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Sample records for china sea experiment

  1. Recent Seismic Experiments of OBS in the South China Sea

    NASA Astrophysics Data System (ADS)

    Ruan, A.; Li, J.; Wu, Z.

    2012-12-01

    Since 2006 some research institutions of China have carried out some important seismic experiments by using ocean bottom seismometer(OBS) in the South China Sea (SCS) and obtained many concrete progresses in modeling the crustal structure of SCS and also in understanding of its formation and evolution as well. In 2006 three wide-angle profiles were completed in the northern margin, named OBS2006-1 across the northwestern sub-basin, OBS2006-2 parallel to the sea basin boundary and OBS2006-3 across the Dongsha Rise and Chaoshan Depression respectively. In 2010 two wide- angle profiles were completed, named OBS2010-1 and OBS 2010-2 both perpendicular to the northern off-shore faulting system. During 2009-2011 four wide-angle profiles were completed in the southern margin, named OBS973-1 from southern margin to the southwestern sub-basin, OBS973-2 from Liyue Bank to the southwestern sub-basin and OBS973-3 from Xisha to the southwestern sub-basin, OBS2011-2 from Xisha to Hainan Island respectively. In 2011 two 3D seismic array of OBS were completed in the Zhongnan-Changlong sea mount chain and Huangyan-Zhenbei sea mount chain respectively. Here we present some primary but important results as follows. (1) The velocity model of OBS2006-1 indicates that the crust under the continental slope decreases from 21km to 11km, and to 7.7km in the northwestern sub-basin with Moho depth ascends from 21km to 11km. The tectonic geometry and velocity structure of the northwestern sub-basin and its margins on both sides shows symmetrical and conjugate and indicates pure shear mode of continental margin rifting mechanism. (2) The velocity model of OBS2006-3 reveals remarkable thickness with maximum 8 km of the Mesozoic sediment in Chaoshan Depression in which velocity increases downward from 4.4 km/s at top to 5.3 km/s at the bottom. The buried depth of Moho decreases from 24-25 km under Dongsha Rise to 17 km in the lower slope and an obviously velocity abnormal is detected in the upper

  2. Overview of ASIAEX field experiments in the South and East China Seas

    NASA Astrophysics Data System (ADS)

    Lynch, James F.; Dahl, Peter H.

    2002-11-01

    In the spring of 2001 the Asian Seas International Acoustics Experiment (ASIAEX) was performed in the South and East China Seas. The ASIAEX program originated from the Office of Naval Research's initiative to develop a Sino-American cooperation in the field of ocean acoustics, and expanded to involve Taiwan, Korea, Singapore, and Japan. In the South China Sea, the emphasis was on lower frequency (50-600 Hz) acoustic propagation through complex oceanography along and across the shelfbreak. The oceanographic variability was driven at the mesoscale by the monsoonal wind stress, buoyancy fluxes from the Chinese coast, and by occasional Kuroshio intrusions through the Luzon Strait. Large, nonlinear internal waves also significantly affected the acoustics. In the East China Sea the emphasis was on low- to- midfrequency acoustic interaction with, and reverberation from, the sea floor and sea surface. The experimental site was chosen for flatness, to minimize the influence of bathymetric trends, and emphasize bottom roughness and subbottom structures, in the measurements. This talk will describe the scope of the ASIAEX experimental program, including the ocean acoustic and environmental characterization of the seafloor, sea surface, and water column. Results from various measurement programs will be described in separate papers.

  3. South China Sea.

    PubMed

    Morton, B; Blackmore, G

    2001-12-01

    The South China Sea is poorly understood in terms of its marine biota, ecology and the human impacts upon it. What is known is most often contained in reports and workshop and conference documents that are not available to the wider scientific community. The South China Sea has an area of some 3.3 million km2 and depths range from the shallowest coastal fringe to 5377 m in the Manila Trench. It is also studded with numerous islets, atolls and reefs many of which are just awash at low tide. It is largely confined within the Tropic of Cancer and, therefore, experiences a monsoonal climate being influenced by the Southwest Monsoon in summer and the Northeast Monsoon in winter. The South China Sea is a marginal sea and, therefore, largely surrounded by land. Countries that have a major influence on and claims to the sea include China, Malaysia, the Philippines and Vietnam, although Thailand, Indonesia and Taiwan have some too. The coastal fringes of the South China Sea are home to about 270 million people that have had some of the fastest developing and most vibrant economies on the globe. Consequently, anthropogenic impacts, such as over-exploitation of resources and pollution, are anticipated to be huge although, in reality, relatively little is known about them. The Indo-West Pacific biogeographic province, at the centre of which the South China Sea lies, is probably the world's most diverse shallow-water marine area. Of three major nearshore habitat types, i.e., coral reefs, mangroves and seagrasses, 45 mangrove species out of a global total of 51, most of the currently recognised 70 coral genera and 20 of 50 known seagrass species have been recorded from the South China Sea. The island groups of the South China Sea are all disputed and sovereignty is claimed over them by a number of countries. Conflicts have in recent decades arisen over them because of perceived national rights. It is perhaps because of this that so little research has been undertaken on the

  4. Data-Model Comparisons for Sea Surface Waves from the ASIAEX East China Sea Experiment

    NASA Astrophysics Data System (ADS)

    Yang, Jie; Zhou, Ji-Xun; Rogers, Peter H.

    2010-09-01

    During ASIAEX, surface directional wave spectra were recorded for nine consecutive days. Data are analyzed in this paper to show the characteristics of the surface wave field in the East China Sea. Three surface spectrum models, Pierson-Moskowitz, JONSWAP, and Toba, are evaluated and compared with the ASIAEX RMS surface wave height data. The data-model comparisons show that the JONSWAP-Mitsuyasu model is the best fit to the experimental results. Model performance can be improved by a combined model, JONSWAP-Mitsuyasu for U/cp<0.8 and Toba-Donelan for U/cp>0.8. The preliminary results suggest that locally measured wave age can be used to find the most appropriate surface model for acoustic prediction purposes.

  5. Experiments in optimizing simulations of the subsurface chlorophyll maximum in the South China Sea

    NASA Astrophysics Data System (ADS)

    Wang, Siying; Li, Shiyu; Hu, Jiatang; Geng, Bingxu

    2016-04-01

    The subsurface chlorophyll maximum (SCM) is widespread in the oligotrophic ocean and significantly contributes to primary production. One reason for the SCM formation is believed to be the rapid export of phytoplankton from surface layers, which might be caused by aggregation, faster sinking rates under nutrient limitation, or the formation of a resting stage. In this study, these three processes were included in a biological model to investigate their contributions to subsurface chlorophyll. To further identify their individual effects on SCM formation, four modeling experiments were carried out. Three used a simple approach with either (a) density-dependent aggregation, (b) accelerated sinking rate of phytoplankton, or (c) a resting stage. The other experiment combined all three approaches (a-c). A set of observations in the South China Sea was used to optimize the four experiments and compare their abilities to replicate observed values. The results of the experiments with the resting stage showed the best fit to the field observations. All experiments were able to capture major features of the chlorophyll field (e.g. surface bloom and SCM). The experiment with accelerated sinking rate failed to reproduce the observed profile of particulate organic carbon. The experiment with only aggregation predicted lower chlorophyll concentrations in summer than those measured in the field, while experiments with the resting stage reproduced more accurate chlorophyll concentrations. Formulas including the resting stage more successfully captured the timing of phytoplankton export than did those including aggregation and accelerated sinking rate. The processes of aggregation and accelerated sinking rate made small contributions to the SCM formation in the last experiment. Overall, these results show that introducing the resting stage improves SCM simulations of the South China Sea. The results of the experiment with only the resting stage showed that the resting cells shift

  6. Sea experiments of the Underway Conductivity-Temperature-Depth prototype made in China

    NASA Astrophysics Data System (ADS)

    Song, Xiangzhou; Li, Hui; Lin, Xiaopei; Chen, Xueen; Guo, Xinshun; Tian, Jiwei

    2009-12-01

    A new instrument for upper ocean survey, namely the UCTD (Underway Conductivity-Temperature-Depth), which combines some of the advantages of other underway instruments, is introduced in this paper. The Introduction section presents a description of the construction and function of the UCTD, and the experiments conducted in the South China Sea on board the R/V Dong Fang Hong 2 in July 2007 and August 2008. The UCTD system, with pressure and temperature sensors in the probe, is conveniently portable, cost-effective and environment-friendly. It is hopefully suitable for future cruises. An intercomparison based on regressing with the experiment temperature data from both SeaBird plus911 CTD and the UCTD showed that the standard deviation is 0.88°C and the correlation coefficient is 0.96, achieving the goals set for the current oceanography uses. In the hydrodynamic experiments, the descending velocities and depths were calculated for different ship speeds. A pulling test was designed with a tensiometer to measure the magnitude of the pull. The maximal tension of the line was found to be 66.2 kg, which is far lower than the bearing limit of the Hollow Spectra line. Finally, some improvement suggestions are put forward for future experiments and production.

  7. Clear-Sky Surface Solar Radiation During South China Sea Monsoon Experiment

    NASA Technical Reports Server (NTRS)

    Lin, Po-Hsiung; Chou, Ming-Dah; Ji, Qiang; Tsay, Si-Chee; Einaudi, Franco (Technical Monitor)

    2000-01-01

    Downward solar fluxes measured at Dungsha coral island (20 deg. 42 min. N, 116 deg. 43 min. E) during the South China Sea Monsoon Experiment (May-June 1998) have been calibrated and compared with radiative transfer calculations for three clear-sky days. Model calculations use water vapor and temperature profiles from radiosound measurements and the aerosol optical thickness derived from sunphotometric radiance measurements at the surface. Results show that the difference between observed and model-calculated downward fluxes is less than 3% of the daily mean. Averaged over the three clear days, the difference reduces to 1%. The downward surface solar flux averaged over the three days is 314 W per square meters from observations and 317 W per square meters from model calculations, This result is consistent with a previous study using TOGA CAORE measurements, which found good agreements between observations and model calculations. This study provides an extra piece of useful information on the modeling of radiative transfer, which fills in the puzzle of the absorption of solar radiation in the atmosphere.

  8. A three-dimensional variational data assimilation system for the South China Sea: preliminary results from observing system simulation experiments

    NASA Astrophysics Data System (ADS)

    Peng, Shiqiu; Zeng, Xuezhi; Li, Zhijin

    2016-03-01

    A three-dimensional variational data assimilation (3DVAR) system based on the Regional Ocean Modeling System (ROMS) is established for the South China Sea (SCS). A set of Observing System Simulation Experiments (OSSEs) are performed to evaluate the performance of this data assimilation system and investigate the impacts of different types of observations on representation of three-dimensional large-scale circulations and meso-scale eddies in the SCS. The pseudo-observations that are examined include sea surface temperatures (SSTs), sea surface heights (SSHs), sparse temperature/salinity (T/S) profiles, sea surface velocities (SSVs), and sea surface salinities (SSSs). The results show that SSHs can extend their impacts into the subsurface or even the deep ocean while other surface observations only have impacts within surface mixed layer. SSVs have similar impacts though confined to their spatial coverage, suggesting that SSVs could be a substitute of SSHs nearshore where SSHs are of poor quality. Despite their sparseness, the T/S profiles improve the representation of the temperature and salinity structures below the mixed layer, and a combination of T/S profiles with surface observations leads to a better representation of the meso-scale eddies. Based on the OSSE results, an affordable observing network for the SCS in the near future is proposed.

