Volume articles

The surface cold and warm tongues are used as a key characteristic to describe the spatial feature of SST. However, that characteristic is often used qualitatively rather than quantitatively because of lacking quantitative parameters. In this paper, we use nine years (2006-2014) merged microwave and infrared SST data to analyze quantitatively the spatial and temporal variations of the surface cold and warm tongues in the Bohai, Yellow and East China Seas (BYES). The characteristics of the surface cold and warm tongues are expressed in terms of their path and associated temperature. Two cold tongues and six warm tongues are identified in the BYES in February. The Empirical Orthogonal Function (EOF) analysis shows that the total variance of the path of tongues is explained mostly by the three leading EOF modes (73.4%). Specifically, the first spatial mode of path shows that every tongue moves coherently in same direction, and the most significant movement occurs in the central and the west of East China Sea. In contrast, the second and third spatial modes show that most tongues move with a seesaw pattern, and the most significant movement occurs at the south of Kyushu and in the Yellow Sea respectively. The total variance of temperature on the path of tongues is explained mostly by the first EOF mode (69.6%),which has a coherent increase or decrease of temperature in each tongue with a large amplitude in the Bohai and Yellow Seas. Both the path and associated temperature of the tongues have a 2-3 year inter-annual variation, however only the second EOF temporal mode of the path has passed the significant test. In winter, the relatively even loss of the heat in the sea leads to a much faster decrease of SST in the shallow area than in the deep area and forms cold and warm patterns associated with the bathymetry of the BYES. The uneven advectional heat transport plays a different role at various areas to reinforce and compensate the decrease of SST. In the cold tongue area, the advectional heat transport reinforces the heat loss of the water and leads to a much colder SST than the surrounding area, consequently forms the cold tongues. In contrast, in the warm tongue areas, the advectional heat transport compensates the heat loss of the water and leads to a much warmer SST than the surrounding area, consequently forms the warm tongues. The advectional heat transport plays a major role at the formation of the cold and warm tongues in the BYES.

Thorpe scale and turbulent diffusivities in Prydz Bay of Antarctica were calculated based on Thorpe method and Conductivity-Temperature-Depth data. The strength of turbulent overturn was analyzed and its spatial distribution was also investigated. The results show that the larger Thorpe scale and turbulent diffusivities occur in rough topographic area and near the sea floor, and the maximum value of turbulent diffusivities exceeds 10 ^-2 m ²/s, which is about two or three orders of magnitude larger than that in the open ocean. Turbulent diffusivities and dissipation rate of turbulent kinetic energy show high-low-high vertical structure in some observational stations, especially in deep area. The larger values of buoyancy frequency appear in upper 500 m water column in deep area, but this phenomenon is not obvious in shallow area. The dissipation rates of turbulent kinetic energy in the stations around the point(67.25°S,73°E) and along the 78°E sections are quite large, which exceed 10 ^-6 w/kg, and even reach 10 ^-5 w/kg in a few stations.

The operation of Three Gorges Reservoir causes the variation of runoff in the middle and lower reaches of the Yangtze River, inevitably resulting in the changes in tidal dynamics. Based on the data of river discharge and tidal level in recent 20 years, the response of hydrodynamics in tidal reach of the Yangtze River to variation in runoff was investigated by statistical analysis and tidal harmonic analysis. The results show that the operation of Three Gorges Reservoir causes the significant change in interannual distribution of runoff, with river discharge increase by more than 20% percent in discharging period and decease during storage period. Besides, in river reach between Datong and Jiangyin, the tidal level with guarantee ratio of 10%~70% is significantly decreased, but the tidal level with guarantee ratio of 80%~100% is slightly increased. Furthermore, the tidal range and amplitude of M ₂ tidal constitute is decreased during discharging period, indicating a decrease in tidal dynamics, while the tidal range and amplitude of M ₂ tidal constitute is increased during storage period, indicating a increase in tidal dynamics.

The evolution of tidal bore in Qiantang Estuary were successfully reproduced by applying FVCOM model through improving the sea bed roughness coefficient and setting suitable background vertical eddy viscosity. Sea bed roughness coefficient,calculated using the Manning formulation, is between 0.000 2~0.002 9 with the varying depth. The background vertical eddy viscosity is 1×10 ^-4 m ²/s. The simulation well reproduces the tidal bore arriving time, tidal level, setup height, horizontal velocity magnitude and vertical profile, which implies the choice of parameters such as the bed roughness coefficient and background vertical eddy viscosity are reasonable. The procedure could be extended to simulate the 3D tidal movement for tidal bores.

