Volume articles

To accurately simulate the typhoon track and intensity, the WRF model was used to compare the sensitivity of different microphysical processes parameterization and cumulus convection parameterization on typhoon track and intensity simulation. The ensemble prediction method was been considered on the effect of the track and intensity error of typhoon Kai-tak. Four microphysical parameterization schemes and three cumulus convection parameterization schemes were selected to simulate for the track and intensity of Typhoon Kai-tak. The results show that different parameterization schemes have obvious influence on the simulation results of the track and intensity of typhoon. The parameterization scheme of cumulus convection is more sensitive than the parameterization scheme of microphysical process. Based on the ensemble prediction method of disturbing members based on different parameterization schemes, the simulation accurate of typhoon track and intensity is improved obviously. The error of typhoon track increases little with time, and the result is better than the simulation results of all twelve single schemes. From the aspect of typhoon intensity, the trend of typhoon intensity based on the ensemble prediction method is consistent with the actual result, which is better than the most of the test schemes. The results show that the ensemble prediction model constructed with different microphysical parameterization schemes and cumulus convection parameterization schemes can improve the simulation of typhoon track and intensity, reducing the track uncertainty produced by different parameterization schemes, which can provide a scientific reference for improving the forecasting ability of typhoon.

Various types of ocean detection data with high spatial and temporal resolution provides possibilities for the application of signal decomposition and machine learning algorithms. In order to establish an effective sea surface temperature (SST) prediction model, the high time resolution of the SST and the fusion of products were used in this study, introducing the ensemble empirical mode decomposition (EEMD) in the field of signal processing and autoregressive integrated moving average model (ARIMA) in the field of machine learning. Firstly, the SST data were decomposed into several frequency sequences by EEMD method, which was the most suitable for decomposing natural signals. After that the ARIMA was used to predict the sequence of frequencies, and then the predicted results of each sequence were combined. Compared with the previous method of directly using SST data to build prediction model, this method achieves higher accuracy because of its abundant data, and provides a new way for better SST prediction.

Low salinity lens is a common mesoscale phenomenon in the continental shelf outside the Pearl River Estuary, and its appearance will affect the underwater acoustic waveguide. The structure characteristics of low salinity lenses were analyzed based on the CTD profiles in the northern shelf of the South China Sea. Based on the normal mode and ray model, the two-dimensional waveguide environment was established, the characteristics of sound transmission in the low salinity lenses environment were studied under different sound source conditions. The results show that the low salinity lens will become the acoustic channel in the upper layer of sea water, and the transmission loss at 15 km is about 15 dB less than that without low salinity lens. Although the channel thickness of low salinity lens is usually smaller than surface acoustic channel, the large salinity gradient can effectively trap energy in the acoustic channel. When the sound source whose frequency is higher than the cut-off frequency is placed in a low-salt lens, the acoustic channel can help the long-distance propagation of sound.

Three special polymetallic oxides were taken from the Challenger Deep of Mariana Trench. They were at the initial stage compared to the normal polymetallic nodules. Samples were taken for mineralogical and geochemical analyses, such as X-ray diffraction(XRD) and Mossbauer spectra. Major, trace and rare earth elements(REE) were also measured for all the samples. The results showed that: (1)Compared to the normal polymetallic nodules, the mineralogy of samples were dominated by quartz, plagioclase and clay minerals, but vernadite and todorokite were deficient, which were often seen in polymetallic nodules. (2)Data obtained by Mossbauer spectra indicated that the iron phases were akaganeite(91.6%) and lepidocrocite(8.4%), we suggested it was due to the transmutation from lepidocrocite to akaganeite, a more stable mineral. (3)Higher contents of SiO ₂ and Al ₂O ₃ were found in the samples, but lower contents of Mn, Fe, Cu, Co, Ni in contrast. They were caused by the contamination of pelagic clay and short duration of sorption. (4)Due to the short time for absorption, value of ΣREE was about 0.4×10 ^-3 in the samples, consumedly lower than that in the normal nodules, of which ΣREE content was usually higher than 1.0×10 ^-3. The absent of the positive Ce anomaly was due to the reducing bottom-water redox condition and the active hydrothermal fluid.

The contents and distribution of Glycerol Dialkyl Glycerol Tetraethers (GDGTs) in 15 surface sediment samples from Ross Sea, Antarctica were analyzed. Besides, the source of GDGTs and environmental implications of TEX ₈₆ were disscussed. The results show that the content of GDGTs is from 93.67 to 2 663.37 ng/g with the isoprenoid GDGTs accounts for 90.33%98.56%, which are much more higher than those of branched GDGTs. Isoprenoid GDGTs have significant positive correlation with branched GDGTs ( R ²=0.88, p<0.01). The result indicates that isoprenoid GDGTs come from marine Archaea while branched GDGTs are mainly from bacteria in sea waters and sediments. Correlation analysis with the WOA database shows that the TEX ^L ₈₆ index reconstructed temperatures are of significant positive correlation with the sea surface temperatures in summer in the study area. Thus,the TEX ^L ₈₆ could be used as a potential index for paleo-SST reconstruction in the Ross Sea.