  9. A three-dimensional variational data assimilation system for the South China Sea: preliminary results from observing system simulation experiments

    NASA Astrophysics Data System (ADS)

    Peng, Shiqiu; Zeng, Xuezhi; Li, Zhijin

    2016-05-01

    A three-dimensional variational data assimilation (3DVAR) system based on the Regional Ocean Modeling System (ROMS) is established for the South China Sea (SCS). A set of Observing System Simulation Experiments (OSSEs) are performed to evaluate the performance of this data assimilation system and investigate the impacts of different types of observations on representation of three-dimensional large-scale circulations and meso-scale eddies in the SCS. The pseudo-observations that are examined include sea surface temperatures (SSTs), sea surface heights (SSHs), sparse temperature/salinity (T/S) profiles, sea surface velocities (SSVs), and sea surface salinities (SSSs). The results show that SSHs can extend their impacts into the subsurface or even the deep ocean while other surface observations only have impacts within surface mixed layer. SSVs have similar impacts though confined to their spatial coverage, suggesting that SSVs could be a substitute of SSHs nearshore where SSHs are of poor quality. Despite their sparseness, the T/S profiles improve the representation of the temperature and salinity structures below the mixed layer, and a combination of T/S profiles with surface observations leads to a better representation of the meso-scale eddies. Based on the OSSE results, an affordable observing network for the SCS in the near future is proposed.

  10. First results from experiment in South China Sea using marine controlled source electromagnetic

    NASA Astrophysics Data System (ADS)

    Li, Yuan; Wang, Lipeng; Deng, Ming

    2016-04-01

    We concentrated on the use of marine controlled-source electromagnetic (CSEM) sounding with a horizontal electric dipole source towed close to the seafloor and receivers anchored on the seafloor. We applied the CSEM method in South China Sea for the first time in 2014, which not only test the application of our instrument, but also test our data processing method. Electromagnetic fields transmitted by a towed electric dipole source in deep sea were measured by a linear array of six seafloor receivers, positioned 600 meter (m) apart. Our results provided two highly resistivity layers beneath the survey line and the gas hydrate saturation profile associated with the anomalous resistivity. In the letter, we discussed some anomalous layers during the interpretation steps. The most plausible explanation of the first resistivity layer anomalies is that large amounts of gas hydrate have accumulated at 200 m depth below the seep sites, and the second layers is considerable volumes of gas hydrate have accumulated the seafloor at survey line according to the conceptual model, during the resistivity compared with other evidence like seismic and well data from the same survey. We should try other observation like heat flow, geochemical or other evidence to test the statement in the future.

  11. Monsoon Convective During the South China Sea Monsoon Experiment: Observations from Ground-Based Radar and the TRMM Satellite

    NASA Technical Reports Server (NTRS)

    Cifelli, Rob; Rickenbach, Tom; Halverson, Jeff; Keenan, Tom; Kucera, Paul; Atkinson, Lester; Fisher, Brad; Gerlach, John; Harris, Kathy; Kaufman, Cristina

    1999-01-01

    A main goal of the recent South China Sea Monsoon Experiment (SCSMEX) was to study convective processes associated with the onset of the Southeast Asian summer monsoon. The NASA TOGA C-band scanning radar was deployed on the Chinese research vessel Shi Yan #3 for two 20 day cruises, collecting dual-Doppler measurements in conjunction with the BMRC C-Pol dual-polarimetric radar on Dongsha Island. Soundings and surface meteorological data were also collected with an NCAR Integrated Sounding System (ISS). This experiment was the first major tropical field campaign following the launch of the Tropical Rainfall Measuring Mission (TRMM) satellite. These observations of tropical oceanic convection provided an opportunity to make comparisons between surface radar measurements and the Precipitation Radar (PR) aboard the TRMM satellite in an oceanic environment. Nearly continuous radar operations were conducted during two Intensive Observing Periods (IOPS) straddling the onset of the monsoon (5-25 May 1998 and 5-25 June 1998). Mesoscale lines of convection with widespread regions of both trailing and forward stratiform precipitation were observed following the onset of the active monsoon in the northern South China Sea region. The vertical structure of the convection during periods of strong westerly flow and relatively moist environmental conditions in the lower to mid-troposphere contrasted sharply with convection observed during periods of low level easterlies, weak shear, and relatively dry conditions in the mid to upper troposphere. Several examples of mesoscale convection will be shown from the ground (ship)-based and spaceborne radar data during times of TRMM satellite overpasses. Examples of pre-monsoon convection, characterized by isolated cumulonimbus and shallow, precipitating congestus clouds, will also be discussed.

  12. Assessment of aerosol optical property and radiative effect for the layer decoupling cases over the northern South China Sea during the 7-SEAS/Dongsha Experiment

    NASA Astrophysics Data System (ADS)

    Pani, Shantanu Kumar; Wang, Sheng-Hsiang; Lin, Neng-Huei; Tsay, Si-Chee; Lolli, Simone; Chuang, Ming-Tung; Lee, Chung-Te; Chantara, Somporn; Yu, Jin-Yi

    2016-05-01

    The aerosol radiative effect can be modulated by the vertical distribution and optical properties of aerosols, particularly when aerosol layers are decoupled. Direct aerosol radiative effects over the northern South China Sea (SCS) were assessed by incorporating an observed data set of aerosol optical properties obtained from the Seven South East Asian Studies (7-SEAS)/Dongsha Experiment into a radiative transfer model. Aerosol optical properties for a two-layer structure of aerosol transport were estimated. In the radiative transfer calculations, aerosol variability (i.e., diversity of source region, aerosol type, and vertical distribution) for the complex aerosol environment was also carefully quantified. The column-integrated aerosol optical depth (AOD) at 500 nm was 0.1-0.3 for near-surface aerosols and increased 1-5 times in presence of upper layer biomass-burning aerosols. A case study showed the strong aerosol absorption (single-scattering albedo (ω) ≈ 0.92 at 440 nm wavelength) exhibited by the upper layer when associated with predominantly biomass-burning aerosols, and the ω (≈0.95) of near-surface aerosols was greater than that of the upper layer aerosols because of the presence of mixed type aerosols. The presence of upper level aerosol transport could enhance the radiative efficiency at the surface (i.e., cooling) and lower atmosphere (i.e., heating) by up to -13.7 and +9.6 W m-2 per AOD, respectively. Such enhancement could potentially modify atmospheric stability, can influence atmospheric circulation, as well as the hydrological cycle over the tropical and low-latitude marginal northern SCS.

  13. A Sea Experience.

    ERIC Educational Resources Information Center

    Glickstein, Neil

    1989-01-01

    Described is a teacher education program organized by the Sea Education Association in Woods Hole (Massachusetts). The experience, including activities and examples of studies conducted, is discussed. Contact information for future cruises is included. (CW)

  14. Monsoon Convection during the South China Sea Monsoon Experiment Observed from Shipboard Radar and the TRMM Satellite

    NASA Technical Reports Server (NTRS)

    Rickenbach, Tom; Cifelli, Rob; Halverson, Jeff; Kucera, Paul; Atkinson, Lester; Fisher, Brad; Gerlach, John; Harris, Kathy; Kaufman, Cristina; Liu, Ching-Hwang; Market, Pat

    1999-01-01

    A main goal of the recent South China Sea Monsoon Experiment (SCSMEX) was to study convective processes associated with the onset of the Southeast Asian summer monsoon. The NASA TOGA C-band scanning radar was deployed on the Chinese research vessel Shi Yan #3 for two 20 day cruises, collecting dual-Doppler measurements in conjunction with the BMRC C-Pol dual-polarimetric radar on Dongsha Island. Soundings and surface meteorological data were also collected with an NCAR Integrated Sounding System (ISS). This experiment was the first major tropical field campaign following the launch of the Tropical Rainfall Measuring Mission (TRMM) satellite. These observations of tropical oceanic convection provided an opportunity to make comparisons between surface radar measurements and the Precipitation Radar (PR) aboard the TRMM satellite in an oceanic environment. Nearly continuous radar operations were conducted during two Intensive Observing Periods (IOPS) straddling the onset of the monsoon (5-25 May 1998 and 5-25 June 1998). Mesoscale lines of convection with widespread regions of both trailing and forward stratiform precipitation were observed during the active monsoon periods in a southwesterly flow regime. Several examples of mesoscale convection will be shown from ship-based and spacebome radar reflectivity data during times of TRMM satellite overpasses. Further examples of pre-monsoon convection, characterized by isolated cumulonimbus and shallow, precipitating congestus clouds, will be discussed. A strong waterspout was observed very near the ship from an isolated cell in the pre-monsoon period, and was well documented with photography, radar, sounding, and sounding data.

  15. A Tale of Sea Turtles: Job-Seeking Experiences of "Hai Gui" (High-Skilled Returnees) in China

    ERIC Educational Resources Information Center

    Hao, Jie; Welch, Anthony

    2012-01-01

    A key feature of contemporary globalization is the increasing mobility of high-skilled talent. While for many countries in the developing world the loss of such individuals represents a longstanding concern, countries such as China have now developed key policies to harness their overseas talent. The article examines the job-seeking experiences of…

  16. Origin, Transport, and Vertical Distribution of Atmospheric Polluntants over the Northern Sourth China Sea During the 7-SEAS-Dongsha Experiment

    NASA Technical Reports Server (NTRS)

    Wang, Sheng-Hsiang; Tsay, Si-Chee; Lin, Neng-Huei; Chang, Shuenn-Chin; Li, Can; Welton, Ellsworth J.; Holben, Brent N.; Hsu, N. Christina; Lau, William K. M.; Lolli, Simone; Kuo, Chun-Chiang; Chia, Hao-Ping; Chia-Yang, Chiu; Chia-Ching, Lin; Bell, Shaun W.; Ji, Qiang; Hansell, Richard A.; Sheu, Guey-Rong; Chi, Kai-Hsien; Peng, Chi-Ming

    2012-01-01

    During the spring of 2010, comprehensive in situ measurements were made for the first time on a small atoll (Dongsha Island) in the northern South China Sea (SCS), a key region of the 7-SEAS (the Seven South East Asian Studies) program. This paper focuses on characterizing the source origins, transport processes, and vertical distributions of the Asian continental outflows over the region, using measurements including mass concentration, optical properties, hygroscopicity, and vertical distribution of the aerosol particles, as well as the trace gas composition. Cluster analysis of backward trajectories classified 52% of the air masses arriving at ground level of Dongsha Island as having a continental origin, mainly from northern China to the northern SCS, passing the coastal area and being confined in the marine boundary layer (0-0.5 km). Compared to aerosols of oceanic origin, the fine mode continental aerosols have a higher concentration, extinction coefficient, and single-scattering albedo at 550 nm (i.e., 19 vs. 14 microg per cubic meter in PM(sub 2.5); 77 vs. 59 M per meter in beta(sub e); and 0.94 vs. 0.90 in omega, respectively). These aerosols have a higher hygroscopicity (f at 85% RH = 2.1) than those in the upwind inland regions, suggesting that the aerosols transported to the northern SCS were modified by the marine environment. In addition to the near-surface aerosol transport, a significant upper-layer (3-4 km) transport of biomass-burning aerosols was observed. Our results suggest that emissions from both China and Southeast Asia could have a significant impact on the aerosol loading and other aerosol properties over the SCS. Furthermore, the complex vertical distribution of aerosols-coinciding-with-clouds has implications for remote-sensing observations and aerosol-cloud-radiation interactions.

