Volume articles

Acoustic Doppler Current Profiler (ADCP) is an effective way to monitor ocean internal waves. However, due to the influence of the instrument itself and complex ocean environment noise, there are a lot of noise and some abnormal velocity values in the velocity data recorded by ADCP. In order to further improve the extraction accuracy of internal solitary waves in the sea, the weight function factor of IGG3 method was introduced according to the characteristics of the shipboard ADCP velocity data, and the Robust Vondrak filter was designed. In order to verify the effectiveness and superiority of Robust Vondrak filtering method, it was compared with three traditional filtering methods: fast Fourier transform, wavelet transform and sliding average. The experimental results show that the Robust Vondrak filtering method can not only remove the flow velocity noise, but also effectively eliminate abnormal flow velocity values, so it has certain advantages compared with the traditional filtering methods. The Robust Vondrak filtering method can extract internal solitary waves accurately and the horizontal velocity of each layer is clear. It is a good method to extract internal solitary wave.

Diurnal cycle in two satellite-derived precipitation datasets(IMERG and TMPA) based on both Global Precipitation Measurement (GPM) and Tropical Rainfall Measuring Mission (TRMM) are compared with data obtained from 23 rain gauges mounted on floating buoys in the tropics for the period 1 April, 2014 to 30 April, 2018. The results show that both satellites underestimate the ranges of precipitation diurnal variations. In the Pacific Ocean and the Indian Ocean, both IMERG and TMPA observe the rainfall maximum in the early morning and the minimum in the evening, which are consistent with the rain gauge buoys. However, in the tropical Atlantic, both satellite datasets show quite different patterns of the diurnal cycle from the rain gauge buoys, which is due to little precipitations over the Atlantic Ocean leading to large biases in both satellites and rain gauge buoys.

From the continental shelf at the east of Hangzhou Bay, 28 sample columns were acquired. The thermal conductivities of soils at different depths (0.2 m,1.0 m and 1.8 m) from these cores were tested by thermal probe. Correspondingly, particle size of the soils were also tested. Through the comparison between six kinds of soils in the study area, It was found that those with higher sand content (>10%) have bigger thermal conductivities. Besides, water content and dry density have significant effect on thermal conductivities of certain type of soil. Average value of thermal conductivity for superficial soils in Hangzhou Bay area,mixed deposit area and shelf sandy area are respectively 1.25 W·m ^-1·K ^-1, 1.45 W·m ^-1·K ^-1 and 1.46 W·m ^-1·K ^-1, which indicates that thermal conductivities increase from the coast to open waters. On the other hand, vertical variation of thermal conductivities shows that spatial factors including water depth and buried depth have no direct effect on the thermophysical properties of seabed soils.

Based on the multi-beam bathymetric data of the Yap-Mariana Trench in the Western Pacific Ocean, the high-precision bathymetric topographic maps in the rectangular areas of 9.8°N-13.2°N and 132.2°E-145°E were obtained. Then the detailed geomorphologic analysis shows that there are large-scale horst-graben geomorphology on the slope of the southern part of Mariana Trench, obvious segmentation in the northern part of the Yap Trench, and large-scale ridge-trough geomorphology in different distribution directions in the Philippine Basin and the Parece Vela Basin. The results show that the complex topographic and geomorphological features are mainly controlled by plate motion, and the topographic and geomorphological features of the region are classified according to the published research results.

Underway sea surface pCO ₂, sea surface temperature, sea surface salinity data, and discrete DO data in the East China Sea were obtained from August 23, 2017 to September 6, 2017. The distributions of pCO ₂ in the Changjiang River Estuary and the adjacent sea areas were examined. Meanwhile, the effect of strong wind on air-sea CO ₂ flux in this area was discussed based on data of a revisited section before and after a strong wind event. The results show that sea surface pCO ₂ (145~929 μatm) in the study area was higher in the nearshore and lower in the offshore area. Biological production consumed dissolved inorganic carbon, and lowered sea surface pCO ₂ of the Changjiang plume waters, which acted as carbon sink. The wind event (the maximum wind speed was 9.7 m·s ^－1) triggered vertical mixing, enhanced carbon source significantly at nearshore area(from 0.2±1.9 to 55.0±12.4 mmol·m ^－2·d ^－1). While, the estimated CO ₂ sink at offshore waters was stronger than that before the wind (from -12.7±2.3 to -16.8±2.5 mmol·m ^－2·d ^－1). Therefore, large bias in air-sea CO ₂ flux estimation will be introduced if the influence of typhoon and cold-air events are not considered.

