1998 Vol. 20, No. 1
Display Method:
1998, 20(1): 1-10.
Abstract:
From Februarg.26 to March 6,1995, the currents on 15 stations between Xinghai and Sitang are measured.The characteristics of the currents are as follows:The speeds of flood current are larger than ebb current.The maximum flood speed is 172 cm/s,the maximum ebb speed is 142 cm/s;the speed of mean residual current on north 6 stations is 18.4 cm/s.The speed of mean residual current on middle 3 stations of the straits is 18.3 cm/s.The speed of mean residual current on south 6 stations is 10.2 cm/s.The directions of residual currents are in range W-S on northern and middle stationss,and in range N-NE on southern stations, because of the influence of the topography.This paper has used a model to calculate the tidal currents in the straits.The sum of the water amount passing through the west section (Dengloujiao-Yubaojiao) is 4.73×1010m3 (by ebb current).and is 4.29×1010m3 (by flood tide).The sum of the water amount passing through the east section (Dongying-Longtangzhen) is 5.22×1010m3 (by ebb current) and is 1.90×1010m3 (by flood tidal current).The net amounts are 0.43×1010m3 (west section) and 0.32×1010m3 (east section).The direction of the net transportation points toward west.
From Februarg.26 to March 6,1995, the currents on 15 stations between Xinghai and Sitang are measured.The characteristics of the currents are as follows:The speeds of flood current are larger than ebb current.The maximum flood speed is 172 cm/s,the maximum ebb speed is 142 cm/s;the speed of mean residual current on north 6 stations is 18.4 cm/s.The speed of mean residual current on middle 3 stations of the straits is 18.3 cm/s.The speed of mean residual current on south 6 stations is 10.2 cm/s.The directions of residual currents are in range W-S on northern and middle stationss,and in range N-NE on southern stations, because of the influence of the topography.This paper has used a model to calculate the tidal currents in the straits.The sum of the water amount passing through the west section (Dengloujiao-Yubaojiao) is 4.73×1010m3 (by ebb current).and is 4.29×1010m3 (by flood tide).The sum of the water amount passing through the east section (Dongying-Longtangzhen) is 5.22×1010m3 (by ebb current) and is 1.90×1010m3 (by flood tidal current).The net amounts are 0.43×1010m3 (west section) and 0.32×1010m3 (east section).The direction of the net transportation points toward west.
1998, 20(1): 11-20.
Abstract:
Based on, the data of CTD in the Prydz Bay and the vicinity sea area by CHINARE-9, hydrographic structure and the source of Antarctic Bottom Water (AABW) is analysed in the paper.Results show that,near-surface current flows from west to east in the deep waters,there is a cyclonic eddy in the Prydz Bay.The main characteristics of oceanography hydrographic structure are that:(1) the upwelling phenomenon of Circumpolar Deep Water (CDW).The strongest location of upwelling is sea area north of Mcrobsion Land.The most obvious depth is in 50~200 m.The cold water in winter is divided in two parts by the CDW of upwelling.An isolated warm water is formed among them.(2)Boundary of continental margin water is obvious.This is the front between CDW and Antarctic cold water of subsurface,it is in 64°~66°S.(3) There is double thermocline structure.(4) During observation there is AABW north of the Prydz Bay.The source of AABW may have two: (1) it is formed in the locality, (2) it comes from the Ross Sea.
Based on, the data of CTD in the Prydz Bay and the vicinity sea area by CHINARE-9, hydrographic structure and the source of Antarctic Bottom Water (AABW) is analysed in the paper.Results show that,near-surface current flows from west to east in the deep waters,there is a cyclonic eddy in the Prydz Bay.The main characteristics of oceanography hydrographic structure are that:(1) the upwelling phenomenon of Circumpolar Deep Water (CDW).The strongest location of upwelling is sea area north of Mcrobsion Land.The most obvious depth is in 50~200 m.The cold water in winter is divided in two parts by the CDW of upwelling.An isolated warm water is formed among them.(2)Boundary of continental margin water is obvious.This is the front between CDW and Antarctic cold water of subsurface,it is in 64°~66°S.(3) There is double thermocline structure.(4) During observation there is AABW north of the Prydz Bay.The source of AABW may have two: (1) it is formed in the locality, (2) it comes from the Ross Sea.