  17. Chemical Composition of Sea Fog Water Along the South China Sea

    NASA Astrophysics Data System (ADS)

    Yue, Yanyu; Niu, Shengjie; Zhao, Lijuan; Zhang, Yu; Xu, Feng

    2012-12-01

    The chemical and microphysical properties of sea fog were measured during a field experiment on Donghai Island, Zhanjiang of China from March 15 to April 18, 2010. The average pH and electrical conductivity (EC) value of the six sea fog cases during the experiment was 5.2 and 1,884 μS/cm. The observed total ion concentration of sea fog was four orders of magnitude higher than those in the North Pacific and other sea areas of China. The dominant anion and cation in all sea fog water samples were Cl- and Na+, respectively. From backward trajectory analysis and ion loading computation, it can be concluded that the ions in the samples were transported either from pollutants in distant industrial cities or from local ion deposition processes. The concentration of Ca2+ in the sea fog water samples in Case 2 suggested that a dust storm in the Inner Mongolia, a northern region of China several thousand kilometers away, could reach the South China Sea. The data also showed that the sea fog droplet spectrum over the South China Sea is unimodal. Through relationship analysis, it is illustrated that the evolution of microphysics (such as droplet concentration, diameter, and liquid water content) during fog process could affect the chemical properties of sea fog.

  18. Personal Experiences of China

    ERIC Educational Resources Information Center

    Hessler, Peter; Bradeen, Ryan; Wang, Richard; Masalski, Kathleen Woods

    2010-01-01

    This article presents four stories of personal experiences of China. In "A Journey Between China's Past and Present," Peter Hessler, a former Peace Corps volunteer and author, highlights misconceptions between Chinese and Americans and the desire both peoples share for knowledge about one another. In "Life on Liberation Avenue," Ryan Bradeen…

  19. Crustal Structure and Fracture Zone in the Central Sea Basin of the South China Sea from Wide Angle Seismic Experiments Using OBS

    NASA Astrophysics Data System (ADS)

    Ruan, Aiguo; Wei, Xiaodong

    2015-04-01

    We present two E-W trending wide-angle seismic profiles (OBS2013-ZN, OBS2014-ZN), which cross the boundary (Zhongnan fault) between the east sub-basin and the southwest sub-basin of the South China Sea (SCS). We processed the data and used 2D ray-tracing to determine the oceanic crust thickness, velocity structures and Moho depth variations related to faults. The simulated velocity models show that the sea basin of the SCS has a typical oceanic crust covered by a 1~2 km thick sediment layer with a velocity of 2~3.5 km/s. The crust has a thickness of 5~8 km, of which the oceanic layer 2 is 1.8~3 km thick, with velocity increasing downward from 4.3 km/s to 6.4 km/s, and the oceanic layer 3 is 3~5 km thick, with velocity increasing downward from 6.4 km/s~7.0 km/s. The sea basin Moho depth is approximately 10 km. The Moho discontinuity has an obvious upheaval zone with a low velocity of 7.6 km/s, which corresponds to the low velocity zone in oceanic layer 2. We constructed an arc-shaped fracture zone (40-50 km wide) by connecting the upheaval portions of the Moho in the two profiles based on seabed relief and sea mounts distribution and suggest that it is the trace of the break-up of the Macclesfield and Reed Banks caused by the triangular opening system of the southwest sub-basin. We suggest that the faults or fracture zones in the oceanic basin of the SCS were formed in segmentation with varied directions controlled by varied stress fields during the multi-episode evolution of the SCS. The seafloor spreading abrupt direction change around 116°E maybe is because of lithosphere heterogeneity caused by early episode seafloor spreading in the east sub-basin or caused by the arc-shaped fracture zone, which results in different local stress filed.

  20. Aerosol chemical properties and related pollutants measured in Dongsha Island in the northern South China Sea during 7-SEAS/Dongsha Experiment

    NASA Astrophysics Data System (ADS)

    Chuang, Ming-Tung; Chang, Shuenn-Chin; Lin, Neng-Huei; Wang, Jia-Lin; Sheu, Guey-Rong; Chang, You-Jia; Lee, Chung-Te

    2013-10-01

    Aerosol observations were conducted at Dongsha Island in two batches from 19 to 23 March and 10 to 19 April 2010. Dongsha Island is located in a remote area over the northern South China Sea (SCS), distantly surrounded by southern China, Taiwan, the Philippines, and the Indochinese Peninsula. During the study period, the average PM10 and PM2.5 mass concentrations were 26.5 ± 19.4 and 12.6 ± 6.0 μg m-3, respectively. In particular, a daily PM10 concentration of 94.1 μg m-3 caused by a yellow-dust event originating from the Asian Continent was recorded on 21 March. Other than this event, the PM2.5 and PM10-2.5 daily levels were 7.1 ± 1.2 and 12.6 ± 5.0 μg m-3, respectively, on days without pollution from anthropogenic sources in the surrounding areas. Water-soluble ions (WSIs) were the predominant components that accounted for 58.7% ± 10.5% and 51.1% ± 7.2% of the PM10 and PM2.5 mass. The second most abundant component was carbonaceous content, which accounted for 9.5% ± 4.7% and 17.5% ± 5.3% of PM10 and PM2.5, respectively. SO42- was the most abundant PM2.5 WSI, whereas the Na+ and Cl- pair was the most abundant PM10-2.5 WSI. Based on the U.S. IMPROVE protocol, the resolved carbonaceous fractions were mainly distributed in PM2.5 and influenced by coal combustion, mobile vehicles, and biomass burning. Most of the resolved WSIs in particles were in the liquid phase due to the humid environment around the northern SCS.

  1. Marine environments in the China Seas and their prediction

    SciTech Connect

    Bao, C.

    1993-12-31

    The China Seas surround the China continent to its south and east, and connect with the Pacific Ocean. In this paper, marine environmental elements in the China Seas such as marine climate, storm surge, sea wave, sea temperature, sea ice, tsunami and red tide, are analyzed. The predication of marine environments, especially oceanic disasters with good accuracy are also given in this paper.

  2. The Impact of Sea Surface Temperature Front on Stratus-Sea Fog over the Yellow and East China Seas

    NASA Astrophysics Data System (ADS)

    Zhang, S.; Li, M.; Liu, F.

    2013-12-01

    A stratus-sea fog event occurred on 3 June 2011 over the Yellow and East China Seas (as shown in figure) is investigated observationally and numerically. Emphasis is put on the influences of the sea surface temperature front (SSTF) and of the synoptic circulations on the transition of stratus to sea fog. The southerly winds from a synoptic high pressure transport water vapor from the East China Sea to the Yellow Sea, while the subsidence induced by the high contributes to the formation of the temperature inversion on the top of the stratus or stratocumulus that appears mainly over the warm flank of a sea surface temperature front in the East China Sea. Forced by the SSTF, there is a secondary cell within the atmospheric boundary layer (ABL), with a sinking branch on the cold flank and a rising one on the warm flank of the SSTF. This sinking branch, in phase with the synoptic subsidence, forces the stratus or stratocumulus to lower in the elevation getting close to the sea surface as these clouds move northward driven by the southerly winds. The cloud droplets can either reach to the sea surface directly or evaporate into water vapor that may condense again when coming close to the cold sea surface to form fog. In this later case, the stratus and fog may separate. The cooling effect of cold sea surface counteracts the adiabatic heating induced by the subsidence and thus helps the transition of stratus to sea fog in the southern Yellow Sea. By smoothing the SSTF in the numerical experiment, the secondary cell weakens and the sea fog patches shrink obviously over the cold flank of the SSTF though the synoptic subsidence and moist advection still exist. A conceptual model is suggested for the transition of stratus to sea fog in the Yellow and East China Seas, which is helpful for the forecast of sea fog over these areas. The satellite visible image of the stratus-fog event. The fog appears in the Yellow Sea and the stratocumulus in the East China Sea.

  3. SMOS Sea Surface Salinity Validation in the South China Sea

    NASA Astrophysics Data System (ADS)

    Ren, Yongzheng; Li, Xiaoming; Dong, Qing

    2013-01-01

    In November 2009, the European Space Agency (ESA) launched the first soil moisture and ocean salinity (SMOS) satellite, which represented the first use of spaceborne remote sensing tools to probe global sea surface salinity (SSS). The SMOS satellite carries a microwave imaging radiometer with aperture synthesis (MIRAS) for detection in the microwave L-band as the only payload. The MIRAS instrument is expected to provide a global SSS distribution with a spatial resolution of approximately 100 km and an accuracy of 0.1-0.2 practical salinity units (psu). The South China Sea is semi-enclosed, and the sea conditions are relatively complex. The suitability of ESA SMOS salinity products for the South China Sea has not been validated. Therefore, using SSS data measured during an expedition in the South China Sea, which was sponsored by China Natural Science Foundation and conducted in the fall of 2011, this paper validated the SSS products released by ESA, which were retrieved using three sea surface roughness models. To analyze the effect of the spatial resolution on the weekly average SMOS SSS distribution, the weekly average salinity data were averaged to reduce the spatial resolution to 0.25 ° x 0.25°. These average data were then compared to the measured data, followed by an analysis of the error variation. In addition, the effects of the orbital track (ascending or descending) on the SSS retrieval were analyzed.

  4. Regional sea level variability in the Bohai Sea, Yellow Sea, and East China Sea

    NASA Astrophysics Data System (ADS)

    Cheng, Yongcun; Plag, Hans-Peter; Hamlington, Benjamin D.; Xu, Qing; He, Yijun

    2015-12-01

    The regional sea level variability in the Bohai Sea (BS), Yellow Sea (YS) and East China Sea (ECS) is investigated based on tide gauge, satellite altimeter data and an independent oceanic general circulation model for the Earth Simulator (OFES) model outputs. It is found that atmospheric forcing significantly affects local sea level variability in the BS and YS and local sea level variability at the Southern ECS is highly correlated with along-shore currents. Particularly, the annual sea level fluctuations potentially change inundation risk and the frequency and magnitude of flooding in regions with high annual sea level. Hence, the cyclostationary empirical orthogonal function (CSEOF) analysis is carried out to investigate the variations of annual sea level cycle amplitude. Similar spatial distribution characteristics of annual sea level amplitude fluctuations are presented from satellite altimeter data and model outputs. The variability of annual sea level amplitude estimated from the satellite altimeter data agrees well with that from the tide gauge data, and positively (negatively) correlates with Southern Oscillation Index (Pacific Decadal Oscillation). The OFES model, however, underestimates the fluctuation of the annual cycle. After removing the annual signal, the low-passed (i.e., 13-month running mean) tide gauge data shows high correlations with SOI and PDO on time scales over 8 years in the BS and ECS.

  5. Using High-Resolution Satellite Observations for Evaluation of Cloud and Precipitation Statistics from Cloud-Resolving Model Simulations. Part I: South China Sea Monsoon Experiment

    NASA Astrophysics Data System (ADS)

    Zhou, Y.; Hou, A.; Lau, W. K.; Shie, C.; Tao, W.; Lin, X.; Chou, M.; Olson, W. S.; Grecu, M.