The study of the impact of landscape pattern changes on ecosystem service value in the island areas plays a positive role in understanding the landscape difference between lands and islands, properly utilizing land resources in the island areas, and steadily developing the regional ecosystem. Based on the land use data in 1995, 2005 and 2015 respectively, the characteristics of changes in landscape patterns and ecosystem service value of the Zhoushan Archipelago from 1995 to 2015 were analyzed, as well as the correlation between landscape index and ecosystem service value. The results are shown as follows: (1)The areas of waters, cities and villages in the Zhoushan Archipelago have been continuously increasing while the areas of other landscapes have been continuously declining, which shows the continuously deepened degree of fragmentation, complexity and diversity of landscape patterns. (2)The ecosystem service value presents an uptrend after a decline, increasing by 376.6 million yuan. Other values have been dropping except that the values of water supply, environment purification and hydrological regulation have been in an overall uptrend. Areas with a comparatively high and low value have been continuously increasing, while areas with a value ranging from 5 to 15 million yuan show a slight reduction. (3)The total value of ecosystem services is significantly positively correlated with the complexity and diversity of landscape patches, but significantly negatively correlated with the aggregation index and contagion index of landscapes.

Li ⁺-doped nano-CNTS-TiO ₂ composite photocatalyst (Li ⁺/CNTS-TiO ₂ composite photocatalyst) was prepared by sol-gel method using CNTS-TiO ₂ as precursor. The sample was characterized by X-ray diffraction and Scanning electron microscope methods. The photocatalytic degradation of marine diesel was carried out using the 3% Li ⁺/CNTS-TiO ₂ composite photocatalyst. The effects of different factors, such as the amount of Li ⁺ doping, calcination temperature, dosage of 3% Li ⁺/CNTS-TiO ₂ composite photocatalyst, initial diesel concentration, photocatalytic reaction time and H ₂O ₂ concentration were investigated under visible light conditions. According to the analysis of orthogonal test results, the optimum process conditions for degradation of marine diesel pollution with 3% Li ⁺/CNTS-TiO ₂ composite nano-photocatalyst were as follows: calcination temperature of 3% Li ⁺/CNTS-TiO ₂ composite nano-photocatalyst at 600 ℃, photocatalytic reaction time at 3 h, dosage of 3% Li ⁺/CNTS-TiO ₂ at 0.1 g/L, initial concentration of degraded diesel at 0.4 g/L, concentration of H ₂O ₂ at 0.6 g/L. Using these conditions, the degradation rate could reach more than 95%. At the same time, the photocatalyst was applied and tested. The test results showed that the photocatalyst degradation effect was excellent, and the degradation rate was up to 91.87%.

The strait channels are densely covered in the sea area of Zhoushan Islands, and the instability of the slopes of the strait channels is generally developed and varied in scale. The frequent subaqueous landslides pose a greater threat to coastal engineering facilities such as submarine cables and port terminals. In December 2012, the sub-bottom profiles were detected in the sea area of Liuheng Island. Three main acoustic reflection interfaces and four formation units were divided, and the upper three formations were Holocene sedimentary layers. Six subaqueous landslides were found, which were scattered along the coast of Liuheng Island or adjacent to the strait channel slope. The landslides structure were whole landslide, and some of them were multi-step. From the scale of the subaqueous landslides, the volumes were between 1.6×10 ⁵ to 2.7×10 ⁷ m ³, with 2 super-large landslides, 3 large landslides and 1 medium landslide. According to the correlation between the interface and the landslide body, it was speculated that the subaqueous landslides occurred in the late Holocene since 2.5 ka.

Hydraulic jet trenching technology has been widely used in submarine pipeline and optical cable embedding engineering. However, jet trenching construction in stiff clay is difficult. In order to elucidate the mechanism of soil breaking, the physical simulation experiment of submerged vertical jet trenching was carried out. During the process of soil breaking, it is found that there are some differences between the development characteristics of scour hole in soft clay and stiff clay. Shear-compression stress is the main factor of soil breaking in stiff clay and the breaking mode in stiff clay can be explained by the Prandtl foundation ultimate bearing capacity theory. Based on this, the model of jet to break hardpan is established, and the diameter of hole's neck is proposed to replace the diameter of scour hole as a prediction index.

The characteristics of the tidal and residual currents were investigated via the harmonic analysis based on the 31-day duration current observations at S station near the main channel of Tianjin Port. Effects of the local wind on the surface residual currents were explored in combination with the simultaneous wind velocities data. It is found that: (1)Tianjin Port belongs to the weak-current sea area, and the average velocity of the surface currents is about 31.4 cm/s. The current velocity generally decreases from the top to the bottom, and the main current direction is along the northwest-southeast. (2)The sea area is dominated by the regular semidiurnal tidal currents with a significant to-and-fro movement. The dominant tide component is M ₂, and the shallow water tide is also remarkable over there. The flood currents velocities are larger than the ebb currents. (3)The average residual currents during the observation period are between 2.8 cm/s and 13.8 cm/s. The current velocity decreases as the depth increases, and the main current direction is along the northwest. The residual currents in the surface layer of the station are dramatically affected by the local wind, and the southeast wind shifts the residual currents to northwest.

