Evidence for a counter-wind current in winter off the southeast coast of China

Regarding the current pattern in winter in the near-sea region of Zhejiang, Fujian and Guangdong (including the western and central parts of the Taiwan Strait), oceanographers both at home and abroad had considered unanimously that under the intense influence of the northerly monsoon, the current (not only at the surface but also in the deep and near-bottom layers) flows southwestward with the wind. It was not until the end of the fifties that scientists began to question such a traditional concept. In this paper, based on the results of more than 20 years’ studies on the current patterns of the East China and South China Seas, all kinds of current data available are reanalysed comprehensively. These data include: 1) current measurements at day-night anchored stations, and with mooring buoys, collected mostly from 1959 to 1982 by many Chinese oceanographic and fisheries organizations; 2) current vectors derived from the ship-drift of Japanese naval vessels in the period from 1910 to 1921; and 3) geostrophic current velocities deduced from hydrographic observations in the periods of the CSK and 1975–1976 conducted by the Fisheries Research Station, Hong Kong, and the SOA. A combination of all the evidences revealed in the above data suggests and confirms that, besides the China Coastal Current flowing southwestward at a shallow layer of a zone closely adjacent to the coast, there also exists a northeastward counter-wind current in winter off the southeast coast of China (though its surface current may be weakened or even covered up by the drift current when the northerly monsoon strengthens). Furthermore, the two parts of the winter counter-wind current in the South China Sea and the East China Sea are connected through the Taiwan Strait. This suggestion now has been confirmed by the recent observations in the Taiwan Strait, i.e., 1) with sea-bed drifters released in 1984 (Zhang, 1985) and 2) with current meter moorings deployed in 1983 (Chuang, 1985). It is suggested that detailed field investigation in winter for filling the gap of observations should be needed to give further confirmation of this important new finding. At the same time, dynamical, numerical and experimental studies should also be carried out for a better understanding of the mechanism of this counter-wind current, and its variations and correlation with the adjacent currents, such as the southward flowing coastal current and the northward flowing Kuroshio Branch. The paper was presented at the symposium sponsored by the Chinese Society of Oceanology and Limnology in November, 1978, Qingdao. Some recent contents were supplemented before publication. Contribution No. 1364 from the Institute of Oceanology, Academia Sinica.     

Influences of wind on vertical structures of temperature and salinity,and upwelling off Zhejiang coast in summer

In this paper the influences of short-term wind on vertical structures of temperature and salinity, and the upwelling off the Zhejiang coast are studied on the basis of hydrographic data and wind near the coast in Summer (1959–1979). It is pointed out that the variations of vertical distributions of temperature and salinity, and upwelling in this region are closely related to short-term (several days to a week) variation of wind observed. The occurrence of double thermocline, a special oceanographic phenomenon, is partially related to unstable SSW wind field. SSW and NE winds in June are two dynamic factors making intermediate warm water form or disappear. Contribution No. 792 from the Institute of Oceanology, Academia Sinica. This paper was published in Chinese inOceanologia et Limnologia Sinica 14 (1): 14–21, 1983.     

Sea level along the southeast coast of China during El Niño

In El Niño years, along the southeast China coast, the seasonal cycle of sea level variation—low in spring, high in autumn—is attenuated: specifically, the autumn peak is reduced by about 10 cm. This negative anomaly increases toward the south and occurs at the same time as a similar (but five times larger) sea level anomaly at Truk Island (7.5°N) in the western Pacific.     

Phytoplankton community dynamics during Alexandrium blooms in 2019 off the Qinhuangdao coast,Bohai Sea,China

Journal of Oceanology and Limnology - Alexandrium blooms in the northwest area of the Bohai Sea (Qinhuangdao coastal area), China, produce large amounts of toxins that could be enriched in...     

The gulf stream off the east coast of the United States

Current and temperature data from a one-year-long instrument deployment in the region just northeast of Cape Hatteras have shown the oceanic variability to be, intense and quite complex. Changes in the position of the Gulf Stream’s path were observed to occur following cold core Gulf Stream passages through the area. The time between these changes was a few months. The Gulf Stream jet itself was seen to meander in a manner previously observed, as long as it was not undergoing a strong ring/stream interaction. Several isolated vortices progressed through the array, with the majority of them being in the submesoscale coherent vortex class. Two mid-depth, anticyclonic warm eddies progressed through the array. It is likely the two events were caused by two different transits of the same eddy. The deep waters below the main thermocline oscillated as topographic Rossby waves progressed through the array area.     