    2006-05-01

    The cloud and precipitation statistics simulated by 3D Goddard Cumulus Ensemble (GCE) model during the South China Sea Monsoon Experiment (SCSMEX) is compared with Tropical Rainfall Measuring Mission (TRMM) TMI and PR rainfall measurements and the Earth's Radiant Energy System (CERES) single scanner footprint (SSF) radiation and cloud retrievals. It is found that GCE is capable of simulating major convective system development and reproducing total surface rainfall amount as compared with rainfall estimated from the soundings. Mesoscale organization is adequately simulated except when environmental wind shear is very weak. The partitions between convective and stratiform rain are also close to TMI and PR classification. However, the model simulated rain spectrum is quite different from either TMI or PR measurements. The model produces more heavy rains and light rains (less than 0.1 mm/hr) than the observations. The model also produces heavier vertical hydrometer profiles of rain, graupel when compared with TMI retrievals and PR radar reflectivity. Comparing GCE simulated OLR and cloud properties with CERES measurements found that the model has much larger domain averaged OLR due to smaller total cloud fraction and a much skewed distribution of OLR and cloud top than CERES observations, indicating that the model's cloud field is not wide spread, consistent with the model's precipitation activity. These results will be used as guidance for improving the model's microphysics.

  6. Tsunami in the China Seas and its warning service

    SciTech Connect

    Ye Lin; Wang Xinian; Bao Chenglan

    1993-12-31

    This paper briefly describes the tsunamis that took place in the China Seas, discusses the possibility of influence of crossing oceanic tsunami on the China Seas, and emphatically introduces the tsunami along Hainan Island coasts in January 1992. It is the seldom tsunami recorded completely by instruments in China. Last, the operation of tsunami warning service in China is presented.

  7. Future acidification of marginal seas: A comparative study of the Japan/East Sea and the South China Sea

    NASA Astrophysics Data System (ADS)

    Luo, Yiming; Boudreau, Bernard P.

    2016-06-01

    The response of marginal (peripheral) seas to ocean acidification on short and long time scales is not well established. Through modeling, we examine the future acidification of two adjacent marginal seas, the South China Sea (SCS) and the Japan/East Sea (J/ES). Our results illustrate the importance of unique features in determining their acidification. The J/ES basin will become completely undersaturated with regard to calcite rapidly in the next few decades, while the SCS basin will experience relatively slower acidification. During its acidification, the J/ES will continually act as a sink for atmospheric CO2, whereas the SCS will temporarily switch from a source to a sink during the peak pCO2 interval, only to return slowly to being a source again. Marginal sea acidification will be determined by multiple factors, including their connections with the open ocean and their unique physical and biogeochemical dynamics, in addition to the level of atmospheric CO2.

  8. Polarimetric SAR Models for Oil Fields Monitoring in China Seas

    NASA Astrophysics Data System (ADS)

    Buono, A.; Nunziata, F.; Li, X.; Wei, Y.; Ding, X.

    2014-11-01

    In this study, physical-based models for polarimetric Synthetic Aperture Radar (SAR) oil fields monitoring are proposed. They all share a physical rationale relying on the different scattering mechanisms that characterize a free sea surface, an oil slick-covered sea surface, and a metallic target. In fact, sea surface scattering is well modeled by a Bragg-like behaviour, while a strong departure from Bragg scattering is in place when dealing with oil slicks and targets. Furthermore, the proposed polarimetric models aim at addressing simultaneously target and oil slick detection, providing useful extra information with respect to single-pol SAR data in order to approach oil discrimination and classification. Experiments undertaken over East and South China Sea from actual C-band RadarSAT-2 full-pol SAR data witness the soundness of the proposed rationale.

  9. Dynamics of the cross-shelf circulation in the Yellow and East China Seas in winter

    NASA Astrophysics Data System (ADS)

    Yuan, Dongliang; Hsueh, Ya

    2010-10-01

    to the northerly wind forcing is a sea-level tilt to the south, which forces the East China Sea Current to flow cross the continental shelf and slope into the Okinawa Trough. The numerical experiments thus suggest that both the inshore and offshore branches of the Taiwan Warm Current are forced primarily by the northerly winds in winter.

  10. Climate modulation on sea surface height in China seas

    NASA Astrophysics Data System (ADS)

    Zhang, Xiaoshuang; Wang, Xidong; Cao, Yingzhi; Zhang, Lianxin; Shao, Caixia; Sun, Chunjian; Wu, Xinrong; Fu, Hongli; Xuan, Lili

    2015-09-01

    The climate modulation on the sea surface height (SSH) in China seas is investigated using a China Ocean Reanalysis (CORA) dataset from 1958-2008. The dataset is constructed by assimilating the temperature/salinity profiles derived from the satellite altimetry data and historical observational temperature/salinity profiles. Based on the Empirical Orthogonal Function (EOF), the CORA sea surface height anomaly (SSHa) is decomposed, and the interannual and decadal variability of the first three leading modes are analyzed. On the interannual timescale, the first principal component (PC1) is significant positively correlated with the El Niño/Southern Oscillation (ENSO). On the decadal timescale, North Pacific Gyre Oscillation (NPGO) has significant negative correlation with PC1 whereas Pacific Decadal Oscillation (PDO) is in phase with PC3. Analysis shows that the decadal variability of SSH is mainly modulated by the wind stress curl variability related to the NPGO and PDO. In addition, the effect of net heat flux associated to the NPGO and PDO on SSH is also investigated, with net heat flux variability in the Luzon strait and tropic Pacific found to influence the decadal variability of SSH.

  11. The wave and wave forecasting in the China Seas

    SciTech Connect

    Xu Fuxiang

    1993-12-31

    The China Seas located at the Southeastern part of the large Eurasia continent, and beside the largest ocean, the Pacific. They are greatly influenced by continent and the ocean. Due to it across the tropical zone, the subtropical zone and the extropical zone, the cold and warm air circulation in Northsouth is a very active exchange. In the summer, the South China Sea and the East China Sea are frequently hit by typhoon waves. In spring and autumn, the bohai sea, the Yellow sea and the East China Seas had series disasters caused by the extropical cyclone wave and the cold air wave. In this paper the time-space distribution and formative cases of wave disaster in the China Seas, and the wave monitoring and prediction system, the wave prediction method, and two automatic systems of numerical wave forecasting are briefly introduced.

  12. Open Ocean Internal Waves, South China Sea

    NASA Technical Reports Server (NTRS)

    1989-01-01

    These open ocean internal waves were seen in the south China Sea (19.5N, 114.5E). These sets of internal waves most likely coincide with tidal periods about 12 hours apart. The wave length (distance from crest to crest) varies between 1.5 and 5.0 miles and the crest lengths stretch across and beyond this photo for over 75 miles. At lower right, the surface waves are moving at a 30% angle to the internal waves, with parallel low level clouds.

  13. Typhoon emergency response planning for the South China Sea

    SciTech Connect

    Corona, E.N.; Lynch, R.D.; Riffe, D.; Cardone, V.J.; Cox, A.; Chen, H.

    1996-12-31

    This paper describes the development, implementation and performance of a comprehensive typhoon emergency response plan (ERP) utilized during 1995 by Arco China Inc. (ACI) for their offshore Hainan Is. South China Sea development. An important component of the enhanced plan is a new system to forecast winds and sea states generated by tropical cyclones (TC) built around known uncertainties in forecasts of cyclones and well proven numerical models of the TC surface wind field and the spectral wave field. The forecast system provides specification of time histories of the winds and waves at the site for the nominally predicted track as well as the probabilities of exceedance of critical evacuation thresholds of wind speed and sea state. The ERP and forecast system were operated throughout the 1995 typhoon season and evaluated at the Yacheng development, which was seriously threatened by 15 tropical cyclones between June and November. The response to these threats in terms of interruption of operations, partial or total evacuation of offshore personnel and average downtime is described and compared to previous experience which used more conventional forecast services. The evaluation has shown the new system to provide significant benefits in terms of safety, efficiency and cost savings. The wind and sea state forecast histories provided year-round by the forecast system are also of significant benefit to the management of floating production systems.

  14. Intensified Springtime Deep Convection over the South China Sea and the Philippine Sea Dries Southern China

    PubMed Central

    Li, Zhenning; Yang, Song; He, Bian; Hu, Chundi

    2016-01-01

    Springtime rainfall, accounting for 25–40% of the annual rainfall in southern China, exerts great agricultural and socioeconomic impacts on the region. In the recent decades, southern China has experienced a significant declining trend of precipitation in boreal spring. Meanwhile, precipitation has increased over the South China Sea and the Philippine Sea (SCS-PhS). This paper presents observational and modeling evidences suggesting that the intensified latent heating released by the convection over SCS-PhS leads to suppressed springtime rainfall over southern China. Moisture budget analysis indicates that the drying trend over southern China is due mainly to weakened convergence of moisture flux, which is controlled by a heat-induced anomalous overturning circulation reinforced by the convection over SCS-PhS. Further idealized simulations support the feature that the heat-induced overturning circulation and its corresponding anomalous cyclone can be well established in several days under the spring mean flow condition. Thus, this rapid dynamic process is associated with both the intraseasonal-to-interannual variations and the long-term change of the springtime rainfall over southern China. PMID:27461985

  15. Intensified Springtime Deep Convection over the South China Sea and the Philippine Sea Dries Southern China

    NASA Astrophysics Data System (ADS)

    Li, Zhenning; Yang, Song; He, Bian; Hu, Chundi

    2016-07-01

    Springtime rainfall, accounting for 25–40% of the annual rainfall in southern China, exerts great agricultural and socioeconomic impacts on the region. In the recent decades, southern China has experienced a significant declining trend of precipitation in boreal spring. Meanwhile, precipitation has increased over the South China Sea and the Philippine Sea (SCS-PhS). This paper presents observational and modeling evidences suggesting that the intensified latent heating released by the convection over SCS-PhS leads to suppressed springtime rainfall over southern China. Moisture budget analysis indicates that the drying trend over southern China is due mainly to weakened convergence of moisture flux, which is controlled by a heat-induced anomalous overturning circulation reinforced by the convection over SCS-PhS. Further idealized simulations support the feature that the heat-induced overturning circulation and its corresponding anomalous cyclone can be well established in several days under the spring mean flow condition. Thus, this rapid dynamic process is associated with both the intraseasonal-to-interannual variations and the long-term change of the springtime rainfall over southern China.

  16. Intensified Springtime Deep Convection over the South China Sea and the Philippine Sea Dries Southern China.

    PubMed

    Li, Zhenning; Yang, Song; He, Bian; Hu, Chundi

    2016-01-01

    Springtime rainfall, accounting for 25-40% of the annual rainfall in southern China, exerts great agricultural and socioeconomic impacts on the region. In the recent decades, southern China has experienced a significant declining trend of precipitation in boreal spring. Meanwhile, precipitation has increased over the South China Sea and the Philippine Sea (SCS-PhS). This paper presents observational and modeling evidences suggesting that the intensified latent heating released by the convection over SCS-PhS leads to suppressed springtime rainfall over southern China. Moisture budget analysis indicates that the drying trend over southern China is due mainly to weakened convergence of moisture flux, which is controlled by a heat-induced anomalous overturning circulation reinforced by the convection over SCS-PhS. Further idealized simulations support the feature that the heat-induced overturning circulation and its corresponding anomalous cyclone can be well established in several days under the spring mean flow condition. Thus, this rapid dynamic process is associated with both the intraseasonal-to-interannual variations and the long-term change of the springtime rainfall over southern China. PMID:27461985

  17. Wintertime current meter measurements from the East China Sea

    SciTech Connect

    Trump, C.L.; Burt, W.V.

