Volume articles

Post-rift subsiding anomalies have been discovered in many basins in the northern continental margin of South China Sea, of which Baiyun Sag is a typical one. We used software Temis Suite 2007 to build the backstripping model of three NNW—SEE-oriented seismic profiles crossing the Baiyun Sag, and analyzed the post-rift subsidence. The results show that the Baiyun Sag experienced anomalous post-rift subsidence. Compared with the Mckenzie's classic port-rift subsidence model, the Main Baiyun Sag subsided over 2.6 km deeper and the Southern Baiyun Sag subsided nearly 2 km. An accelerated subsidence stage could be conducted during 16.5~10.5 Ma, which might relate to the end of sea-floor spreading in the South China Sea. The ductile extension and extreme quick and thick deposition in the Baiyun Sag indicate that the lower-crustal flow might have been the mechanism for the anomaly subsidence.

Numerous sedimentary thickness data provided by seismic profiles were collected and drawn into the sedmimentary isopach in the East China Sea. The residual gravity anomalies were obtained by subtracting the gravity effect generated by the sediments from the complete Bouguer gravity anomalies. Depths to the Moho of the East China Sea were inversed from the residual gravity anomalies with constraint of the seismic penetration depths to the Moho. Our results show that depths to the Moho change between 25 km and 28 km gently and crustal thicknesses change between 14 km and 26 km on the East China Sea Shelf, depths to the Moho change between 16 km and 26 km and crustal thicknesses change between 12 km and 22 km within the Okinawa Trough. Crusts at the east of the East China Sea Shelf Basin and the south of Okinawa Trough are thinned evidently, and their crustal stretching factors are up to 2.6 and 3, respectively. Preliminary analyses suggest that the crust of Okinawa Trough is mainly transition type and there is no obvious evidence to prove the existence of oceanic crust.

Based on the OAFlux3, the NCEP/NCAR reanalysis data for the period of 1985-2008 and the daily data of summer precipitation at 108 observational stations of eastern China, the relationship between the inter-annual variations of summer precipitation in eastern China and the latent heat flux anomalies in the East China Sea (ECS) are analyzed by using the composite and the linear regression analysis methods. The mechanism of summer precipitation anomalies in eastern China caused by the latent heat flux in ECS is also further analyzed from the perspective of atmospheric zonal and meridional circulation and water vapor transport in East Asian area. In order to focus on the inter-annual timescles, the long-term trend in the variations of laten heat flux in ECS, summer precipitation in eastern China and atmospheric circulation over East Asia have been removed in this study. The analyzed results show that the latent heat flux displays strong inter-annual variations signal in ECS and is closely related to summer precipitation in eastern China. When the latent heat flux in ECS is above (below) normal in summer, an anomalous anticyclonic (cyclonic) circulation appears over the northwest Pacific and the northeasterly (southwesterly) anomalies appear over eastern China, which are unfavorable (favorable) for the northward transportation of water vapor and result in more (less) water vapor in South China and less (more) water vapor in the middle and lower reaches of the Changjiang River and north areas. Furthermore, the atmospheric zonal and meridional circulations will be manifested as a downward (upward) motion with a divergence (convergence) in low level and a convergence (divergence) in upper level can appear over the middle and lower reaches of the Changjiang River, which may result in less (more) summer rainfall. While in South China, the atmospheric zonal and meridional circulations will be manifested as upward (downward) anomaly and convergence (divergence) at low levels,which may result in more (less) summer rainfall. The variations of atmospheric zonal and meridional circulation and water vapor transportation over East Asia caused by the latent heat flux anomalies in ECS could lead to the precipitation anomalies in the above mentioned area. It is suggested that the abnormal change of the latent heat flux in ECS may be one of the most important factors for the abnormal of summer rainfall in East China on the inter-annual timescales.

In this paper, a mixed layer heat budget analysis is used to investigate the possible causes of ENSO asymmetry by analyzing the HadISST data, the SODA and NCEP reanalysis data. The significant positive skewness of SSTA appears in the eastern Pacific by analyzing the SSTA data. This feature indicates the amplitude of El Nio is larger than that of La Nia. A mixed layer heat budget analysis indicates that there may be 3 possible reasons for the asymmetry of ENSO events. The first is attributed to the nonlinear temperature advection. The horizonal nonlinear advection tends to enhance the mixed layer temperature tendency during the developing phase both in El Nio and La Nia, and contribute to the positive skewness in the eastern Pacific. The second possible reason is attributed to the nonlinear response of the subsurface temperature anomaly to the variations of the thermocline depth anomaly. Because of the structure of vertical temperature distribution in the eastern Pacific, the subsurface temperature is more sensitive to the positive thermocline depth anomaly than the negative thermocline depth anomaly. This can cause the subsurface temperature anomaly larger in El Nio events than in La Nia events, and enhance the upper ocean temperature skewness through the term -wT′_z. The third is attributed to the positive skewness of equatorial zonal wind stress in the central Pacific, which may cause the positive SSTA skewness in the eastern Pacific. The positive skewed zonal wind anomaly in the central Pacific creates the positive skewness of the thermocline depth anomaly in the eastern Pacific, make the asymmetry of the subsurface temperature anomaly, and influence the skewness of the SSTA through the term -wT′_z.