1998, 20(1): 21-24.
Abstract:
The present paper defines the generalized apparent energy distribution and derives the analytical form of the so-called generalized outer frequency spectrum of nth order apparent frequency spectrum.It is shown the generalized outer frequency spectrum has an equilibrium range with an exponent-(n+3) and the upper limit of the exponent is -3.The results of this paper are universal and are applicable for any other wave phenomena if the ray theory of waves and the Longuet-Higgins' linear random wave model are exact enough for their description.
The present paper defines the generalized apparent energy distribution and derives the analytical form of the so-called generalized outer frequency spectrum of nth order apparent frequency spectrum.It is shown the generalized outer frequency spectrum has an equilibrium range with an exponent-(n+3) and the upper limit of the exponent is -3.The results of this paper are universal and are applicable for any other wave phenomena if the ray theory of waves and the Longuet-Higgins' linear random wave model are exact enough for their description.
1998, 20(1): 25-32.
Abstract:
By deriving an equation for relative humidity, the effects of advection, turbulence and radiation on the formation of seafog are analysed.
By deriving an equation for relative humidity, the effects of advection, turbulence and radiation on the formation of seafog are analysed.
1998, 20(1): 33-40.
Abstract:
Firstly,this paper illustrates the global structure of the sea surface temperature CSST)anomalies associated with El Nino and La Nina events and the Southern Oscillation (SO) structure associated with the sea Level pressure (SLP) anomaly.Secondly, the typical structure of the SO forced by global ocean heat source and real topography was simulated by using IAP two-level atmospheric general circulation model.The simulated location of the SLP anomaly centers over the eastern Pacific differs significantly with the observations if only the SST heat source without topography was considered.It suggests that the SO may be a response to the global SST anomaly under the real topography.
Firstly,this paper illustrates the global structure of the sea surface temperature CSST)anomalies associated with El Nino and La Nina events and the Southern Oscillation (SO) structure associated with the sea Level pressure (SLP) anomaly.Secondly, the typical structure of the SO forced by global ocean heat source and real topography was simulated by using IAP two-level atmospheric general circulation model.The simulated location of the SLP anomaly centers over the eastern Pacific differs significantly with the observations if only the SST heat source without topography was considered.It suggests that the SO may be a response to the global SST anomaly under the real topography.
1998, 20(1): 41-49.
Abstract:
In the summer of 1991 studies of sound propagation and reverberation were carried out in the Huanghai (Yellow) Sea with a strong thermocline by using explosive sound sources.Experimental results of both the sound transmission loss along a certain course and the average reverberation intensity showed an abnormally large attenuation over a frequency range from 1 000 to 2 000 Hz when both the source and the receiver were located above the thermocline.An interesting point is that the anomalous attenuation of the average reverberation intensity obtained by using omnidirectional source and receiver and that of the transmission loss along the certain course exhibit a resonance-like or frequency-selective characteristic with the same centre frequency, similar bandwidth and comparable extra attenuation values.Obviously,this anomalous attenuation cannot be explained by any anisotropic mechanism (e.g.,internal waves,regular fluctuations of sea surface or bottom, etc.).On the basis of the depth dependences of the transmission loss and reverberation intensity obtained by the authors and some indirect evidences,it is believed that the observed frequency-selective attenuation is due to fish with swimbladders (probably, anchovies) living dispersedly above the thermocline.