Using the WorldView-2 high-resolution satellite images, two models were studied: log transform model(Stumpf 2003) and dual bands linear regression model(Lyzenga 1985). Firstly, the correlation between water depth and each band was analyzed under different sediment conditions. Then the L-M(Levenberg-Marquardt) algorithm was used to solve the model parameters. Finally, the accuracy of the two models was compared and analyzed. The results show that for coral sediment, the determination coefficient and root mean square error of Lyzenga 1985 model are 0.902 and 1.651 respectively, which are better than those of Stumpf 2003 model(0.882, 6.421); For sandy sediment, the determination coefficient and root mean square error of Lyzenga 1985 model are 0.897 and 0.529 respectively, which are better than those of Stumpf 2003 model(0.779, 0.723). It can be seen that Lyzenga 1985 model is better than Stumpf 2003 model in the area of clear coral and sandy sediment, and Lyzenga 1985 model has stronger universality and can present relatively stable inversion effect.

The object-oriented classification method was utilized to interpret 4 time-series Landsat data of 1990,2000,2010 and 2015 to identify the aquaculture ponds in coastal area of Hainan Island. Based on the landscape indexes and centroid migrate model,the temporal and spatial characteristics of aquaculture ponds and its impact on the coastal ecological environment were explored. The results showed that the area of aquaculture ponds of Hainan Island continued to grow from 1990 to 2015 and the regional differences were obvious. The distribution position of aquaculture area moved to the northeast of Hainan Island and the landscape indexes showed that the landscape pattern of the aquaculture area tended to be fragmention. The expansion of aquaculture ponds invaded natural wetlands such as mangroves, causing damage to the coastal ecological environment. Therefore, reasonable planning and scientific upgrading are needed for the sustainable development of aquaculture.

Mangrove is a kind of biological coast composed of salt tolerant mangrove plant communities. Its growth status is of great significance to the coastal zone. Remote sensing technology has become one of the main means for mangrove monitoring. In this study, taking the mangrove in Shankou, Beihai of Guangxi as an example, using the coastal zone imager data of HY-1C satellite, combined with its texture parameters, the mangrove information was extracted, and the mangrove vegetation indexes were analyzed. The results showed that from October to November 2018, the RVI value of mangroves was greater than 1, and this in some areas was greater than 5; the NDVI value of mangroves varied from 0 to 0.01, and the average value was greater than 0.5; the EVI value of mangroves was mainly concentrated between 0.2 and 0.7. The results of different vegetation indexes showed that mangrove in Shankou grew well.

An Archiving Validation and Interpretation of Satellite Oceanographic(AVISO) mesoscale eddy tracking dataset from satellite altimeter during the period from 1993 to 2017 was used to classify the mesoscale eddies in the East China Sea(ECS) according to the path. The results show that 318 cyclones and 276 anticyclones were detected in the ECS during the 25-year period. These mesoscale eddies were classified into the following types according to the path: (1) Eddy generated on the continental shelf of the ECS intrudes into deep sea(148 cases); (2) Eddy generated in deep sea intrudes into the continental shelf of the ECS(35 cases); (3) Eddy spreads along the isobath(180 cases); (4) Eddy wanders around(121 cases); (5) Eddy generated in Pacific Ocean intrudes into the shelf area of the ECS(25 cases) and (6) Eddy generated in Pacific Ocean intrudes into the ECS(85 cases). There existed very obvious seasonality for these six types. And the seasonal distribution for cyclones and anticyclones is diverse. The quantity of eddies for the type 3 is higher in spring and summer, lower in autumn and winter. The distribution of eddies for the type 1 is more evenly. The quantity of cyclones for the type 1 is the lowest in summer, and higher in spring and winter. The seasonal distribution for mesoscale eddies is related to the variations of the Kuroshio. The mean lifetime of eddies for type 4 is the longest, about 44 days. The mean amplitudes of eddies for type 1 and 5 are the largest, about 13.2 cm. The maximum mean diameter of the eddies is for type 5, about 122 km. The mean lifetime, amplitude and diameter of eddies for type 6 are the smallest.

Marine survey is the basis for marine sciences. Survey components and demand have been developed with input from blooming new technology and research methods. Also, the related products gradually become highly professional, diversified and international. Thus it will be necessary to develop international standards for marine survey. Here we compare the differences of strategies, organizations, standard systems and the published marine survey standards among China, the United States and the European Union. It is suggested to bring China national marine survey standards into the international market by: (1) learning from the American standardization system which features free-competition; (2) learning from the European standardization system which has perfectly met the requirements of international community; (3) the better bridge of ISO/TC8/SC13 (Marine technology subcommittee of International Organization for Standardization).

The UK Met Office EN4 analyses product revealed that the surface area and the volume of the North Pacific subtropical high-salinity center, namely North Pacific Tropical Water (NPTW), decreased in the period of 2000-2008 and 2014—2017, and grew in 2008—2014. The changing period of NPTW was highly correlated with Pacific Decadal Oscillation (PDO). Using the ECCO2 reanalyzing data, the fresh water flux was calculated through the NPTW surface. Our results show that the fresh water flux has less contribution to changes of NPTW, while the horizontal advection contributes significantly to the surface area and volume changes of NPTW, which is related to the northward(southward) swing of North Equatorial Current (NEC) during the PDO positive(negative) phase.