    1981-09-01

    An array of three current meters were anchored on the continental shelf of the East China Sea during the last half of February 1975 as part of the Japanese Air Mass Transformation Experiment, AMTEX-75. The results indicate that the currents are dominated by the rotational semidiurnal M/sub 2/ tidal component superimposed on a slow mean drift to the northeast. Differences in direction of several days duration between two of the current meters suggest the presence of transient mesoscale eddies or meanders in the flow regime.

  18. Platform cathodic protection design in the South China Sea

    SciTech Connect

    Rippon, I.

    1997-09-01

    The 1993 revision of one of the industry recommended practices on cathodic protection design offers the operator the opportunity to use his own experience and data to justify more or less conservative designs. Examples of the use of this option to achieve an economic South China Sea design are presented. The design approach on how to subdivide the object being cathodically protected can be applied in any operating area where there is good environmental data. An example of the cost savings achievable by using this approach is presented. The optimized design is 55% of the cost of the design following the 1993 code.

  19. Internal Wave Study in the South China Sea Using SAR

    NASA Technical Reports Server (NTRS)

    Liu, Antony K.; Hsu, Ming-Kuang; Zukor, Dorothy (Technical Monitor)

    2000-01-01

    Recently, the internal wave distribution maps in the China Seas have been compiled from hundreds of ERS-1/2, RADARSAT, and Space Shuttle SAR (Synthetic Aperture Radar) images from 1993 to 1999. Based on internal wave distribution map, most of internal waves in the northeast part of South China Sea were propagating westward. The wave crest can be as long as 200 km with amplitude of 100 m due to strong current from the Kuroshio branching out into the South China Sea. Based on the observations from drilling rigs near DongSha Island by Amoco Production Co., the solitons may be generated in a 4 km wide channel between Batan and Sabtang islands in Luzon Strait. The proposed generation mechanism is similar to the lee wave formation from a shallow topography. Both depression and elevation internal waves have been observed in the same RADARSAT ScanSAR image on May 4, 1998 near DongSha Island. Furthermore, depression and elevation internal waves have also been observed by SAR at the same location on the shelf in April and June, 1993 (in different seasons) respectively. Numerical models have been used to interpret their generation mechanism and evolution processes. Based on the SAR images, near DongSha Island, the westward propagating huge internal solitons are often encountered and diffracted/broken by the coral reefs on the shelf. After passing the island, the diffracted waves will re-merge or interact with each other. It has been observed that after the nonlinear wave-wave interaction, the phase of wave packet is shifted and wavelength is also changed. Examples of mesoscale features observed in SAR images, such as fronts, raincells, bathymetry, ship wakes, and oil spills will be presented. Recent mooring measurements in April 1999 near Dongsha Island, future field test ASIAEX (Asian Seas International Acoustics Experiment) planned for April 2001, and some pretest survey data will be discussed in this paper.

  20. Distribution characteristics of marine litter on the sea bed of the East China Sea and the South Sea of Korea

    NASA Astrophysics Data System (ADS)

    Lee, Dae-In; Cho, Hyeon-Seo; Jeong, Sun-Beom

    2006-10-01

    The types, quantities, and distribution of marine litter found on the sea bed of the East China Sea and the South Sea of Korea are surveyed. Surveys were evaluated using bottom trawl nets during 1996-2005 cruises. Mean distribution densities were high in coastal seas, especially in the South Sea of Korea offshore from Yeosu, with 109.8 kg km -2, and low in the East China Sea, with densities of 30.6 kg km -2. Fishing gear, such as pots, nets, octopus jars, and fishing lines, accounted for about 42-72% and 37-62% of litter items in the East China Sea and the South Sea of Korea, respectively, whereas the contributions of rubber, vinyl, metal, plastic, glass, wood, and clothing were below 30% mainly. Rope and drum composition fluctuated greatly, between 54% and 0%. Eel and net pots dominated the marine debris of the South Sea of Korea, and some vinyl, plastics, and fishing gear made in Korea, China, and Japan were collected in abundance in the East China Sea. Fishing gear was probably discarded into the sea, deliberately or inadvertently, by fishing operations. A comprehensive joint approach by Korea, China, and Japan is needed for the continuous monitoring of input sources, the actual conditions, and the behavior of marine litter for protection against litter pollution and fisheries resource management in this area.

  1. South China Sea throughflow: A heat and freshwater conveyer belt

    NASA Astrophysics Data System (ADS)

    Qu, T.; Du, Y.

    2006-12-01

    Water of the Pacific origin enters the South China Sea through Luzon Strait. From there it flows southward into the Java Sea through Karimata Strait. Part of the water returns to the Pacific through Makassar Strait, while the rest leaks into the Indian Ocean through Indonesian archipelago. Analysis of surface flux data suggests that this circulation, termed the South China Sea throughflow, acts as a heat and freshwater conveyer belt transferring up to 0.2 PW of heat and 0.1 Sv of freshwater from the South China Sea to the Maritime Continent. As both surface heat and freshwater fluxes display substantially different temporal variabilities with the South China Sea throughflow, we hypothesize that the upper South China Sea is a buffer receiving an excess of heat in certain years and releasing it in others. Results from a high-resolution general circulation model confirm this hypothesis, implying that the South China Sea is likely to play a more active role than previously thought in regulating the sea surface temperature pattern in the Maritime Continent and its adjoining western Pacific and eastern Indian Oceans.

  2. Polycyclic aromatic hydrocarbons in sediments of China Sea.

    PubMed

    Li, Yanxia; Duan, Xiaoyong

    2015-10-01

    Increasing pollution pressures were placed in the coastal and estuarine ecosystems in China because of the elevated pollutants discharged from various sources. Polycyclic aromatic hydrocarbons (PAHs) in the environment were closely linked to human activities, which have been intensively studied for their geochemical interest as markers. In this review, the status of PAH contamination in China Sea was assessed by comprehensive reviews of the concentrations, sources, and fates of PAHs in sediments of China Sea. PAH concentrations in China Sea sediments decreased from north to south due to the higher emissions in North China. Atmosphere was probably the main carrier of PAHs in the north due to the higher contents of atmospheric fine particles and higher wind speeds. However, riverine inputs were probably the most important sources of PAHs in the coastal sediments of South China due to higher rainfall. PMID:26341340

  3. On Study of Sea Fog over the Yellow and Bohai Seas in China

    NASA Astrophysics Data System (ADS)

    Fu, G.; Gao, S.; Yang, Y.; Xu, X.; Wang, X.; Chen, Y.; Xue, D.; Shen, J.

    2010-07-01

    A ubiquitous feature of the Yellow and Bohai Sea (YBS) in the eastern Asian region is the frequent occurrence of the sea fog in spring and summer season. The pioneer work on sea fog over YBS can be traced back to Prof. Binhua Wang as early as 1940's. He investigated sea fog systematically and published his book Sea Fog in 1985 (by China Ocean Press and Springer-Verlag). Recently, a research group in the Department of Marine Meteorology at Ocean University of China (OUC) continued sea fog research collaborated with Shandong Meteorological Bureau and Qingdao Meteorological Bureau under the financial supports of National Natural Science Foundation of China and China Meteorological Administration. Their researches involved in both observation analyses and high-resolution modeling of sea fog over YBS. In this talk, the brief history of sea fog research in China will be reviewed firstly. Then, a typical heavy sea fog event over YBS occurred in the morning of 11 April 2004 will be documented by using all available observational data and high-resolution Regional Atmospheric Modeling System (RAMS) modeling results. Finally, the applications of a quasi-operational sea fog forecasting system which was mainly based on RAMS model will be introduced.

  4. Impacts of wind forcing on sea level variations in the East China Sea: Local and remote effects

    NASA Astrophysics Data System (ADS)

    Li, Yanfang; Zuo, Juncheng; Lu, Qing; Zhang, Hua; Chen, Meixiang

    2016-02-01

    The regional sea level variation in the East China Sea (ECS) was influenced not only by local factors but also by remote wind from adjoining ocean with the oceanic connectivity influenced by upper-ocean circulation. The satellite altimeter observations showed that from 1993 to 2008, the inter-annual sea level variation in the ECS was negatively related to the strength of Kuroshio. To investigate the relative role of local and remote wind, two sensitive experiments were carried out using the POP model. Model experiments revealed that wind-induced redistributions of water played a significant role in the sea level variation of the ECS. The seasonal variations were induced by both local winds and remote Pacific wind stress with approximately equal contribution. However, on the inter-annual sea level variations, the remote wind forcing over the North Pacific could contribute substantially more than that of local wind which modulated sea level immediately. Remote wind influenced the China Sea in forms of changing of wind stress curl and ocean currents, which influenced the intensity of the Kuroshio, especially during El Nino episodes.

  5. A potential submarine landslide tsunami in South China Sea

    NASA Astrophysics Data System (ADS)

    Huang, Z.; Zhang, Y.; Switzer, A. D.

    2010-12-01

    Submarine earthquakes and submarine landslides are two main sources of tsunamis. Tsunami hazard modeling in the South China Sea has been primarily concerned with the potential large submarine earthquakes in the Manila trench. In contrast, evaluating the regional risk posed by tsunamis generated from submarine landslide is a new endeavor. At offshore south central Vietnam, bathymetric and seismic surveys show evidence of potentially tsunamigenic submarine landslides although their ages remain uncertain. We model two hypothetical submarine landslide events at a potential site on the heavily sediment laden, seismically active, steep continental slope offshore southeast Vietnam. Water level rises along the coast of Vietnam are presented for the potential scenarios, which indicate that the southeast coastal areas of Vietnam are at considerable risk of tsunami generated offshore submarine landslides. Key references: Kusnowidjaja Megawati, Felicia Shaw, Kerry Sieh, Zhenhua Huang, Tso-Ren Wu, Y. Lin, Soon Keat Tan and Tso-Chien Pan.(2009). Tsunami hazard from the subduction megathrust of the South China Sea, Part I, Source characterization and the resulting tsunami, Journal of Asian Earth Sciences, Vol. 36(1), pp. 13-20. Enet, F., Grilli, S.T. and Watts, P. (2003). Laboratory experiments for tsunami generated by underwater landslides: comparison with numerical modeling, In: Proceedings of 13th International Conference on Offshore and Polar Engineering, Honolulu, Hawaii, USA, pp. 372-379.

  6. The interannual oscillation of sea surface temperature in the South China Sea

    SciTech Connect

    Zhou Faxiu; Yu Shenyu; Fu Gang; Wang Dongxiao

    1994-12-31

    The South China Sea (SCS) is located in the area of the Asia monsoons and is a quasi-closed deep basin near the tropical western Pacific. The sea surface temperature anomalies (SSTA) in the South China Sea have an influence on the precipitation in flood season in the South China. The anomalies of the Asia monsoons have great effect on SST in the SCS. This paper aims at finding the features of the interannual oscillation of SST and discussing the mechanism of the SST oscillation in the SCS.