Waters and sediments in coastal waters are important sites for nutrient translocation. By sampling the Bohai Sea waters and sediments in August 2016, the spatial distribution characteristics of different forms of nutrients in the waters and sediments of the Bohai Bay were analyzed. In addition, the migration and transformation of nutrients in waters and sediments were studied. The results show that nutrients in Bohai Bay waters are higher in the nearshore area of the west coast and lower in the open sea areas far from the coastline, showing a clear concentration gradient. It shows that the contribution of man-made activities to the nutrient content in the water body in coastal waters is obvious. Nutrients in waters are mainly in inorganic forms, and inorganic nitrogen and inorganic phosphorus account for 76.65% and 76.46% of the total. Nitrogen and phosphorus in sediments show similar spatial distribution of nutrients in waters. However, the main form of nitrogen is organic nitrogen, while the content of inorganic phosphorus also drops to 30.42%. This shows that the nitrogen and phosphorus in Bohai Bay waters mainly enter the sediments through the assimilation of organic compounds in waters by the organism. Part of inorganic phosphorus enter the sediments through the adsorption form, but the effect of nitrogen entering the sediments from the water body through adsorption is not obvious.

The interannual and season spatial distribution of the peak phase speed of the wave, wave age, wave slope etc, which described for swell and wave-driven wind regime are given by the ERA-40 reanalysis data. The swell speed is the largest in the eastern Pacific equatorial region and other sea, and the propagation from south to north is obvious. The wave boundary layer (WBL) height in the Pacific Ocean shows the distribution situation with the higher in east and lower in the west. The wave-driven wind regime occurs mainly in the equatorial tropical seas, which is stronger in summer and weaker in winter in the northern hemisphere, but that in southern hemisphere is contrary. The northern seas of the northern hemisphere are more prone to the wave-driven wind regime in summer, while the seas near the equator are opposite. The waves in South China Sea is mixture waves of wind waves and swell, therefore it is necessary to discuss separately for the wave climate research.

In the previous studies, some traditional theoretical models and empirical models were used to construct the typhoon dynamic field, and the typhoon wind field and pressure field were used to drive the wave model. It could not reflect the sea-air dynamic process induced by typhoon and it was difficult to provide high-precision wind and pressure field data for the wave model. In order to solve this problem, a mesoscale meteorological model (WRF) and the third-generation wave model (SWAN) had been used to construct a two-way coupled atmosphere-wave model. This coupled model had been applied to the simulation of an idealized typhoon. The results show that the coupled WRF-SWAN model can successfully simulate the distribution of typhoon waves induced by an ideal typhoon and reveal the spatially asymmetric distribution called right side enhancement of typhoon wind field and waves field. This coupled atmosphere-wave model can be further promoted for simulation analysis of actual typhoon.

Gondwana breakup and the complex rift of Madagascar-Seychelles-India were associated with the formation and evolution of the Seychelles micro-continent and Northern Seychelles Plateau. Based on the high resolution multibeam and gravity data acquired from the China-Seychelles continental margin marine science joint cruise in 2016, high resolution topographic and gravity anomaly map were drew at the first time. Combined with the topography and other geological and geophysical data, the evolution of the Northern Seychelles Plateau was discussed by using the method of the tectonic geomorphology. Here, three narrow ridges and flat abyssal plain which were separated by Amirante Trench from the Seychelles micro-continent were found at the Northern Seychelles Plateau. These ridges extend seaward and apparent discontinuity on topography, which approve that the studying area is an independent tectonic unit that doesn't belong to the Seychelles micro-continent natural extension part. By reviewing the geochemical evidence from the scraping rock samples and plate tectonic evolution history, we suggest that Northern Seychelles Plateau are likely formed during the early expansion phase of the Indian Ocean and the seaward discontinuous ridges are affected by the magma eruption along the transform fault.

Submarine canyons are well developed in the northern continental slope of the South China Sea, featured with different evolution history and controlling factors. Four typical submarine canyons in this region, including the Pearl River Canyon system, Dongsha Canyon, Taiwan Bank Canyon, and Penghu Canyon were selected in this study. Based on combined geological interpretations with multi-channel seismic data and high-resolution bathymetric data, as well as previous works, the morphological characteristics, sedimentary structures, the formation processes, and the controlling factors of these submarine canyons were studied. Results show that the formation of various submarine canyons in the northern continental slope of the South China Sea are dominated by various factors, including the tectonic activities, sea level change and sediment gravity flow. The rivers on land and local tectonics (such as magma intrusion, uplifting) also affect their formation. For submarine canyon developed on the active continental margin, such as the Penghu Canyon, is mainly controlled by tectonic activities. While for those developed on the passive margins, their formations are dominated by Cenozoic tectonics, sediment supply, and eustasy. The exogenic process is the main influencing factor.

Abundant information about tectonic evolution in the northeastern South China Sea margin is essentially important for understanding the evolution of the South China Sea. The deep reflection seismic profiles and wide-angle reflection seismic profiles across the northeastern South China Sea were collected, and the crustal thickness and high-velocity lower crustal thickness were extracted respectively. Combining with geological and geophysical information such as bathymetry, gravity and magnetic anomalies, and lithospheric rheology, the crustal thinning of the northeastern South China Sea, nature of the Luzon-Ryukyu Transform Plate Boundary and distribution of the high-velocity lower crust and its origins were discussed. The northeastern crust is unevenly thin in lateral and vertical, dominated with lower crust thinning, like in the Taixinan Basin. There are similar extremely thinned crusts in the Baiyun Sag, Xisha Trough and Zhongjiannan Basin. They are always conjugated with or adjacent to rigid blocks. We agree that lower crust flow and mantle upwell caused by the existence of rigid blocks during initiated breakup are responsible for locally extreme thinning of the crust. Both sides of the Luzon-Ryukyu Transform Plate Boundary are different in the bathymetry, Cenozoic reflections, gravity and magnetic anomalies. The LRTPB intersected high magnetic anomaly zone caused by Mesozoic with a large-angle, indicating the Luzon-Ryukyu Transform Plate Boundary may be a boundary fault converted from the Mesozoic Paleo-Tethys tectonic domain to the Pacific tectonic domain. The distribution range of the extensive HVLC in the northeastern margin consistent with post-rift igneous. Combining with distribution interval of ratios V _p/ V _s of the high-velocity lower crust, It is suggested that the high-velocity lower crust primarily consists of mafic rock caused by multiple-epoch underplating.