Phytoplankton is a major component of marine water, an insight investigation of its inherent optical properties is the foundation of understanding the principle of light transferring in water. In the last 30 years, focus was mainly on the absorption measurement and comparison of different algae, very few researchers had a detailed study on their scattering properties. In this paper, a method based on spectrometer was developed to measure the total scattering and backscattering coefficient of algae containing solution. The verification procedure of the method was carried out by measuring the scattering and backscattering results of polystyrene latex micro beads with known size distribution and refractive index. The results showed a maximum deviation of 4% for scattering in the visible spectrum and around 20% higher for backscattering in the red spectrum but quite good consistency in other regions. The method was then used to measure the scattering and backscattering features of two bloom algae in East China Sea: Skeletonema costatum and Prorocentrum donghaiense. It shows that the two algae had comparable amplitudes in both scattering and backscattering cross section, but Skeletonema costatum had a quite opposite scattering pattern to Prorocentrum donghaiense, whose scattering decreases with increasing wavelength. This could be attributed to the different cellular components which determine whether it follows normal or anomalous dispersion for the refractive index. Both algae have a regional minimum of scattering around 670 nm, which was due to the anomalous dispersion and the strong absorption of chlorophyll a. The backscattering cross section for the two algae were similar in both amplitude and spectrum pattern, Prorocentrum donghaiense had a higher but smoother backscattering spectrum. It'd demonstrated that the backscattering spectrum is well influenced by absorption of cellular pigments. Finally, the backscattering to scattering ratio was 0.723% for Skeletonema costatum and 1.104% for Prorocentrum donghaiense, the absolute value of backscattering cross section were 0.001 43 m ²/mg and 0.001 74 m ²/mg respectively.

Optical properties of Chromophoric Dissolved Organic Matter (CDOM) have played an important role in quantitative water-color remote sensing retrieval. The optical properties of CDOM in coastal waters of Changjiang River Estuary were investigated in June of 2011. This area is affected by terrigenous factor strongly with different hydro-dynamic characteristics. CDOM absorption coefficient and spectral slope were got through sampling, laboratory measurements and subsequent data processing. Then, CDOM absorption cofficient and spectral slope were discussed. CDOM absorption coefficients at 440 nm [ a(440)] varied between 0.21 and 0.85 m ^-1, with an average value of 0.44 m ^-1.In addition, the spectral slope, S _g varied between 0.013 3~0.016 7 nm ^-1, with an average value of 0.014 nm ^-1. Significant spatial difference in absorption cofficient and spectral slope was observed varied tremendously in the estuary and the offshore area. The higher absorption coefficients of the cruise appeared in the estuary area while the lower spectral slope of the cruise appeared in the area which is greatly influenced by the terrestrial sources; the lower absorption coefficients appeared in the offshore area while the higher spectral slope of the cruise appeared in the area which is greatly influenced by the mixing of terrestrial humic sources and seawater. A significant positive relationship between salinity and a(440) was found in the whole area showing conservative behavior of CDOM. There was a good correlative relationship between the spectral slope S _g and salinity in the whole area, which also reflected conservative behavior of CDOM.

Benefit from the ability of displaying fine topography features of multi-beam sounding system, a special seabed landform drew much attention of the researchers during the investigation at the north Yellow Sea. This seabed landform was a kind of micro ring depression quite different from the submarine depressions reported previously. It developed at the plain seafloor in the water depth of 55 m to the south of the Changshan Archipelago, circular or irregular ellipse shape, with shallow grooves along the edge, protrusion or depression in the central. Each depression has different size, most of which has a major axis of about 2 km, with the shallow groove along the edge of 200~300 m wide and 0.25~2 m depth. Several micro depressions arranged in a row, with the regional trend of NW—SE or NE—SW.
The topography form and features of the micro ring depressions were described in detail in this paper based on the multi-beam survey data. They were divided it into three types with different distributions and morphologies. TypeⅠdistributed at the northeast of the area, circular or elliptical in plan view, with protrusion in the central. TypeⅡdistributed at the southeast of the area, to the north of TypeⅠarea, elliptical or elongated in plain view with depression in the central. Type Ⅲ distributed at the southwest of the area, curved in plain view, and much shorter and shallower than the previous ones. Given the circular or ellipse morphology, the annular micro depression may relate to the sub-bottom gas leakage, which can produce pockmarks with circular or elliptical shape. Meanwhile, shallow gas leakage produced by sub-bottom profile records and the deposit of peat discovered in boreholes 8 km south to the study area can support this opinion.
Therefore, it is possible that the micro ring depressions were formed by sub-bottom shallow gas leakage, and be transformed by bottom current and submarine slumping. If the suggestion can be confirmed, it will be great significance to the study of environmental evolution of the northern Yellow Sea and will provide new inspiration to the oil and gas exploration in this area.