High Frequency Surface Wave Radar(HFSWR) with small circular array was deployed in Zhujiajian and Shengshan to detect the winds, waves, and currents in the overlapping area in 2007. No. 1509 Typhoon Chan-hom landed in the coastal areas of Jujiajian, and then moved north by east, passing the HFSWR detection area. The HFSWR inversed results were compared to anchored buoy observed data and the large area wind data from ASCAT satellite remote sensing respectively. The results of comparison indicate that HFSWR data basically reflect the real distribution of wind and current at Zhoushan area during Typhoon Chan-hom, showing the HFSWR's applicability in detecting the winds and currents under high sea state conditions.

The contents and distribution of glycerol dialkyl glycerol tetraethers (GDGTs) were analyzed for ten surface sediments from Prydz Bay of Antarctic. The results show that the contents of GDGTs are 27.69~900.78 ng/g with the isoprenoid GDGTs accounts for 94% ~99%, much more higher than branched GDGTs. Isoprenoid and branched GDGTs have same distribution tendency that the highest content area appears in southeast while the lowest area appears in northwest direction. Isoprenoid GDGTs and branched GDGTs both have obvious positive correlation with TOC. Analysis shows that isoprenoid GDGTs comes from marine Archaea, while branched GDGTs derives from bacteria in sediments. Compared with the WOA database, the TEX ₈₆ and TEX ^L ₈₆ derived temperatures are consistent with the sea surface temperatures in January in the study area. This study means TEX ₈₆ and TEX ^L ₈₆ indexes could be applied to reconstruct the paleotemperature in Prydz Bay.

12 surface sediment samples from the western region of CC Zone of the East Pacific Ocean were taken as the research material, and the particle size, chemical composition and mineral composition were analyzed to discuss its sedimentary environment and material source. The study area is located in the deep ocean, and the sediment is mainly composed of the abyssal clay and silicon calcareous clay. It contains a small amount of siliceous clay, clayey siliceous ooze and clayey calcareous ooze. Clay mineral composition is mainly smectite and illite, containing part of the kaolinite and chlorite. Clay minerals indicate that the sediments in the area are mainly terrigenous,which are carried by high airflow. The Antarctic Bottom Water and hydrothermal activity have a certain influence on the source of the provenance. The geochemical characteristics of sediments also indicate that the sediments are mainly derived from terrestrial sources. The distribution curve of the REE is similar to that in the surface water of the North Pacific Ocean, and it shows strong Ce losses, indicating that the bio-deposition caused by biological activities also has a certain impact on the surface sediments.

The extracellular polymeric substance (EPS) was secreted when marine benthic diatom attached on submerged surfaces, the environment factors had a directly impact on the composition and secretion action of EPS. The effects of the oxygen content and the attachment area on EPS were studied. The EPS from marine benthic diatoms were extracted by hot solvent method. The phenol-sulfuric acid method was employed to measure the content of polysaccharide and the Coomassie Brilliant Blue G-250 method was employed to measure the content of protein in the extractions. The cell number of diatoms was measured through the method of blood cell counting plate and UV spectrophotometry. The results show that the growth rate of diatoms is fast and the secretion amounts of EPS in a single cell are great under the higher oxygen content and larger attachment area conditions. The oxygen content has a great impact on the content of water-soluble polysaccharide as the main composition in EPS, while it has little impact on the else components. Compared to the oxygen content, the attachment area has little impact on the attachment and growth of diatoms.

In order to reasonably develop, utilize and protect islands' resources in Liaoning Province and optimize the industry structures and arrangements on islands, the spatial distribution characteristics of islands in Liaoning Province were investigated by application of GIS spatial analysis, Lorenz Curve and Gini Coefficient calculation based on the statistical data of 633 islands'coordinates and land areas, which have been listed in the Standard Directory of Islands in China Sea .The results show that the distribution type of islands in Liaoning Province belongs to aggregated distribution and presents group and zonal distribution in space. The islands of Liaoning Province have shaped Changshan Island aggregation district in the northern of the Yellow Sea and shallow sea aggregation zones in the southern of Liaoning Peninsula and in the western of Liaodong Gulf in terms of the levels of aggregation. Approximately 60% islands locate within the range of 10 km off the mainland coastline in straight line, leading to near the land at high degree. The land areas are imbalance among islands with the Gini Coefficient of 0.9.

Aiming at the practical demand of deep ocean mining, the hydraulic station on the nodule collector was proposed to separate from the nodule collector and hydraulic station was designed as a floating body, relatively independent and suspended above the front of the nodule collector. Contour of floating body for polymetallic nodule concept vehicle (referred to as floating body) was designed, and its 3D model was established adopting SolidWorks. The hydrodynamic and computational model of the floating body was established, after simplifying the 3D model. Reynolds average navier-stokes algorithm (RANS algorithm) and turbulence model were applied, and drag data under the condition of different working conditions was obtained adopting fluid dynamics simulation and analysis software ANSYS CFX. Drag characteristic of floating body was studied adopting curve fitting function of Matlab, and the feasibility of contour design was verified.

