2001 Vol. 23, No. 5
Display Method:
2001, 23(5): 1-13.
Abstract:
Based on the conductivity-temperature-depth(CTD) dataga thered by R/Vs Science 1 and Shiy an 3 during the South China Sea Monsoon Experiment(SCSMEX) IOP from May through August 1998,ther mohaline properties and their variabilities along sections in the South China Sea(SCS) are discussed.The thermohaline structure in the centr al SCS is found to be mainly controlled by the SCS water masses,while that in the northern SCS, especially adjacent to the Luzon Strait,is significantly influenced by the western Pacific(WP) water in the surface and subsurface layers.A fter the monsoon onset,SST increased in the north SCS with the amplitude decreasing east-ward,while basically unchanged in the central and south SCS,hense the zonal SST gradient in the nor theastern SCS and meridional SST gradient over the basin being weakened.The SSS decreased and mixed layer developed in the northern SCS,resulting from streng thened precipitation and wind after onset of the SCS monsoon.It seems that the Kuroshio Water spread westward through the Luzon Strait with great variation.During April to May 1998,the Kuroshio subsurface water appeared in central and northern Luzon Strait and west of Luzon Island.Part of Kuroshio Water seemed to enter the SCS southw estward along the Luzon coast.During June to July,the salt core of the NPSW in the northern Luzon Strait was extremely strengthened and extended,while the one west of the Luzon Island shrinked.Although entering and depar ting the SCS with strong ervelocity,the Kuroshio Waters impact on the SCS thermal and dynamic structures may not increase.A patch of surface salt water with salinity exceeding 34.55 is found near Palawan,which seems to be originated from the western Pacific surface water through the strait between Palawan and Luzon Islands.
Based on the conductivity-temperature-depth(CTD) dataga thered by R/Vs Science 1 and Shiy an 3 during the South China Sea Monsoon Experiment(SCSMEX) IOP from May through August 1998,ther mohaline properties and their variabilities along sections in the South China Sea(SCS) are discussed.The thermohaline structure in the centr al SCS is found to be mainly controlled by the SCS water masses,while that in the northern SCS, especially adjacent to the Luzon Strait,is significantly influenced by the western Pacific(WP) water in the surface and subsurface layers.A fter the monsoon onset,SST increased in the north SCS with the amplitude decreasing east-ward,while basically unchanged in the central and south SCS,hense the zonal SST gradient in the nor theastern SCS and meridional SST gradient over the basin being weakened.The SSS decreased and mixed layer developed in the northern SCS,resulting from streng thened precipitation and wind after onset of the SCS monsoon.It seems that the Kuroshio Water spread westward through the Luzon Strait with great variation.During April to May 1998,the Kuroshio subsurface water appeared in central and northern Luzon Strait and west of Luzon Island.Part of Kuroshio Water seemed to enter the SCS southw estward along the Luzon coast.During June to July,the salt core of the NPSW in the northern Luzon Strait was extremely strengthened and extended,while the one west of the Luzon Island shrinked.Although entering and depar ting the SCS with strong ervelocity,the Kuroshio Waters impact on the SCS thermal and dynamic structures may not increase.A patch of surface salt water with salinity exceeding 34.55 is found near Palawan,which seems to be originated from the western Pacific surface water through the strait between Palawan and Luzon Islands.
2001, 23(5): 14-23.
Abstract:
An divisional barotropic and baroclinic connection model is employed to study the South China Sea(SCS) upper circulation character istics and its dynamic mechanism in winter.The results are:(1) In the northern SCS, the flow state is mainly affected by Kuroshio,it is controlled by a cyclonic gyre there except in the continental shelf sea areas to the southwest of Dongsha Islands and adjacent to the west shore of northern Luzon Isalnd where there exists an anticyclonic eddy respectively.(2) It is mainly wind-driven current in the southern SCS,the water from alongshore of western Guangdong is driven by the northeast monsoon and then flows southward along the western boundary shorelines of the SCS,thus a rather strong western boundary current is formed;in the meanwhile,due to the actions of β effect and bottom topographic effect of continental shelf to the south of Beikang Shoals,an about 50 d periodic process on which an anticy clonic eddy bears in the Nansha Trough、grows and spreads westward then declines is shown in the southern SCS.