Occurrence of double parasitism on black-barred halfbeak fish from the southeast coast of India

A double parasitism (isopod Cymothoidae and copepod Pennellidae) on black-barred halfbeak fish, Hemiramphus far, was recorded from Pazhayar coastal waters (southeast coast of India) during September 2008. This is the first report from this region and the infection is discussed in relation to environmental and biological parameters.     

Petroleum Hydrocarbon Distribution Features in Water and Sediment off Fujian Shore

This study on the distribution features of petroleum hydrocarbon in water and sedi-ment off the Fujian shore using data obtained from the baseline research on oceanic contamination in Fujian showed that:during the research preiod,petroleum hydrocarbon concentrations in water varied from 5.77μg/L to 37.28μg/L,averaged 14.48 μg/L;was lower in the wet seasson than in the dry season;and was highest in the Minjiang Estuary and Jiulong Estuary in both seasons ,The petorleum hydrocarbon concentrations in shore sediment varied from 14.48 mg/kg to 784.36 mg/kg,averaged 133.3 mg/kg ,and was closely related to sediment types (granularity).     

THE HOLOCENE ALONG THE COAST OF HAINAN ISLAND, CHINA

Based on the new data of the Quaternary along the coast of Hainan Island, China, this paper puts forward that the Holocene in Hainan Island can be divided into four formations: Wanning formation (Q41), Sanya formation (Q42-1), Qiongshan formation (Q42-2) and Ledong formation (Q43). Spore-pollen analysis shows that there are 6 spore-pollen zones existed, reflecting two cycles of climatic fluctuation from warm-dry to hot-humid. The climax of hot-humid period occurred 6,000-5,000 years B.P.. Based on the 14C dating data of the 38 samples representing the positions of ancient sea level, a breakthrough curve representing the sea level change during the Holocone is obtained, in which , a sea level change caused by tectonic movement is subtracted. Two cycles of rise-drop of sea level with three periods of high sea level were found. The period with the highest sea level is some 6,000-5,000 years B.P.. According to the rise-drop rate of sea level, four periods of the sea level change can be distinguished in the     

Middle and Late Permian palynoflora in Tianshan Township,southeast of Bogda Mountain,Xinjiang, China

The Permian is one of the most important periods during which the vegetative earth witnessed the transition from icehouse to greenhouse climate and the global environment changes. Organisms on the planet en-countered great challenge and the demise of swamp caused the extinction of arborescent lycopods and the rising of Mesophytic plants accomplished the floral transition from the Paleophytic to Mesophytic vegetation. In order to depict the climatic changes and floral succession in the middle and high latitudes of the North Hemisphere, palynological investigation was engaged, and 40 samples collected from the uppermost of Taerlang Formation, Hongyanchi Formation and Quanzijie Formation in the Tianshan Town, Turpan-Hami Basin, eastern Xinjiang, China. The result shows that the palynoflora in the studied area is composed of 50 species of 33 genera, domi-nated by disaccites and striatiti gymnosperm pollen, and characterized by diverse Protohaploxypinus, Hamia-pollenites, Alisporites and Klausipollenites. It is quite similar to those Middle and Late Permian palynological as-semblages reported in the Dalongkou section and other localities in southern margin of Junggar Basin, and aged at Middle and Late Permian. The diversity of typical Angara and sub-Angara pollen, such as Falcisporites, Alisporites, Protohaploxypinus, Vittatina, Lunatisporites, Hamiapollenites, etc. indicates that the studied palyno-flora belonged to the sub-Angara phytoprovince, while the presence of Lueckisporites virkkiae implied Euramerica pollen intruded northward sometimes. The paleoclimate of the studied area might be warm and humid with fluc-tuated dry seasons during the late Guadalupian and early Lopingian time.     

