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Revisiting the seasonal wave height variability in the South China Sea with merged satellite altimetry observations

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Acta Oceanologica Sinica 2017年第11期36卷 38-50页

作者： SU Hui WEI Chunlei JIANG Shaocai LI Peiliang ZHAI Fangguo Central Marine Environmental monitoring Station of Xiamen East China Sea BranchState Oceanic Administration beihai Marine Environmental monitoring center South China Sea BranchState Oceanic Administration College of oceanic and Atmospheric Sciences Ocean University of China

The seasonal variability of the significant wave height（SWH） in the South China Sea（SCS） is investigated using the most up-to-date gridded daily altimeter data for the period of September 2009 to August 2015. The results indicate that the SWH shows a uniform seasonal variation in the whole SCS, with its maxima occurring in December/January and minima in May. Throughout the year, the SWH in the SCS is the largest around Luzon Strait（LS） and then gradually decreases southward across the basin. The surface wind speed has a similar seasonal variation, but with different spatial distributions in most months of the year. Further analysis indicates that the observed SWH variations are dominated by swell. The wind sea height, however, is much smaller. It is the the largest in two regions southwest of Taiwan Island and southeast of Vietnam Coast during the northeasterly monsoon, while the largest in the central/southern SCS during the southwesterly monsoon. The extreme wave condition also experiences a significant seasonal variation. In most regions of the northern and central SCS, the maxima of the 99 th percentile SWH that are larger than the SWH theoretically calculated with the wind speed for the fully developed seas mainly appear in August–November, closely related to strong tropical cyclone *** with previous studies, it is also implied that the wave climate in the Pacific Ocean plays an important role in the wave climate variations in the SCS.

关键词： significant wave height seasonal variability South China Sea satellite observations

Comparative study of hydrographic conditions for algal bloom formation in the coastal waters of east and west of Hong Kong during 1998

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Chinese Journal of Oceanology and Limnology 2009年第1期27卷 13-21页

作者：方宏达唐森铭 South China Sea Environmental monitoring center State Oceanic Administration The Third Institute of Oceanography State Oceanic Administration

Phytoplankton abundance was found to be positively correlated with seasonal changes of seawater temperature in Port Shelter and Lamma Channel, Hong Kong in 1998. Rising water temperature from around 20℃ to 25℃ coincided with an increase in phytoplankton abundance at both locations. Heavy rains from June to September reduced salinity from 30 to 20, but the decrease in salinity was not correlated with a decline in phytoplankton abundance. In spring 1998, over 0.6×10^6 cells dm^-3 and 0.1× 10^6 cells dm^-3 of the dinoflagellate, Gymnodinium mikimotoi Miyake et Kominami ex Oda occurred in the coastal waters of Port Shelter and Lamina Channel, respectively. High abundance of the dinoflagellate Ceratium furca （Ehr.） Claparede et Lachmann （〉1×10^6 cells dm^-3） produced long-lasting blooms in the waters of Port Shelter from September to October in 1998. The abundances of both diatoms and dinoflagellates were significantly lower in the waters of Lamina Channel than those in Port Shelter due to the less frequent blooms in 1998. Hydrographic conditions such as stable water masses and water column stratification were the main reasons for the differences in the algal abundance and bloom frequency found between the two locations since neither of the two areas appeared to be nutrient-limited. This type water condition for the formation of algal bloom in Port Shelter has not been reported previously and it is not a general case for many bays along China＇s coast where algal bloom occurs as well.

关键词： algal blooms red tide diatoms dinoflagellates water turbulence Hong Kong

Species identification and phylogenetic analysis of genus Nassarius(Nassariidae)based on mitochondrial genes

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Chinese Journal of Oceanology and Limnology 2010年第3期28卷 565-572页

作者：李海涛林端方宏达朱艾嘉高阳 South China Sea Environmental monitoring center State Oceanic Administration

Genus Nassarius contains many subgenera, such as Zeuxis, Telasco, Niotha, Varicinassa, Plicarcularia, Nassarius s. str. and Reticunassa. On the basis of morphological characteristics of the shell and radula and sequences of mitochondrial cytochrome oxidase subunit I (COI) and 16S rRNA genes, Nassarius specimens collected from the South China Sea were identified and phylogenetically analyzed. Although Nassarius sp. and Nassarius (Varicinassa) variciferus were morphologically different in their shells, few variations were found among their radular teeth and sequences of mtCOI and mt16S RNA genes. Therefore, Nassarius sp. should be classified as N. (Varicinassa) variciferus. Nassarius (Zeuxis) sp. has only a subtle difference from Nassarius (Zeuxis) algidus on the shell, but it shows obvious differences in radular teeth and DNA sequence, indicating that they are two distinct species. Sequence divergence of mtCOI and mt16S RNA genes within Nassarius species was much lower than that between species, suggesting that these two genes are suitable for Nassarius species identification. Phylogenetic analysis (neighbor-joining and maximum parsimony) based on mtCOI and mt16S rRNA genes revealed the presence of two groups in genus Nassarius and a closest relationship between subgenera Zeuxis and Telasco. Species of subgenus Plicarcularia did not form a single clade. The molecular phylogeny was not congruent with the previous morphological phylogeny. The subgeneric divisions of genus Nassarius appear to be uncertain and unreliable.