In the summer of 1991 studies of sound propagation and reverberation were carried out in the Huanghai (Yellow) Sea with a strong thermocline by using explosive sound sources.Experimental results of both the sound transmission loss along a certain course and the average reverberation intensity showed an abnormally large attenuation over a frequency range from 1 000 to 2 000 Hz when both the source and the receiver were located above the thermocline.An interesting point is that the anomalous attenuation of the average reverberation intensity obtained by using omnidirectional source and receiver and that of the transmission loss along the certain course exhibit a resonance-like or frequency-selective characteristic with the same centre frequency, similar bandwidth and comparable extra attenuation values.Obviously,this anomalous attenuation cannot be explained by any anisotropic mechanism (e.g.,internal waves,regular fluctuations of sea surface or bottom, etc.).On the basis of the depth dependences of the transmission loss and reverberation intensity obtained by the authors and some indirect evidences,it is believed that the observed frequency-selective attenuation is due to fish with swimbladders (probably, anchovies) living dispersedly above the thermocline.
1998, 20(1): 50-57.
Abstract:
The distribution of the abundance of phytoplankton,chlorophyll a concentration and primary productivity in the Beibu Gulf were observed from May 23 to June 4,1994.The results showed that there were marked features of spatial zonation in the surveyed area due to the differences between the geographic environment and the hydrological conditions.Chlorophyll a and primary productivity were higher in the inshore than in the middle area and higher in the north than in the south of the Beibu Gulf.The average concentration of chlorophyll a,primary productivity (C) and the abundance of phytoplankton were 0.94±0.45 μg/dm3,351±172mg/(m2·d) and 0.97×104~10050×104/ind./m3 in the surveyed area,respectively.There were 176 species belonging to 4 phyla and 56 genera based on microscope identification.The average chlorophyll a of the anchor station was higher in the north (0.47±0.15 pg/dm') than that in the south (0.15±0.02μg/dm3) of the gulf.The results of the size-fractionation showed that the contribution of nanoplankton with picoplankton to total chlorophyll a was 77%,to total primary productivity was 91%,which proved their importance in phytoplankton community of the Beibu Gulf.
The distribution of the abundance of phytoplankton,chlorophyll a concentration and primary productivity in the Beibu Gulf were observed from May 23 to June 4,1994.The results showed that there were marked features of spatial zonation in the surveyed area due to the differences between the geographic environment and the hydrological conditions.Chlorophyll a and primary productivity were higher in the inshore than in the middle area and higher in the north than in the south of the Beibu Gulf.The average concentration of chlorophyll a,primary productivity (C) and the abundance of phytoplankton were 0.94±0.45 μg/dm3,351±172mg/(m2·d) and 0.97×104~10050×104/ind./m3 in the surveyed area,respectively.There were 176 species belonging to 4 phyla and 56 genera based on microscope identification.The average chlorophyll a of the anchor station was higher in the north (0.47±0.15 pg/dm') than that in the south (0.15±0.02μg/dm3) of the gulf.The results of the size-fractionation showed that the contribution of nanoplankton with picoplankton to total chlorophyll a was 77%,to total primary productivity was 91%,which proved their importance in phytoplankton community of the Beibu Gulf.
1998, 20(1): 58-64.
Abstract:
In this study, based on archaeological survey to Maqiao cultural site,Shanghai, the methods of environmental archaeology and historic geography are employed to understand the Middle and Late Holocene environmental changes of Maqiao area.It is found, consequently, that this area was in a shallow sea environment around 7 200 a BP.Between 6 100 a BP and 4 400 a BP,it got rid of sea transgression,Liangzhu Culture (5~4 ka BP) developed.At its late stage, a large-scale deluge took place in this area,it made the Liangzhu Culture disappear abruptly,and then, Maqiao Culture (4~3 ka BP) developed.At its Late stage,the water spaceexpaned, this area,therefore, was not suitable for human being to domicile.Until Tang Dynasty and Song Dynasty,most part of the present land formed.After that,there were several times of sea transgression, but the coastline merely flickered around Jinshanwei, and the sea water never transgressed Maqiao.