Ultra-short baseline is the necessary device to achieve the accurate positioning of towing equipment, and it is also the important equipment to do the deep-sea resource research in the international seabed area at the present. Because of the influences of acoustic signal propagation loss,multipath effect and other equipment noise, underwater positioning data has many outliers, which has seriously affected the credibility and the use of positioning data.To solve this problem, we propose and implement a correction algorithm based on correlation analysis to reject outliers and random regression which fill and correct positioning data. We use positioning data measured from the international seabed area to validate the reliability of the algorithm.At the same time, we use simulation comparison method for small scale and short time positioning data forecast, and therefore a good result has been achieved. The experimental results show that the algorithm is fast and effective. It is expected to be applied to the international seabed area survey, and can provides direct service to the international seabed resources investigation for accurate positioning equipment.

Suspended particulate matter in seawater was treated separately by high pressure digestion using sulfuric acid-potassium persulfate as the oxidant and soaking extraction in 1 mol/dm ³ hydrochloric acid in order to dissolve total phosphorus and inorganic phosphorus respectively. The dissolved phosphorus was determined using phosphomolybdate blue spectrophotometry to calculate total and inorganic phosphorus in seawater suspended particulate matter and in sediments. Organic phosphorus was subsequently obtained by subtracting inorganic phosphorus from total phosphorus. The relative standard deviation was less than 1.44% when the concentration of PTP and PIP were (632.4～651.7)×10 ^－6 and (436.6～452.6)×10 ^－6 respectively. The recovery rate of PTP, PIP and POP were 97.2%～101.3%, 97.8%～100.4% and 97.3%～102.3% respectively. This analytical method can be used for determination of different forms of phosphorus in marine and estuarine sediment and in suspended particulate matter.

In the present study, the bioaccumulation of lead in four species of seashell including Tegillarca granos, Ruditapes philippinarum, Sinonovacula constricat canarck and Monodonta labio were investigated in a semi-static system. The seashell were cultivated in seawater contaminated with different lead concentrations (0.001 0,0.003 5,0.006 0,0.011 0,0.026 0,0.051 0 mg/L, respectively). The content of Pb was analyzed in muscle tissue using atomic absorption spectrometry with microwave digestion in 0, 1, 3, 5, 10, 15, 20, 25 and 30 d, respectively.The results indicated that the four species of seashell could accumulate lead from aquatic environment. The bioaccumulation of Tegillarca granosa was obvious while the concentration of lead in seawater was higher than 0.003 5 mg/L. The lead concentration in Monodonta labio increased significantly while the concentration of lead in seawater was higher than 0.006 mg/L. Similarly, the lead content in Ruditapes philippinarum and Sinonovacula constricat canarck exhibited significant increases while the concentration of lead in seawater was higher than 0.011 mg/L. As a whole, the levels of Pb in seashell increased with the increase of those in seawater and the enrichment time. While the concentraion of lead in seawater was lower than 0.051 mg/L, the levels of lead in seashell showed significant decrease in 3 d and continued to increase after 5~10 d. Finally, the mechanisms of seashell response to lead enrichment were also investigated.

According to the arrangement parameters of attracting lamps on the light purse seine vessels, the illumination distribution underwater was calculated. The results showed that in the case of the total power of fishing lamps being 180 kW in main light vessel, the equal illumination curve of 10 lx could reach 56 m in horizontal direction in the farthest, and did not exceed 20 m in vertical direction. In 40 m vertical and 40 m horizontal distance from the ship, the illumination was about 0.01 lx. In the second case of the total power of fishing lamps being 120 kW in vice light vessel, the equal illumination curve of 10 lx could reach 46 m in the horizontal farthest,and did not exceed 20 m in vertical direction. In 40 m vertical and 33 m horizontal distance from the ship, the illumination was about 0.01 lx. In the third case of the total power of fishing lamps being 40 kW in net vessel, the equal illumination curve of 10 lx could reach 45 m in the horizontal farthest, and did not exceed 15 m in vertical directiong. In 35 m water depth and 38 m horizontal distance from the ship, the illumination was about 0.01 lx. As to the configuration of fish lamp, the present current configuration of main light vessel is good, but if we increase the space to 0.26 m, and increase the lamps' height to 5 m, 1.6% of the effective water volume can be increased. The present current configuration of vice light vessel is good, but if we decrease the space between to 0.28 m, and increase the lamps' height to 5 m, 2.1% of the effective water volume can be increased. And the present current configuration of the net vessel is also good, but if we decrease the space to 0.64 m, and increase the lamps' height to 9 m, 1.7% of the effective water volume can be increased. The results also show that it is not very effective way to improve the light induced range of the boat by greatly increasing the total power of fishing lamps.

The geomorphology and geological complexity around the global continental margin, and the ambiguity of the rules for the delineation of the outer limits of the continental shelf beyond 200 nautical miles according to the Convention Article 76, led to the delineation of the outer limits of the continental shelf extremely complex. The Commission on the Limits of the Continental Shelf that set up by the Convention is responsible for the consideration of submissions submitted by coastal states and providing the recommendations. Therefore the Commission plays an important role in the delimitation of the outer continental shelf. As of the end of December 2012, the Commission has received 65 submissions, and has completed the consideration of 18 submissions. Some critical issues such as the basic principles, the scientific technique adopted by the Commission during these submissions' consideration were systematically analyzed and summarized. These summary and knowledge can be use to provide the useful reference for our future delimitation of the outer continental shelf and actively respond to other country's claims which infringed on our maritime rights and interests.