By using the method of multi-index extension comprehensive evaluation, the various factors affecting the development and utilization grade of the inhabited islands were analyzed,the matter-element model of the comprehensive evaluation of the development and utilization grades of the inhabited island were established, and its correlation degree was calculated. Quantitative numerical evaluation results were obtained. Taking the four inhabited islands in Taizhou City, Zhejiang Province as an example, the results show that the evaluation of the exploitation and utilization level of the inhabited islands by this method is more objective and reasonable. It can be used as evaluation models of development and utilizing classification for the inhabited islands.

In order to objectively evaluate the management and control effect of marine ecological red line zone in China, the management and control evaluation system for marine ecological red line zone was established to evaluate the effect of Bohai Sea region and three provinces and one city (Shandong, Liaoning, Hebei and Tianjin), and timely to find the problems in the management and control. PSR model was used to evaluate the management and control effect of Bohai Sea marine ecological red line area, and empirical analysis was made on three provinces and one city. The results show that in the overall situation, the management and control continues to improve in Bohai Sea, the stability of pressure layer is poor, the state layer is constantly optimized, and the response layer is greatly affected by the policy. Among them, the pressure layer of Bohai Sea is mainly affected by the population and industry of Shandong Province, the status layer is mainly derived from the rich natural resources of Liaoning Province, and the response layer is mainly derived from the efforts made by Shandong Province for ecological security. Finally, according to the current situation of marine ecological environment in various provinces and cities, management suggestions are put forward from the aspects of management and control as well as the restricted development in the marine protected areas.

To evaluate the effects of hypersalinity and its fluctuation on the photo-physiological and the performances of marine “green tide” algae on salt tolerance, Ulva prolifera was selected as the experimental material. We set up three salinity conditions: salinity 25 as control (CK); treatment 1 (T1), salinity 30 for 3 d, then increased to salinity 35; treatment 2 (T2), salinity 35 for 6 d. The relative growth rate, the content of photosynthetic pigments, the photosynthetic and dark respiration rates and the gene expression levels of ribulose-1, 5-bisphosphate carboxylase/oxygenase (Rubisco) and calmodulin (CaM) were measured. The results showed that compared with control groups, hypersalinity significantly inhibited the relative growth rates and photo-physiological performances. Both T1, T2 treatments inhibited the relative growth rates and net photosynthesis rates of U. prolifera, and the inhibition effects of T2 was much stronger than that of the former one. The effect of hypersalinity stress on the dark respiration rate was not significant, which also had no significant effect on the content of photosynthetic pigments and their ratio of photosynthetic pigments. However, the dark respiration rate was significantly increased and photosynthetic pigments was significantly decreased along with the algae grow up. And the gene expression levels of rbcL and cam were also affected by hypersalinity. U. prolifera cultured in T1 treatment showed better resistance to hypersalinity than T2 treatment after 3 d and 6 d. It showed that U. prolifera could adapt to hypersalinity when the salinity was increased gradually. These results could explain the adaptation ability on hypersalinity stress of U. prolifera at the period of green tide formed and low tide.

According to the numerical forecast data of ECMWF in the past 10 years, we analyzed the spatial distribution of sea surface temperature, sea surface wind field and effective wave height of the four seasons and the whole year of the tuna purse seine fishery in the Western and Central Pacific Ocean, and studied the spatial and temporal variation characteristics using Empirical Orthogonal Function (EOF) and Empirical Mode Decomposition (EMD). Research shows that the spatial and temporal distributions of sea surface temperature, sea surface wind field, effective wave height have significant changes; the first, second, third modal variance contribution rates of sea surface temperature are 62.59%, 10.98%, 6.7%, and have 0.5 year, 1 year, 3 year cycle changes; the first, second, third modal variance contribution rates of sea surface wind field are 40.29%, 18.39%, 9.36%, and have 0.2-0.25 year, 0.5 year, 1 year cycle changes; the first, second, third modal variance contribution rates of effective wave height are 44.17%,17.35%, 10.96%, and have 0.2-0.3 year, 0.5-1 year, 1 year cycle changes.

chlorophyll a concentration is an important index of eutrophication. It becomes very necessary to timely and effectively monitor and evaluate the water chlorophyll a concentration for the environmental protection. Based on the satellite data from 2011 to 2016, the temporal and spatial distribution characteristics of the sea surface chlorophyll a concentration in the Beibu Gulf were analyzed. The results show that the chlorophyll a concentration in the Beibu Gulf has obvious monthly and seasonal variation, the monthly average chlorophyll a concentration reaches its peak in August and January, respectively, the average chlorophyll a concentration in the Beibu Gulf during winter and summer is higher than that during the spring and autumn, the chlorophyll a concentration in the Beibu Gulf sea surface begins to rise rapidly in summer, and the chlorophyll a concentration in the central and southern part of the Beibu Gulf slightly descend in autumn. In the spatial distribution, in the coastal waters of Beibu Gulf, the average chlorophyll a concentration is relatively higher, the high value area of chlorophyll a concentration is basically in the shallow water area along the western coast of the Leizhou Peninsula in the northern part of the Beibu Gulf, while the low value area lies in center and the deep waters of the south of the Gulf.