An divisional barotropic and baroclinic connection model is employed to study the South China Sea(SCS) upper circulation character istics and its dynamic mechanism in winter.The results are:(1) In the northern SCS, the flow state is mainly affected by Kuroshio,it is controlled by a cyclonic gyre there except in the continental shelf sea areas to the southwest of Dongsha Islands and adjacent to the west shore of northern Luzon Isalnd where there exists an anticyclonic eddy respectively.(2) It is mainly wind-driven current in the southern SCS,the water from alongshore of western Guangdong is driven by the northeast monsoon and then flows southward along the western boundary shorelines of the SCS,thus a rather strong western boundary current is formed;in the meanwhile,due to the actions of β effect and bottom topographic effect of continental shelf to the south of Beikang Shoals,an about 50 d periodic process on which an anticy clonic eddy bears in the Nansha Trough、grows and spreads westward then declines is shown in the southern SCS.
2001, 23(5): 24-32.
Abstract:
The comparative analyses are made between 65 seiche processes with the amplitude greater than 50 cm (the amplitude greater than 80 cm in Longkou Harbor) in main harbors along the coasts of the Bohai Sea and the Huanghai Sea and the surface weather charts.The weather situations accompanied with large amplitude seiche processes are also analyzed.The results show that:(1) Among the 22 cases of large-amplitude seiche,19 cases are related to thunderstorm weather(from which three cases are accompanied with squall lines,one case with tornado) and two cases are related to gale weather,and one case is caused by open sea thunderstorm.Thus,thunderstorm and squall line are marn factors for the formation of the large-amplitude seiche.Two weather types(the northern cyclonic,the cyclonic of the south of the Changjiang River,and southw est inverted trough) are benefit to produce thunderstorm and result in largeamplitude seiche.(2) The intensity of thunderstorm is stronger,the greater atmospheric perturbation and the larger amplitude of seiche.(3) The duration of seiche and main period of oscillation in each harbor are determined by the duration and propagation direction of the thunderstorm.(4) A transient variation of the pure wind speed and direction can also induce the large-amplitude seiche,but its amplitude is smaller than that produced by strong thunderstorm,which well combined with transient variation of atmospheric pressure,wind speed and direction.(5) The sea surface fluctuation triggered by the open sea thunderstorm can produce the long wave or isolated wave.When the wave propagates into harbor,it can also cause the large-amplitude seiche.
The comparative analyses are made between 65 seiche processes with the amplitude greater than 50 cm (the amplitude greater than 80 cm in Longkou Harbor) in main harbors along the coasts of the Bohai Sea and the Huanghai Sea and the surface weather charts.The weather situations accompanied with large amplitude seiche processes are also analyzed.The results show that:(1) Among the 22 cases of large-amplitude seiche,19 cases are related to thunderstorm weather(from which three cases are accompanied with squall lines,one case with tornado) and two cases are related to gale weather,and one case is caused by open sea thunderstorm.Thus,thunderstorm and squall line are marn factors for the formation of the large-amplitude seiche.Two weather types(the northern cyclonic,the cyclonic of the south of the Changjiang River,and southw est inverted trough) are benefit to produce thunderstorm and result in largeamplitude seiche.(2) The intensity of thunderstorm is stronger,the greater atmospheric perturbation and the larger amplitude of seiche.(3) The duration of seiche and main period of oscillation in each harbor are determined by the duration and propagation direction of the thunderstorm.(4) A transient variation of the pure wind speed and direction can also induce the large-amplitude seiche,but its amplitude is smaller than that produced by strong thunderstorm,which well combined with transient variation of atmospheric pressure,wind speed and direction.(5) The sea surface fluctuation triggered by the open sea thunderstorm can produce the long wave or isolated wave.When the wave propagates into harbor,it can also cause the large-amplitude seiche.
2001, 23(5): 33-41.
