2009 Vol. 28, No. 5

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Articles
Analyses of the long-term salinity variability in the Bohai Sea and the northern Huanghai(Yellow) Sea
YU Huaming, BAO Xianwen, LÜ Cuilan, CHEN Xu'en, KUANG Liang
2009, (5): 1-8.
Abstract:
Based on the comprehensive collection of the field observed salinity of the Bohai Sea (BHS) and the northern Huanghai Sea (NHS) from the 1950s to the present,the patterns of 10-years-averaged salinity at the different layers in the recent five decades (the 1950s,the 1960s,the 1970s,the 1980s and the 1990s) are obtained by the spatial-temporal interpolation technique with the scrupulous data quality control in this study.Then,by combining the spatial-temporal interpolation technique with successive correction method,the annual distributions of salinity both in the BHS and in the NHS are obtained as well.The data analyses indicate that the overall salinity in the BHS and the NHS increases from the 1960s till the present,with the increase of annual mean salinity of 0.04 psu from the 1950s,and the maximum increase rate of salinity is about 0.14 psu/a in the Bohai Bay.The high salinity tongue extended significantly from the NHS into the BHS.The intensified eastern wind field is related to the western intrusion of the NHS warm current,which probably leads to the moving forward of the high salinity water mass into the BHS.However,it is rather different from the salinity distribution characteristics between the 1950s and the 1960s.The extensive precipitation in the 1960s could lead to an increase in the discharge of the Huanghe River,which might result in the decrease of salinity in the BHS.But the salinity isoline of 32 in the NHS still extended significantly into the BHS in the 1960s.Since the 1980s,the patterns of salinity distribution have changed thoroughly.The salinity in the central area of the BHS was low,while the salinity in the Bohai Bay and the Liaodong Bay was higher than the other regions with its horizontal salinity gradient decreasing in the 1980s.The Empirical Orthogonal Function Analysis (EOF) is also conducted to study the interannual salinity variability of the BHS and the NHS.The correlation coefficient between the time coefficient series of the main mode and the Huanghe River discharge can reach -64.57%.It can be concluded that salinity variation of the BHS and the NHS has strong negative correlation with the Huanghe River discharge.
Estimation of eddy viscosity on the South China Sea shelf with adjoint assimilation method
ZHANG Yanwei, TIAN Jiwei, XIE Lingling
2009, (5): 9-16.
Abstract:
The eddy viscosity of the ocean is an important parameter indicating the small-scale mixing process in the oceanic interior water column.Ekman wind-driven current model and adjoint assimilation technique are used to calculate the vertical profiles of eddy viscosity by fitting model results to the observation data.The data used in the paper include observed wind data and ADCP data obtained at Wenchang Oil Rig on the SCS (the South China Sea) shelf in August 2002.Different simulations under different wind conditions are analyzed to explore how the eddy viscosity develops with varying wind field.The results show that the eddy viscosity endured gradual variations in the range of 10-3-10-2 m2/s during the periods of wind changes.The mean eddy viscosity undergoing strong wind could rise by about 25% as compared to the value under weak wind.
A preliminary study of the variation of phytoplankton absorption coefficients in the northern South China Sea
WU Jingyu, HONG Huasheng, SHANG Shaoling, DAI Minhan, LEE Zhongping, LI Shaojing
2009, (5): 17-29.