Internal waves occur frequently in Andaman Sea, and the study of its internal waves is the hotspot of ocean research today. In this study, more than 3 000 Terra/Aqua MODIS, GF-1, Landsat-8 and Sentinel-1 satellite remote sensing images covering the entire Andaman Sea from 2013 to 2016 were analyzed to obtain spatial and temporal distribution and wave direction feature of internal waves in the Andaman Sea. The statistical result shows that internal waves can be observed by the remote sensing mostly in four areas: north of Sumatra Island, middle of the Andaman Sea, north of the Andaman Sea and west of Nicobar Islands. The internal waves with a relative large spatial scale in northern Sumatra and middle of the Andaman Sea are more active in the Andaman Sea. No internal waves in the deep sea and the gradually changing bathymetric gradients areas of the Andaman Sea have been observed by the remote sensing. The distribution of observed internal waves is similar each year from 2013 to 2016 in the Andaman Sea. Internal waves can be observed in the Andaman Sea all through the year, most in February to April (hot season), next in August and September (rainy season), A minimum number of internal waves are observed in June, however, this may be caused by the small amount of clear optical images in rainy season in the Andaman Sea, it needs to further prove by using more remote sensing images. From the directions distribution, most internal waves propagate to the coast. Internal waves propagate eastward or southeastward in north of Sumatra Island and middle of the Andaman Sea, southeastward or southwestward in eastern Andaman Island. In addition, we found some internal waves propagate from the Andaman Sea to the Bay of Bengal.

The South Atlantic Ocean (SAO) connects the North Atlantic, Indian and Southern Oceans. The variability of SAO Ocean Heat Content (OHC) would improve our understandings of the heat redistribution among global ocean basins in a warming climate. In is study, we analyze the spatial and temporal variability of the upper-layer OHC of SAO from European Centre for Medium-Range Weather Forecasts Ocean Reanalysis System 4 data sets and temperature data sets of Institute of Atmospheric Physics of the Chinese Academy of Sciences. Using empirical orthogonal function (EOF) analysis, the OHC of upper 700 m in the Southern Atlantic shows a basin wide warming during the past 60 years. This warming trend is even more apparent and have longer fluctuation cycle with a deeper integration depth for OHC. Correlation analysis shows that leading EOF mode of SAO OHC is dominated by decadal or longer time scale variabilities, with a 9-12 years leading of AMO, suggesting SAO OHC contribute to the North Atlantic climate variation. The SAO OHC-AMO correlation increases with the increased OHC integration depth while SAO OHC-PDO correlation decreases. Besides, it is found that variation of OHC in the whole basin is positively correlated with variation of thermocline depth, and the variation of OHC reflects the dynamical fluctuation in the thermocline.

Wave set-up and wave-induced current are the significant dynamics for sediment transport, geomorphology and pollutant diffusion in estuaries, however, researches were rare under remote typhoon conditions in the Changjiang Estuary. In this study, we focused on the spatial distribution of wave set-up and wave-induced current under a remote typhoon named “Sanba” by a coupled 3-D model of typhoon-wind, tide and wave. The results showed that the radiation stress and wave set-up increased when wave propagated from the typhoon eye to coast due to wave energy dissipations, the maximum value of wave set-up could reach up to 0.05~0.20 m, which was 15%~22% of the total water level rise induced by typhoon. The along-shore current generated by wave were about 0.05~0.20 m/s, and could reach up to 15%~50% of storm-induced current. It implied that a remote typhoon could have significant influence on wave set-up and wind-induced current. The research could provide the basis for calculation of return period water level and current, sediment transport, geomorphological evolution of subaqueous delta and so on.

In this study, a numerical model based on TELEMAC-2D was developed for the Pacific Ocean and the China Seas to simulate the propagation of the tsunami wave of the Honshu (Japan) tsunami event on March 11 ^th, 2011. After validated against in-situ observation data from buoys, the influence of this event on the Yueqing Bay was investigated. By using a spectrum analysis, the amplitudes and phases of the resonance waves in the Yueqing Bay were found with the dominating periods of 240 min, 180 min and 103 min. A regional model driven by a white-noise-like boundary condition further elucidated the property of the natural oscillation at these periods, further supporting the finding of the three resonance modes. Moreover, the white-noise-driven model suggested that maximum amplitudes would appear both in the upper bay and at the bay mouth when tsunami disasters occurred. The conclusion of this paper can be instructive for disaster management and reduction of local governance.

