A 3-D nonlinear baroclinic ocean model based on Regional Ocean Modeling System (ROMS) has been set up, with the consideration of river discharge, wind, sea surface heat flux and regional ocean circulation to carry out numerical studies of the circulation pattern influenced by runoff input in the Huanghe (Yellow) River Estuary and adjacent waters in summer month of August. The numerical simulations confirm the viewpoint of northward rotation of Huanghe diluted water well, and present the effect of river discharge on circulation in the vicinity of Huanghe Estuary meanwhile. The numerical results show that Huanghe diluted water affects circulation in region of Huanghe Estuary significantly, and the residual speed markedly increased alone with the strengthened northerly rotation as the result of increasingly discharge. The circulation pattern in Laizhou Bay is under almost total controls of Huanghe runoff, and this local circulation is apt to develop and maintain with smaller order of magnitude of Huanghe discharge, vice versa. Surface residual currents tend to increase apparently with larger volume of diluted water, leading to enhanced vertical gradient of residual currents that can cause much stronger bottom flow and vertical circulation near river estuary.

The classical ocean surface current iterative inversion algorithm used constant correction factor to analyze and calculate the whole detection area, so it is time-consuming and the accuracy is limited. In order to improve the efficiency and accuracy of the inversion calculation, this paper used simulated annealing algorithm to optimize the correction coefficient, which can be adaptively changed according to the result of each inversion. Moreover, detection region was divided according to the characteristics of the current distribution. Finally, a modified ocean surface current inversion algorithm is proposed based on the classical method. The simulation results show that the efficiency and accuracy of the improved inversion algorithm are obviously improved.

Temperature inversion (TI) is a seasonal feature in the northern Bay of Bengal during winter. Based on in situ observation from Argo and RAMA buoy, general characteristics and maintenance mechanism are analyzed in the present study. During winter, TI is mostly confined in the northern bay north of 15°N, and it firstly occurs in the estuaries of Ganges, Godavari and Irrawaddy in November. Generally, the intensity and coverage of TI get strongest in January and TI completely disappears in early March. The inversion layer is static stable as the stability loss by temperature is compensated by the salinity gain in the halocline. The thickness of inversion layer is about 35 m and the maximum temperature is found at the depth around 40 to 60 m. Diagnosis indicates the occurrence of TI primarily depends on the sharp surface heat loss induced by the winter monsoon, and the horizontal salinity advection helps the maintenance of the TI.

Sea surface temperature (SST) products are important data sources for global ocean atmosphere system studies, and of great importance for research and applications in marine related fields. Focusing on the Northwest Pacific, three microwave radiometer SST products (AMSR-2, TMI and WindSat) have been analyzed and compared with Argo during 2013 and 2014 in this paper, and intercomparison analysis among seniors. It includes SST analysis, SST gradient analysis, the observation point analysis, the matching point analysis, bias analysis, root mean square error analysis, monthly statistics analysis and SST error bar analysis. The results suggest that the overall trend of the variability changes of the three microwave radiometer SST products is consistent in the Northwest Pacific. Remote sensing data and buoy data have seasonal cycles. The SST data quality of AMSR-2 is more ideal than TMI and WindSat. The difference of SST data quality between AMSR-2 and TMI is smaller than WindSat and TMI. However, for sea area within 100 km of offshore, whether to use the data gathered by AMSR-2 and TMI needs to be taken into consideration.

Sea ice motion adversely plays an important role in the developing the Arctic Passage which is essential for commercial global shipping. This paper developed an automatic extraction and tracking method for Arctic drift ice based on the FY-3/MERSI data that obtained by Medium Resolution Spectral Imager onboard FengYun-3 satellite. Firstly, on the basis of the gray distribution feature of drift ice, the blocky drift ices were extracted by combining sub-region bimodal threshold segmentation with gradient differential technique. Secondly, the matching of same drift ice in pair images was implemented according to the geometric feature and the velocity of the matched ice was calculated. A series image of the Fram Strait was used to compute the drift ice motion. The resulting motion vectors were found to match well with the polar daily grid sea ice motion vectors provided by the National Snow and Ice Data Center, thus verifying the validity of the proposed method of tracking drift ice motion. The prime effect of this method is effectively supplying the actual motion vector of drift ice to improve the distribution and details of grid sea ice motion vectors. So this method is capable of providing comprehensive and detailed information support of the sea ice motion for the Arctic Passage development.