Abstract:
The temporal and spatial variabilities of phytoplankton absorption coefficients (aph (λ)) and their relationships with physical processes in the northern South China Sea were examined,based on in situ data collected from two cruise surveys during May 14 to 25,2001 and November 2 to 21,2002.Significant changes in the surface water in aph values and B/R ratios (aph (440)/aph (675)) were observed in May,which were caused by aph ytoplankton bloom on the inner shelf stimulated by a large river plume due to heavy precipitation.This is consistent with the observed one order of magnitude elevation of chlorophyll a and a shift from a pico/nano dominated phytoplankton community to one dominated by micro-algae.Enhanced vertical mixing due to strengthened northeast monsoon in November has been observed to result in higher surface aph (675) (0.002-0.006 m-1 higher) and less pronounced subsurface maximum on the outer shelf/slope in November as compared with that in May.Measurements of aph and B/R ratios from three transects in November revealed a highest surface aph (675) immediately outside the mouth of the Zhujiang (Pearl) River Estuary,whereas lower aph (675) and higher B/R ratios were featured in the outer shelf/slope waters,demonstrating the respective influence of the Zhujiang River plume and the oligotrophic water of the South China Sea.The difference in spectral shapes of phytoplankton absorption (measured by B/R ratios and bathochromic shifts) on these three transects infers that picoprocaryotes are the major component of the phytoplankton community on the outer shelf/slope rather than on the inner shelf.A regional tuning of the phytoplankton absorption spectral model (Carder et al.,1999) was attempted,demonstrating a greater spatial variation than temporal variation in the lead parameter a0 (λ).It was thus implicated that region-based parameterization of ocean color remote sensing algorithms in the northern South China Sea was mandatory.
Research on extracting method of micro-scale remote sensing information combination and application in coastal zone
YANG Xiaomei, ZHOU Chenghu, GONG Jianming, GAO Zhenyu
2009, (5): 30-38.
Abstract:
Due to the need of rapid and sustainable development in China's coastal zones,the high-resolution information theory using data mining technology becomes an urgent research focus.However,the traditional pixel-based image analysis methods cannot meet the needs of this development trend.The paper attempts to present an information extraction approach in terms of image segmentation based on an object-oriented algorithm for high-resolution remote sensing images.An aim of the author' research is to establish an identification system of "pixel-primitive-object".Through extraction and combination of micro-scale coastal zone features,some objects are classified or recognized,e.g.,tidal flat,water line,sea wall,and mariculture pond.Firstly,the authors extract various internal features of relatively homogeneous primitive objects using an image segmentation algorithm based on both spectral and shape information.Secondly,the features of those primitives are analyzed to ascertain an optimal object by adopting certain feature rules.The results from this research indicate that our model is practical to realize and the extraction accuracy of the coastal information is significantly improved as compared with the traditional approaches.Therefore,this study provides a potential way to serve the author' highly dynamic coastal zones for monitoring,management,development and utilization.
Study of attenuation depths for MODIS bands in the Bohai Sea in China
LIU Ying, LI Guosheng
2009, (5): 39-48.
Abstract:
An attenuation depth is defined for remote sensing purposes as a depth above which 90% of the arising light leaving the water surface is originated.The deeper the attenuation depth,the more information of water is detectable by remote sensing,then the more precise information of water is extracted.Meanwhile,the attenuation depth is helpful to know water layer (by its thickness) from which remote sensing will be able to extract information.A number of investigators are using the moderate resolution imaging spectroradiometer (or MODIS) for remote sensing of ocean color.It is necessary to have a rough idea of the effective attenuation depth of imagery in each of the spectral bands employed by the MODIS.The attenuation depth is directly determined from MODIS data.Though analyzing the spectral distribution of the attenuation depth on 7 August 2003 and the seasonal variation of the attenuation depth (551 nm) in the Bohai Sea indicated that:the spectral distribution of the attenuation depth for the spectral range between 400 to 700 nm is single-peak curve,and it's similar and difference in different regions is consistent with other scholars' results of zoning,moreover,it supports the Bohai Sea is Case 2 water; the maximum attenuation depth shifts toward longer wavelengths,liking the red shift,with increase of turbidity of water,just like the maximum attenuation depth in the outside of the northwest coast of the Bohai Sea and the Bohai Strait is at 531nm,in the central of the Bohai Sea is at 551nm,in the region controlled by the Huanghe (Yellow) River,the region impacted by the old Huanghe River,the western side of the Liaodong Bay and the eastern side of the Liaodong Bay is at 555 nm; the seasonal change of the attenuation depth is the largest in the summer,followed by the fall,and the ranking of winter and spring in different regions is distinct.The attenuation depth in different regions is dissimilar:the order of the attenuation depth in different regions from small to big is the region controlled by the Huanghe River or the eastern side of the Liaodong Bay,the western side of the Liaodong Bay,the region impacted by the old Huanghe River,the central of the Bohai Sea or the outside of the northwest coast of the Bohai Sea,the Bohai Strait (except at 412 nm and 645 nm),in which between the region controlled by the Huanghe River and the eastern side of the Liaodong Bay (and between the central of the Bohai Sea and the outside of the northwest coast of the Bohai Sea) it varies in different seasons and different bands.