Using RAM (Range dependent Acoustic Model) model which was based on parabolic equation algorithm and combined Argo floats with multi-satellite data, effects of typhoon on acoustic propagation characteristics for incomplete deep-sound channel(3 000 m) and complete deep-sound channel(5 500 m) were researched. Results show that the influence of typhoon on sea water is confined in surface layer, which is characterized by the thickening of the mixed-layer, zero temperature gradient and positive sound speed gradient in the mixed-layer. At a certain depth below the mixed-layer, the water temperature increases, and the corresponding sound speed increases. When the sound source is placed in the mixed-layer, sound propagation in sea surface layer will be affected, the surface waveguide sound propagation and leakage modes appear in both incomplete and complete deep-sound channels. When the source is under the mixed layer, typhoon makes the convergence zone close to the sound source under the condition of incomplete deep-sound channel.Under the condition of complete deep-sound channel, the disturbance of typhoon on the location of convergence zone is not obvious, but the flip depth of the sound wave increases nearly 500 m.

Space-borne Synthetic Aperture Radar (SAR) has become one of the new methods for the research of the offshore wind energy resources remote sensing. In this study, progress on the study of offshore wind energy resources remote sensing by space-borne SAR has been reviewed. Especially both the technology and application of the offshore wind energy resources remote sensing, and also the offshore wind turbine wake remote sensing by space-borne SAR are mainly introduced. Meanwhile, we discuss some issues in the present of the studies on the offshore wind energy resources remote sensing by SAR and the research orientation in future.

Higher demand of coastal large-scale projects defense capacity should be put forward together with the frequent marine disaster (MD) such as storm tide. This study investigated the design standard and status quo of Guangxi Beihai Port Shibuling Harbor Project in the coastal defense project (CDP), analyzed the design standard and parameters of storm surge and ocean waves, and evaluated the MD defense capacity of each section by comparing the right theoretical CDP elevations with the measured ones. Results show that evaluation result of extreme high tide level in consideration of sea level is equivalent to the preliminary design value. Theoretical results of waveheight in the north direction are greater than the designed values. The measured minimum elevation in both wharf sections and other CDP ones are lower than the evaluation values considering the wave run-up impact, which carries some risks. Some requisite measures should be immediately adopted to deduct MD risk.

Based on the topographical data of Liaohe Estuary in recent 50 years, the subaqueous delta evolution of Liaohe Estuary was studied by using GIS methods. The research results are showed as follows:The outer edge of the subaqueous delta of Liaohe Estuary(the western and southern edges of Geligangzi Shoal, the western and southern edges of Xitan Shoal) experienced a relatively erosion progress and the eastern edges of Geligangzi Shoal experienced a accumulation progress and the eastern head of the southern part of Geligangzi Shoal had moved northward and eastward.The Nearshore Shoal between the two river mouths experienced a process from accumulation to stability, and the shoal had eroded partially north of East Trough. Because of Geligangzi Shoal moving eastward, East Trough at east of Geligangzi Shoal had became narrow, and the deep water between Geligangzi Shoal and Xitan Shoal appeared a trend of widening and becoming shallow. The decrease of incoming sediments from Liaohe River was the main cause for the erosion of the outer edges of the subaqueous delta. The erosive sediment transport up to the estuary under the action of wave and flow was the main cause for the siltation of east edge of Geligangzi Shoal and East Trough became shallow and narrow. The impact of the artificial reclamation of the nearshore beach on the evolution of the underwater delta was worthy of attention.

When the submarine cable passes through the hard bottom seabed, covering the concrete interlocking mattress can effectively protect it. According to the measured hydrological data in the sea area of the state grid corporation of 500 kV submarine cable project, two methods were used to study the stability of the concrete interlocking mattress under the extreme flow. Based on function analysis of the mechanical balance, it is found that when the bottom length of the concrete block is fixed, there is an extreme height. At this time the concrete block laid on seabed is the most stable, and also the flow velocity that can be resisted is the largest. Through numerical simulation, the three-dimensional flow characteristics of concrete interlocking mattress in current were studied. After comparing the force situation of different shape concrete blocks, it is found that when the edge of the concrete block is rounded, the flow structure around the edge can be changed, and the stability of the concrete block can be strengthened in general. Although the current velocity in the sea area of the state grid corporation of 500 kV submarine cable project is large, the conventional size of 0.4 m×0.4 m×0.3 m blocks can resist the impact of the current and protect the submarine cable.

Due to the necessity of construction, it is proposed to adjust the dike line of Jiuxi reach of Qiantang River. Jiuxi is one of the well-known tidal bore scenic spots of Qiantang River, and the tidal bore is an important natural landscape resource in this reach. In order to mitigate the impact of dike line adjustment on the tidal bore landscape, a three-dimensional SCHISM tidal bore model based on finite element/finite volume method was established, which reproduced the phenomenon of Jiuxi tidal bore. Three comprehensive evaluation indexes were put forward, namely, the height of tidal bore, the length of shoreline with significant bore height and the area with significant height of bore, and the impact of levee adjustment on tidal bore was evaluated. The study has reference significance for other projects to evaluate the tidal bore landscape of Qiantang River.