In this study, based on archaeological survey to Maqiao cultural site,Shanghai, the methods of environmental archaeology and historic geography are employed to understand the Middle and Late Holocene environmental changes of Maqiao area.It is found, consequently, that this area was in a shallow sea environment around 7 200 a BP.Between 6 100 a BP and 4 400 a BP,it got rid of sea transgression,Liangzhu Culture (5~4 ka BP) developed.At its late stage, a large-scale deluge took place in this area,it made the Liangzhu Culture disappear abruptly,and then, Maqiao Culture (4~3 ka BP) developed.At its Late stage,the water spaceexpaned, this area,therefore, was not suitable for human being to domicile.Until Tang Dynasty and Song Dynasty,most part of the present land formed.After that,there were several times of sea transgression, but the coastline merely flickered around Jinshanwei, and the sea water never transgressed Maqiao.
1998, 20(1): 65-73.
Abstract:
Two cores from the Prydz Bay, Antarctica have been recorded paleoclimatic change in 15 000 years.The characteristics of the grain size,mineral composition,diatom assemblage and geochemistry are sensitive to the paleoclimatic change, and especial the Heinrich Eventaround 14.31 ka is discovered.On the basis of the above study, paleoclimatic evolution can be divided into eight stages:Ⅰ.Older Dryas,Ⅱ.Heinrich Event 1,Ⅲ.Bolling-Allerod,Ⅳ.Younger Dryas,Ⅴ.changing warm period,Ⅵ.suitable period, Ⅶ warm period,Ⅷ.cool period.
Two cores from the Prydz Bay, Antarctica have been recorded paleoclimatic change in 15 000 years.The characteristics of the grain size,mineral composition,diatom assemblage and geochemistry are sensitive to the paleoclimatic change, and especial the Heinrich Eventaround 14.31 ka is discovered.On the basis of the above study, paleoclimatic evolution can be divided into eight stages:Ⅰ.Older Dryas,Ⅱ.Heinrich Event 1,Ⅲ.Bolling-Allerod,Ⅳ.Younger Dryas,Ⅴ.changing warm period,Ⅵ.suitable period, Ⅶ warm period,Ⅷ.cool period.
1998, 20(1): 74-80.
Abstract:
Based on the analysis of Radiolaria fossils,in association with the comprehensive data of Foraminifera,sporopollen, plant opal, etc.and the measuring results of AMS 14C and magnetostratigraphy, the paleooceanographic character and change regularity of paleoclimate at the Okinawa Trough in the East China Sea since Quaternary period were roughly studied.
Based on the analysis of Radiolaria fossils,in association with the comprehensive data of Foraminifera,sporopollen, plant opal, etc.and the measuring results of AMS 14C and magnetostratigraphy, the paleooceanographic character and change regularity of paleoclimate at the Okinawa Trough in the East China Sea since Quaternary period were roughly studied.
1998, 20(1): 81-89.
Abstract:
The study of phytoliths in both modern and Quaternary sediments in the coastal zones and in neritic and bathyal areas showed that phytoliths can play an important role in the reconstruction of marine palaeoclimates and palaeoenvironments.Phytoliths can be used as an important indicator in the correlation of unfossiliferous strata with quite high resolution on time scale.
The study of phytoliths in both modern and Quaternary sediments in the coastal zones and in neritic and bathyal areas showed that phytoliths can play an important role in the reconstruction of marine palaeoclimates and palaeoenvironments.Phytoliths can be used as an important indicator in the correlation of unfossiliferous strata with quite high resolution on time scale.
1998, 20(1): 90-93.
Abstract:
From May to November of 1995,P.chinensis were used experiments using excessive artifical diets as organic pollutants.Twenty about 8, 10 or 12cm body length P.chinensis were put into the test pond and control pond.After 2~3 weeks,susceptibilities to pathogenic bacteria the number of haemocyte and lysozyme,SOD, PO activities were compared.The results were as follows.Susceptibilities to Vitrio parahaemolyticus, were 1~3 times that of the control pond shrimp (Table 1),the haemocyte number of the test shrimps decreased about 50%,the SOD, PO and lysozyme activities of the test pond decreased about 22%, 50% and 28%-86% compared with those of the control pond (Table 2).Additionally it has been proved that in the test pond following the excessive artifical diets degreded,the DO content decreased,NH3-N increased markedly.So the conclusion could be drawn:organic pollution affects aquatic environment,decreases immune level,enhances susceptibilities to pathogen bacteria.
