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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.

Variable characteristics of the free air gravity anomaly and Bouguer gravity anomaly were analyzed by using the ship gravity data obtained from international cooperative survey between China and Nigeria. Through analyzing two gravity profiles that start from continental shelf, slope and extend to the deep sea basin, we can get the density structure of the crust. The results of research imply that the crustal thickness has been cascade thinning from continental shelf, slope to deep sea plain. The thinned range on the east side is greater than that on the west side, it decreases from 24 km to 10 km on the east side and 21 km to 14 km on the west side.

A comprehensive investigation involving biological, chemical and physical parameters was conducted in the Changjiang Estuary and its adjacent waters (29°30′N~32°30′N,120°00′E~127°30′E) in four seasons (from July 2006 to December 2007). The biomass of zooplankton, the key species affecting the biomass and their seasonal variation were studied based on the identification result of zooplankton samples and field measurement of environmental parameters. The results showed that there was a significant seasonal change in zooplankton biomass in the Changjiang Estuary and its adjacent waters. A significant decreasing trend was observed from spring to winter. The main contributors to zooplankton biomass included Calanussinicus, Diphyeschamissonis, Zonosagittabedoti and Pseudeuphausiasinica. The characteristics of this area were closely related to the influence of Changjiang River Plume, Taiwan Warm Current, Zhejiang Coastal Current and Kuroshio Current, thus formed an unique physical and chemical environment. Nutrient were the main environmental factor influencing the zooplankton biomass distribution in this area. Besides, other environmental factors also influenced the biomass of zooplankton, and there was seasonal difference. In spring, water temperature and salinity were the main influence factors. The zooplankton biomass had a significant positive correlation with water temperature and salinity. In summer, temperature, dissolved oxygen and chlorophyll a concentration were the main factors affecting the biomass of zooplankton. The zooplankton biomass was significantly negatively related to water temperature, and significantly positively related to dissolved oxygen and chlorophyll a concentration. In autumn, salinity, dissolved oxygen and suspended particles were the main factors affecting the biomass of zooplankton. The zooplankton biomass was significantly positively related to salinity, and significantly negatively related to dissolved oxygen and suspended particles. In winter, the water temperature in the Changjiang Estuary and its adjacent waters decreased significantly under the influence of cold front and current. Lower temperature depressed the growth and metabolism of zooplankton community. In addition, the community structure was simpler and the zooplankton biomass decreased. Therefore, no significant correlation between zooplankton biomass and environmental factors was found.