To investigate monochromatic wave nonlinear characteristics around coral reefs with large surface roughness, laboratory experiments were carried out in a wave flume. A cylinder array was used to model the reef roughness and a series of monochromatic wave conditions were tested. Results show that magnitudes of the wave skewness, the wave asymmetry and the Ursell Number reach their peaks at the endpoint, in the interior and at the stating location of the reef surf zone, respectively. All the three parameters increase with the increasing wave height. Meanwhile, the skewness decreases with the increase of wave period while both the asymmetry and the Ursell Number increase with the increase of wave period. Moreover, the skewness increases with the increase of reef-flat water level while both the asymmetry and the Ursell Number decrease with the increase of reef-flat water level. The deep-water Ursell Number is able to describe the variations of the three examined parameters on the reef flat, and the empirical formulas are finally proposed in this study to predict these parameters.

The polymetallic nodule samples were analyzed for their mineralogical and geochemical features, which were acquired on the northeastern slope of the South China Sea using the ROV named as Sea Dragon III. The results showed that the nodules in the study area were predominantly by rod-shaped with a two-layer structure. The outer layer of the polymetallic nodules was mineralogically and geochemically similar to hydrogenic nodules. While the inner layer was porously and composed of goethite with residual minor pyrite. Geochemically, the inner layer was characterized by high concentration of Fe and As but extremely low concentration of Mn, REE and other elements. The inner layer carbon isotopes ( δ ¹³C ) of sample NH-2 was -30.91‰. The study presented that the early forming process of the nodules was related to the activities of cold seep, but the pyrite was oxidized following the extinction of cold seep. Under the influences of contour current in the area, the ferromanganese oxides continued to grow in the outer layer of the nodules.

The Landsat TM/OLI remote sensing images from 1973 to 2018 were obtained as the data source by using the remote sensing and GIS technology. Based on the geographical background information, the spatial and temporal evolutions of the coastline in the Pearl River Delta region over 45 years were analyzed. The results show that the Pearl River Delta changed significantly, a large number of muddy coast changed into urban industrial coast and port coast. The artificialization index of Pearl River Delta coastline was rising, the types of coastline were developed in a diversified direction, the total length and fractal dimension of shoreline were increasing continuously, the main factors of increase shoreline length and fractal dimension were port construction, coastal industrial zone and reclamation.The evolution of the coastline had obvious regional characteristics, and the regions with large changes were mainly concentrated in Shenzhen Mirs Bay, Guangzhou Nansha and Zhuhai Doumen. From the perspective of the main structure of shoreline, each region presented different type changing tendency, substituted the natural shoreline, the industrial and port shorelines became the main type in each region. The intensity of development and utilization was increasing in various regions, among which the intensity of development in Shenzhen was growing the fastest. Social activities and location policies were the main driving factors for the evolution of shoreline.

In the past two decades, large scale blooms Prorocentrum donghaiense Lu ( P. donghaiense) have frequently occurred in the coastal water of the East China Sea (ECS). Previous studies have shown that P. donghaiense blooms in the ECS originated from the front of Taiwan Warm Current (TWC) and expanded with its invading inshore. However, little is known about the location where the P. donghaiense blooms firstly occur, as it is limited by the investigation section of previous studies. In this research, four surveys in the East China Sea (24 °N-30 °N) in spring and summer of 2013 were conducted. Results clearly showed that P. donghaiense blooms occurred firstly at the northern end of the Taiwan Strait and spread northward and inshore with the invading of the front of TWC. It was not only confirmed again that the TWC played a seed bank role for P. donghaiense blooms in the ECS, but also confirmed the location where P. donghaiense blooms firstly occurred in the ECS. This research was useful to monitor P. donghaiense blooms and similar algal blooms.

The Comesomatidae are a group of free-living marine nematodes that widely distributed in the ocean sediments. The development and progress of systematics research of Comesomatidae are briefly summarized and key to the species of each genera is also provided. Our review recognizes 3 subfamilies, 19 valid genera, 239 valid species, 4 genera including 4 species without enough morphological information for accurate identification (species inquirenda).

In order to evaluate the ecological environment quality of the estuarine coastal zone, based on remote sensing information technology in land, a remote sensing assessment system of the ecological environment of the estuarine coastal zone was established.Through the analytic hierarchy process and the Delphi Method, the area of 5 km land forward along the coastline of Baoshan District was taken as an example to evaluate. The results show that the estuarine coastal zone of Baoshan District is dominated by industrial and mining warehousing land, and the ecological environment quality in this area gradually decreases from west to east, reaches the lowest point in the area between the Lianqi River and the Malu River, and starts to rebound to the east,the overall situation is poor.