Abstract:
The ice conditions in the Bohai Sea and the northern Huanghai Sea greatly change from year to year with winter climate.Ice only covers less than 15% of waters during the warmest winter,while it covers more than 80% during the coldest winter.Ice obser vation and data acquisition are outlined.The ice covered area,the position of ice edge and the ice grades give indication of the ice conditions.The local climate of waters can be expressed by using the air temperature of Stas Dalian and Yingkou.The variation of the ice condition index es with the monthly mean air temper ature at Sta.Dalian from 1952 to 2000 is shown as well.The local climate and ice conditions in the waters are affected by many factors,such as evolution of the general atmospheric circulation and the solar activity.The delayed correlation between the ice conditions and affecting factors is analysized.The ice conditions are continuously mild since the 1990s,which is related to the tendency of the global warming.The ice condition variation of the Bohai Sea is related to the El-Nino event and the sunspot period.The seasonal evolution of the ice conditions is also described.
The ice conditions in the Bohai Sea and the northern Huanghai Sea greatly change from year to year with winter climate.Ice only covers less than 15% of waters during the warmest winter,while it covers more than 80% during the coldest winter.Ice obser vation and data acquisition are outlined.The ice covered area,the position of ice edge and the ice grades give indication of the ice conditions.The local climate of waters can be expressed by using the air temperature of Stas Dalian and Yingkou.The variation of the ice condition index es with the monthly mean air temper ature at Sta.Dalian from 1952 to 2000 is shown as well.The local climate and ice conditions in the waters are affected by many factors,such as evolution of the general atmospheric circulation and the solar activity.The delayed correlation between the ice conditions and affecting factors is analysized.The ice conditions are continuously mild since the 1990s,which is related to the tendency of the global warming.The ice condition variation of the Bohai Sea is related to the El-Nino event and the sunspot period.The seasonal evolution of the ice conditions is also described.
2001, 23(5): 42-48.
Abstract:
Based on the temper ature,salinity and depth data measured from 1975 to 1998 in the northern South China Sea,variation of sound velocity of upper water(0~100 m) is discussed.The results show that annual variation of sound velocity of sea water is of importance.Dist ribution of sound velocity of sea water in the surface is notably influenced by water masses.There is a largest horizontal gradient near the continental shelf margin in the northern South China Sea in winter,it gets weaker and weaker from spr ing to summer,to autumn.Distribution of sound velocity of sea water in 50 m depth is complex because of jointaction of circulation and water masses.In spring and summer sound velocity decreases as depth increasing,but in autumn and winter it increases as depth increases in the upper layer and then decreases as depth increasing.Variation of monthly-averaged sound velocity looks like a annual wave variation and is similar to variation o f temper ature.Variation amplitude decreases as depth increasies and its phase in the surface is almost opposed to that in 100 m depth.
Based on the temper ature,salinity and depth data measured from 1975 to 1998 in the northern South China Sea,variation of sound velocity of upper water(0~100 m) is discussed.The results show that annual variation of sound velocity of sea water is of importance.Dist ribution of sound velocity of sea water in the surface is notably influenced by water masses.There is a largest horizontal gradient near the continental shelf margin in the northern South China Sea in winter,it gets weaker and weaker from spr ing to summer,to autumn.Distribution of sound velocity of sea water in 50 m depth is complex because of jointaction of circulation and water masses.In spring and summer sound velocity decreases as depth increasing,but in autumn and winter it increases as depth increases in the upper layer and then decreases as depth increasing.Variation of monthly-averaged sound velocity looks like a annual wave variation and is similar to variation o f temper ature.Variation amplitude decreases as depth increasies and its phase in the surface is almost opposed to that in 100 m depth.
2001, 23(5): 49-57.
Abstract:
Long-chain alkenone compounds have been first detected in surface sediments from the Chukchi Sea and the Bering Sea in the Arctic.The result shows that C37:3 methy alkenones predominate in the Arctic.Abundances of C37～C39 methy and ethyl alkenones change in or der of C37>C38>C39.The ratio between total abundances of C37 and C38 alkenone(∑C37/∑C38) may indicate the production ratio of alkenones derived from the coceolithophrid (Emiliania huxleyi).Calibration of alkenone unsaturation ratios(U37k and U37k') is used to estimate paleotemperature,U37k-T is used to the indication of SST range from 4.147 to 5.706℃ (average value is 5.092℃).