关键词： Nassarius species identification mtCOI gene mt16S rRNA gene

Numeric modelling and risk assessment of pollutions in the Chinese Bohai Sea

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Science China Earth Sciences 2017年第8期60卷 1546-1557页

作者： LIU YongZhi SHEN YouLi LV XianQing LIU Qiang Key Laboratory of Physical Oceanography Ocean University of China beihai Marine Environmental monitoring Centre Station of state oceanic administration College of Engineering Ocean University of China

To simulate the dynamic process of total nitrogen(TN) in seas, numerical modelling combined with the adjoint method is implemented in this study. Because nonpoint source terms(ST) and initial values(IV) of TN are essential but difficult to determine, the adjoint method was applied to a numerical model, and the ST and IV terms of TN were inverted via routine monitoring data in the Bohai Sea. In twin experiments, the adjoint method was capable of inverting the prescribed spatio-temporally distributed ST and the spatial distributed IV. In practical experiments, the results demonstrated that the simulation precision with ST inversion was higher than that with IV inversion and was accurate with joint initial values and source term(IST) inversion. This result indicates that nonpoint source TN is essential for the simulation of TN concentration. Furthermore, the simulated results indicate that the pollution in three bays of the Bohai Sea is rather severe. The model in this study is not specific to the Bohai Sea and can be generalized to other areas, such as the Beibu Gulf. These findings may assist in the development of cost-effective controls for accidental or planned industrial pollutant releases into coastal waters.

关键词： Risk assessment Adjoint method Initial value Numeric modelling Bohai Sea of China

The morphological identification of Protoperidinium(Peridiniales, Dinophyceae) species on the coasts of China

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Acta Oceanologica Sinica 2016年第4期35卷 108-117页

作者： LI Ruixiang PAN Yulong SUN Huiying LI Yan MA Xin WANG Yan Key Laboratory of Science and Engineering for Marine Environment First Institute of OceanographyState Oceanic Administration North China Sea Environment monitoring center State Oceanic Administration College of Marine Sciences Shanghai Ocean University Marine Environment monitoring center Station of Qinhuangdao State Oceanic Administration Marine Information and Computing center First Institute of OceanographyState Oceanic Administration

The classification and identification for Protoperidinium species are the most difficult work during its taxonomic study. In this research, taxonomic status of Protoperidinium was clarified by tracing its taxonomic history, 23 species belong to genus Protoperidinium on the coasts of China were preliminarily identified, and morphological description and plate patterns were given for each species. The key differences of similar species were also discussed in this study, we believe that P. oceanicum and P. murry, P. tumidum and P. fatulipes, P. globules and *** are separate species; P. diabolum should be treated as the valid name instead of the reported names Peridinium globosum or Peridinium longipes; the taxonomic relationship between P. punctulatum and *** requires further study.

关键词： coasts of China Protoperidinium morphological identification

Using a semi-analytical model to retrieve Secchi depth in coastal and estuarine waters

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Acta Oceanologica Sinica 2020年第8期39卷 103-112页

作者： Xianfu Liu Xuejiao Meng Xiaoyong Wang Dayong Bi Lei Chen Quansheng Lou South China Sea Institute of Planning and Environmental Research State Oceanic AdministrationGuangzhou 510300China Shanwei Marine Environmental monitoring center Station State Oceanic AdministrationShanwei 516600China National Ocean Technology center State Oceanic AdministrationTianjin 300112China Environmental monitoring center of South China Sea State Oceanic AdministrationGuangzhou 510300China

Secchi depth(SD,m)is a direct and intuitive measure of water's transparency,which is also an indicator of water *** 2015,a semi-analytical model was developed to derive SD from remote sensing reflectance,thus able to provide maps of water's transparency in satellite *** an in-situ dataset(338 stations)is used to evaluate its potential ability to monitor water quality in the coastal and estuarine waters,with measurements covering the Zhujiang(Pearl)River Estuary,the Yellow Sea and the East China Sea where measured SD values span a range of 0.2–21.0 *** a preliminary validation result,according to the whole dataset,the unbiased percent difference(UPD)between estimated and measured SD is 23.3%(N=338,R^2=0.89),with about 60%of stations in the dataset having relative difference(RD)≤20%,over 80%of stations having RD≤40%.Furthermore,by excluding the field data which with relatively larger uncertainties,the semi-analytical model yielded the UPD of 17.7%(N=132,R^2=0.92)with SD range of 0.2–11.0 *** addition,the semi-analytical model was applied to Landsat-8 images in the Zhujiang River Estuary,and retrieved high-quality mapping and reliable spatial-temporal patterns of water *** into account the uncertainties associated with both field measurements and satellite data processing,and that there were no tuning of the semi-analytical model for these regions,these findings indicate highly robust retrieval of SD from spectral techniques for such turbid coastal and estuarine *** results suggest it is now possible to routinely monitor coastal water transparency or visibility at high-spatial resolutions from measurements,like Landsat-8 and Sentinel-2 and newly launched Gaofen-5.