Data INterpolating Empirical Orthogonal Functions (DINEOF) were used to reconstruct the chlorophyll a mass concentration from the three-level product of the MODIS-Aqua satellite. The monthly chlorophyll a mass concentration from 2003 to 2009 was obtained. The analysis on the filled data showed that the 7-years averaged chlorophyll a mass concentration in the nearshore is significantly larger than the one in the offshore. The seasonal chlorophyll- a mass concentration supports the conclusion that chlorophyll a in the East China Sea is mainly controlled by runoff of Changjiang River, sea surface temperature and monsoon. Furthermore, Empirical Orthogonal Functions were imposed on the chlorophyll a anomaly, and results showed that the first mode contribution is 37.8%, also the spatial pattern shows large value in the north-east of Changjiang River, and the corresponding temporal period is dominated by half a year or less. Meanwhile, the second mode contribution is 21.4%, the spatial pattern presents high value in the east of Changjiang River, and its temporal coefficient shows the inter-annual variance.

The Kuroshio Current undergoes large variations on various time scales in the vicinity of the Luzon Strait. Based on the output of a high-resolution regional ocean model (ROMS), this study analyzed the variability of the Kuroshio axis near the Luzon Strait and its possible causes. It is shown that the Kuroshio axis exhibits apparent interannual, seasonal and intra-seasonal fluctuations, with the intra-seasonal signal being the strongest. On the interannual and seasonal scales, the Kuroshio axis is primarily influenced by the wind-driven Ekman drift in the surface layer and by the inertia of the Kuroshio itself in the subsurface water column, while on the intra-seasonal scale, it is largely controlled by the interaction of eddies with the Kuroshio.

Red tide is one of the most serious marine hazards. It not only destroys marine fishery production, deteriorates the marine environment, affects coastal tourist industry, but also causes human health problems. The East China Sea is the region of the “high incidence” of the red tide disaster in China: both in the frequency and the area are significantly higher than others. Remote sensing technology has been proved to be one of the most effective means of red tide monitoring. From the spectral curves, we can see that the spectral of the red tide water and non-red tide water has significant difference: there are two peaks and two valleys in red tide water, while there are no these two peaks and two valleys in non-red tide water. Based on the spectral differences, a new algorithm was developed with conditions of R _rs 555/ R _rs 488> 1.5, and R _rs 678- R _rs 667 > 0 to extract the red tide information. The algorithm can determine effectively the locations from satellite data of red tide, and it is good corresponding to the results in the official bulletin. Therefore, this algorithm is suitable to monitor the red tide from satellite data in the East China Sea.

Based on gray level co-occurrence matrix(GLCM), different multi-scale texture images were extracted, and then the texture bands were combined with original bands to get new composited multispectral bands. The maximum likelihood supervised classification method was applied to new different composited images to test the differences of classification accuracy. Taking Ximen Island as a case study, through analyzing the differences of classification accuracy of different composited images, the following preliminary conclusions were got: (1)the total classification accuracy can be improved from 75.41% to 89.41% by using multi-scale texture images; (2)among different texture indices, correlation and homogeneity texture image calculated from the first band and second band of SPOT-5 image, mean texture image calculated from the third band, homogeneity texture image calculated from the fourth band can both improve classification accuracy than other texture indices images calculated from other bands.

The wind data from ASCAT were compared with those of HY-2 satellite, and their accuracy were verified with the data from oil platform in the northern South China Sea, which were collected from Jul. 19, 2011 to Sept. 17, 2012. The RMS (root-mean-square error) between ASCAT wind speed data and the platform-measured wind speed data is about 2.53 m/s. The RMS between ASCAT wind direction data and the platform-measured wind direction data is about 47.87°. The RMS between HY-2 wind speed data and the platform-measured wind speed data is about 3.41 m/s. The RMS between HY-2 wind direction data and the platform-measured wind direction data is about 58.66°(The temporal and spatial differences between the ASCAT and HY-2 date were limited to less that 30 min and 25 km). With the temporal and spatial differences between ASCAT and HY-2 date were limited to less than 150 min and 15 km, the RMS between ASCAT wind speed data and HY-2 wind speed data were also calculated in this paper, which were about 0.72 m/s. The RMS between ASCAT wind direction data and HY-2 wind direction data were about 8.50°. In conclusion, the measured data of ASCAT were a little better than those of HY-2, and it provide a basis for using seawind data of satellite in the northern South China Sea.