Long-chain alkenone compounds have been first detected in surface sediments from the Chukchi Sea and the Bering Sea in the Arctic.The result shows that C37:3 methy alkenones predominate in the Arctic.Abundances of C37～C39 methy and ethyl alkenones change in or der of C37>C38>C39.The ratio between total abundances of C37 and C38 alkenone(∑C37/∑C38) may indicate the production ratio of alkenones derived from the coceolithophrid (Emiliania huxleyi).Calibration of alkenone unsaturation ratios(U37k and U37k') is used to estimate paleotemperature,U37k-T is used to the indication of SST range from 4.147 to 5.706℃ (average value is 5.092℃).
2001, 23(5): 58-64.
Abstract:
Resear ches on phosphorus recoveries from sodiumpy rophosphate(Na4P2O7) after ignition at temper ature from 200 to 550℃ with auxiliary,such as MgSO4,Mg(NO3)2,MgCl2,MgAc2,CaCl2,Ca(NO3)2 and so on,are finished.The results indicate that MgSO4 gives poor phosphorus recovery at any ignition temperature from 200 to 550℃,when the final residue is extracted with 0.2 mol/dm3 HCl at 80℃ for 30 min.By contrast,Mg(NO3)2, MgCl2,MgAc2,CaCl2 and Ca(NO3)2 give very good phosphorus recovery with ignition temperature being equal to or greater than 450℃.It is sugg ested that MgCl2(or MgAc2) rather than MgSO4 can be used as ashing assistant in the phosphorus determination by ignition method.
Resear ches on phosphorus recoveries from sodiumpy rophosphate(Na4P2O7) after ignition at temper ature from 200 to 550℃ with auxiliary,such as MgSO4,Mg(NO3)2,MgCl2,MgAc2,CaCl2,Ca(NO3)2 and so on,are finished.The results indicate that MgSO4 gives poor phosphorus recovery at any ignition temperature from 200 to 550℃,when the final residue is extracted with 0.2 mol/dm3 HCl at 80℃ for 30 min.By contrast,Mg(NO3)2, MgCl2,MgAc2,CaCl2 and Ca(NO3)2 give very good phosphorus recovery with ignition temperature being equal to or greater than 450℃.It is sugg ested that MgCl2(or MgAc2) rather than MgSO4 can be used as ashing assistant in the phosphorus determination by ignition method.
2001, 23(5): 65-69.
Abstract:
Based on the investigation information from four cruises on the Nansha Islands in May 1990,December 1993,September 1994 and July 1999,respectively,distribution featur es and seasonal variations for dissolved ox ygen maximum in vertical profile in waters of the Nansha Islands are studied.By comparing with the dissolved oxygen maximum occurred in the East China Sea and the Huanghai Sea in spring and summer,it is found that seasonal features of the dissolved oxygen maximum in the Nansha Islands differ from those in the East China Sea and the Huanghai Sea in many sides.
Based on the investigation information from four cruises on the Nansha Islands in May 1990,December 1993,September 1994 and July 1999,respectively,distribution featur es and seasonal variations for dissolved ox ygen maximum in vertical profile in waters of the Nansha Islands are studied.By comparing with the dissolved oxygen maximum occurred in the East China Sea and the Huanghai Sea in spring and summer,it is found that seasonal features of the dissolved oxygen maximum in the Nansha Islands differ from those in the East China Sea and the Huanghai Sea in many sides.
2001, 23(5): 70-77.
Abstract:
Three hundred and seventy vibrocores were obtained from the East China Sea continental shelf during 1994~1995,aiming at surface geochemical exploration for oil and gas.Samples from the bottom o f each vibrocore were tested for magnetic properties.The result demonstrates there exist SIRM anomalies in the study area.It is suggested that greigite is the mineral causing the SIRM highs according to the magnetic properties.Magnetic minerals were separated from the high SIRM sediments to further identify them.Analyses conducted by scanning electron microscopy attached with energy dispersive X-ray analysis,X-ray diffracto grams,and Mssbauer spectrum prove that the magnetic separations are predominantly greigite and pyrrhotite.Distribution of SIRM highs in the study area coincides with that of the tectonic contr olled hydrocarbon traps and surface geochemical anomalies.This suggests that the greigite generating the SIRM anomalies of the study area is products of hydrocarbon seepage.It is thus proposed that SIRM can be selected as a proper parameter for magnetic detection of oil fields in the study area.