To elucidate the composition and structure of macrobenthic communities and their inter-annual variations in the Yellow Sea and the Bohai Sea, Agassiz trawling was conducted in May 2010 and June 2013. The composition and structure of macrobenthic communities in the Yellow Sea and the Bohai Sea were revealed and analyzed, including species composition, dominant species, abundance, biomass and community structure, and AMBI and m-AMBI were also used to assess the ecological status. The results showed as follows: A total of 131 macrobenthic species were identified, with Mollusca (51 species) and Crustacea (42 species) as the dominant groups in these waters, followed by fishes, polychaetes and echinoderms. There were four species whose dominance were over 0.02, including Alpheus japonicus, Crangon hakodatei, S tegophiura sladeni and Acila mirabilis, of which Stegophiura sladeni had the highest abundance and dominance. The results of benthic biological indices (AMBI and m-AMBI) showed that the benthic ecological status in the Yellow Sea and Bohai Sea was relatively stable, however, the benthic ecological quality had degraded during the last few decades when compared with historical data and published researches.

The Kuroshio on-shelf intrusion northeast of Taiwan manifests as the subsurface Kuroshio water upwelling and a "cold dome" structure in summer. Using ROMS (Regional Ocean Modeling System) model, the three-dimensional structure of the cold dome and the circulation along with upwelling induced by Kuroshio intrusion were analyzed, and the mechanisms of the formation of upwelling were also discussed. Model results show that the center of the cold dome is located near 25.5°N, 122.5°E in the layers upper of 50 m with maximum 5 ℃ cooling, and close to the north end of Taiwan Island in the layers lower of 50 m. The result of current structures show that Kuroshio surface intrusion is not obvious at the north end of Taiwan Island. A cyclonic circulation exists near the region where the shelf break turns eastward. Upwelling mainly occurs near the large slope of shelf break, with two obvious routes of the subsurface water upwelled onto the shelf. One of the routes is north of the Taiwan Island and between the isobaths of 100 m and 200 m, while the other one is near the region where the shelf break turns eastward. In the upper layer, the advection term is the main dynamical factor of the upwelling. While in the near-bottom layer, both the advection and bottom friction terms contribute to the upwelling.

High resolution shallow seismic exploration with dense grids,line intervals of mostly 120 m and 200 m, was carried out in tidal ridges and troughs area west of Taiyangshan Ridge in the South Yellow Sea. The maximum sediment penetration was about 80~90 m. Two seismic sequences(SQ1 and SQ2) were identified and further divided into five sub-sequences (U1~U5). The underlain Sequence 1(U1) consisted of land sediments of Late Pleistocene, while the upper Sequence 2(U2~U5) was mainly formed by marine sediments of Holocene. Sedimentary environments of each sub-sequence were studied based on seismic facies characteristics. Since the later period of Late Pleistocene, the study area has been mainly undergone sedimentary environment evolution of delta distributaries—river incision—paleo-river channel fill—estuary offshore—delta offshore-shallow sea —present tidal ridges and troughs. A tidal sand ridge in narrow river mouth was developed during the middle Early Holocene in the study area, but afterwards were buried due to fast sea level rise. Present tidal sand ridges were formed after the last high sea level. They did not have any inherited relationship with paleo-tidal sand ridges, nor with paleo-topography of Late Pleistocene, but were controlled by tidal current system.

Chemical composition of plagioclase phenocryst zone, plagioclase crystallite and silicate of basalts in CA Seamount (sample CAD21), was examined using EPMA method and X-Ray fluorescence spectrometry (XRF) on basis of petrography. The basalts of CA Seamount are intraplate basalts formed by the activity of mantle plume. The core and the edge of zones of plagioclase phenocrysts show nonsequence optical extinction phenomenon, indicating a discontinuous zoning structure. The sequence of zones is labradorite to bytownite from edge to core, showing a normal zoning in the process of magmatic evolution. Such a phenomenon is constrained by melt composition and temperature-pressure condition. Average temperatures of plagioclase phenocrysts are 1 281 ℃(temperature of magmatic source),1 198℃(temperature of magmatic chamber) and 1 071 ℃(temperature of magmatic exhalation) respectively. The small temperature difference indicates a rapidly eruption process, in accord with the formation and eruption characteristics of oceanic island basalt magma.