  7. Environmental audit experiences in China

    SciTech Connect

    Anwar, H.A.; Stover, J.

    1999-07-01

    As part of the massive government reforms announced at the meeting of the Ninth National People's Congress (NPC) in March 1998, the State Environmental Protection Administration (SEPA) was elevated to a new type of government entity. The new status, described as ministry-level, represents a substantial strengthening of SEPA's authority, however, significant questions remain as to whether or not this will translate into more effective environmental policies. Previously SEPA lacked authority and backing within the government to advance and support personnel and policy decisions down through its own administrative hierarchy from central to regional to local levels. This paper will use these issues to present a proper background when examining Environmental Audit (EA) case studies in China, and examining what future EA experiences may be like. It will include discussions of regional differences in enforcement standards and methods, the implications of the new Land Management Law, and elaboration on environmental liability issues and potential Superfund-type legislation in China.

  8. Distinguishing Terrestrial Organic Carbon in Marginal Sediments of East China Sea and Northern South China Sea

    NASA Astrophysics Data System (ADS)

    Kandasamy, Selvaraj; Lin, Baozhi; Wang, Huawei; Liu, Qianqian; Liu, Zhifei; Lou, Jiann-Yuh; Chen, Chen-Tung Arthur; Mayer, Lawrence M.

    2016-04-01

    Knowledge about the sources, transport pathways and behavior of terrestrial organic carbon in continental margins adjoining to large rivers has improved in recent decades, but uncertainties and complications still exist with human-influenced coastal regions in densely populated wet tropics and subtropics. In these regions, the monsoon and other episodic weather events exert strong climatic control on mineral and particulate organic matter delivery to the marginal seas. Here we investigate elemental (TOC, TN and bromine-Br) and stable carbon isotopic (δ13C) compositions of organic matter (OM) in surface sediments and short cores collected from active (SW Taiwan) and passive margin (East China Sea) settings to understand the sources of OM that buried in these settings. We used sedimentary bromine to total organic carbon (Br/TOC) ratios to apportion terrigenous from marine organic matter, and find that Br/TOC may serve as an additional, reliable proxy for sedimentary provenance in both settings. Variations in Br/TOC are consistent with other provenance indicators in responding to short-lived terrigenous inputs. Because diagenetic alteration of Br is insignificant on shorter time scales, applying Br/TOC ratios as a proxy to identify organic matter source along with carbon isotope mixing models may provide additional constraints on the quantity and transformation of terrigenous organics in continental margins. We apply this combination of approaches to land-derived organic matter in different depositional environments of East Asian marginal seas.

  9. Territorial disputes simmer in areas of South China Sea

    SciTech Connect

    Not Available

    1992-07-13

    This paper reports that China's award of an exploration cooperation contact in the Nansha area of the South China Sea has revived territorial disputes in the area centering ton the Spratly and Paracel islands. The key dispute is between China and Viet Nam, which earlier engaged in military action over ownership of the islands, believed to have world class potential for hydrocarbon discoveries. Those two nations, as well as Brunei, Malaysia, Philippines, and Taiwan, lay claim to overlapping boundaries of the Spratly Islands. Separately, China and Viet Nam dispute territorial claims in the Paracels. Tensions continue to mount, and regional governments are trying to negotiate compromises to avoid a repeat of warfare.

  10. Status of Marine Biodiversity of the China Seas

    PubMed Central

    2013-01-01

    China's seas cover nearly 5 million square kilometers extending from the tropical to the temperate climate zones and bordering on 32,000 km of coastline, including islands. Comprehensive systematic study of the marine biodiversity within this region began in the early 1950s with the establishment of the Qingdao Marine Biological Laboratory of the Chinese Academy of Sciences. Since that time scientists have carried out intensive multidisciplinary research on marine life in the China seas and have recorded 22,629 species belonging to 46 phyla. The marine flora and fauna of the China seas are characterized by high biodiversity, including tropical and subtropical elements of the Indo-West Pacific warm-water fauna in the South and East China seas, and temperate elements of North Pacific temperate fauna mainly in the Yellow Sea. The southern South China Sea fauna is characterized by typical tropical elements paralleled with the Philippine-New Guinea-Indonesia Coral triangle typical tropical faunal center. This paper summarizes advances in studies of marine biodiversity in China's seas and discusses current research mainly on characteristics and changes in marine biodiversity, including the monitoring, assessment, and conservation of endangered species and particularly the strengthening of effective management. Studies of (1) a tidal flat in a semi-enclosed embayment, (2) the impact of global climate change on a cold-water ecosystem, (3) coral reefs of Hainan Island and Xisha-Nansha atolls, (4) mangrove forests of the South China Sea, (5) a threatened seagrass field, and (6) an example of stock enhancement practices of the Chinese shrimp fishery are briefly introduced. Besides the overexploitation of living resources (more than 12.4 million tons yielded in 2007), the major threat to the biodiversity of the China seas is environmental deterioration (pollution, coastal construction), particularly in the brackish waters of estuarine environments, which are characterized by

  11. Status of marine biodiversity of the China seas.

    PubMed

    Liu, J Y

    2013-01-01

    China's seas cover nearly 5 million square kilometers extending from the tropical to the temperate climate zones and bordering on 32,000 km of coastline, including islands. Comprehensive systematic study of the marine biodiversity within this region began in the early 1950s with the establishment of the Qingdao Marine Biological Laboratory of the Chinese Academy of Sciences. Since that time scientists have carried out intensive multidisciplinary research on marine life in the China seas and have recorded 22,629 species belonging to 46 phyla. The marine flora and fauna of the China seas are characterized by high biodiversity, including tropical and subtropical elements of the Indo-West Pacific warm-water fauna in the South and East China seas, and temperate elements of North Pacific temperate fauna mainly in the Yellow Sea. The southern South China Sea fauna is characterized by typical tropical elements paralleled with the Philippine-New Guinea-Indonesia Coral triangle typical tropical faunal center. This paper summarizes advances in studies of marine biodiversity in China's seas and discusses current research mainly on characteristics and changes in marine biodiversity, including the monitoring, assessment, and conservation of endangered species and particularly the strengthening of effective management. Studies of (1) a tidal flat in a semi-enclosed embayment, (2) the impact of global climate change on a cold-water ecosystem, (3) coral reefs of Hainan Island and Xisha-Nansha atolls, (4) mangrove forests of the South China Sea, (5) a threatened seagrass field, and (6) an example of stock enhancement practices of the Chinese shrimp fishery are briefly introduced. Besides the overexploitation of living resources (more than 12.4 million tons yielded in 2007), the major threat to the biodiversity of the China seas is environmental deterioration (pollution, coastal construction), particularly in the brackish waters of estuarine environments, which are characterized by

  12. Geology and petroleum prospects in East China Sea

    SciTech Connect

    Liu, G.

    1986-07-01

    Geologic studies of the petroleum potential of the East China Sea have progressed through three stages. (1) The tectonic divisions and evolution of the East China Sea were investigated using geophysical data, including gravimetric, magnetic, and seismic information. (2) Seismic data over the Shelf basin were interpreted and mapped, to understand the Cenozoic structural history of the East China Sea. (3) More detailed seismic shooting has allowed for detailed prospect mapping and seismo-stratigraphic studies. This stage has resulted in the mapping of numerous drillable prospects, several among them having been proved to contain commercial quantities of oil and gas. Presently, results from the Lingfeng 1 well point to new and different directions for exploration in the basin.

  13. South China Sea: New geodynamic constraints

    NASA Astrophysics Data System (ADS)

    Sibuet, Jean-Claude; Yeh, Yi-Ching; Hsu, Shu-Kun; Lee, Chao-Shing; Lin, Jing-Yi; Wu, Jonny

    2015-04-01

    Magnetic modeling shows that the youngest magnetic anomaly in the South China Sea (SCS) is either younger than C5c (15.5 Ma, Briais et al., JGR, 1995) or C6A1 (20.5 Ma, Barckhausen et al., MPG, 2014). Close to the rift axis of the East basin, Ar-Ar age dating of oceanic crustal rocks collected during IODP Leg 349 gives ages of 15 and 15.2 +/- 0.2 Ma (Koppers, Fall AGU meeting, 2014), which seems to favor the 15.5 Ma age given by Briais et al. modeling. However, basaltic samples were recovered in a sill and further below in another sill or inside the true oceanic crust. As post-spreading magmatic activity (~8-13 Ma) largely masks the spreading fabric, in particular near the previously identified E-W portion of the extinct ridge axis of the East Basin, the location of the central magnetic anomaly and spreading rates are incorrect. The compilation of the extremely dense set of magnetic data and published swath bathymetric data shows that if post-spreading volcanics hide the seafloor spreading magnetic fabric mostly along and near the extinct spreading axis, the whole SCS is characterized by rift directions following three directions: N055°in the youngest portion of the SCS, N065° and N085° in the oldest portions of the SCS. We conclude that the extinct ridge axis is N055° trending instead of E-W. We are also able to propose a preliminary kinematic sketch of the evolution of the SCS in 6 steps, which will be used to carefully establish the SCS magnetic pattern and forward magnetic modeling of the SCS. From this preliminary kinematic sketch, we have established a new fracture zone pattern, which highlights conjugate segments of SCS continental margins. We have also used the unfolded and restored Manila slab to highlight a roughly N-S dVp discontinuity located inside the slab, suggesting the existence of a roughly N-S limit, which defines a new segment of conjugate margins. In addition, the extinct spreading center, which ends close to the Manila trench, jumps to the

  14. Nonlinear Internal Waves in the South China Sea During ASIAEX

    NASA Technical Reports Server (NTRS)

    Liu, Antony K.; Tang, David T.; Ramp, Steve R.

    2002-01-01

    Internal wave distribution maps have been compiled from more than one hundred ERS-1/2, RADARSAT and Space Shuttle SAR images in the South China Sea (SCS) from 1993 to 2000. Based on these distribution maps, most of internal waves in the northeast part of SCS were propagating westward. The wave crest can be as long as 200 km with amplitude of 100 m, due to strong current from the Kuroshio branching out into the SCS. In recent Asian Seas International Acoustics Experiment (ASIAEX), moorings have been deployed in April 2000 and May 2001. Simultaneous RADARSAT ScanSAR images have been collected during the field test to integrate with the model and the in-situ measurements in the SCS. During ASIAEX in May 2001, many large internal waves were observed at the test area and were the major features for acoustic volume interaction. The environmental parameters have been calculated based on extensive CTD castings and mooring data. Nonlinear internal wave models have been applied to simulate the wave evolution on the continental shelf and the results compare reasonably with mooring measurements. The evolution and dissipation of huge internal waves on the shelf break, mode-two waves, elevation waves, and wave-wave interaction are very important issues for acoustic propagation. The implication of internal wave effects on acoustic propagation will also be discussed.

  15. The South China Sea Deep: A Research Project on Life History of Marginal Sea

    NASA Astrophysics Data System (ADS)

    Wang, P.