Three hundred and seventy vibrocores were obtained from the East China Sea continental shelf during 1994~1995,aiming at surface geochemical exploration for oil and gas.Samples from the bottom o f each vibrocore were tested for magnetic properties.The result demonstrates there exist SIRM anomalies in the study area.It is suggested that greigite is the mineral causing the SIRM highs according to the magnetic properties.Magnetic minerals were separated from the high SIRM sediments to further identify them.Analyses conducted by scanning electron microscopy attached with energy dispersive X-ray analysis,X-ray diffracto grams,and Mssbauer spectrum prove that the magnetic separations are predominantly greigite and pyrrhotite.Distribution of SIRM highs in the study area coincides with that of the tectonic contr olled hydrocarbon traps and surface geochemical anomalies.This suggests that the greigite generating the SIRM anomalies of the study area is products of hydrocarbon seepage.It is thus proposed that SIRM can be selected as a proper parameter for magnetic detection of oil fields in the study area.
2001, 23(5): 78-86.
Abstract:
The Sanmen Bay is frequently influenced by the typhoon,sediment exchange between beach and channel is stronger when storms hit this bay.Tidal currents are forceful with strong bottom current due to the topographic effect and predominantebb occurs in the Maotou Channel.These features of tidal currents are a dynamic foundation to form deeper trough and to keep stability.The seabed is in the equilibrium of erosion and siltation with slight siltation in last 100 a.However,when the storms hit the bay,siltation occurs obviously in the trough and erosion in the broad tidal flat.The sediments which are eroded from tidal flat provide resources for rapid deposit in the Maotou Channel.An average depth of profile across deeper trough reduced about 142 cm measured on August 26,1994,a week after No.9417 typhoon passed the bay.T he data show that siltation streng thens from the slope to the bottom. Then the setting sediment by the storm can be resuspended and removed with the tidal current during normal weather.The depth in the trough is restored with slight erosion measured in January 1995,comparing the depth measured in June 1994.But some years,sedimentation occurred in the Maotou Trough.Three and 4 continued strong tropical storms hit the bay in 1989,1990 respectively,they resulted in storm sediment to retain the trough.It is considered that deposited strata have stored in information of storm sediments in the deeper trough.Some "black mud" layers which contain higher water content,high organic content,low solidity and no-bedding in the undisturbed core are recognized as a rapid deposit retained in the Maotou deeper trough by all previous storms.
The Sanmen Bay is frequently influenced by the typhoon,sediment exchange between beach and channel is stronger when storms hit this bay.Tidal currents are forceful with strong bottom current due to the topographic effect and predominantebb occurs in the Maotou Channel.These features of tidal currents are a dynamic foundation to form deeper trough and to keep stability.The seabed is in the equilibrium of erosion and siltation with slight siltation in last 100 a.However,when the storms hit the bay,siltation occurs obviously in the trough and erosion in the broad tidal flat.The sediments which are eroded from tidal flat provide resources for rapid deposit in the Maotou Channel.An average depth of profile across deeper trough reduced about 142 cm measured on August 26,1994,a week after No.9417 typhoon passed the bay.T he data show that siltation streng thens from the slope to the bottom. Then the setting sediment by the storm can be resuspended and removed with the tidal current during normal weather.The depth in the trough is restored with slight erosion measured in January 1995,comparing the depth measured in June 1994.But some years,sedimentation occurred in the Maotou Trough.Three and 4 continued strong tropical storms hit the bay in 1989,1990 respectively,they resulted in storm sediment to retain the trough.It is considered that deposited strata have stored in information of storm sediments in the deeper trough.Some "black mud" layers which contain higher water content,high organic content,low solidity and no-bedding in the undisturbed core are recognized as a rapid deposit retained in the Maotou deeper trough by all previous storms.
2001, 23(5): 87-94.