The island is one of the core contents of the value of marine resources development and utilization. In order to reasonably develop, utilize and protect island resources in Guangdong-Hong Kong-Macao Greater Bay Area and optimize the industry structures and arrangement on islands, from the perspective of the spatial distribution of island resources, the role of islands in the development of the key platforms in Guangdong-Hong Kong-Macao Greater Bay Area was explored. The spatial distribution characteristics of islands in Guangdong-Hong Kong-Macao Greater Bay Area were investigated by application of ArcGIS software platform, Nuclear Density Estimation Method, Lorenz Curve and Gini Coefficient calculation based on the statistical data of 850 islands coordinates and land areas, which have been listed in the China Seas Island Standards Directory. The results show that the distribution type of islands in Guangdong-Hong Kong-Macao Greater Bay Area tends to be concentrated and presents the overall band distribution, the characteristics of local group distribution in space. The islands in Guangdong-Hong Kong-Macao Greater Bay Area have shaped the western part of the bay area and 4 obvious gathering areas,Including Dapeng Bay-Daya Bay Area, Kyushu Islands Area, Wanshan-Jia Peng Islands Area, Chuanshan Islands Area. The islands in Guangdong-Hong Kong-Macao Greater Bay Area are mainly coastal islands and the area distribution of islands is characterized by an imbalance, with a Gini coefficient of 0.58.

The Pearl River Estuary (PRE) is one of the coastal areas with serious land subsidence, which forms a serious threat to the quality and safety of human life and production. In response to the problems associated with the lack of man-made targets of traditional time-series Interferometric Synthetic Aperture Radar (InSAR) in estuaries and other coastal areas, a distributed scatterers InSAR (DS-InSAR) method based on a spatially adaptive filter and an eigendecomposition algorithm to estimating the optimal phase of statistically homogeneous DS was applied to obtain the deformation information in PRE between 2015 and 2018. High-density and high-coherence points were extracted in asphalt pavement, bare soil and other non-urban areas, to improve the inversion accuracy. The results suggest that land subsidence in the PRE was widespread and unevenly distributed. The northwest and southeast are the main subsidence areas, with a maximum subsidence rate greater than 25 mm/a.

In order to explore the biochemical and genetic characteristics of Scomberomorus niphonius, Gradient Polyacrylamide Gel Electrophoresis (GPGE) was used to analyze the expression patterns of eight isozymes (LDH, MDH, GDH, G6PDH, SOD, EST, SDH and MEP) in nine tissues (cardiac, gill, intestine, muscle, stomach, liver, eyes, kidney and gonad) of six individuals (3 females, 3 males) from Xiangshan Bay. The results showed that all eight isozymes were tissue-specific expression in nine tissues. LDH, MDH and G6PDH expressed in all nine tissues, while GDH only expressed little in the liver and eyes. Isoenzyme expressions were most abundant in liver among nine tissues. Eight isozymes were detected in the liver, in which the enzyme bands of EST were most abundant. GDH and G6PDH were more active in the liver than in other tissues. Isozyme expression patterns had no difference between male and female. The results provide a theoretical basis for the germplasm identification of Scomberomorus niphonius.

A preliminary assessment of the Pacific Equatorial Intermediate Currents (EICs) in five ocean models outputs (OFES, LICOM, HYCOM, ECCO2 and SODA) were conducted according to the spatial and temporal features using observation data which was calculated from Argo trajectories. The EICs in Argo currents field are mainly composed of the alternating east-west zonal jets. In the east-west direction, the currents are strong in the western but weak in the eastern, in the south-north direction, the currents are strong in the southern but weak in the northern. Besides, there are seasonal variations and the phase of seasonal variations is characterized by westward propagation and meridionally symmetrical on the equator. The assessment results show that SODA is the best dataset in these five models, all the characteristics are almost consistent with the observation. The second is ECCO2, the flow field is almost consistent with the observation except the kinetic energy. Then comes the OFES, LICOM and HYCOM, all of them are able to simulate the structures of the alternating zonal jets.

The tidal residual current in the adjacent area of Sanggou Bay plays an important role in material transport. However, due to the lack of observation data, the overall spatial pattern of the tidal residual current in this area is still unclear. 22 sets of observational data and high-resolution numerical simulation data of the ocean current were used to analyze the overall spatial characteristics of tidal residual currents and to reveal its formation mechanism. The tidal residual currents within the Sangou Bay are generally weak, while in the areas near the three headlands (Lidao, Xunshan and Chushan), the tidal residual currents show significant pair of eddies. To the northern part of each headland, there is a cyclonic tidal residual eddy; while to the southern part of each headland, there is an anticyclonic tidal residual eddy. The pair of eddies near the headlands of Lidao and Chushan are much stronger and cover wider area than those of Xunshan. Dynamic diagnosis based on the residual vorticity equation shows that the tidal residual eddies are mainly induced by the horizontal shearing due to the lateral boundary friction, the bottom friction stress curl only affects the tidal residual eddies near the headland of Lidao, and the effect of potential vorticity conservation is not significant in the formation process of the all three pair of the tidal residual eddies.