Luodousha Island is one of the first batches of the nonresidential islands that can be used to exploit and utilize. Luodousha Island is composed of sands. Therefore, it is unstable and its dynamic changes are highlighted. We used 12 remote sensing images spanning from 1973 to 2011, to analyze the dynamic change of Luodousha Island. The research results show that its position, shape and area changed obviously during the past forty years. The dynamic change of Luodousha Island can be roughly divided into three stages. The first was before 1987 and the island was a whole. The second was from 1987 to 2001 and the island was composed of northeastern and southwestern components. The third was after 2001 and the southwestern component of the island disappeared. These monitoring results may provide scientific basis and supporting data for compiling the protection and utilization plan, formulating the specific scheme of exploitation and utilization, putting forward the environmental protection measures. And then they may serve the ecological protection and the related management of Luodousha Island.

Seafloor sulfide is an important undersea resource after the polymetallic nodules and the cobalt rich manganese crusts. China has made great achievements since starting sulfide investigation in 2005, but the most important problem how to deal with 3D structure of sulfide has been questioning us. On land, the electromagnetic methods have always been important for that. With the first independently developed TEM device, China has gained the first data for seafloor sulfide at South Atlantic Ridge(13.2°S,14.4°W) in June 2011 during cruise DY22 segment 5. The preliminary results correspond well with the actual hydrothermal vent area, and the detection depth reached 50~100 m below seabed, which verifies the reliability of the equipment.

The total organic carbon, chloroform bitumen “A”, and its compositions ( total alkanes, saturated hydrocarbons, aromatic hydrocarbons, resin and asphalt ) in sedimental core WP02-1 from Western Pacific area were systematically analyzed. Then the nC ^- ₂₃/ nC ⁺ ₂₄ and CPI of n-alkanes,Pr/Ph, Pr/ nC ₁₇, Ph/ nC ₁₈ of isoprenoids were discussed. The geochemical characteristics of its original, biomarker and the relationship between organic matter and Fe, Mn were studied. The result showed that the alkanes had close relationship with diagenesis in sediments and the organic matter played an important role in mineralization process of Fe and Mn.

In order to study on real-time tracking the seabed reflection in sub-bottom profile data acquisition, the two improved algorithms were discussed: energy ratio based on amplitude information and cross-correlation based on phase information, and the best window of energy ratio and the model trace of cross-correlation were especially studied. Because of the different advantages of the two improved algorithms, we should be agile when making the choice between them. The algorithms mentioned in the article are superior to most of these applied in foreign commercial software, and could be widely used in actual survey.

To investigate the effects of different mass concentration of exogenous salicylic acid on the marine red algae Gracilaria lemaneiformis, the physiological parameters and the chlorophyll fluorescence characteristics of G. lemaneiformis were studied. Results showed that salicylic acid could increase the growth rate and the 10 μg·mL ^-1 treatment group was better than other groups. The daily relative growth rate reached to 6.92%/d with a increase of 26.3% compared with the control group. When on the 3rd day, the 10 μg·mL ^-1 treatment group of salicylic acid reached the maximum value with proline increased 32.5%, SOD increased 24.3%, and phycoerythrin increased 24.6% respectively. It also promoted the accumulation of Ca ²⁺ and K ⁺ in G. lemaneiformis. The chlorophyll fluorescence ΦPSⅡbegan to increase on the fifth day after 10 μg·mL ^-1 treatment of salicylic acid and increased 9.6% compared with the control group. F _v/ F _o reached a maximum on the fifth day, and increased 5.6% more than the control group. In conclusion, exogenous salicylic acid can enhance the growth of G. lemaneiformis and the 10 μg·mL ^-1 treatment group of salicylic acid is the best concentration.

This study was carried out in the Daya Bay in October 2011 and April 2012. Based on the data collected from 12 stations, phytoplankton taxonomic composition, abundance, dominance species and their impacting factors were examined. Surfer 8.0 software was used for drawing and illustrating, while SPSS 17.0 software was used for analyzing principal component factors (PCA). At the same time, it used multiple stepwise regression analysis method, and principal component scores as explanatory variables, aiming at studying the effect of environmental factor for phytoplankton abundance and picking out the main factors which influenced the distribution of phytoplankton in the Daya Bay. Furthermore, its distribution characteristics and the correlation with environmental factors were discussed. A total of 51 species (4 phyla, 31 genera) were identified. Among those species, Bacillariophyta is the dominant species, Pyrrophyta is subdominant species, and Xanthophyceae and Chromophyia are even rarely. The dominant species are Heterosigma akashiwo、Skeletonema costatum、Rhizosolenia setigera、Nitzschia pungens、Thalassionema nitzschioides in autumn, and Ceratium furca、Prorocentrum minimum、Ceratium fusus、Ceratium tripos in spring. The abundance of phytoplankton range from 1.56×10 ⁴ to 8.03×10 ⁴ cell/dm ³ and the average value is 3.95×10 ⁴ cell/dm ³ in autumn and range from 1.21×10 ⁴ to 4.70×10 ⁵ cell/dm ³ and the average value is 7.84×10 ⁴ cell/dm ³ in spring. Temperature、pH、PO ^3- ₄-P and TP are the main factors influencing the distribution of phytoplankton in the Daya Bay.