    2011-12-01

    A major research project has been launched in China to investigate evolution and various processes in the deep-water part a of the South China Sea. The "South China Sea Deep" project (2011-2018) is supported by the NSF of China with a total budget no less than ~23 US Dollar (150 Million Chinese yuan), and covers a broad spectrum of scientific topics. Advanced geophysical and geochemical tools will be applied to re-estimate the age of its oceanic crust, to verify the existence of the "Hainan Mantle Plume", and to explore the origin of volcanic chains in the deep basin. Sedimentary archives, both off-shore and on-shore, will be analyzed to reconstruct the history of sediment response to the basin evolution, with focus on changes of deep-water circulation driven by tectonic deformation of the basin. Deep-water observations will be organized to examine near-bottom sediment transport, methane seepages, and microbial distribution and ecology above and below sea-floor. With a combination of tectonic-magmatic, sedimentologic-paleoceanographic, and microbiological-geochemical approaches, the project is expected to reveal the life history of the South China Sea, the largest low-latitude marginal sea in the modern world. Recent progress of the project will be presented, and perspectives of international cooperation will be discussed.

  16. A Sea-Surface Radiation Data Set for Climate Applications in the Tropical Western Pacific and South China Sea

    NASA Technical Reports Server (NTRS)

    Chou, Ming-Dah; Chan, Pui-King; Yan, Michael M.-H.

    2000-01-01

    The sea-surface shortwave and longwave radiative fluxes have been retrieved from the radiances measured by Japan's Geostationary Meteorological Satellite 5. The surface radiation data set covers the domain 40S-40N and 90E-170W. The temporal resolution is 1 day, and the spatial resolution is 0.5 deg x 0.5 deg latitude-longitude. The retrieved surface radiation have been validated with the radiometric measurements at the Atmospheric Radiation Measuring (ARM) site on Manus island in the equatorial western Pacific for a period of 15 months. It has also been validated with the measurements at the radiation site on Dungsha island in the South China Sea during the South China Sea Monsoon Experiment (SCSMEX) Intensive Observing Period (May and June 1998). The data set is used to study the effect of El Nino and East Asian Summer monsoon on the heating of the ocean in the tropical western Pacific and the South China Sea. Interannual variations of clouds associated with El Nino and the East Asian Summer monsoon have a large impact on the radiative heating of the ocean. It has been found that the magnitude of the interannual variation of the seasonal mean surface radiative heating exceeds 40 W/sq m over large areas. Together with the Clouds and the Earth's Radiant Energy System (CERES) shortwave fluxes at top of the atmosphere and the radiative transfer calculations of clear-sky fluxes, this surface radiation data set is also used to study the impact of clouds on the solar heating of the atmosphere. It is found that clouds enhance the atmospheric solar heating by approx. 20 W/sq m in the tropical western Pacific and the South China Sea. This result is important for evaluating the accuracy of solar flux calculations in clear and cloudy atmospheres.

  17. Coastal Seafloor Observatory Of The East China Sea At Xiaoqushan And Its Primary Observations

    NASA Astrophysics Data System (ADS)

    Xu, H.; Xu, C.; Qin, R.; Zhang, Y.; Chen, H.

    2010-12-01

    East China Sea seafloor observational network. It not only accumulates experiences in technology and engineering, but also paves the way for performing important sciences using the long term continuous observation platform.

  18. Inter-annual sea level variability in the southern South China Sea

    NASA Astrophysics Data System (ADS)

    Soumya, M.; Vethamony, P.; Tkalich, P.

    2015-10-01

    The South China Sea (SCS) is the largest marginal sea in the western Pacific Basin. Sea level anomalies (SLAs) in the southern South China Sea (SSCS) are assumed to be governed by various phenomena associated with the adjacent parts of the Indian Ocean and the Pacific Ocean. We have used monthly sea level anomalies obtained from 12 tide gauge stations of PSMSL and UHSLC and merged and gridded AVISO products of SLAs (sea level anomalies) derived from satellite altimeter. We find that IOD-influenced inter-annual variations are found only in the southwestern and southeastern coastal regions of SSCS. Our analysis reveals that inter-annual regional sea level drops are associated with positive phase of the IOD, and the rises with negative phase of the IOD. SLA variations at decadal scale in the southeastern and northern Gulf of Thailand correlate with Pacific Decadal Oscillations (PDO). Multiple linear regression analysis of inter-annual SLAs and climate indices shows that IOD induced inter-annual variations dominate in the southwestern SCS and it contributes to about ~ 40% of inter-annual sea level variation. Meanwhile, ENSO contributes to around ~ 30% variation in sea level in the southwestern and ~ 40% variation in the southeastern SSCS. The present study also suggests that inter-annual SLA variations in the SSCS can occur by ENSO and IOD induced changes in wind stress curl and volume transport variations.

  19. The complexity of South China Sea kinematics

    NASA Astrophysics Data System (ADS)

    Sibuet, Jean-Claude; Gao, Jinyao; Zhao, Minghui; Wu, Jonny; Ding, Weiwei; Yeh, Yi-Ching; Lee, Chao-Shing

    2016-04-01

    Magnetic modeling shows that the age of the youngest South China Sea (SCS) oceanic crust is controversial (e.g. 15.5 Ma, Briais et al., JGR 1993 and 20.5 Ma, Barckhausen et al., MPG 2014). Close to the rift axis of the East sub-basin, Ar-Ar age dating of oceanic crustal rocks collected during IODP Leg 349 gives ages of 15 and 15.2 +/- 0.2 Ma (Koppers, Fall AGU meeting, 2014), which seems to favor the 15.5 Ma age given by Briais et al. modeling. However, basaltic samples might belong to a sill and not to the typical oceanic crust. As post-spreading magmatic activity (~8-13 Ma) largely masks the spreading fabric, in particular near the previously identified E-W portion of the extinct ridge axis of the East sub-basin, the published locations of the axial magnetic anomaly and spreading rates are incorrect. The compilation of available swath bathymetric data shows that if post-spreading volcanics hide the seafloor spreading magnetic fabric mostly along and near the extinct spreading axis, the whole SCS is globally characterized by rift directions following three directions: N055°in the youngest portion of the SCS, N065° and N085° in the oldest portions of the SCS (Sibuet et al., Tectonophysics 2016) suggesting the extinct ridge axis is N055° trending instead of E-W. We present an updated version of the whole SCS structural sketch based on previously published swath bathymetric trends and new detailed magnetic lineations trends compiled from an extremely dense set of magnetic data. The new structural sketch shows: - The distribution of conjugate kinematic domains, - The early opening of the NW and East sub-basins, before a jump of the rift axis, - A second ridge jump in the East basin, - The different expressions of the post-spreading magmatism in the East and SW sub-basins. In the East sub-basin, crustal magmatic intrusions led to the formation of extrusive basalts associated with the presence of numerous volcanoes (Wang et al., Geological Journal 2016). In the SW

  20. Dissolved Trace metal distributions and speciation in Yellow Sea, China

    NASA Astrophysics Data System (ADS)

    Li, Li; Wang, Xiaojing; Zhang, Cuiqin; Liu, Jihua; Shi, Xuefa

    2016-04-01

    Trace metals play an important role in marine biogeochemical cycling processes. However, owing to the lack of trace-metal clean sampling and analytical techniques, high quality data for dissolved trace metals in coastal seawaters of China are scarce. In this study, by employing stringent trace-metal clean sampling and analytical techniques, we investigated spatial distribution patterns of several dissolved trace metals (Cu, Ni, Co, Pb, Cd, Zn, and Ag) in Yellow Sea and Bohai Sea of China, and discussed their potential sources and sinks. In general, the dissolved metal concentrations decreased from Bohai Sea to Yellow Sea, and from nearshore to offshore. Despite the severe contamination status reported in coastal seawaters of China, the trace metal concentrations found in seawater are comparable to the concentrations found in pristine coastal seawaters of the US and the EU. In the meantime, the speciation of several metals (Cu, Pb, Zn, Cd) were also studied with the electrochemical (ASV and CLE-CSV) methods in the Yellow Sea. Natural organic ligands were found in seawaters that strongly complexed with dissolved metals. The concentrations and binding constants of the complexing ligands for each metal were reported and compared with the ones found in other coastal seawaters.

  1. Archaeal diversity in surface sediments of the South China Sea

    NASA Astrophysics Data System (ADS)

    Wang, P.; Wei, Y.; Zhang, C.

    2010-12-01

    The South China Sea is one of the largest marginal seas on Earth and known to be one of the global hot spots of biodiversity. Yet, little is known about the abundance, diversity, and distribution of archaea in it. In this study the diversity and distribution of archaea in the surface sediments of the South China Sea were investigated. The samples were collected from seven sites from south to north of the sea with water depths ranging from 1455 m to 3697 m. Phylogenetic analysis revealed that the relative abundances of Euryarchaeota and Crenarchaeota species (OTUs at 2% cutoff) varied from site to site (Eury: 19.4%-67.6%, Cren: 32.4%-80.6%); however, they were about equal in species distribution (46.9% and 53.1%, respectively) for the total seven archaeal clone libraries. The Crenarchaeota predominates in MD05-2902 and MD05-2904 (80.6% and 70.4%); the Euryarchaeota predominates in MD05-2894 (67.6%). The archaeal groups MGI, MBGB, MCG and SAGMEG were dominant in most of the surface samples. MBGE was only dominant in MD05-2894 (64.7%). Overall, these results indicate that the community structures of archaea vary considerably in the surface sediments of the South China Sea.

  2. The Continent-Ocean Boundary of the South China Sea

    NASA Astrophysics Data System (ADS)

    Wan, Ling; Yao, Bochu; Zhang, Huodai; Han, Bin

    2014-05-01

    The Continent-Ocean Boundary of the South China Sea Ling Wan Bochu Yao Huodai Zhang Bin Han (Guangzhou Marine Geological Survey, Guangzhou, China, 510760) The determination of the Continent-Ocean Boundary (COB) of the South China Sea (SCS) is a key issue related to fully understanding the rifted continental margins and evolutionof the SCS. But the COB of the SCS is highly variable in different ways by different researcher. In this paper, we investigate the boundary between the continental and oceanic crust of this basin mainly relied on the multiple-channel seismic profiles constrained by free air gravity anomaly and magnetic anomaly. Based on the synthesied gephysical interpretation the COB of the SCS is relocated. Furthermore, the COB patterns of the SCS are presented.

  3. [Chemical characteristics of precipitation in South China Sea].

    PubMed

    Xiao, Hong-Wei; Long, Ai-Min; Xie, Lu-Hua; Xiao, Hua-Yun; Liu, Cong-Qiang

    2014-02-01

    Rainwater samples were collected in the summer on "Shiyan 3" during the 2012 South China Sea Sectional Scientific Survey. The concentrations of anion and cation, and pH in precipitation were determined and backward trajectories of air mass were simulated to analyze the chemical characteristics of ions and examine the source of ions. The results indicated that the mean pH value of precipitation was 6.3, with 5.6 of minimal value in summer in South China Sea. The order of anion and cation abundance was Cl(-) > S04(2-) > NO3(-) and Na(+) > Mg(2+) > Ca(2+) > K(+). Cl(-) was the major anion and Na(+) was the major cation, with concentrations of 2 637.5 microeq x L(-1) and 2095.5 microeq x L(-1), respectively, showing that they were the characteristics of marine atmospheric precipitation. There was a good linear relationship between each pair of 7 ions, with correlation coefficient above 0.9, suggesting that they may have a common source. However, the correlation coefficients were lower between NO3(-) and other ions than the others, suggesting that NO3(-) had more complex sources. The concentrations of Ca(2+) and K(+) in precipitation may be related to coral environment in South China Sea. The backward trajectories in 6 stations showed that the air mass was from south and southwest of South China Sea, without passing through above the continent. These results suggested that precipitation affected by human ion source can be ignored in summer in South China Sea. PMID:24812936

  4. Early Continental Rifting of the South China Sea

    NASA Astrophysics Data System (ADS)

    Lee, C.; Chiu, M.; Chan, C.