Distribution of eddy originations and characteristics of eddies in summer and winter in the Bay of Bengal (BOB) from 1993 to 2017 were analyzed based on Mesoscale Eddy Trajectory Atlas Product provided by AVISO. Seasonal variabilities of mesoscale eddies were found mainly in the western BOB, the Andaman Sea and the southern BOB. Eddies in the Andaman Sea distribute from north to south with order of “anticyclones-cyclones-anticyclones” and “cyclones-anticyclones-cyclones” in winter and summer respectively. Growth of eddies has seasonal variabilities and varies from different regions. Eddies in the western BOB intensify rapidly but vanish slowly in summer. Sri Lanka cold eddies intensify slowly but vanish rapidly. Amplitude and radius of eddies are different in different regions. Amplitude and radius of anticyclones are larger than those of cyclones whenever in summer or winter in the western BOB. Radius of anticyclones is larger than that of cyclones near the Southwest Monsoon Current. While, amplitude of anticyclones is smaller than that of cyclones. Amplitude and radius of eddies northernmost are the largest whenever in summer or winter in the Andaman Sea. Eddies with lifetime about 30-40 days are the largest number in the Bay of Bengal. Eddies with long lifetime mainly distribute in the western BOB.

The phenomenon of “double peak” of tidal water level in Daya Bay and Dapeng Bay was reproduced by means of the measured data, and it is determined that the abnormal growth of shallow water tide is the main cause of the phenomenon, among which the one-quarter-day tide and the one-sixth-day tide played a crucial role. The high-resolution hydrodynamic model of Daya Bay and Dapeng Bay was constructed by using the SCHISM model. The simulation shows that in the open sea outside Daya Bay and Dapeng Bay, tidal type is irregular diurnal tide in the eastern sea, tidal type is irregular semidiurnal tide in the western sea and two bays. The pattern of current is irregular semidiurnal currents in study area. The difference of hydrology between the two adjacent bays is directly caused by the deformation process of one-quarter-day and one-sixth-day tide in Daya Bay and Dapeng Bay. Through the numerical experiments of building different bottom friction intensity, eliminating bottom topography and changing water depth, it is shown that whether the direction of split tide propagation is consistent with the direction of shallower water depth is the fundamental reason that leads to the different tidal wave deformation in two bays.

The characteristics of tropical-cyclone(TC) activities over the western North Pacific during 1951-2016 were analyzed using three TC best track datasets(CMA, JTWC and RSMC). The consistent conclusions in three datasets are as follows: TCs mainly occurred in the latitude of 10°N-25°N. Before 1980, there was a southward latitude shift of TC position points, while it was the opposite after 1980. The TC translation speed was mostly distributed in the 2~6 m/s, and TCs significantly sped up near 25°N. The TC translation speed had a significant decrease trend before 1980. The maximum wind speed was mainly distributed in the range of 10~15 m/s, and it decreased before 1980. The radius of maximum wind speed was relatively smaller in the region with larger maximum wind speed. The radius of maximum wind speed of TCs and typhoons decreased by 0.46 km and 0.54 km per year respectively during 2001-2016. The results of CMA and RSMC were highly consistent, while the results of JTWC were different from them to some extent. The difference between the three datasets had a great influence on the change of TC intensity and the numbers of position points, but had a little influence on the change of the TC location and translation speed.

In order to solve the problem that there is a large deviation in retrieving SST by using reanalysis data of NCEP and Radiative Transfer Equation Algorithm, taking HJ-1B SST retrieval as an example and starting from the correction of the atmospheric transmittance, two improved Radiative Transfer Equation Algorithm: algorithms of the Center Point Algorithm and the Mean Point Method are proposed, and they are verified by MODIS SST and buoy SST. The two improved algorithms have improved the atmospheric transmittance deviation and HJ SST retrieval deviation significantly, and both HJ SST and MODIS SST show significant consistency. The MODIS SST verification shows that the average deviation and mean square error of the two improved algorithms are about 0.5 ℃. The buoy SST verification shows that the Mean Point Algorithm has higher retrieval accuracy, which average deviation is 0.55 ℃, the average deviation of the Center Point Algorithm is 0.81 ℃.