Tidal current and tidal energy changes imposed by a dynamic tidal power system in the Taiwan Strait,China

The Taiwan Strait has recently been proposed as a promising site for dynamic tidal power systems because of its shallow depth and strong tides. Dynamic tidal power is a new concept for extracting tidal potential energy in which a coast-perpendicular dike is used to create water head and generate electricity via turbines inserted in the dike. Before starting such a project, the potential power output and hydrodynamic impacts of the dike must be assessed. In this study, a two-dimensional numerical model based on the Delft3D-FLOW module is established to simulate tides in China. A dike module is developed to account for turbine processes and estimate power output by integrating a special algorithm into the model. The domain decomposition technique is used to divide the computational zone into two subdomains with grid refinement near the dike. The hydrodynamic processes predicted by the model, both with and without the proposed construction, are examined in detail, including tidal currents and tidal energy flux. The predicted time-averaged power yields with various opening ratios are presented. The results show that time-averaged power yield peaks at an 8% opening ratio. For semidiurnal tides, the flow velocity increases in front of the head of the dike and decreases on either side. For diurnal tides, these changes are complicated by the oblique incidence of tidal currents with respect to the dike as well as by bathymetric features. The dike itself blocks the propagation of tidal energy flux.     

Types and distribution patterns of modern tidal channels along the Huanghe River Delta coast

INTRODUCTIONTidalchannelsareimportantgeomorphologicunitsalongsiltcoasts.Theyhaveanevidentfunc tionfortidalflatbecausetheyareassociatedwithitsrapidbayheadwarderosionandlateralswing ing.Thetidalchannelsdevelopalongthecoastandplayanimportantroleinseaandlandinterac tion .Manyscientistsresearchedthetidalchannels (Bayliss Smith ,1 978;Shao ,1 988;Zhang ,1 995) .TheScientificandTechnicalCommitteeofShandongProvince (1 991 )investigatedthecoastoftheHuanghe (Yellow)RiverDeltaandresearchedtheti…     

Sustainable development and coastal management of tidal flat in Jiangsu Province, China

ＳＵＳＴＡＩＮＡＢＬＥＤＥＶＥＬＯＰＭＥＮＴＡＮＤＣＯＡＳＴＡＬＭＡＮＡＧＥＭＥＮＴＯＦＴＩＤＡＬＦＬＡＴＩＮＪＩＡＮＧＳＵＰＲＯＶＩＮＣＥ,ＣＨＩＮＡ①ＨｕａｎｇＱｉａｏｈｕａ（黄巧华）１ＣｈｅｎＦａｎｇ（陈方）１,２ＺｈｕＤａｋｕｉ（朱大奎）１１...     

Sustainable development and coastal management of tidal flat in Jiangsu Province, China

With huge area, favorable light, heat and water conditions, rich biological diversity, and a unique ecological system of submarine sand ridges, Jiangsu tidal flat has great significance to its economic development. Based on the geomorphological characteristics, Jiangsu tidal flat is dynamically divided into stable, erosional and accumulative types. In light of resources distribution, evolution rules of Jiangsu tidal flat, existing problems in coastal management, exploitation and utilization, the sustainable development theory is applied to guide the comprehensive exploitation and utilization of tidal flat. Taking different regions with different local conditions in consideration, and in order to make economic development coordinate with local resources and environments, four regional sustainable development models, i.e. (A) Abandoned Huanghe (Yellow) River delta section for salt and aquatic products industries, (B) Sheyang section for reed, aquaculture and rare animal protection, (C) Dafeng and Dongtai section for agricultural comprehensive exploitation, (D) Nantong section for aquaculture and agriculture, are suggested. Meanwhile, the paper takes the guiding ideology of sustainable development to be reflected in modern integrated coastal management and legislation. Supported by Natural Sciences Foundation of Fujian (D 97006) and State Pilot Laboratory of Coast & Island Exploitation, Nanjing University.     

Numerical hydrodynamics study around turbine array of tidal stream farm in Zhoushan,China

In recent decades, great efforts have been made to efficiently explore tidal stream energy due to its unique advantages of easy prediction and great potential. China recently launched a national tidal stream farm demonstration project in the waterway between Putuoshan and Hulu Islands in the Zhoushan area. Before deployment of the turbine array, it is necessary to understand the hydrodynamic changes associated with the construction of a turbine array. In this study, we developed a depth-averaged hydrodynamics model that solves the shallow water governing equations to simulate the tidal hydrodynamics around the Zhoushan Archipelago. The simulation results agree with field data in terms of the water elevation and stream velocity. We considered two types of turbine arrays in this study and investigated their impacts on the local hydrodynamics. In general, the stream velocity in the northern and southern areas is reduced due to the power take-off of the turbine array, whereas stream velocity in the western and eastern areas is slightly increased due to the blockage impact of the turbine array.     