With the application of GIS technology, the hydrographic data were transformed to DEM (digital elevation model) to calculate the amount of erosion and deposition, and then the evolution process of the main geomorphic units and their mechanism were also analyzed. There were several cognitions after analyzing: (1) The tendency of the sea bed erosion-accretion process was light scour, with 27 cm rang in 72 years and at the rate of 0.375 cm/a. (2) The deep channels expanded all the time. the Wenzhou Sand Bank was kept accretion tendency, and human activities speeded up this tendency for these years. Zhongsha Sand Bank and Chongshan Sand Bank were kept scour tendency, finally linked each other and became a new Zhongsha Sand Bank in 1992. (3) Under the dynamic mechanism, the sediment movement occured between deep channels and sand banks, which was the mechanism of erosion-deposition evolution in the sea bed.

In order to research the coupling interaction among mooring dynamic positioning vessel, wharf and cables, lumped mass method was used to calculate the effective tension, and nonlinear reaction force of dock fenders was simulated by Link unit in OrcaFlex. The thrust allocation of thrusters was based on PID control system. Under mooring conditions, with the comparison the difference in horizontal degree of freedom motion and cable's effective tension between general vessel and dynamic positioning vessel, the effect of thrusters on eliminating ship movement caused by first order wave loads has been explained. According to the results of mooring DP vessel and DP vessel in the same environment load, the influence of wharf-cable and target position on side thrusters and positioning ability were discussed. The results show that the performance of the side thrusters and vessel's positioning capability can be improved effectively under the reasonable selection of target position.

A positive six prism type artificial reef was designed to improve the marine fisheries habitat of the Zhoushan Archipelago. Two parameters of ε and η were used to evaluate the structure of artificial reefs, the value ε reflects the water permeability of artificial reefs and the value η reflects the adhesion ability of artificial reefs. The positive six prism type artificial reef was found to have a good permeability, and could also provide a larger area for the attachment of marine organisms. The design objectives were met. Based on the Fluent software, the CFD simulation of the fish reef was carried out, it was found that the maximum height of the upwelling increased with the flow velocity, and the length of the back vortex was about 9.3-9.6 times of the height of the fish reef, which indicated that it had a good hydrodynamic performance. In order to validate the performance of simulation further, flume experiment was conducted, which yielded consistent results as the simulation study. This further proved the validity of the hydrodynamic performance of the positive six prism artificial reef. The field experiment was also conducted at the end to evaluate the effect of the positive six prism reefs and to compare with the regular artificial reefs. Both the reefs could improve marine environment, but the average of density and biomass in the area of the positive six prism type artificial reef was higher than those in the control reef area, showing that the positive six prism artificial reef tended to have better hydrodynamic characteristics leading to more efficient in improving local habitats.

Based on the three phase of remote sensing images of Zhoushan Island in 1995, 2005 and 2015, through the interpretation of human-computer interaction, the image of the land resources and urban land use data were obtained. And then using the ecology analysis method, spatial statistics analysis method, urban expansion index method, the Zhoushan Island reclamation activities and urban land expansion characteristics were explored, and meanwhile the association between them was also analyzed. Finally, the following conclusions were acquired: (1) The total reclamation area in Zhoushan Island was expanded from 1995 to 2015. (2) In the first ten years, land use at the beach resources was mostly in land near the beach, while it gradually went to the shallow sea in the late ten years. (3) In the years from 1995 to 2005, the growth intensity was 0.53 and the growth speed was 3.01 km ²/a. In the years from 2005 to 2015, the growth intensity was 1.46 and the growth speed was 8.11 km ²/a. (4) The city development center of Zhoushan Island had experienced a move from west to east and then had a northward jump process during the past 20 years. Coordinated development had been made among the various regions so that the economic integrity of Zhoushan Island and the rationality of urban functions had been upgraded. (5) The cultivation of land by tideland reclamation and urban land expansion were positively related, the research data showed that natural succession took about 8-10 years, artificial intervention could significantly shorten the process.

Using “exposure-sensitive-adaptation” model, the ecological vulnerability evaluation system of Xiangshangang Bay was established through the analysis and calculation. The vulnerability of Xiangshangang Bay ecosystem is moderate fragile, and the main stress factors are the development of harbor industry and aquaculture activities. The sensitive factors are marine biodiversity index, fish eggs and larvae density. The best adaptation strategies are to improve the environmental protection laws and regulations and management mechanism, strengthen the control of pollutants into the sea, improve the sewage treatment rate, improve citizen's environmental protection awareness and participation degree.