The northern South China Sea, located in tropical and subtropical areas,is one of the important fishing grounds along the coast of China and has abundant fishery resources. Phytoplankton are the basic link in the marine food chain, change in their community structure will directly or indirectly influence fishery resources. According to the survey data in May 2015, the structure characteristics of phytoplankton community and its relationship with environmental factors were analyzed. The results showed that a total of 378 species (excluding the unidentified species) belonging to 4 phyla were identified, including 209 species of diatoms, 157 species of dinoflagellate, 9 species of cyanobacteria and 3 species of chromophyte. The dominant species were Proboscia alata,Proboscia alata f . gracillima,Thalassiothrix frauenfeldii,Pseudo-nitzschia pungens,Eucompia zoodiacus and Chaetoceros lorenzianus.The dominant species differed obviously among sections, only Thalassiothrixfrauenfeldii was dominant along four sections. The phytoplankton abundance ranged from 0.63×10 ⁴ cells/m ³ to 1 430.04×10 ⁴ cells/m ³, with an average of 76.20×10 ⁴ cells/m ³. Diatoms were overwhelmingly dominant in phytoplankton community, which abundance ranged from 0.3×10 ⁴ cells/m ³ to 1 420.39×10 ⁴ cells/m ³, with an average of 72.89×10 ⁴ cells/m ³, accounting for 95.66%. Dinoflagellate abundance ranged from 0.03×10 ⁴ cells/m ³ to 23.78×10 ⁴ cells/m ³, with an average of 2.71×10 ⁴ cells/m ³, accounting for 3.56%. Shantou section (H) had the highest abundance, with an average of 250.01×10 ⁴ cells/m ³, followed by Zhanjiang section (D), with an average of 99.48×10 ⁴ cells/m ³. The low abundances were found in the Pearl River Estuary (F), Shanwei (G) and Yangjiang (E) sections, with an average of 11.67×10 ⁴ cells/m ³, 10.61×10 ⁴ cells/m ³ and 9.23×10 ⁴ cells/m ³, respectively. High-abundance areas were mainly occurred at inshore stations in the Shantou (H) and Zhanjiang (D) sections. Overall, the phytoplankton Shannon-Wiener diversity index was high, ranged from 1.06 to 5.56,with an average of 3.99, indicating that the community structure of phytoplankton was relatively stable in the northern South China Sea in spring. Redundancy analysis showed that temperature, salinity and phosphate were the main environmental factors associated with the phytoplankton community structure in the northern South China Sea. Spearman's rank correlation analysis showed that abundances of phytoplankton, diatoms and dinoflagellates were negatively correlated with temperature. The results showed that the species composition, abundance distribution and dominant species composition of phytoplankton were different from section to section. Phytoplankton distribution was characterized by high nearshore and low offshore,and water temperature and salinity were the main environmental factors affecting its distribution in the continental shelf of the northern South China Sea in spring.

Intraseasonal variabilities (ISVs) are important factors in tropical climate. The ISVs like sea surface temperature (SST) and sea surface height (SSH) from oceanic reanalysis ECCO2, SODA3 and CORA were compared with the satellite observations during boreal summer and winter. Intraseasonal SST anomalies were also further compared during MJO and CIO cases. Results show that the ISVs from reanalysis data have the same clear variabilities nearshore as the observations, while within the ocean, the ISVs standard deviation (STD) of reanalysis data is weaker than that of the observation data for at least 20%, SODA3 even faces the differences up to 60%. During the eastward propagation of MJO and northward propagation of CIO, the SST anomalies induced by thermal force is well simulated by the reanalysis data, only ECCO2 and CORA encounter a phase lag of 5-10 days. During the westward propagation of SST anomalies at CIO, reanalysis data have an awful simulation for this dynamic forced ISVs. ECCO2 and CORA propagate to the west in a small area from 85°E-95°E feebly, and even that in SODA3 doesn’t show its westward signals. Temperature in all reanalysis data is a half weaker than the observations at eastern Indian Ocean (90°E-100°E). Through comparison in intraseasonal velocity anomalies, the STD of reanalysis data is far less than RAMA (51.42%), the averages among the peaks of velocity are also weaker than observations for 65.16%. This suggests that improper simulation of dynamically-forcing ISVs may lead to the weaker variabilities within Indian Ocean. Therefore, in order to upgrade the ISVs in reanalysis, it is necessary to modify the heat forcing as well as dynamic forcing in atmospheric modeling and, more importantly, add up the oceanic assimilation. Equatorial Indian Ocean, as the prevalent area for ISV events and the area with clear difference in STD, is surely a region for more observation plans with oceanic variabilities like currents.

Geostationary Ocean Color Imager (GOCI) provides ocean water color data with time resolutions up to the hour, making it possible to monitor the marine environment in a time-varying manner. However, due to the influence of clouds, fog and haze over the ocean, the continuous high-missing rate or even complete loss of data makes the data use value greatly reduced. Based on the Data INterpolating Empirical Orthogonal Functions, highlighting the position of time elements in reconstruction, a reconstruction method using abnormal pixel detection, Laplacian smoothing and temporal coefficient twice decomposition interpolation was proposed for geostationary satellite ocean color data (DINEOF-G). This method is used to reconstruct the total suspended matter data of Hangzhou Bay in 2017. The results show that the proposed method improves the reconstruction accuracy by 8% and the data reconstruction rate by 36% compared with the classical method. The reconstructed data reflects the seasonal variation and spatial distribution characteristics of the total suspended matter in Hangzhou Bay.