Abstract:
Based on the stratigraphic and buried geomorphic analysis of three seismic profiles located in the inner and outer shelves of the East China Sea out of the present Changjiang Rivers mouth,and contr asting with some relevant geologic cores and Quaternary researches on the modern Changjiang River Delta,it is found that there are no paleosediments and paleo channels of the Changjiang River formed in the lasticeage maximum in the study area.The paleo channels of the Changjiang River as which former researchers were considered are actually present tidal chan-nels.There fore,probably the Changjiang River did not flow by the East China Sea shelf and enter the Okinawa Trough during that period.
Based on the stratigraphic and buried geomorphic analysis of three seismic profiles located in the inner and outer shelves of the East China Sea out of the present Changjiang Rivers mouth,and contr asting with some relevant geologic cores and Quaternary researches on the modern Changjiang River Delta,it is found that there are no paleosediments and paleo channels of the Changjiang River formed in the lasticeage maximum in the study area.The paleo channels of the Changjiang River as which former researchers were considered are actually present tidal chan-nels.There fore,probably the Changjiang River did not flow by the East China Sea shelf and enter the Okinawa Trough during that period.
2001, 23(5): 95-103.
Abstract:
The features and present positions of the boundary faults of Nansha microplate and its dynamic process during Cenozoic are discussed.According to the view point of "interlayer-glide-dip-slip-strike-slip 4-dimensional associated fault systematic motion of laye-rblock tectonics",it is proposed that the microplate is enclosed by differe transcrustal faults and can be regarded as a typical Cenozoic microplate.Facts show that the northern boundary the micr oplate moves to the present location of Chang long-Huangy an seamount chain (spreading ridge fault zone) from Kangtai-Shuangzi-Xiongnan transcrustal normal dip-slip fault zone,Baxian-Baram-Yoca-Cuyo trascrustal reversed-slip thrust fault zone as the southern boundary,Wan'an-Natuna transcrustal strike-slip pullapatransfer zone as the western boundary and Manila-Panay transcrustal strike-slip compressional transfer zone as theastern boundary.These boundary fault zones take the same top layer of Nansha asthenosphere as their shared dtachmental layer.In the light of the viewpo int of multivariant dynamic force origin,the Cenozoic dynamic process the microplate can be divided into four stages.(1) K2-E21,the delamination of lower lithosphere of South Chin continental margin resulted in the microplateps dispersing away from the margin of SE China-Indochina continen paleo-South China Sea(SCS) southward subducting under Sunda craton in the SW section of the southern bounda and under the oceanic crust of eastern Calimantan-Sulawesi Sea in the SE section of the southern boundary respetively,and the formation of Sibuaccretion wedge.(2) E22-E31,eastward hydraulic-pressure-transfe-rtype creepo the mantle flew under Tibet plateau lithosphere,eastward strike-slip extrusion of East A sian lithosphere and equtorward longitudinal inertia for cecaused by the incr ease of the earthps rotation rate,all of these forces initiated thopening of SW subbasin of the SCS,Sibu accretion wedge's collision with Kuching zone and the formation of C gayan-Kalumpang-Tungku-Sulu volcanic arc.(3) E32-N11,the central subbasin of the SCS opened,Miriaccrtion wedge formed.Mean while,Sulawesi Sea northwards subducted under Sulu arccaused by northward driftin and compression of Australian plate,Sulu Sea opened in Cagayan-Suluarc.And the southern margin of N or Palawan continental block subducted under Cagayan volcanic ridge,like the A-type subjection.(4) N12 to present the collision of the Australian-derived Banggai-Sula block with the northernarm of Sulawesi caused the southe boundary fault zone of the microplate thrusting and orogenic movementon a large-scale.And the spreading of the SCS stopped.