The automatic extraction of coastline based on multi-spectral data has been an important question which has received attention for a long time. In this paper, aiming at the situation of the coastline extraction with a relatively single method based on either the spectral characteristic or the spatial relation, the authors present an automatic extraction method which concludes both spectral characteristics and spatial relations. Firstly, through comparing the measured spectrums with the Landsat8-OLI image of 2014 and choosing sensitive bands to build extraction model, we classified and extracted the coastline of the Yellow River Delta. Secondly, through using the method of visual interpretation, we extracted the coastline of experimental coastal section based on the coastline revision of Shandong Province in the 908 special project. Thirdly, through using the ROC (Receiver Operating Characteristic) curve, we evaluated the accuracy of the extraction result by 0.5 pixels and 1 pixel individually. Finally, the experimental result of vector-based coastline was directly applied in the subsequent GIS analysis. On the whole, through this new method, we can extract the coastline of Yellow River Delta quickly with an accuracy of one pixel and an extraction confidence level of higher than 90%.

Because of the characteristics of low cost and high spatio-temporal resolution, nearshore video remote sensing technology has become an alternative means for coastal dynamic monitoring in recent years. For nearshore video monitoring, the waterline position can be used as a proxy indicator for mapping the shoreline changes of beach. Under the influence of complex beach terrain and irregular variation of waves and tides, accurate detection of waterline changes from video images has become one of the challenge problems in nearshore video remote sensing. A combined CIELab color model with ant colony optimization algorithm to detect the edge of waterline has been proposed and it has been evaluated under high water level changeduring typhoon storm surge in Shilaoren Beach, Qingdao city. The results of both comparison with traditional methods for edge detection and field images evaluation have showed that the proposed method has better reliability, accuracy and the ability to preserve the detail edges and anti-noise capability, which is particularly suitable for quantifying waterline efficiently. The feasibility of the proposed method for extracting waterline automatically from field video images in extreme weather conditions is demonstrated and it is showed this method is capable to incorporate into an automotive coastal video system for long term shoreline dynamic change monitoring.

The Arctic is rich in hydrocarbon resources, but its level of geological research is almost lowest in the world due to harsh natural climatic conditions and complicated tectonic evolution. Herein, the tectonic map of the Arctic (1:5 000 000) was compiled based on newly updated geophysical data, and combination of geology, geomorphology, and resource data. From compiling of the tectonic map, this paper recognized the tectonic evolution of Arctic to be influenced by the vertical effect of Iceland Mantle Plume, and the horizontal effect of clockwise rotation of Eurasia-Laurentia supercontinent. The tectonic evolution of Arctic Ocean is divided into three stages: (1) Early Mesozoic. Paleo-Pacific Ocean subducted northwards. Paleo-Asian Ocean closed, leading to the formation of supercontinent. (2) Jurassic-Cretaceous. South Anui Suture was formed, accompanied by the coupling of Canada Basin opening and South Anui Ocean closing. This process is accommodated by development of transform faults. (3) Cenozoic. North Mid-Atlantic Ridge extended northwards, leading to the forming of Gakkel Ridge. Arctic Ocean represents the hinge of global tectonic domains. Along with the extension of Gakkel Ridge, it will connect with North Pacific tectonic domain (Far East Orogen), changing the global tectonic pattern since Mesozoic.

The sediment provenances were discussed in this paper based on grain-size, Sr-Nd isotopes, major element (Al₂O₃, TFe₂O₃, K₂O, MgO, Na₂O, TiO₂, CaO, P₂O₅, and MnO) and AMS¹⁴C dating for core X2, which was retrieved from the offshore mud area of the eastern Hainan Island in the South China Sea (SCS). Results showed that core X2 can be divided into two sedimentary strata units (unit A1 and unit A2). Compared with unit A1 (240-120 cm, 7.6-4.0 ka BP), sediment mean grain size in unit A2 (120-0 cm, 4.0-0 ka BP) became coarser and the content of major elements decreased. In addition to the abnormal value, the trends of ⁸⁷Sr/ ⁸⁶Sr and ε_Nd in core X2 were relatively stable. The sediments of core X2 were mainly derived from Hainan and Taiwan islands, and partly Pearl River. The sediments in unit A1 were primarily a mixture of Hainan and Taiwan islands. In unit A2, the sediments were mainly from Hainan Island, and partly Pearl River. The results suggested that the contribution of world-class river (i.e., the Pearl River) to the continental shelf of the northern SCS may be overestimated, while the influence of small rivers (i.e., Taiwan and Hainan islands) may be underestimated in the previous studies. Therefore, more attention should be paid to the contribution of small rivers to the continental shelf area in the future studies.