The application of geographic information technology to coastal geomorphology
GUO Wei, LI Shuheng, ZHU Dakui
2009, (5): 49-57.
Abstract:
With the development of modern oceanic observation technologies,coastal survey data have been experiencing a substantial growth.The integration management of the data from different disciplines,different sources and different formats has become a major research field in coastal geomorphology by using Geographic Information System (GIS).This paper puts forward a new methodology framework of GIS techniques in coastal ocean geomorphology,including data acquisition,process,analysis,and representation.It focuses on some major GIS techniques to study the land-ocean interaction mechanism,such as spatial analysis,submarine topography model and three-dimension (3D) visualization,and apply its result to coastal urban planning,harbor site selection and geomorphology environment about coral reef and islands on the continental shelf.The case studies cover the whole coastal ocean to serve the social community,economical development and diplomatic rights for decision-making all round in the coastal zone.The research shows clearly that the application of coastal multi-source geospatial platform has changed the traditional coastal geomorphology science dramatically from its research scope,fields and methods,however,as made clear in this paper,extracting accurate information from remote sensing data and GIS databases for coastal geomorphological applications is a nontrivial challenge that requires the combined knowledge and skills of information scientists and geomorphologists.
Morphology and internal architecture of a banner bank off Chengshan Headland, Shandong Peninsula
ZHOU Liangyong, LIU Jian, XUE Chunting, KONG Xianghuai, BAI Dapeng
2009, (5): 58-65.
Abstract:
A banner bank off the north coast of the Chengshan Headland,Shandong Peninsula,has been described on the basis of echo sounder bathymetry,side-scan sonar and high-resolution seismic data sets.The bank is in NWW direction,approximately parallel to the coastline.The bank consists of sandy silt or clayed silt.Sand waves and megaripples are observed on the north side,which result from strong tidal currents around the headland and storm waves in winter.These bed forms indicate that the bank is influenced by the modern hydrodynamics.The bank is separated from the coast and Holocene subaqueous clinoform around the Shandong Peninsula in its east part.High-resolution seismic profiles reveal that the bank was formed during two periods:the earlier seismic unit Ua,and later seismic units Ub and Uc which overlays Ua with erosional surfaces on its south side and north side,respectively.As comparing with the clinoform,the bank has a different internal architecture.In the west of the bank,however,topography and surface sediment characteristics suggest that the bank links to the clinoform.The authors propose that seismic Ua is a residual part of early clinoform deposit.After the sediments in the north and south of Ua were eroded by strong currents,the Ub and Uc started to deposit probably by a complex hydrodynamic process.These results provide new insights into the evolution of the bank and its relation with the Holocene subqueous clinoform.
The vertical attenuation of irradiance as a function of turbidity: a case of the Huanghai(Yellow) Sea in spring
LIN Shaoying, ZOU Tao, GAO Huiwang, GUO Xinyu
2009, (5): 66-75.
Abstract:
The planar photosynthetically available radiation (PAR),turbidity and concentration of chlorophyll a (chl a),were measured at 26 stations in the Huanghai (Yellow) Sea during a cruise of China SOLAS from 19 to 27 March 2005.Due to low chl a (<0.35 mg·m-3) in upper layers (above 5 m),suspended particulate matter became the major factor that influenced the turbidity in early spring.The calculated vertical diffuse attenuation coefficient of PAR,KPAR,varied with water depths with a maximum value in the upper 5 m layer.The mean KPAR in survey area was 0.277±0.07 m-1 that is considerably higher than most of the other case 2 waters.Within the survey area,KPAR also showed distinct regional characteristics,corresponding to the distribution of turbidity.Based on measurements,the relationship between KPAR and turbidity as well as chl a was established.It was suggested that suspended particulate matter plays an important role in light attenuation in the Huanghai (Yellow) Sea in spring.