Sediments from the site GC16 of Haiyang IV, the South China Sea show anomalous values of δ ¹³C _org, δ ¹⁵N and δ ¹³C _inorg. The sulfate methane transition zone (SMTZ) is a key biochemical interface in CH ₄ fluid flowing area. The values of δ ¹³C _org and δ ¹⁵N show obviously depleted in STMZ. Comparing with the date above the STMZ, depleted 1.4‰PDB and 0.93‰ respectively within the zone. The data of δ ¹³C _inorg also identify the authigenic carbonates as microbially-mediated methane-derived precipitates. The 2 times of vigorous methane-rich fluid expulsion had occurred since the bottom sediments deposition of the core. The depth of methane fluid arriving coincident with the up limited of STMZ.

Using the data from the 3th version of U.S. Navy Generalized Digital Environment Model(GDEM), we diagnosed the intermediate circulation and deep circulation in the west of Luzon Island with the P-vector method. The diagnosed result shows that it is an anticyclonic circulation in the west of Luzon Island in the intermediate layer (1 000~2 000 m vertical-averaged), different from the deep layer circulation (2 400 m to bottom vertical-averaged) in the same region, which has been reported as cyclone in the previous studies. These two eddies both correspond with the low salinity water in geographical location. The results further show that the velocity of anticyclonic circulation reduces as the depth increases, and the velocity of cyclonic circulation is stronger in the deeper layer. The current at the depletion layer (about 2 200 m) is weak and disorder. Further research demonstrates that low salinity water and anticyclonic circulation in the intermediate layer have distinct seasonal variation, they both become stronger in May to July, which may suggests that the anticyclonic circulation is influenced by the upper layer circulation to some degree.

Luzon Strait is an important water exchange channel between South China Sea and Philippine Sea. As a famous western boundary current in the North Pacific, the Kuroshio has an important impact on the South China Sea circulation. In this research, we extracted the salinity-maximum at density of 23.0~25.5 kg/m ³ and studied further the relation between the Kuroshio intrusion and bifurcation of the North Equatorial Current with CTD data of 1991—2011 and the satellite altimeter data. The results show that: (1) The ways of Kuroshio intrusion in SCS are diverse, including branch, bending and loop. (2) In different years, Kuroshio intrusion is quite different and the range of salinity-maximum can be more than 0.3 in the 120°E section. (3) The bifurcation of North Equatorial Current has a great effect on the intrusion of Kuroshio in South China Sea: When the bifurcation of North Equatorial Current moves to north, the Kuroshio intrusion in South China Sea is strong; when it moves to south, the Kuroshio intrusion is weak.

The cohesive sediment dynamics have great potential engineering and environmental impacts in the Pearl River Estuary (PRE). In this study, we established a 3D unstructured triangular grid hydrodynamics model by using the SELFE (Semi-implicit Eulerian-Lagrangian Finite Element) model for the PRE, considering the baroclinic current, tidal current and wind current. On the basis of the hydrodynamics model, we then developed a cohesive sediment model including a bed change module. From the numerical results which are in good agreement with the field data obtained in the wet season, the characteristics of turbidity maximum (TM) in the PRE can be well reproduced, and the relevant sediment dynamics can be explained. The results show that the suspended sediment concentration (SSC) in the west side is higher during the wet season, which indicates that the suspended sediment in the PRE is terrigenous. The TM is found in all “three shoals”, and the suspended sediment concentration is up to 0.5 g/L. The tidal dynamics, gravitational circulation and sediment resuspension and deposition processes are the primary formation mechanisms of TM in the PRE. TM in the middle shoal is mainly caused by the sediment resuspension and deposition processes, on the other hand, the gravitational circulation is the predominant formation mechanisms of TM in the west shoal.

The ditching probability caused by typhoon wave was analyzed by using WAVEWATCH-III (WW3) wave model. Results show that: (1) The WW3 wave model can simulate the typhoon wave well with CCMP (Cross-Calibrated, Multi-Platform) wind data as driving field, and the simulation significant wave height (SWH) has high precision. (2) The ditching probability field has good agreement with the wave field, and the large areas mainly locate in the quadrants of 1st and 4th. (3) When the flying height is at 10 m, ditching probability in big wave area is above 20%, and it is even more than 35% in the large center, ditching probability is about 15%~20% in the wake of typhoon, and 10%~15% in other waters. When the flying height is at 15 m, ditching probability is greatly reduced and ditching probability in big wave area is 5%~15%, while it is below 5% in other waters.

Marine surface sediments from the Fuzhou Bay, the western Liaodong Peninsula, were obtained for sedimentary analysis. The characteristics of grain size are corresponding to the sedimentary environment. The grain size parameters show a significant difference among samples from various positions, as the average grain sizes range from 1.2Φ to 6.5Φ. The grain sizes are all poor sorted (1.4~2.6) with fine to coarse skewness, and display a spatial change as fine to coarse to fine from the estuary to the shallow sea. The 5 m and 10 m isobaths mark the edge of these boundaries, probably resulting from sediment transport and submarine topography. Most of river sediments can be transported to the 5 m isobath, and sediments in the area between 5 m to 10 m isobaths are mainly from river and outer sea, while little river sediments can get to west of 10 m isobaths. With the evidence of both Weibull function and mineralogy, most of the sediments in Fuzhou Bay are from the erosion of Liaodong Bay and Fuzhou Bay.