Tumen River is one of the most important international rivers in China. Because of the differences in the policy, economy and culture, there are many differences in the wetland landscape among Chinese, Russian and DPR Korean wetlands in Tumen River Estuary. Taking GF-1 and GF-2 images as the data sources and according to the wetland classification of national standard, the classification system of wetlands in Tumen River Estuary was set up, which included lake, river, marsh, tidal flat, pit, paddy field and reservoir. The Tumen River Estuary wetland information was extracted by visual interpretation, and then the status and differences among Chinese, Russian and DPR Korean wetlands were analyzed. By the means of Fragstats software, the landscape pattern indexes, such as NP, LPI, MPS, SHAPE, FRAC, SHDI and SHEI were used to analyze the characteristics of wetland landscape pattern in Tumen River Estuary. The results show:(1)The total area of wetlands in the study area is 39 503.38 hm ², which is dominated by marsh and lake, and is presented as an aggregate distribution pattern close to the Japan Sea.(2)The wetland area of Russia is the largest, followed by those of DPR Korea and China. The disturbance is serious in that of DPR Korea.(3)The landscape fragmentation of wetland in DPR Korea is most serious, followed by those of China and Russia. Because of the serious development of paddy field, the landscape regulation degree is highest in DPR Korean wetland. The diversity of Chinese wetland is more abundant than those of other countries.

With the wave observation off the southeastern coast of Zhaitang Island from 2013 to 2014, the wave characteristics were analyzed. The statistical results show that annual average of significant wave height is 0.60 m, the maximum wave height is 5.30 m, the average period is 3.3 s, the maximum period is 8.3 s and the dominant wave direction is E-SE. The wave height distribution and the joint distribution of wave height and period were also discussed. Based on the basic spectrum structure of JONSWAP, the spectrum applied to this sea area is presented using fitting method. All the work would provide reference for wave research and engineering application in this sea area.

Argo data have become an important data source in basic researches of ocean and atmosphere sciences. But with the hybrid storage of profile metadata and its observations, it is difficult for existing shared platforms to realize the real-time visualizing of the drift trajectory and profile chart. A method of collaborative management of structured and semi-structured Argo data were proposed. Based on the analysis of Argo data structure and characteristics, Argo data were separated as structured and semi-structured data. By means of extended support of relational database to a semi-structured property, a relationship between profile metadata and observation data was established. Faced of the rapid growth of data, a multi-table storage method was used to reduce storage pressure of single data table. Finally, an Argo database was set up and global Argo data in period of 1997-2016 are parsed and imported. The results indicate that the method has good scalability of both storage and query, as well as high efficiency of float trajectory query, and it is able to support real-time visualization of float trajectory and profile chart. Our result will offer a reference for management of other similar observation profile data.

A key factor of numerical typhoon prediction models is the initial field. COSMIC(Constellation Observation System of Meteorology, Ionosphere and Climate) satellite data assimilation was used to improve the initial condition, and its effect on improving tropical storms(or typhoon) prediction was evaluated. Employing the GRAPES(Global/Regional Assimilation and Prediction System)which was developed independently by China, typhoon Usagi(1319) was simulated. Analyses are made based on the various outputs, such as temperature, humidity, vorticity, divergence and pseudo-equivalent temperature. The results show that COSMIC data, comparing to the radiosonde data, can enhance the ability of typhoon path and precipitation forecast assimilation. So this research indicates that assimilation of satellite data contributes to the improvement of GRAPES model as well as provides an example on preventing typhoon disasters and reducing damages.

Airborne LiDAR sounding technology is considered to be a promising new technique for earth observation. In China, most of the LiDAR sounding experiments were conducted in areas with relatively clear water quality, such as the South China Sea. This is the first time to introduce the advanced CZMIL(Coastal Zone Mapping and Imaging LiDAR) system in China. The Luoma Lake in Jiangsu Province was selected for experimental area. The test results show that although the survey area has low bottom reflectivity and high bottom reflection diffuse attenuation coefficient, CZMIL system can successfully detect the bottom data. The accuracy of result can meet the accuracy requirement of CZMIL system. The CZMIL system has better detection ability and precision.

According to the principle of remote sensing water depth inversion, WorldView-2 multi-spectral satellite data and chart depth data of Longwan Port in Hainan Island were used. The water depths in 0-2 m, 2-5 m, 5-10 m, 10-15 m and 15-20 m were partitively treated, tidal correction,the correlation analysis and regression analysis of chart water depth and the corresponding image band reflectivity values were also developed, and a piecewise linear model was built for shallow water bathymetry with which the actual calculation of shallow water depth and precision analysis were carried out. The results show that the depth accuracy of the partitioned linear regression model is higher than that of the non-partitioned model in different water depth ranges. In the partition model, the multi-band model has the highest inversion accuracy of 0-5 m, and the double-band ratio model has the highest inversion accuracy of 5-20 m, but inversion of the depth in the most shallow yet to be improved. The water depth extracted by this method is similar to that of chart water depth data, which can meet the requirements of marine scientific research on large-scale shallow underwater detection requirements.