The fitting depth and calculated interval velocity will be inaccurate when the time-depth fitting of vertical seismic profile (VSP) data is applied to deep strata. In this study, polynomials and power functions were used to fit the time-depth relation based on VSP data from 41 drilling holes in the East China Sea Shelf Basin. The applicability of the fitting in deep strata was analyzed by analyzing the seismic velocity volume data and seismic profiles. The three-dimensional seismic velocity volume from migration has a maximum depth of 8 s in two-way travel time (TWT). The average fitting depth from the quadratic polynomial is 9.2% higher and the average interval velocity is 36.2% higher, respectively, whereas the power fitting depth and interval velocity are 28.9% lower and 35.6% lower, respectively in the deep strata (TWT=8 s), where the seismic velocity volume data shows that the average depth and interval velocity at 41 drilling holes are 18 140 m and 6 208 m/s, respectively. To solve this problem, a segmented fitting model was proposed, in which the interval velocity increase turning point of the VSP data was firstly identified, then the quadratic polynomial function was used to fit the VSP data above the turning point and the power function was used to fit the VSP data beneath the turning point. At TWT=8 s, the errors of the average fitting depth and interval velocity are reduced to 3.3% and 4.7%, respectively. The segmented fitting model shows that the average fitting depth and interval velocity are 27 516 m and 7 334 m/s, respectively, and these values basically are consistent with the observed Moho depth(TWT=11 s) in the seismic section of the study area. The segmented fitting method can significantly improve the accuracy of time-depth conversion of the strata, especially at large depths.

The preparation of standard reference material for five heavy metals in low salinity seawater was studied, which was prepared by volumetric method using the diluted seawater from oceans. The statistical results for each metal indicated that the homogeneity and stabilities were very well at 95% confidence level. Using three analytical methods including atomic absorption spectrophotometry (AAS), inductively coupled plasma mass spectrometry (ICP-MS), and anodic stripping voltammetry (ASV) the characterization was determined by a total of 9 laboratories qualified by China Metrology Accreditation (CMA). Certified standard materials were used for metrological traceability. The total average value of 9 laboratories measurements which satisfied statistical requirements was taken as the standard value. The results of standard values and uncertainties were Cu 15.2 ± 0.7 μg/L, Pb 15.3 ± 0.7 μg/L, Zn 98.9 ± 4.7 μg/L, Cd 2.02 ± 0.10 μg/L, and Cr 15.3 ± 0.6 μg/L, respectively. The developed standard reference material can be used for quantity transfer and quality control of heavy metals analysis in low salinity seawater from near shore and estuary areas.

The Free-Fall Penetrator(FFP) is a new type of in-situ measurement equipment for seabed sediments, which is used for in-situ investigation of engineering properties of seabed sediments. Based on the self-developed FFP equipment, field tests were carried out at two stations in the Yellow Sea to analyze the influence of probe size on judging sediment properties. The results show that the probe size has different effects on the determination of penetration depth, penetration resistance and sediment type in different sediments. In fine sediments the probe size has less influence of penetration depth and the penetration resistance. When delineating geological stratification, smaller diameter probes can reflect more subtle changes in penetration resistance. There is more obvious influence of the probe size in coarse sediments. The larger size probe makes the bigger penetration resistance, and the penetration depth is reduced. Depending on the standardized depth and hardness factor, coarse sediments and fine sediments can be distinguished. The size of the probe is increased in the coarse sediment, the hardness factor is reduced, which is advantageous to refine the type of deposit.

Taking Jinshanzui-Longquangang marginal shoal in the northern Hangzhou Bay as the study area, based on the measured and chart data from 1989 to 2014, we analyzed the topographic change of beach section and the variation characteristics of erosion and deposition of regional beach section along the Jinshanzui to Longquangang(JSZ-LQG) segment. The results showed that during study period there was relative stable eroded deepen channel in the study area, and the scouring and silting of the nearshore seabed showed a "fluctuating" law. The shallow area above 5 m water depth(2014) presented accreted patterns, meanwhile, seabed below 5 m water depth(2014) showed a general scouring trend since 1989. Moreover, variation of sediment discharge into the Yangtze River is an influencing factor of erosion/deposition in the study area. The typhoon waves, movement of the erosion and accretion sand body induced complexity in erosion and accretion in seabed of the JSZ-LQG segment.

Due to the lack of geological and geophysical data of the Diaoyudao Uplift, the previous studies on this area are unsystematic, so there are many controversies about its tectonic evolution. Based on gravity, magnetic, and multichannel seismic data, the tectonic and sedimentary characteristics of the middle Diaoyudao Uplift were analyzed, which located to the east of the Xihu Depression, East China Sea Basin. The evolution model of the middle Diaoyudao Uplift was further refined. More residual sags are found in the north than in the south of the middle Diaoyudao Uplift. Accordingly, the middle Diaoyudao Uplift can be divided into the north and south segments. The boundary of the two segments is on the extended trace of the Zhoushan-Guotou Fault. In addition, magmatic intrusions are confined below the T20 unconformity in the west, whereas a basement pinnacle caused by magmatic activity exists in the east. It is found that the gradient zone of gravity anomaly corresponds exactly to the western edge of the basement pinnacle. Taking the west edge of the basement pinnacle as the boundary, the middle Diaoyudao Uplift can be divided into two parts from west to east. And the western zone can be further divided into two subzones, including part Ⅰ with magnetic rocks and part Ⅱ with residual sags. The western part of the middle Diaoyudao Uplift is from the strong tectonic and magmatic deformation of the eastern Xihu Depression, whereas the east part retained the original Diaoyudao Uplift. The comprehensive analysis of above features showed that the present-day middle Diaoyudao Uplift was formed by many episodes of tectonic events and magmatic activities around an ancient uplift.