Occurrence of gonadtropins like substance in the thoracic ganglion mass of the mud crab, Scylla paramamosain(Crustacea: Decapoda: Brachyura)
YE Haihui, HUANG Huiyang, WANG Guizhong, LI Shaojing
2009, (5): 76-80.
Abstract:
The identification and localization of vertebrate follicle stimulating hormone (FSH) and luteinizing hormone (LH) in crustaceans may further elucidate the regulation mechanisms in arthropod repro-duction.Using immunocytochemical staining techniques,this study has localized vertebrate FSH-like and LH-like substances in neurons in the subesophageal and thoracic ganglia from the thoracic ganglion mass (TGM) of Scylla paramamosain (Crustacea:Decapoda:Brachyura).Enzyme-linked immunosorbent assay (ELISA) has shown that the concentrations of both FSH-and LH-like sub-stances increased markedly in the TGM during the vitellogenic stage compared with that in the previtellogenic stage.These results indicate that substances resembling the vertebrate FSH and LH are present in S.paramamosain,and they may be involved in the development of the ovary as well as in ovulation.
Community structure of macrobenthos in coastal water off Rushan, southern Shandong Peninsula, and the relationships with environmental factors
LI Xinzheng, LI Baoquan, WANG Hongfa, WANG Jinbao, WANG Xiaochen, ZHOU Jin, HAN Qingxi, MA Lin, DONG Chao, ZHANG Baolin
2009, (5): 81-93.
Abstract:
To understand the present actuality of the marine ecosystem in the southern coastal water region of the Shandong Peninsula and the impact of the global change and the human activities to the marine ecosystem of the region,the macrobenthic community structure was researched based on data from 26 sampling stations carried out on four seasonal cruises from December 2006 to November 2007.The data was analyzed using PRIMER 6.0 and SPSS 15.0 software packages.The results showed that 236 macrobenthic species in total were collected from the research region by the field works.Most of the species belong to Polychaeta (76 species),Mollusca (75) and Crustacea (60).Of which,33 species were common species by the four cruises.The dominant species were different among the four seasons,however,the polychaete species Nephtys oligobranchia and Sternaspis scutata were always dominant in the four seasons.The abundances and biomasses of the macrobenthos from the research region were variable in the four seasons.The results of CLUSTER and MDS analysis showed that the similarities of macrobenthic structures among the stations were low,most of the similarities were at about 40% of similarity values,only that of two stations were up to 60%.In accordance with the similarity values of the macrobenthic structures,the 26 stations were clustered as six groups at arbitrary similarity level of 30%.The ABC curve indicated that the marcofauna communities in the research region had not been disturbed distinctly.The results of BIOENV and BVSTEP (Spearman) analysis implied that the concentrations of organic matter in bottom water and heavy metal copper in sediment,water depth and temperature of bottom were the most significant environmental factors to affect the macrobentic community.
Phylogenetic diversity of bacterial biofilms covering the settlement substrates of nona-porous abalones(Haliotis diversicolor supertexta)
MA Ying, WANG Zhiyong, CHEN Zhengqiang, LU Yu, WANG Lin
2009, (5): 94-102.
Abstract:
The settlement substrates of nona-porous abalones (Haliotis diversicolor supertexta) are covered with biofilms in which several types of microorganisms coexist and interact.These microorganisms are usually important causes of juvenile abalone disease as well as organisms useful in promoting abalones' adhesion.The bacterial community structure of the biofilms remains unclear.The aim of this research was to determine the genetic diversity and phylogenetic affiliation of the biofilm bacteria.Total DNA of bacteria in biofilms was extracted,and 16S rRNA gene clone library was constructed using the primers specific for the domain bacteria.Subsequently,30 randomly selected positive clones were screened by PCR-restriction fragment length polymorphism (PCR-RFLP) analysis,and resulted in 15 different RFLP patterns.Sequences analysis of representatives from each unique RFLP type revealed high genetic diversity in the bacterial populations.These sequences fell into nine major lineages of the bacterial domains:α-,β-,γ- and δ-subdivisions of the Proteobacteria; Planctomycete,Actinobacteria,Firmicutes,Verrucomicrobium spp.,and CytophagaFlexibacter-Bacteroides spp.Phylogenetic analysis indicated that the dominant phylotypes were most closely related to environmental and clinical Burkholderia cepacia of the β-Proteobacteria,and Roseobacteria of the α-Proteobacteria.