A set of monthly mean global ocean(0~1 500 m)Argo data sets (1°× 1°) from 2004 to 2017 was constructed by using “Gradient-dependent Correlation Scale Method”. And based on the comparative test of the data set, we have initially applied the data set to the fisheries analysis of yellowfin tuna in the Central and Western Pacific Ocean. The results show that the temperature and salinity deviations between the Argo data set and the WOA13 historical data set were slightly larger in the upper surface layer of the ocean about 0.5 ℃ and 0.1 respectively, and the two deviations both decreases gradually with the increase of depth. The temperature deviations between the Argo data set and time series of the TAO buoy were less than 1 °C in 2004-2017, and the maximum salinity deviations were less than 0.5 while most of those in the sea areas were close to 0. In the Central and Western Pacific Ocean, the central fishing ground of yellowfin tuna mostly concentrated at the isotherm of the range of 28 ~ 29 ℃, and in the sea areas where temperature below 22 ℃, the catch per unit effort (CPUE) value was very small. In the central fishery area, the upper boundary depth of the thermocline was in the range of 20 m and 120 m, and the frequency of formation of the center fishing ground at each depth was generally normal distribution. When the upper boundary depth of the thermocline was 90 m, the possibility of forming the center fishing ground was the greatest. While further verifying the reliability of the data set, it is also shown that the data set constructed in our study has certain application value in hydrologic environment analysis and resource assessment.

In order to understand the impact of marine environment and terrestrial environment on GPS multipath effect, Anubis software was used to analyze the multipath error in the marine environment and terrestrial environment based on the observation data of two stations at the seaside. The differences were compared and analyzed. The results show that: (1) When the satellite elevation is low, the multipath error in the marine environment and the terrestrial environment increases gradually with the decrease of the satellite elevation angle, and the multipath error increase in the marine environment is significantly greater than that in the terrestrial environment. (2) When the satellite elevation angle is less than 20°, the multipath error in the marine environment is greater than the multipath error in the terrestrial environment; when the elevation angle is greater than 20°, the difference in the multipath error between the sea surface direction and the land direction is small.

Based on the theoretical analysis, wave flume experiments were carried out employing vegetation models with quantifiable root, stem and canopy. The attenuation characteristics of irregular wave height within the vegetation filed was investigated by a combination of water depth, incident wave height and vegetation distribution density. Variation of wave spectra associated with vegetation was studied using FFT. The results show that the vegetation models in this experiment have good wave-absorbing effect, but the boundary effect of vegetation wave attenuation is rare. The variation of irregular wave height along the flora is inconsistent with Mendez's theoretical curve most of the time. At the same time, there is no fixed variation of wave energy loss within different sections of the vegetation filed. In addition, the attenuation of wave energy is concentrated at the peak frequency, and increasing incident wave height result in a bigger difference between spectra values of transmitted wave and incident wave at peak frequency, while spectra of both transmitted wave and incident wave show similar bands. This study can provide a theoretical basis for using coastal vegetation to reduce shoreline erosion by surface waves.

In this study, the content of bio-silicon and organic matter in the surface sediments were analyzed, which were collected by the Ocean 40 voyage in the mountain basin of the Marcus-Wick Sea area in the western Pacific, and the preliminary research on its distribution characteristics and sources were also conducted. The results show that the content of bio-silicon in the deep sea surface sediments near the Marcus-Wicker Sea area is generally low, ranging from 0.88% to 12.41%, with an average content of 2.19%. The distribution shows a high content in the southwest and a diminishing trend toward the northeast. The content of organic carbon in the surface sediments is low, and the distribution of δ ¹³C is the same as that of bio-silicon. Sediment core studies show that the primary production of siliceous organisms in the surface waters of the study area during the past 100-200 ka is gradually increasing.

The sustainable development of island resources is an important issue in marine development and management. In order to optimize the allocation of island resources and promote the coordinated development as well as ecological environment protection of island, in view of the particularity of island ecosystem, and based on the related researches, the concept, connotation and characteristics of island ecosystem vulnerability(IEV) were describes. The islands in Liaoning were paid more emphasis on, and a large number of typical cases of islands were analyzed to establish the impact mechanism framework and analyze the causes and manifestations of IEV. On this basis, the assessment system and methods of IEV were discussed. Finally, the research prospect was put forward. The study shows that the IEV is the sensitive response and self-recovery ability of island ecosystem when the island is interacted with the natural environment and in the process of island development under the background of certain natural factors and human factors. The IEV is objective, sensitive and difficult to recover. It has the characteristics of long-term, difference and controllability. The IEV varies with different types and degrees of natural disturbance and human disturbance, and the establishment of its driving mechanism and evaluation system can provide ideas for further research. The results of the study can provide scientific basis for island ecological environment protection and have important practical significance for promoting sustainable development of the island.

The classification and grading of sea area is the making collecting standard for the sea area using charge, and it is also the premise and basis for carrying out the appraisal of sea area asset price. Based on the technical guidelines for sea area grading (Trial implementation) and following the principles of resource endowment difference, income difference, economical utilization and ecological sea use, we selected two grading factors of sea natural conditions and sea area location conditions, and 10 assessment factors, such as seawater quality, marine natural disasters, et al., and then established the index quality assessment system of Shenzhen bathing beaches grading. Using the comprehensive index assessment method, we could get the scores of 207 assessment units, and use cluster analysis method and coefficient of variation (CV) to check the level. Finally, the bathing beaches are divided into three levels: level-Ⅰ(22.22%), level-Ⅱ(33.82%) and level-Ⅲ(43.96%). The research results provide a basis to evaluate the reference price of different levels bathing beaches for the marine management department in Shenzhen.