In order to detect sedimentary sequences and formation history of transverse ridge and barchan dune in the Changli coast, images from Ground-penetrating radar (GPR) are interpreted. The result shows that sand barrier formed under wave action along the coast 2 000 years ago. In landward and seaward slope of the barrier, reversed dip cross-lamination developed respectively. High transverse ridge and barchan dunes formed on the sand barrier, which is the basis of Aeolian dunes. The transverse dune evolved from fordunes in supratidal zone. High angle landward-dipping reflectors dominate the section inside the transverse dune. Under the reaction of the northeast wind, the dip direction of these bedding is SWW. Meanwhile, secondary changes of wind lead to the differences in angle of bedding, which record phases of wind-sand activity. The processes of barchan dune are more complex. According to some extensive reactivation and erosion surfaces in the barchan dune, four sedimentary units can be distinguished. The different structures of units indicated that the barchan dune experiecned a transition from a dome to a typical barchan dune, and got eroded thereafter.

Single channel seismic and shallow profiles are the main methods to research sedimentary features with a wide range since Cenozoic. Because of the limited resolution of seismic data, only larger sedimentary units can be recognized. It is difficult to divide the sub-facies and micro-facies. However, three instantaneous attributes can be more refined to describe the formation information. Based on the data obtained in 2013, which is belong to the Southern Yellow Sea, is used to analyze the Quaternary, recognize the seismic stratigraphic units, talk about the sedimentary environment and summarize the wave characteristics with instantaneous attributes. The research results show that the layer which is in 74.64 m depth below the seafloor are divided into 7 seismic stratigraphic sedimentary units and more sub-units at the Core Qc2 in the WE2 line according to the three instantaneous attributes. The instantaneous phase displays the contract of stratum clearly and the relationship of sequence in space better, solving a worse recognition in the seismic profile. The Quaternary sedimentary based on instantaneous attributes' partition matches well with Core Qc2, which is in the same location. The study found that the application of three instantaneous attributes could enhance the ability to identify the contact surface in the profiles with the absence of drilling data and provide reference to well location of the plan in the Chinese continental scientific drilling.

Due to the seabed undulating, the slope changed the action properties of wave on pipeline and seabed necessarily and then will affect three-dimensional scouring below pipelines. For the experimental research of the three-dimensional scouring characteristics of submarine pipeline, a median particle size of 0.22 mm and the 45° angle of the slope are used by considering the effect of the oblique wave, which is based on the experimental results of the wave basins. The malconformation of pipelines three-dimensional scour is analyzed by measuring the width and depth of the scour hole in the pipeline. The experimental results show that the existence of pipeline makes the wave height on the slope to reduce; under the action of slope, the malconformation of the three-dimensional scouring characteristics of submarine pipelines is assumed by the malconformation of the depth and width, and the malconformation of the width is responsible for the sediment behind the pipeline is moved backwards. The influence of the malconformation of three-dimensional scour of the cycle is higher than the wave height. With the decrease of the water depth, scour depth is divided into slow development stage and rapid development phase when the pipelines extend from the deep sea to the seacoast.

Currently,the limit equilibrium method (LEM) has been one of the most popular approaches to assess the seafloor stability. But still,the method has some limitations and only the approximate solutions can be obtained. To achieve the true solution,the upper bound approach based on kinematic theorem of limit analysis incorporating a log-spiral rotational failure mechanism,is established to solve the stability of submarine slopes,in which the simplified linear wave loading is considered,and the external work rates produced by the effective self-gravity of sliding body and the wave-induced pressure on the seafloor slope are equal to the internal energy dissipation rates yielded by the cohesion along the critical sliding surface (CSS). The safety factor (FS) and the corresponding CSS at different time under waves are obtained by combining multivariate stepwise iterative method without derivative and the mathematically optimal technique with strength reduction method (SRM). And,typical example is introduced to carry out the verification of the finite element numerical solution. On the basis of these,the effect of wave parameters such as wave length,wave height and water depth on the slope stability and failure mechanism are discussed. Calculation results show that the FSs and the corresponding CSSs obtained by the upper bound approach agreet well with the numerical solutions,and are also consistent with the general rules. The proposed approach provides a new path for the analysis of seafloor stability.