The Andaman Sea is highly valued because of its large number of internal solitary waves. Most of its research is based on remote sensing but lacks field observation. A mooring system located in the central Andaman Sea from 2016 to 2017 to investigate internal solitary waves, and the body forcing theory, as well as three internal solitary wave theories: shallow water Kortweg-de Vries (KdV), deep water and finite-depth theory have been used to explore the sources of the internal solitary waves. The result shows that the internal solitary waves in the study area mainly propagate to the northeast, and the maximum amplitude of them is above 100 m. the sources calculated by body forcing theory are consistent with the previous remote sensing results, however, it could provide a ability estimation of different sources to excite internal solitary waves. The phase velocity of internal solitary waves shows that the central Andaman Sea may have a Lee waves generation mechanism, and the finite-depth theory is proved to correspond to the observation result in the Andaman Sea.

The climatology distribution of isopycnal layer in the Indian Ocean were analyzed based on the WOA18 (World Ocean Atlas 2018) dataset firstly. And then three time periods were defined as 1985-1994, 1995-2004 and 2005-2017 to research the decadal variation. The results show the climatology distributions of 11 isopycnal layers. As far as σ ₀=26.00kg/m ³ (reference pressure as 0 dbar) isopycnal layer was concerned, the layer was outcropping at roughly 40°S. As the potential density increased, the outcrop area of the isopycnal layer gradually moved southward until it disappeared. When the potential density was greater than σ ₀=26.95 kg/m ³ and less than or equal to σ ₂=37.00kg/m ³, the deepest part of the isopycnal layers were located in southern Madagascar, and the depth of the North Indian Ocean was almost the same. Furthermore, present study investigates the decadal variances of depth and salinity of isopycnal layers, where the three layers include σ ₀=26.00 kg/m ³, σ ₁=31.87 kg/m ³ (reference pressure as 1 000 dbar) and σ ₂=36.805kg/m ³ (reference pressure as 2 000 dbar). Studies show that the depth and salinity of the isopycnal layer had significant decadal changes in the three periods from 1985 to 2017. For the isopycnal layer of σ ₀=26.00kg/m ³, the depth decreased first and then increased during the three periods. And the decadal variation of the isopycnal depth was mainly located in 30°S-40°S(the rapid change area of the isopycnal depth). The difference of salinity between 1995-2004 and 1985-1994 was basically opposite to the difference between 2005-2017 and 1995-2004 when the isopycnal layer was σ ₀=26.00kg/m ³. For the isopycnal layer of σ ₁=31.87kg/m ³ and σ ₂=36.805kg/m ³, the decadal variations of the depth were concentrated on 40°S-50°S. Overall, the salinity of σ ₁=31.87kg/m ³ show a decreasing trend but σ ₂=36.805kg/m ³ show an increase trend.

The annual greatest tidal bore in the Qiantang River almost occurs during typhoons. Based on the measured tidal data and combined with the harmonic analysis of astronomical tides, the influence of typhoon on tide downstream of the tidal bore formation section in the Qiantang River Estuary was studied, and then the tidal bore changes indirectly caused by tidal changes was discussed. The results show that typhoons cause the changes in low tide level, tidal range, tidal bore arrival time and duration of flood tide, and indirectly affect tidal bore through typhoons, resulting in the changes in tidal bore height, steepness, propagation speed, arrival time and flow velocity. In general, during a typhoon, the tidal bore height at Yanguan increases by 0.18 m on average, and the time of tidal bore arrives 37 min earlier on average, the propagation speed of tidal bore from Ganpu to Yanguan increases by 8.9% on average, the steepness of tidal bore increases, and the velocity of tidal bore increases or decreases, but the unit width flow rate increases.

Based on the SRTM15_Plus depth data, the submarine canyons in the Asian Continental Margin were identified by using the method of combining topographic surface flow analysis with contour geometry analysis. And the morphology, distribution characteristics and evolution process of the canyons in the study area were analyzed. A total of 531 submarine canyons are identified and divided into linear, meandering and dendritic according to the plane shape. The numbers of each type of canyon are 239, 75 and 217 respectively. Linear canyons are mainly distributed in the Bering Sea Basin, the Kuril Basin and the South China Sea. Meandering canyons are mainly distributed in the subduction zone east of the Bay of Bengal. Dendritic canyons are mainly distributed in the junction of the Japan Trench, the Izu Bonin Trench and the Nankai Trough, the South China Sea and the Sumatra subduction zone. According to the distribution of the canyons and the tectonic background in the study area, the morphological evolution process of “Linear-Meandering” was discussed. According to the morphological information of the main valley of dendritic canyons, it is inferred that there are “Linear-Dendritic” and “Meandering-Dendritic” morphological evolution processes.