关键词： Secchi depth water quality coastal and estuarine waters semi-analytical model remote sensing Landsat-8

Mercury distribution in the Jiaozhou Bay

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Chinese Journal of Oceanology and Limnology 2007年第4期25卷 455-458页

作者：陈豫高振会曲延峰杨东方唐红霞 College of Information Shanghai Fisheries University beihai monitoring center of state oceanic administration College of Information Shanghai Fisheries University

The Jiaozhou Bay is a semi-enclosed bay, Qingdao, China. More than 10 rivers enter the bay, of which most take wastes from industrial and household discharges. According to historical seasonal investigations in May, August, November 1979, the content, distribution, and development of heavy metal mercury are analyzed as a historical reference. Water samples were taken from the surface and bottom. The results revealed clear seasonal and regional changes in both horizontal and vertical directions, and close relation with major discharging rivers and plankton production. The seawater was polluted more seriously in spring than in any other seasons. However, it was the cleanest in winter during which least waste was input with low plankton production. According to historical data, the state of mercury pollution in seawater was worsening in the period, and has been improving in recent years. Terrestrial contamination was the main reason for mercury pollution in the bay.

关键词： mercury distribution pollution the Jiaozhou bay

Study of relationship between wave transport and sea surface temperature anomaly(SSTA) in the tropical Pacific

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Acta Oceanologica Sinica 2016年第9期35卷 58-66页

作者： SHI Yongfang WU Kejian ZHU Xianye YANG Fan ZHANG Yuming Key Laboratory of Marine Science and Numerical The First Institute of OceanographyState Oceanic Administration College of oceanic and Atmospheric Sciences Ocean University of China National Marine Environmental monitoring center State Oceanic Administration

Large-scale water transport is one of the key factors that affect sea surface temperature anomaly（SSTA） in the eastern equatorial Pacific（EEP）.The relationship between the wave transport in the tropical Pacific and the SSTA in the EEP is examined by different methods,including band-pass filtering,period analysis,correlation analysis,significant analysis,and empirical orthogonal function（EOF） *** have found that the eastward shift of the wave transport anomaly in the tropical Pacific,with a period of 2 a and enhancing the transport of warm waters from the western Pacific warm pool,precedes the increase of sea surface temperature（SST） in the *** wave transport and the SSTA in the EEP have a maximum correlation of 0.65 with a time-lag of 6 months（transport variation precedes the temperature）.The major periods（3.7 a and 2.45 a） of the wave transport variability,as revealed by the EOF analysis,appear to be consistent with the SSTA oscillation cycle in the *** on the first occurrence of a significant SSTA in the Ni？o 3 region（5°S–5°N,90°–150°W）,two types of warm events are *** wave transport anomalies in two types present predominantly the west anomaly in the tropical Pacific,it is that the wave transport continues transport warm water from west to east before the onset of the warm *** impact of wave-induced water transport on the SSTA in the EEP is confirmed by the heat flux of the wave *** wave transport exerts significant effect on the SSTA variability in the EEP and thus is not neglectable in the further studies.

关键词： wave transport eastern equatorial Pacific sea surface temperature anomaly warm events

Modelling of 2-D extended Boussinesq equations using a hybrid numerical scheme

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Journal of Hydrodynamics 2014年第2期26卷 187-198页

作者：房克照张哲邹志利刘忠波孙家文 state Key Laboratory of Coastal and Offshore Engineering Dalian University of Technology National Marine Environment monitoring center State Oceanic Administration

In this paper, a hybrid finite-difference and finite-volume numerical scheme is developed to solve the 2-D Boussinesq equations. The governing equations are the extended version of Madsen and Sorensen＇s formulations. The governing equations are firstly rearranged into a conservative form. The finite volume method with the HLLC Riemann solver is used to discretize the flux term while the remaining terms are discretized by using the finite difference method. The fourth order MUSCL-TVD scheme is employed to reconstruct the variables at the left and right states of the cell interface. The time marching is performed by using the explicit second-order MUSCL-Hancock scheme with the adaptive time step. The developed model is validated against various experimental measurements for wave propagation, breaking and runup on three dimensional bathymetries.

关键词： hybrid scheme Boussinesq equations TVD Riemann solver