Distribution of sediment chloroplastic pigments in the Southern Yellow Sea,China

The distribution of sediment chloroplastic pigments (Chl-a, i.e. chlorophyll a and Pha-a, i.e. phaeophorbide a) in the Southern Yellow Sea of China was studied. Samples were collected from four cruises in January and June 2003, and January and June 2004. The results show that the vertical distribution of Chl-a and Pha-a in the sediment layers 0-2cm, 2-5cm and 5-8cm, follows a stable ratio, 5:3:2. The average ratio of Pha-a to Chl-a in sediment is 2.83. Spearman 2-tailed rank correlation analysis shows that Chl-a and Pha-a contents in each sediment layer have a highly significant correlation. The average contents of Chl-a and Pha-a in the sediment of the 0-8cm layer in the investigated area are 0.31 -0.47μgg-1 and 1.28-1.40 μgg-1 sediment (dry weight), respectively. The average Chl-a and Pha-a contents in sediment are higher in summer than in winter. ANOVA analysis shows that there is a highly significant variation among the Chl-a contents (P = 0.002 <0.01) of the four cruies, but this is not true for the case of Pha-a content (P = 0.766>0.05). The average Chl-a and Pha-a contents in the 2 sediment layers (0-2cm and 2-5cm) have significant or highly significant correlations with organic matter (OM), median diameter (Mdφ), silt plus clay percentage in the January 2003 cruise. In the June 2003 cruise, the average Chl-a content in the 3 sediment layers (0-2cm, 2-5cm, and 5-8cm) has a significant correlation with meiofauna biomass, and Pha-a content has highly significant correlations with water depth, bottom water temperature, OM and Mdφ The contents of Chl-a and Pha-a are lower than those in estuaries and intertidal areas, but close to those in the same area studied previously.     

LATE QUATERNARY SEISMIC SEQUENCES AND SEDIMENTATION ALONG THE COAST OFF TAISHAN, GUANGDONG, AS REVEALED BY HIGH RESOLUTION SEISMIC DATA

Seismic stratigraphic analysis of 150 km of high-resolution seismic profiles (GEO-PULSE and 3.5 kHz) obtained along the muddy coast off Taishan, Guangdong provided valuable information on the offshore Quaternary stratigraphy, tectonics, sedimentary evolution, and environmental and engineering geology of this area. The following late Quaternary stratigraphic sequences were mapped. (1) Pleistocene alluvial silty sand and shallow marine clay; (2) coarse fluvial channel sand; (3) nearshore and bay clayey sediments. The incision of fluvial channels occurred in two stages: dttring the Late Pleistocene and at the beginning of the Holocene. The Pleistocene fluvial channels have been filled by coarses and overlain by more than 10 m of late Pleistocene clay and 20 - 30 m of Holocene clay. The coastal area is dissected by two major fault systems: the first group strikes ENE-WSW and controls the evolution of the adjacent Quaternary basin, while the second one trends NNE-SSW. These fault systems must be taken into account in any coastal engineering considerations. In addition, both granitic and metamorphic basements were recognized.     

Application of MODIS data in monitoring suspended sediment of Taihu Lake,China

Application of MODIS in ocean color is mainly based on bands 8-16 with the spatial resolution of 1 000 m.This spatial resolution,however,can not meet the application demand of inland waters where the areas are relatively small.With the assumption of the black water at shortwave infrared(SWIR) wavelengths(>1 000 nm),we first propose an atmospheric correction method for bands 1 and 2 with their spatial resolution of 250 m,and we then establish a quantitative retrieval model for suspended sediment concentratio...     

Predicting sediment flux from continental shelf islands,southeastern China

Continental shelf islands are contributors of terrestrial sediment supply to shelf regions,and the sediment flux from these islands shall be quantified.We calculated the sediment flux of continental shelf islands in the southeastern China using two empirical equations under two preconditions.The first,the sediment load/yield of the islands has the same pattern as the adjacent small,mountainous rivers along the coastline;and the second,each of the islands was treated as a single catchment.The results show that the sediment supply from these islands reached an order of magnitude of 1 Mt/a,which is comparable to the supply from the local smaller rivers.A sensitivity analysis indicates that this value repre sents the lower limit of estimate;if the accurate amount of sub-catchments of any island is considered,then this value will be enhanced slightly.This study demonstrates that the sediment supply from continental shelf islands to oceans is an important factor affecting the regional sedimentation and,therefore,should be paid with attention.