Pyropia haitanensis is one of the most important economic seaweeds for mariculture in China. In order to investigate genetic diversity of P. haitanensis, we collected 125 individuals from 11 populations along the southeast coast of China. We amplified 408 bp length of COX gene fragments and 488 bp length of rbcL gene fragments. The concatenated COX and rbcL gene fragments had a length of 896 bp, and the ratios of T, C, A, G were 34.9%, 14.6%, 34.2% and 16.3%, respectively. We detected 128 mutation sites, including 19 single-base mutation and 109 simple information sites. The mean nucleotide and haplotype diversity of 11 populations were 0.035 9±0.028 4 and 0.817 0±0.024 0, respectively. The concatenated COX and rbcL gene fragments defined 31 haplotypes from 125 individuals, and Hap1,Hap10 and Hap16 were the core haplotypes, accounting for 32.8%, 12.8% and 24.8% of all individuals, respectively. The result of distance analysis showed a linear correlation between population-pairwise genetic distances and geographic distances ( R ²=0.002 2, p=0.735 4). Genetic distance increased with the increased geographic distance, but geographic isolation had not yet been formed. The ML tree constructed from haplotypes showed no obvious geographical lineage structure in P. haitanensis, indicating potential gene exchange among populations.

In order to study the occurrence and distribution of organotin compounds(OTs) in marine shellfishes from coastal areas of Zhejiang, six OTs including butyltin and phenyltin species were determined in shellfishes which were collected from seven sampling sites of Zhejiang by GC-FPD after sample treatment with pentylized derivatization, and then the health risk assessment was studied. The results showed that phenyltin species were the main contaminants in shellfishes, while the concentration ranges of phenyltin compounds were from nd to 203.6 ng·g ^-1(dw). The concentrations in shellfishes varied from nd to 8.2 ng·g ^-1(dw) for butyltin compounds. DPT and TBT were high levels in phenyltin compounds and butyltin compounds, respectively. Concentrations of OTs in mussels (Mytilus edulis) were obviously higher than those in other species, indicating that they had stronger abilities of enrichment for OTs. The distributions of OTs concentrations in different sampling sites showed that both butyltin and phenyltin compounds mainly came from antifouling paints for ships. The results of human health risk assessment showed that food exposure of OTs posed no health risks for consumers living the coastal areas.

Based on 2007-2018 Landsat series of multi-source remote sensing satellite data, the spatial-temporal characteristics and affecting analysis were carried. The radiative transfer equation algorithm and split-window algorithm were used to retrieve sea surface temperature. After verifying the algorithm through Landsat-MODIS comparison, it shows that the inversed results have a significant linear correlation with the MODIS SST products. Based on the temperature retrieve results of the study area, the characteristics of the seasonal, annual and tidal variation were analyzed. In the aspect of seasonal distribution, the range of spring thermal discharge which is the largest in four seasons is 7 times of autumn one. In the aspect of interannual distribution, with the expansion of installed capacity, the range of thermal discharge continues to expand, reaching to the peak in 2018. In terms of the influence of tides on thermal discharge, the thermal discharge at the moment of high water slack is larger than that of the low water slack. West wind is beneficial to the diffusion of thermal discharge, but its impact on thermal discharge is limited.

With the increasing saturation of coastal nuclear power plant sites, it is a new idea to select islands as nuclear power plant sites. In view of the problem that the island sites are vulnerable to typhoon disasters, the design basis flood level of the sites is determined by studying astronomical high tide, sea level rise, possible maximum storm surge and maximum typhoon wave. The results show that the astronomical high tide level of 10% superfrequency in this region is 3.14 m and the predicted sea level rise in the next 80 years will be 0.31 m. Based on MIKE21 model, a variety of hypothetical typhoon paths were constructed using tropical cyclone parameters. The northwest moving path of typhoon with 0.5 R (R is the maximum wind speed radius of typhoon) to the left of the site produces the possible maximum storm surge, with the maximum water level of 2.99 m. When the typhoon moves in the direction of west, with R to left of the site, the maximum H _1/100 wave height reaches 8.02 m, especially on the east side of the island, which suffers from severe typhoon wave threats. Considering the superposition of various basis flood factors, the design basis flood level of the island nuclear power plant site reaches 11.25 m. Because the proposed site is located on an island and surrounded by sea waters, compared with other coastal sites, the storm surge level is relatively small, but the impact of waves is more significant.