Numerical study on vertical structures of undertow inside and outside the surf zone
ZHANG Chi, WANG Yigang, ZHENG Jinhai
2009, (5): 103-111.
Abstract:
Nearshore shoaling and breaking waves can drive a complex circulation system of wave-induced currents.In the cross-shore direction,the local vertical imbalance between the gradient of radiation stress and that of pressure due to the setup drives an offshore flow near the bottom,called ‘undertow’,which plays a significant role in the beach profile evolution and the structure stability in coastal regions.A 1DV undertow model was developed based on the relationship between the turbulent shear stress and the gradient of horizontal current velocity.A shear stress boundary condition at the wave trough level derived from the momentum balance equation combined with a no-slip condition at the sea bed were applied to solve the vertical structure of undertow.The turbulent eddy viscosity was assumed to be relevant to the breaking energy dissipation and linearly distributed over depth.The wave characteristics as inputs for the present model were obtained by solving an extended wave energy balance equation incorporating the surface roller effect.Numerical results showed generally good agreements with three series of experimental data for various bathymetries and wave conditions.Comparisons indicated that the formula proposed in this paper for the shear stress at wave trough level could reasonably improve the modeled undertow profiles especially outside the surf zone and a little distance shoreward of the breaking point,and revealed that the model performs well in simulating both vertical and horizontal distributions of undertow and is capable of providing hydrodynamic forcing for the cross-shore sediment transport.
Research Notes
The study on a new technology of waterway information system
HUANG Yu, WU Honghai, HE Ye, YAO Shengchu
2009, (5): 112-115.
Abstract:
It is a lot limitations to survey and design waterway by the CAD technique,due to timely variation of hydrology and ecology in the complicated estuary area,such as Changjing River estuary.In this paper,the advantages of GIS technique is applied to manage and process the multi kind,multi scale and multi time hydrographic parameters,including water depth,current velocity,tidal,waves,wind speed,temperature and salinity etc.,also to deal with different projection,different scale charts.Meanwhile,in the paper,combination techniques of GIS and CAD has been developed for unification of the charts for efficient management,two-way automatic carts conversion between GIS and CAD,automatic cutting and assemble of a number of Charts,flight path of the projection of spatial data and coordinate transformation.This new technique has been applied to survey and design waterway of Changing River estuary.The result shows that the combination technology of GIS and CAD has application potentiality in the waterway survey and design.
Characteristics of sediment transport in the Zhoushan Archipelago sea area
HU Rijun, WU Jianzheng, LI Guangxue, ZHU Longhai, MA Fang
2009, (5): 116-127.
Abstract:
Based on the field data including tidal current,suspended sediment concentration,grain size of surface sediments,the transport mechanism and movement trend of sediments are analyzed using the method of flux decomposition and Grain Size Trend Analysis.The results show that the concentration and flux of suspended sediments decrease sharply from the Hangzhou Bay to the offshore area.The suspended sediment transport is mainly controlled by advection transport including average current transport and Stokes drift-induced transport and the gravitational circulation transport.The surface sediments are transported from the entrance of the Hangzhou Bay to the offshore area in general; meanwhile,the sediment transport has two obvious transport trends in the offshore area.The interaction of tidal currents,residual currents,the East China Sea coastal current,Taiwan Warm Current and wind waves appear to play important roles in the sediment transport.Furthermore,the sediment distribution and transport are significantly affected by the Zhoushan Archipelago.