.a and primary productivity in the Taiwan Strait were investigated during a summer and a winter cruise in August 1994 and February 1995,respectively.Results show that the horizontal distribution of phytoplanktat bianass was quite similar to that of productivity.In summer,there was a relatively barren,low productive region in the central location of the northern Taiwan Strait (NTS),and high productive regions were located at the nearshore and to the north of Cape Fugui of Taiwan Island;meanwhile,high productivity regions were only located at coastal waters of the southern Taiwan Strait (STS).In winter,high productive regions of NTS occurred off northwestern coast of Taiwan Island,while that of STS was located along the southern edge of Minnan (South Fujian)-Taiwan Bank.Vertical patterns of the diurnal variation of Chl.a indicated that in non-stratified waters,phytoplankton biornass changed in tidal rhythm;as for the stratified waters,the depth at which the highest variation amplitude located coincided with the depth where the highest variation frequency occurred.The grazing pressure of zooplankton strongly influenced the diumal variation of size-ractionated structure of phytoplankton biomass.As a result of our investigations,we conclude that in the Taiwan Strait,biological pcncesses may be more important at smaller scales where behaviors such as vertical migration and predation may control the phytoplankton production,whereas physical processes may be more important at larger scales in structuring phytoplankton patchness.
1999, (3): 435-441.
Abstract:
Three new species of Genus Euphysora (Hydrozoa:Anthomedusae,Corymorphidae) from China seas were described in great detail.All type specimens are deposited in the Department of Oceanography,Xiamen University.
Three new species of Genus Euphysora (Hydrozoa:Anthomedusae,Corymorphidae) from China seas were described in great detail.All type specimens are deposited in the Department of Oceanography,Xiamen University.
1999, (3): 443-447.
Abstract:
The chemical composition of marine zooplankton was studied through two seasonal cruises (August 1994 and February 1995) in the Taiwan Strait.The carbon(C),nitrogen(N) and hydrngen(H) dry weight contents of planktonic copepods were in the range of 36.24%-45.63%,8.50%-11.37% and 4.23%-6.50% respectively.Data comparison among the three southern sea areas of China showed the same subtropical characteristics in the chemical composition of planktonic crustaceans.The seasonal changes of C and N contents and CAN ratio in the Taiwan Strait implied the different nutritional conditions in the open sea from those in the inner gulf.
The chemical composition of marine zooplankton was studied through two seasonal cruises (August 1994 and February 1995) in the Taiwan Strait.The carbon(C),nitrogen(N) and hydrngen(H) dry weight contents of planktonic copepods were in the range of 36.24%-45.63%,8.50%-11.37% and 4.23%-6.50% respectively.Data comparison among the three southern sea areas of China showed the same subtropical characteristics in the chemical composition of planktonic crustaceans.The seasonal changes of C and N contents and CAN ratio in the Taiwan Strait implied the different nutritional conditions in the open sea from those in the inner gulf.