From May to November of 1995,P.chinensis were used experiments using excessive artifical diets as organic pollutants.Twenty about 8, 10 or 12cm body length P.chinensis were put into the test pond and control pond.After 2~3 weeks,susceptibilities to pathogenic bacteria the number of haemocyte and lysozyme,SOD, PO activities were compared.The results were as follows.Susceptibilities to Vitrio parahaemolyticus, were 1~3 times that of the control pond shrimp (Table 1),the haemocyte number of the test shrimps decreased about 50%,the SOD, PO and lysozyme activities of the test pond decreased about 22%, 50% and 28%-86% compared with those of the control pond (Table 2).Additionally it has been proved that in the test pond following the excessive artifical diets degreded,the DO content decreased,NH3-N increased markedly.So the conclusion could be drawn:organic pollution affects aquatic environment,decreases immune level,enhances susceptibilities to pathogen bacteria.
1998, 20(1): 94-100.
Abstract:
By taking China's seas as a unit for study,this paper analyzes in general the law of abundance variation of planktonic ostracoda and illustrates the difference of individual density in different seasons and areas.In addition, based on the features of horizontal distribution of planktonic ostracoda,this paper points out that except the waters off Shantou in the Eastern Guangdong,all the other coastal areas are very low in abundance,that the waters deeper than the 200 m isobar have a homogenous distribution of low abundance and that the waters between the isobars of 50 m and 200 m have distinctly increased abundance, though in China's seas,there exist all the year round three zones with concentrated abundance of planktonic ostracoda.
By taking China's seas as a unit for study,this paper analyzes in general the law of abundance variation of planktonic ostracoda and illustrates the difference of individual density in different seasons and areas.In addition, based on the features of horizontal distribution of planktonic ostracoda,this paper points out that except the waters off Shantou in the Eastern Guangdong,all the other coastal areas are very low in abundance,that the waters deeper than the 200 m isobar have a homogenous distribution of low abundance and that the waters between the isobars of 50 m and 200 m have distinctly increased abundance, though in China's seas,there exist all the year round three zones with concentrated abundance of planktonic ostracoda.
1998, 20(1): 101-112.
Abstract:
The present study is based on the analysis of the data collected in ten cruises during the periods of two surveys (from May 1992 to Jan.1993 and from Aug.1993 to May 1994).The results show that the number of phytoplankton species in highly eutrophic waters of Maluan Bay is less,only 66 species in total and 6~35 species for each cruise.The phytoplankton abundance is high.The mean cell density of phytoplankton from the net samples and the water samples reached 21 386×104cell/m3 (from May 1992 to Jan.1993) to 110 136×104cell/m3(from Aug.1993 to May 1994) and 1 150.7 cell/cm3 respectively.The mean concentration of chlorophyll a reached 6.67 mg/m3.Both the species diversity (H')and evenness (J) were low, on 0.78 and 0.28 respectively.The temporal and spatial fluctuation of the cell density of phytoplankton was quite significant,that was dominated mainly by the pennate diatom Nitzschia delicatissima which often occurried abundantly in closed waters riched in organic matter and could be taken as an ecologic indicator of highly eutrophic harbour.The existence of good correlation between the cell density of Nitzschia delicatissima and some environmental variables (e.g.PO43--P and COD etc.)and the heterotrophic tendancy of the species are also discussed.