The features and present positions of the boundary faults of Nansha microplate and its dynamic process during Cenozoic are discussed.According to the view point of "interlayer-glide-dip-slip-strike-slip 4-dimensional associated fault systematic motion of laye-rblock tectonics",it is proposed that the microplate is enclosed by differe transcrustal faults and can be regarded as a typical Cenozoic microplate.Facts show that the northern boundary the micr oplate moves to the present location of Chang long-Huangy an seamount chain (spreading ridge fault zone) from Kangtai-Shuangzi-Xiongnan transcrustal normal dip-slip fault zone,Baxian-Baram-Yoca-Cuyo trascrustal reversed-slip thrust fault zone as the southern boundary,Wan'an-Natuna transcrustal strike-slip pullapatransfer zone as the western boundary and Manila-Panay transcrustal strike-slip compressional transfer zone as theastern boundary.These boundary fault zones take the same top layer of Nansha asthenosphere as their shared dtachmental layer.In the light of the viewpo int of multivariant dynamic force origin,the Cenozoic dynamic process the microplate can be divided into four stages.(1) K2-E21,the delamination of lower lithosphere of South Chin continental margin resulted in the microplateps dispersing away from the margin of SE China-Indochina continen paleo-South China Sea(SCS) southward subducting under Sunda craton in the SW section of the southern bounda and under the oceanic crust of eastern Calimantan-Sulawesi Sea in the SE section of the southern boundary respetively,and the formation of Sibuaccretion wedge.(2) E22-E31,eastward hydraulic-pressure-transfe-rtype creepo the mantle flew under Tibet plateau lithosphere,eastward strike-slip extrusion of East A sian lithosphere and equtorward longitudinal inertia for cecaused by the incr ease of the earthps rotation rate,all of these forces initiated thopening of SW subbasin of the SCS,Sibu accretion wedge's collision with Kuching zone and the formation of C gayan-Kalumpang-Tungku-Sulu volcanic arc.(3) E32-N11,the central subbasin of the SCS opened,Miriaccrtion wedge formed.Mean while,Sulawesi Sea northwards subducted under Sulu arccaused by northward driftin and compression of Australian plate,Sulu Sea opened in Cagayan-Suluarc.And the southern margin of N or Palawan continental block subducted under Cagayan volcanic ridge,like the A-type subjection.(4) N12 to present the collision of the Australian-derived Banggai-Sula block with the northernarm of Sulawesi caused the southe boundary fault zone of the microplate thrusting and orogenic movementon a large-scale.And the spreading of the SCS stopped.
2001, 23(5): 104-109.
Abstract:
A total of 862 biobenthic species are found in the intertidal zone Fujian islands,which belong to 734 species of animals,128 species of algae.Jaccard's similarity index of species is measured,and the distribution of the benthic community is studied using hierarchical clustering(WPGMA) and polarordination.The result indicates that the benthic communities are divided into three classifications:the estuary type,harbour type and wide sea type of the community.The distribution of the benthic community is related to the island location and its environment.The salinity and motive power of the water are major factors which influence the community.
A total of 862 biobenthic species are found in the intertidal zone Fujian islands,which belong to 734 species of animals,128 species of algae.Jaccard's similarity index of species is measured,and the distribution of the benthic community is studied using hierarchical clustering(WPGMA) and polarordination.The result indicates that the benthic communities are divided into three classifications:the estuary type,harbour type and wide sea type of the community.The distribution of the benthic community is related to the island location and its environment.The salinity and motive power of the water are major factors which influence the community.
2001, 23(5): 110-115.
Abstract:
Two hundred and sixty-six species coastal vascular plants distributed along the Minjiang River Estuary in Fujian are recorded.Among them,herbaccounts for 70.2%,frutex accounts for 21.4%,vine and arbor account for 8.4%.Salt-loving species distributed along the inner,middle and outer estuary account for 5.7%,6.8% and 11.8%,respectively.Ipomoea pes-caprae,Suaeda australis,Tetragonia tetragonoides are saline-alkali indictor. Near fresh waters in the inner estuary there are rankness of Cyperus malaccensis var.brevifolius,Arundo donax and Phragmites communis
Two hundred and sixty-six species coastal vascular plants distributed along the Minjiang River Estuary in Fujian are recorded.Among them,herbaccounts for 70.2%,frutex accounts for 21.4%,vine and arbor account for 8.4%.Salt-loving species distributed along the inner,middle and outer estuary account for 5.7%,6.8% and 11.8%,respectively.Ipomoea pes-caprae,Suaeda australis,Tetragonia tetragonoides are saline-alkali indictor. Near fresh waters in the inner estuary there are rankness of Cyperus malaccensis var.brevifolius,Arundo donax and Phragmites communis
2001, 23(5): 116-120.