Reflection feature and seismic event continuity appeared in 3D seismic acquisition data was cluttered and poor in one study region of the Laizhou Bay. The sparker investigation was carried out in shallow strata and two geological borings were drilled in the abnormal and normal region respectively, at the same time, the strata were sampled entirely from 0 m to 150 m below the seabed. Through comprehensive comparison and analysis of the geophysical data and geotechnical data, it is clear that anomalous seismic reflection in shallow strata of the study region relates to various influence factors below: (1) The study region is in the eastern Laizhou Bay Sag strike-slip zone, and therefore many small faults which were affected by the fault system were developed in the shallow strata.(2) An amount of shallow gas was revealed in the shallow strata.(3) Comparing with the shallow strata of nearby region, the soil characteristic was anomalous in the study region; the soil strength and shear wave velocity were significantly larger.

Estuary is a transitional area from river to sea, which represent an environment with complex essential factors, so they are highly different from each other in terms of the patterns of temporal and spatial variability of the processes. Generally, there are many parameters to define the boundary between the river and the sea. The relationship among the demarcation methods based on the geometric and geomorphologic character and other estuarine parameters was analyzed. For each of these, a geomorphic node may be the most suitable method to determine the location of boundary. At a point on the river centerline, a function of B=f(L) was defined, where B is the channel width at this point and L is the distance from this point to the entrance of estuary along the central axis of the river. By constructing a mapping function, the geomorphic node can be found and the quantitative segmentation of the boundary between the river and the sea can be realized. For different kind of estuaries, the B-L curve was constructed to defined the river-sea boundary based on the geomorphic node. The result show that for the blocked estuary the rates of river width variation at the geomorphic node are -0.5 to 0. For the channel-form estuary and interconnected estuary, the rates of river width variation at the geomorphic node are 0.5 to 1.2. For the firth estuary,the rates of river width variation at the geomorphic node are 0.6 to 1.5. For the funnel-shaped delta, the rates of river width variation at the geomorphic node are 1.3 to 4.5. For the bird-foot delta and fan delta,the rates of river width variation are always 0 to 0.2, and the entrance of estuary is regarded as geomorphic node. This B-L curve is applied to measure and calculate the length of estuary shoreline of China mainland, and some perfect results are acquired.

Surface zooplankton samples were collected between 21°S and 38°S during the Dayang-1 scientific cruise in Southwest Indian Ocean in summer of 2013. By using zooplankton community structure analysis and clustering method, the distribution pattern of community structure and biodiversity of this region were explored. The results showed that the zooplankton species belonged to 69 species of 50 genus, including copepods, euphausiids, amphipods, decapods, ostracods, chaetognaths, tunicates, heteropods, pteropods, cnidarians, polychaetes and etc. In terms of abundance, copepods and euphausiids accounted for the largest percentages (69% and 27%, respectively). The variation of H′, D, J biodiversity indices with the latitude accorded a linear trend, i.e. most biodiversity indices decreased with the increase of latitude. In contrast, a binomial relationship was found between the biodiversity indices and longitude. Most biodiversity indices increased with the longitude. The clustering results showed that northern and southern zones could be distinguished by the latitude boundary around 36°S, with the predominant species of copepods (small particle) in northern zone and euphausiids (large particle) in southern zone respectively. Moreover, the similarity of species composition indicated that the spatial connectivity of zooplankton communities was week between the southern zone and Crocker Strait or Great Wall Bay in Antarctica, as well as between the northern zone and Northwest Indian Ocean.

Size-fractionated chlorophyll a concentration (Chl a) and primary production (PP) of phytoplankton in the northern South China Sea (nSCS) were investigated during the winter of 2009. The results showed that Chl a and PP had obviously spatial variation in the nSCS. The water column integrated average values of Chl a varied from 0.11 to 8.37 mg/m ³, the average value was (1.28±2.23) mg/m ³, and decreased from the coastal zone to the open sea. The lowest and highest value of PP were 344.8 mgC/(m ²·d) and 1 222.5 mgC/(m ²·d), respectively, with the high value appearing in the coastal zone and continental shelf. The result of size-fractionated Chl a showed that microplankton (Net-Chl a) was greater contributor (about 40.9%) to phytoplankton stocks in the eutrophic coastal zone and the proportions of nanoplankton (Nano-Chl a) and picoplankton (Pico-Chl a) were 34.6% and 24.5%; while in the oligotrophic continental shelf and open sea, the contributions of three size-fractionated Chl a from greatest to least in order were Pico-Chl a (78.9%), Nano-Chl a (17.2%) and Net-Chl a (3.9%). Relevant analysis results showed that the regional distributions of Chl a were closely related to the nutrient dynamics driven by the ocean currents; meanwhile the distributions of Chl a drastically affected the distributions of PP as well. Furthermore, compared P ^B _opt in situ with that estimated by the depth-resolved model for carbon fixation (VGPM), it was found that the later were less than the former obviously, and this indicated that the underestimated value of P ^B _opt through temperature might be exited in nSCS.