The present study is based on the analysis of the data collected in ten cruises during the periods of two surveys (from May 1992 to Jan.1993 and from Aug.1993 to May 1994).The results show that the number of phytoplankton species in highly eutrophic waters of Maluan Bay is less,only 66 species in total and 6~35 species for each cruise.The phytoplankton abundance is high.The mean cell density of phytoplankton from the net samples and the water samples reached 21 386×104cell/m3 (from May 1992 to Jan.1993) to 110 136×104cell/m3(from Aug.1993 to May 1994) and 1 150.7 cell/cm3 respectively.The mean concentration of chlorophyll a reached 6.67 mg/m3.Both the species diversity (H')and evenness (J) were low, on 0.78 and 0.28 respectively.The temporal and spatial fluctuation of the cell density of phytoplankton was quite significant,that was dominated mainly by the pennate diatom Nitzschia delicatissima which often occurried abundantly in closed waters riched in organic matter and could be taken as an ecologic indicator of highly eutrophic harbour.The existence of good correlation between the cell density of Nitzschia delicatissima and some environmental variables (e.g.PO43--P and COD etc.)and the heterotrophic tendancy of the species are also discussed.
1998, 20(1): 113-122.
Abstract:
A numerical model of spill oil movement for those waters with sea ice is presented in the paper.In description of the sea ice movement in the model,different constitution laws of the sea ice are employed to estimate sea ice forces according to its compactness:a visco-plastic model, which is based on the continuous medium theory, is accepted for the nearshore areas with high compactness of sea ice;and a collision model is used for those marginal areas with low compactness of sea ice, which is based on the discret medium theory.In the prediction models of spill oil drifting/spreading movements the following situations of sea ice are considered:sea ice with low, middle and high compactness,respectively, in addition to that in an integral ice cover.The results of simulation calculations by using the model indicated its correctness and applicability in prediction of the potential influence in a cold region offshore oil spill accident.
A numerical model of spill oil movement for those waters with sea ice is presented in the paper.In description of the sea ice movement in the model,different constitution laws of the sea ice are employed to estimate sea ice forces according to its compactness:a visco-plastic model, which is based on the continuous medium theory, is accepted for the nearshore areas with high compactness of sea ice;and a collision model is used for those marginal areas with low compactness of sea ice, which is based on the discret medium theory.In the prediction models of spill oil drifting/spreading movements the following situations of sea ice are considered:sea ice with low, middle and high compactness,respectively, in addition to that in an integral ice cover.The results of simulation calculations by using the model indicated its correctness and applicability in prediction of the potential influence in a cold region offshore oil spill accident.
1998, 20(1): 123-129.
Abstract:
The hydrodynamic pressure induced by earthquake to the cylindrical structure in extreme shallow water is studied.The earthquake hydrodynamic pressure for the cylindrical structure may approximately be calculated by the chopras formula for the rectilinear wall when the ratio of external water depth to the cylinder radius is smaller than 0.3.The effects of elastically hydrodynamic pressure can be ignored if water depth is smaller than half height of the structure in engineering.The simplified formula for calculating earthquake-induced hydrodynamic to cylindrical structure in extreme shallow water is suggested.
The hydrodynamic pressure induced by earthquake to the cylindrical structure in extreme shallow water is studied.The earthquake hydrodynamic pressure for the cylindrical structure may approximately be calculated by the chopras formula for the rectilinear wall when the ratio of external water depth to the cylinder radius is smaller than 0.3.The effects of elastically hydrodynamic pressure can be ignored if water depth is smaller than half height of the structure in engineering.The simplified formula for calculating earthquake-induced hydrodynamic to cylindrical structure in extreme shallow water is suggested.
1998, 20(1): 130-133.
Abstract:
The method which is based on the solution of a singular integral equation is first used in the artificial harbor with the water depth of steep variation.The result is proper to the one-dimensional theoretical solution and hydraulic model test.
The method which is based on the solution of a singular integral equation is first used in the artificial harbor with the water depth of steep variation.The result is proper to the one-dimensional theoretical solution and hydraulic model test.
1998, 20(1): 134-143.
Abstract:
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