Abstract:
The ultrastructure of sper matog enesis and spermiog enesis in the grey mullet(Mugil cephalus) is investigated by means of transmission electron microscope.The results reveal that there are two types of spermatogonia, Type A and Type B,in the early developmental stage of testes.Nuages appear around nucleus in Type B spermatogonia,which indicates that sper matogonia are ready to develop into primary spermatocytes.Pairing of autochromo-somes is clearly observed in the early period of meiosis in the primary spermatocytes.There exist cell junctions between the two spermatids.Matured sper matozoo n is composed of head,midpiece and tail.The head has a horse-hoo-flike nucleus with a shallow nuclear hollow.There is not any acrosome in front of nucleus.Chromtin within nucleus is rough granule in shape and there is a larger space between nuclear membrane and cytoplasmic membrane. The midpiece of spermatozoon is short.The proximal centriole and distal centriole are perpendicular to each other. The tail is long and there is a pair of lateral fins along the two sides of flag ellum.The flagellum shows a typical microtube organization of "9+2" in the view of cross-section.The ultrastructural character istics and endocrine functions of the non-germinal cells,both Sertoli cell and Leydig cell,in the mullet testes are also discussed.
The ultrastructure of sper matog enesis and spermiog enesis in the grey mullet(Mugil cephalus) is investigated by means of transmission electron microscope.The results reveal that there are two types of spermatogonia, Type A and Type B,in the early developmental stage of testes.Nuages appear around nucleus in Type B spermatogonia,which indicates that sper matogonia are ready to develop into primary spermatocytes.Pairing of autochromo-somes is clearly observed in the early period of meiosis in the primary spermatocytes.There exist cell junctions between the two spermatids.Matured sper matozoo n is composed of head,midpiece and tail.The head has a horse-hoo-flike nucleus with a shallow nuclear hollow.There is not any acrosome in front of nucleus.Chromtin within nucleus is rough granule in shape and there is a larger space between nuclear membrane and cytoplasmic membrane. The midpiece of spermatozoon is short.The proximal centriole and distal centriole are perpendicular to each other. The tail is long and there is a pair of lateral fins along the two sides of flag ellum.The flagellum shows a typical microtube organization of "9+2" in the view of cross-section.The ultrastructural character istics and endocrine functions of the non-germinal cells,both Sertoli cell and Leydig cell,in the mullet testes are also discussed.
2001, 23(5): 121-129.
Abstract:
A reformed numerical model based on one-line theory for beach deformation is presented.In this model, the change of slope of beach during beach procession is considered.A wave numerical model combined with wave refraction,diffraction and reflection is used to simulate wave climate to increase the numerical accuracy.The results show that the numerical model has a good precision based on enough field data.The results can be applied to real engineering.
A reformed numerical model based on one-line theory for beach deformation is presented.In this model, the change of slope of beach during beach procession is considered.A wave numerical model combined with wave refraction,diffraction and reflection is used to simulate wave climate to increase the numerical accuracy.The results show that the numerical model has a good precision based on enough field data.The results can be applied to real engineering.
2001, 23(5): 130-135.
Abstract:
A SAR ocean image data enhancement system based on the wavelet transformation is represented,and implemented.This system includes functions of wavelet transfor mation,Speckle and Pepper-Salt denoising,ship targets obtaining,internal wave obtaining,target character istics and imagezoom.The system can enhance some image with Gaussian noise,Speckle and Pepper-Salt non-Gaussian noise,and image of microwave,optical sensors, such as SAR image.It has a variety of applications.
A SAR ocean image data enhancement system based on the wavelet transformation is represented,and implemented.This system includes functions of wavelet transfor mation,Speckle and Pepper-Salt denoising,ship targets obtaining,internal wave obtaining,target character istics and imagezoom.The system can enhance some image with Gaussian noise,Speckle and Pepper-Salt non-Gaussian noise,and image of microwave,optical sensors, such as SAR image.It has a variety of applications.
2001, 23(5): 136-140.
Abstract:
2001, 23(5): 141-145.
Abstract:
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