The temporal and spatial distribution of seawater transparency was analyzed according to the marine monitoring data of Qingdao coastal area in 2014. Multiple linear regression analysis was utilized to find out seven key environmental factors as the independent variables, and an optimal multiple linear regression statistical model was established. In addition, the single-factor correlation analysis and curve fitting analysis were also utilized to further prove that the seawater transparency was significantly correlated with the content of chlorophyll a, suspended matter and water depth, and the curve fitting equation is drawn.

To understand the diversity of bacteria during the seedling stage of Apostichopusjaponcicus, bacteria were isolated and identified. On the basis of the morphology, physiology and biochemistry, 16S rDNA sequence homology analysis, the 19 marine bacteria were identified to be Brevibacillus sp., Pseudoalteromonas sp., Cobetia sp., Enterobacter sp., Bacillus sp., Providenciasp., and Oceanospirillaceae sp.. Isolation and screening of bacteria from the marine environment is of great significance to the development and utilization of marine resources. In addition, the identification of the bacterial species in the period of seedling stage of Apostichopusjaponcicus is helpful to the prevention and treatment of disease, and it has a certain guiding significance for the aquaculture of Apostichopusjaponcicus.

Three-dimensional mathematical model of scour around Trawl Resistant Seabed Basement on sand bed was established using Flow-3D. By changing the flow velocity and sediment particle size, the scour on sand bed under different conditions was simulated, and the changes in the trend of maximum scour depth around Trawl Resistant Seabed Basement with the two factors was analyzed. The results show that the scour depth around Trawl Resistant Seabed Basement is increased with current velocity increases, under the other setting conditions unchanged, the scour pit deepened velocity with increasing flow velocity is gradually slowed down, and ultimately achieved sedimentation balance. At the same time, due to the complex and changeable seabed environment, the model and the actual situation are different, and therefore further research should be continued.

On the basis of observed hydrological data in the East China Sea during April 2001, a three-dimensional model—FEOM (Finite Element Ocean Model) was applied to perform numerical analysis on the circulation in this region. The model uses single node linear triangular mesh for the horizontal grid and z-coordinate in vertical direction. Objective analysis method was introduced to interpolate this data to all the nodes to obtain the initial temperature and salinity condition, preparing for numerical experiments running respectively by diagnostic and robust diagnostic calculation. The computed results show that: (1) Stream function and flux calculated from the modified inverse method can reveal the velocity distribution of the study area well, and it can provide reliable open boundary condition to this simulation. (2) The finite element model has obvious advantages in respects to grid degree of freedom and full coverage of the study area. The high resolution vertical z-coordinate can also fit well with sea bottom topography, resulting in higher resolution results of three-dimensional numerical simulation. (3) Through the diagnostic calculation, the multi-eddy structure of the spring circulation in the East China Sea is reproduced, and the flow system of the Taiwan Warm Current, the Yellow Sea Coastal Current and the Yellow Sea Warm Current are distinguished. (4) Diagnostic and robust diagnostic calculation results agree qualitatively, but there are still some differences. In terms of overall distribution, the structure of the robust diagnostic calculation is more reasonable.

The construction of water transport project in China is frequently attacked by typhoon waves. To provide useful help for disaster prevention and mitigation of typhoon waves, the third generation wave model SWAN was established,which is suitable for South China Sea. Meanwhile, No. 0906 typhoon “Molave” was taken as an example to analyze the simulation results. Results show that the wind field and wave field are similar, i.e. the magnitude decreases from center to periphery, and the direction is counterclockwise rotation; the wind field is circular symmetric, while the wave field is elliptically symmetric due to the topography and coastline. The effective wave height contour also decreases from center to periphery, and the shape is influenced greatly by the topography and the coastline. Finally, the composition mechanism of typhoon wave was discussed. The results show that both storm wave and surge can form typhoon waves, and the submarine topography and coastline(e.g, island effect) also influence the characteristics of typhoon waves.

A violent tornado occurred in Funing County, Yancheng City in June 23, 2016, causing heavy casualties and enormous property loss. Based on meteorological data, such as weather maps and doppler weather radar maps, the mechanism of the tornado was analyzed. Then the range of wind speed exceeding 42 m/s was estimated based on the conclusion inferred by other author that “when the wind speed reaches about 42 m/s in the gale, the percentage of broken trees in the woods rises sharply to 50%”, according to the investigation data of the broken trees in the five areas where the disaster was relatively serious. The results show that atmospheric unstable stratification, cold, warm and humid air intersection, wind vertical shear can induce tornadoes; the length of range of the tornado wind speed exceeding 42 m/s is at least 20 km, and the maximum width is at least 952 m.