A series of experiments about dynamic triaxial apparatus were carried out to study the dynamic response behavior of silt from Hangzhou Bay. We studied the influence of structure, loading frequency, dynamic stress on dynamic strain, critical cyclic stress ratio, and the dynamic strength. The test results implied that, under the same loading conditions,the remoded samples are more likely to undergo structural failure than the undisturbed ones in smaller cycles. However, the dynamic strength of undisturbed soil is greater than that of remoded ones. Structural impact become an important factor influencing the dynamic strength of soil samples, the influence increased with the increase of dynamic stress, and decreased with the increase of frequency. On the other hand, the variation of loading frequency has significant effect on the dynamic characteristics of silt, the more frequency increased, the more cycles sample required to reach a failure, at the same time, the critical cyclic stress ratio of silt is also enlarged.

Coastline is of great importance for coast protection and management. Traditional coastline draughting methods are mainly based on field mapping and remotely sensed images. Field mapping is usually time consuming and difficult to carried out in complicated area. Coastline interpretation requires high criterion for operators and the proper coastline is hard to extract. Aiming at the problems mentioned above, a coastline extraction method for natural coastline based on airborne LiDAR data and tidal estimation was proposed and Feiyantan and Zhifu Island were chosen as study area in this research. Instantaneous water edge was firstly extracted from ortho-rectified images acquired by airborne LiDAR system. Coastline of study area was estimated through tidal data, by utilizing inter-conversion model of elevation system and DEM retrieved by airborne LiDAR system. Compared with “908 coastline”, the RMSE of 3 types of natural coastline (sandy coastline, rocky coastline and silty coastline) extracted using this method are 1.66 m, 5.23 m and 32.48 m, individually. Results show that the method established in this research is efficient and capable of extracting sandy coastline and rocky coastline, without the need of field mapping.

The aim of this study is to develop the exploitative intensity evaluation for the residential islands, and set the evaluation processes which are suitable for the residential islands on account of land resources specificity. In addition, Donghai Island was taken as an example, while 2006 SPOT images and 2010 ALOS images were used as data sources, and finally, the evaluation on land resources exploitative intensity from 2006 to 2010 was given. The assessment results can be divided into 6 degrees: they are weak, less weak, medium, less strong, strong and extremely strong. Each level accounted for 94.00%, 3.28%, 1.98%, 0.59%, 0.04% and 0.11%, respectively. The results show that the land resources exploitative intensity for Donghai Island was less weak from 2006 to 2010. More importantly, the evaluation results can service for the managerial and decision-making departments.

Due to the fact that oil spill has been increasing damage to the marine environment, to quickly detect the oil spill is certainly of significance for preventing and alleviating the disasters. Currently using polarized SAR in the detection of the oil spill is an important approach of remote sensing. In this paper, the SIR-C data were employed in the monitoring of oil spills, in which the polarized parameters entropy, scattering angle and anti-entropy were first extracted and then used to retrieve the oil spill information using the support vector machine (SVM) classifier. The assessment showed that SVM-based classification can achieve more accurate result than that of H-α decomposition based oil spill identification of SAR data.

Using HPLC-CHEMTAX method, pigments data collected from the nearshore surface water of the East China Sea in spring of 2008 were analyzed for understanding phytoplankton community structure and relationships with environmental factors. Results showed that the dominant groups are diatoms and dinoflagellates, which averagely contributed to chlorophyll a (Chl a) up to 42% and 32%, respectively. Both diatoms and dinoflagellates preferred in the environment with lower temperature, lower salinity, and higher N/P ratio, but the diatoms bloom occurred in the salinity front formed by the interaction of the Changjiang diluted water and the open ocean water which is higher in salinity and lower in temperature and N/P ratio, while the dinoflagellates bloom occurred in the temperature front formed by the interaction of the Changjiang diluted water and the Taiwan Warm Water which is higher in temperature, lower in salinity and N/P ratio. LOWESS results revealed that both Chl a and dinoflagellates increased incipiently and then decreased as temperature or salinity increasing, while relationships between diatoms and temperature or salinity showed a larger fluctuation. Both Chl a and diatoms increased as N/P ratio increasing, while the relationship between dinoflagellates and N/P ratio displayed a larger fluctuation.

Based on the three-dimensional hydrodynamic and water exchange numerical model——FVCOM, the water exchange numerical model of Bohai Bay was established, then the observed tide and currents data was used to validate the model result. Using this model, Bohai Bay water exchange was simulated, and the water exchange regularity of Bohai Bay was also studied. The results showed that: Bohai Bay water exchange rate was low, the half period of water exchange was 323 days; the water exchange rate of central Bohai Bay was higher, while the water exchange rate was lower at northwest and southern area; due to the role of the barrier strip, the water exchange rate in the southwest area was the lowest. Therefore, the place and time should be selected before discharging pollutant.