In 2015, a hydrothermal field named Daxi was discovered during the Chinese DY33 cruise at 6°48′N, Carlsberg Ridge, Northwest Indian Ocean. The chemistry of water samples and particles of a CTD station near Daxi Hydrothermal Field was studied. In the water depth of 3 150~3 400 m, the water chemistry shows slight depletion of Cl, Br, Mg and intense enrichment of DFe and DMn. The concentrations of Cl, Br, Mg deplete 2.87%~5.27%, 3.21%~4.53% and 2.52%~3.82%, respectively, when comparing to background seawater. It is suggested that the hydrothermal fluid has been subjected to phase separation, resulting in the depletion of Cl and Br. The depletion of Mg suggests that the hydrothermal plume has been well mixed with the ambient seawater and the contribution of hydrothermal fluid is account for about 3.90%. The concentrations of DFe and DMn reach to 127 nmol/L and 29.0 nmol/L, respectively, for the sample collected at 3 150 m water depth. The particles have been investigated under scanning electron microscope and analyzed by energy dispersive X-Ray spectrometer. The results show that among the particles in the water depth of 2 900~3 400 m, there are more iron oxides or hydroxides (49.1%~95.2% FeO) present, and this discovery is consistent with the enrichment of DFe and DMn in the water samples. According to the current speed and the diffuse radius of Fe(Ⅱ), the calculated value of Fe(Ⅱ) oxidation half-live in Daxi hydrothermal field is 0.56~2.22 h.

The major and trace elements as well as Sr-Nd-Pb isotope compositions of basalt samples were studied, which were obtained from the ridges adjacent to Aden-Owen-Carlsberg(AOC) Triple Junction. The results show that samples from Carlsberg Ridge are typical N-MORB derived from DMM-type mantle source; samples from Sheba also belong to N-MORB, but the mantle source contains some EMII component and hence is more enriched than that of Carlsberg Ridge; samples from Owen Ridge are OIB, probably reflecting the contamination of continental crust; the types of samples from Aden Ridge vary from N-MORB, E-MORB and perhaps continental basalt which derived from the different extent mixture of end-members from DMM, EMII and HIMU. Except for Carlsberg Ridge, all of the other ridges adjacent to AOC have been influenced by Afar Hot Spot.

Typhoon can cause storm surge and strong waves. Since the reclamation projects are built on soft soil foundation, which may cause the seawall subsidence. In that case, disaster strikes when the strong waves cause sea dike breaching and seawater pours into the reclaimed area. An improved numerical method based on classic staggered grid was introduced in this study. In flow expansions, a numerical approximation was applied that was consistent with conservation of momentum, and in flow contractions, a numerical approximation was applied that was consistent with the Bernouilli Equation. The flood evolution model of Zhoushan Donggangxincheng was established, and the evolution process of the flood and breach under Probable Maximum Storm Surge was calculated. The results show that orographic terrain plays a decisive role in the evolution process and final distribution of the flood. The range and degree of influence differs when fissure occurred in different location. Almost the entire southern region of Donggang can be affected by a 50-metres-wide fissure nearby due to the low terrain and lacking of large-scale artificial lakes, while the influence in the northern area is limited due to the relatively high terrain.

Zooplankton is widely distributed in the marine ecosystem, which plays an important role in global climate change. Zooplankton analysis based on image processing needs rapid development. According to the shape of marine zooplankton microscopic image characteristics, a hybrid method based on template matching and invariant central moment description method was proposed in this study. Template matching was used to define the target initial range, and the final target organisms were determined by comparing the moment invariants. The amount and size of the target were calculated. This method was not affected by the rotation of biological azimuth and the scaling of size. The verified experiments show that the proposed method is fast and efficient, which is suitable for situ zooplankton monitoring in real time.

Geochemical and mineralogical analysis was carried out by ICP-OES, ICP-MS and XRD for the polymetallic nodules collected from the East Mariana Basin and western portions of the China Contract Zone. The genesis and grade control factors of main economic elements in the nodules from the East Mariana Basin were explored. The results show that the nodules are mainly hydrogenetic type in major and ∑REYs elements concentrations and to some extent, their mineral compositions are influenced by diagenetic processing. The contents of Fe, Co, P and other main elements and ∑REYs in the upper surface layer of nodules are higher than those in the lower surface layer, while the contents of Mn, Cu and Ni are significantly higher in the lower surface layer. Based on the characteristics of mineralogy and marine environment as well as the statistical analysis data in this research and other literatures, it can be concluded that the grades of Mn, Ni, Cu, Co, Fe and Ce of nodules from East Mariana Basin are mainly controlled by Mn mineral and the dissolved oxygen of bottom currents as well as the primary productivity of surface seawater, while the grades of La, Y and other rare earth elements are also subjected to the hydrothermal activities from East Pacific Rise.