The distribution and enrichment characteristics of seven dispersed elements ( Ga, Ge, Rb, Tl, Cd, Te and Se ) in the surface sediments around Hainan Island waters were analyzed and their correlations with sediment grain size, total organic carbon and organic nitrogen were also studied. Nemerow Comprehensive Evaluation Index and Pollution Load Index methods were used respectively to preliminarily evaluate the contamination of these elements. The results show that the dispersed elements enrichment has close relation with sediment grain size, organic carbon and organic nitrogen content. Except Te, the other six kinds of dispersed elements have shown high enrichment in silt or clay sediments, and they tend to concentrate in the sediment where organic carbon and organic nitrogen contents are high. In general, the dispersed element pollution degree is a slight, but in some sediments (such as the sediments from northwest, west, southeast coastal waters and from Lingshui and Sanya waters of Hainan Island), the pollution reaches to the moderate degree, indicating that these areas have been impacted by human activities seriously, which should attract the attention of the competent authorities for the marine environment protection.

Based on satellite remote sensing products, the seasonal and interannual variations in the wind and wave over the South China Sea (SCS) were presented in the study. A vector empirical orthogonal function (VEOF) method was employed to study the temporal and spatial patterns of the wind field. Results indicate that the first VEOF is a seasonal oscillation mode, which represents the monsoon feature in the SCS. The second VEOF is an approximate annual oscillation mode, it represents the wind field features during the monsoon transition period. The third VEOF shows that the wind field is the land-sea interaction mode. For SWH, an empirical orthogonal function (EOF) method was employed and the similar two modes are forced by the first two modes of wind data, the third mode is caused by the bottom topography variation. The correlation coefficient (CC) between wind field's first mode and SWH's first mode is 0.76, which shows that the wave variation is forced by the sea surface wind. The two third modes are nearly unconnected, there may be a link between the bottom topography and SWH's third mode.

Based on the high resolution satellite Sea Surface Temperature ( SST) and wind data, the decadal variation of the warm tongue and sea surface wind field of East China Sea (ECS) Kuroshio during spring (March-May) were analyzed using the Empirical Orthogonal Function (EOF) and Composite Analysis methods. The results show that: the Kuroshio warm tongue in spring exists significant decadal variation, and experiences a phase change in 1996/1997. The phase change is mainly influenced by the North Pacific Gyre Oscillation (NPGO). Further study find that there is a significant negative correlation between the SST and wind divergence field on decadal time scale. Composite Analysis indicates that the abnormal warming of continental shelf in ECS mainly influence the negative correlation.

In order to establish a sufficient available data both for the spatial coverage and temporal duration, the reflectance data of three satellites of Aqua, Terra and SeaWiFS from July 27 to August 8, 2006 were merged by linear regression. A coastal water extension process was analyzed with the established data in the area adjacent to the Changjiang River Estuary. The results show that there is an obvious extension process from July 27 to August 8, 2006. During the extension process, the remote sensing reflectance of the coastal water decreases with the increase of distance from shore, the coastal water tongue extends almost in the east-west direction. According to the spatial coverage of reflectance and its concentration, the whole process is further divided into two stages, i.e., an eastward growing period from July 23 to August 2, and a westward extinction period from August 3 to August 8. During the eastward growing period, the coastal water tongue extends gradually to the east along the latitude of 32.4°N, and reaches the east-most longitude of 124.4°E. On the way to east, the coastal water tongue gradually narrows its shape and decreases its concentration. The moving speed of the tip of coastal water tongue boundary changes from 17.6 km/d to 33.4 km/d, with an average speed of 24.5 km/d. During the westward extinction period from August 3 to August 8, the coastal water tongue is getting narrow as well as decreasing concentration as a whole, but remains the spatial position unchanged. Based on the preliminary analysis of the mechanism of such process, it is believed that the tidal current would constrain the movement of coastal current along the coastal during the eastward growing period. The southerly wind during the eastward growing period and the easterly wind during the westward extinction period are found most-likely to be the cause of the coastal water extension process.

The wave field caused by tropical cyclone “Thane” in the Bay of Bengal during December 2011 was simulated by using WW3(WAVEWATCH-Ⅲ) wave model with CCMP (Cross-Calibrated, Multi-Platform) wind data as the driving field. Results show that: (1) With CCMP wind data as the driving field, the WW3 wave model can simulate the wave field caused by tropical cyclone “Thane” properly. The simulated SWH (significant wave height) has good consistent with the observed SWH. Simulated value is slightly smaller than observed value when the SWH is smaller than 2 meters or larger than 5 meters. The simulated value is slightly greater than observed value when the SWH is between 2 meters and 5 meters. (2) There are some differences between wind field and wave field caused by tropical cyclone “Thane”. The gale district distributes more evenly around the cyclone. When the cyclone is in the middle of the ocean, big wave areas mainly distribute in the right semicircle, and big wave areas mainly distribute in the front of the cyclone in offshore. (3) During tropical cyclone “Thane”, the wave direction has good consistency with the wind direction except the second quadrant. In the second quadrant, the wind direction is northwest, but the wave direction is north.