    2010-12-01

    Combined two years (2007 and 2008) of OBS and MCS studies in the northern slope of the South China Sea, we suggest that the early rifting, probably during 60 - 30 mabp, is an asymmetrical Atlantic-type continental rifting. The crust thin out from 35-40 km of possible continental crust to about 10-15 km of typical oceanic crust. Along the continent-ocean boundary, we observe an intrusion of the high P-wave velocity (about 7.5-8.0 km/sec). This is possible of mantle exhumation as comparable to other Atlantic-type continental margins. The OBS result is revealed by the gravity data. Along the upper layers of the continental crust as well as the oceanic crust, the MCS and multi-beam bathymetry data show that they are covered by numerous submarine seamounts. This probably relate to a volcanic origin of the Cenozoic sea-floor spreading during 30-15 mabp as mapped by previous magnetic anomalies in this region. The sea-floor spreading spread apart in the central, NW and SW sub-basins with several different episodes. Lack of the deep crustal data in the southern slope of the South China Sea, particularly around the Sprately area, the interpretation is speculative. However, several very large-size atolls (150 - 200 km in diameter), such as the Chen-Ho, Shun-Zu, Chung-Yeh and Chiu-Cheng fringing reefs, are sub-parallel located along the south margins. We interpret that these are the upper portions of the continental rifting. Combined the two tectonic stories in the northern and southern slope of the South China Sea, we believe that it is in consistent with the complicate nature of the South China Sea crust.

  5. Modal recovery of sea-level variability in the South China Sea using merged altimeter data

    NASA Astrophysics Data System (ADS)

    Jiang, Haoyu; Chen, Ge

    2015-09-01

    Using 20 years (1993-2012) of merged data recorded by contemporary multi-altimeter missions, a variety of sea-level variability modes are recovered in the South China Sea employing three-dimensional harmonic extraction. In terms of the long-term variation, the South China Sea is estimated to have a rising sea-level linear trend of 5.39 mm/a over these 20 years. Among the modes extracted, the seven most statistically significant periodic or quasi-periodic modes are identified as principal modes. The geographical distributions of the magnitudes and phases of the modes are displayed. In terms of intraannual and annual regimes, two principal modes with strict semiannual and annual periods are found, with the annual variability having the largest amplitudes among the seven modes. For interannual and decadal regimes, five principal modes at approximately 18, 21, 23, 28, and 112 months are found with the most mode-active region being to the east of Vietnam. For the phase distributions, a series of amphidromes are observed as twins, termed "amphidrome twins", comprising rotating dipole systems. The stability of periodic modes is investigated employing joint spatiotemporal analysis of latitude/longitude sections. Results show that all periodic modes are robust, revealing the richness and complexity of sea-level modes in the South China Sea.

  6. Interdecadal changes in summer TC activity in East China Sea

    NASA Astrophysics Data System (ADS)

    Choi, Ki-Seon; Cha, Yu-Mi; Kang, Sung-Dae; Kim, Hae-Dong

    2015-04-01

    The study analyzed the time series of the tropical cyclone (TC) frequencies which passed through the East China Sea between July and September from 1963 to 2012. The result of applying the statistical change-point analysis to this time series shows that a climate regime shift occurred in 1983 when the TC frequencies which pass the East China Sea area started increasing. The study then analyzed the average difference after 1983 (1984-2012) and before 1983 (1963-1983). The TC genesis frequency shows a tendency in mainly appearing in the tropical and subtropical Northwestern Pacific between 1963 and 1983 and the southern part between 1984 and 2012. The TC passage frequency shows a pattern that the TCs move from the far northeast sea of Philippines and change direction to Korea and Japan, passing through the East China Sea between 1984 and 2012. Meanwhile, the TC passage frequency shows a pattern which moves from the far southeast sea of the Philippines to southern China in the west direction in the previous period (1963-1983). These TC movement patterns coincide with the development status of the subtropical western North Pacific high (SWNPH) which averages for each period. It shows that the SWNPH in the second period stays away from the SWNPH in the second period from the northeast direction, but that the SWNPH in the first period expands to western Taiwan. This study analyzes the difference between the two periods in the 500-hPa streamline to understand the changes in such TC activities in the two groups. The anomalous anticyclonic circulations centered in the southern part of Japan are fortified in most of the subtropical Northwestern Pacific. The anomalous southerlies from the anomalous circulations are outstanding in the East China Sea area, Korea, and Japan. Therefore, the TCs generated in the tropical and subtropical Northwestern Pacific move along with the anomalous steering flow (anomalous southwesterlies) and up toward the East China Sea area, Korea, and

  7. Mercury Export from Mainland China to Adjacent Seas and Its Influence on the Marine Mercury Balance.

    PubMed

    Liu, Maodian; Chen, Long; Wang, Xuejun; Zhang, Wei; Tong, Yindong; Ou, Langbo; Xie, Han; Shen, Huizhong; Ye, Xuejie; Deng, Chunyan; Wang, Huanhuan

    2016-06-21

    Exports from mainland China are a significant source of mercury (Hg) in the adjacent seas (Bohai Sea, Yellow Sea, East China Sea, and South China Sea) near China. A total of 240 ± 23 Mg was contributed in 2012 (30% from natural sources and 70% from anthropogenic sources), including Hg from rivers, industrial wastewater, domestic sewage, groundwater, nonpoint sources, and coastal erosion. Among the various sources, the Hg from rivers amounts to 160 ± 21 Mg and plays a dominant role. The Hg that is exported from mainland China increased from 1984 to 2013; the contributions from rivers, industrial wastewater, domestic sewage and groundwater increased, and the contributions from nonpoint sources and coastal erosion remained stable. A box model is constructed to simulate the mass balance of Hg in these seas and quantify the sources, sinks and Hg biogeochemical cycle in the seas. In total, 160 Mg of Hg was transported to the Pacific Ocean and other oceans from these seas through oceanic currents in 2012, which could have negative impacts on the marine ecosystem. A prediction of the changes in Hg exportation through 2030 shows that the impacts of terrestrial export might worsen without effective pollution reduction measures and that the Hg load in these seas will increase, especially in the seawater of the Bohai Sea, Yellow Sea, and East China Sea and in the sea margin sediments of the Bohai Sea and East China Sea. PMID:27243109

  8. South China Sea throughflow impact on the Indonesian throughflow

    NASA Astrophysics Data System (ADS)

    Gordon, Arnold L.; Huber, Bruce A.; Metzger, E. Joseph; Susanto, R. Dwi; Hurlburt, Harley E.; Adi, T. Rameyo

    2012-06-01

    In 2008-2009 the Makassar throughflow profile changed dramatically: the characteristic thermocline velocity maximum increased from 0.7 to 0.9 m/sec and shifted from 140 m to 70 m, amounting to a 47% increase in the transport of warmer water between 50 and 150 m during the boreal summer. HYCOM output indicates that ENSO induced change of the South China Sea (SCS) throughflow into the Indonesian seas is the likely cause. Increased SCS throughflow during El Niño with a commensurate increase in the southward flow of buoyant surface water through the Sulu Sea into the northern Makassar Strait, inhibits tropical Pacific surface water injection into Makassar Strait; during La Niña SCS throughflow is near zero allowing tropical Pacific inflow. The resulting warmer ITF reaches into the Indian Ocean, potentially affecting regional sea surface temperature and climate.

  9. Directional drill keys completion of South China Sea pipeline

    SciTech Connect

    Callnon, D.; Weeks, K.

    1996-04-08

    Directional drilling laid dual 12-in. natural gas pipelines beneath a critical sea wall on Lantau Island, Hong Kong New Territories, to complete a 30-mile gas-pipeline crossing of the South China Sea. The project was part of Towngas Lantau construction for Hong Kong`s new Chek Lap Kok International Airport on the island. To avoid disturbing a newly installed sea wall at Ta Pang Po beach, NKK subcontracted parallel beach approaches to Cherrington Corp., Sacramento. Between July 11 and Aug. 2, 1995, Cherrington Corp. drilled and forward-reamed two, 20 in., 1,294-ft holes to pull back the twin pipelines. The project was completed during typhoon weather, high seas, strong currents, and logistical problems associated with operating in a remote uninhabited area. This paper reviews the design of the beach approach entries; staging and site preparations; drilling equipment used; and overall project operations.

  10. Distribution of drifting seaweeds in eastern East China Sea

    NASA Astrophysics Data System (ADS)

    Komatsu, Teruhisa; Tatsukawa, Kenichi; Filippi, Jean B.; Sagawa, Tatsuyuki; Matsunaga, Daisuke; Mikami, Atsuko; Ishida, Kenichi; Ajisaka, Tetsuro; Tanaka, Katsuhiko; Aoki, Masakazu; Wang, Wei-Ding; Liu, Hui-Fei; Zhang, Shou-Du; Zhou, Min-Dong; Sugimoto, Takashige

    2007-09-01

    In offshore waters with relatively low primary production, drifting seaweeds composed of Sargassum species form an identical ecosystem such as an oasis in desert. Commercially important pelagic fishes such as jack mackerel ( Trachurus japonicus) and yellow tail ( Seriola quinqueradiata) spawn in East China Sea pass their juvenile period accompanying drifting seaweeds. Therefore drifting seaweeds are very important not only in offshore ecosystem but also fishery resources. However the distribution of drifting seaweeds in East China Sea has scarcely known. Then we conducted two research cruises of R/V Hakuho-Maru in May 2002 and in March 2004. During the cruises, drifting seaweeds were visually observed from the bridge and sampled with a towing net. The observation revealed that the drifting seaweeds were distributed along the front between the Kuroshio Current and coastal waters and mainly composed of one seaweed species, Sargassum horneri (Turner) C. Agardh from spring to early summer. There are no reports on geographical distribution of this species in the coasts south of southern Kyushu Island in Japan. Kuroshio Current flows northeastward there. Buoys with GPS attached to drifting seaweeds released off Zhejiang Province, China, in March 2005 to track their transport. Their positions monitored by ORBCOM satellite showed that they were transported to the area in East China Sea, where the drifting seaweeds were observed during the cruises, in 2 months. These facts suggest that S. horneri detached from Chinese coast in March or months earlier than March could be transported to fringe area of continental shelf and waters influenced by Kuroshio Current from March to May. Therefore the Sargassum forests, especially S. horneri, along the Chinese coast play a very important role in the ecosystem of the East China Sea as a source of drifting seaweeds.

  11. Coastal upwelling in the East China Sea in winter

    NASA Astrophysics Data System (ADS)

    Qiao, Fangli; Yang, Yongzeng; Lü, Xingang; Xia, Changshui; Chen, Xianyao; Wang, Baodong; Yuan, Yeli

    2006-11-01

    The dynamic mechanisms of the upwelling off the East China Sea (ECS) coast in wintertime are studied. First, the upwelling signals off the ECS coast are identified by the observed temperature, salinity, nutrients, and dissolved oxygen data obtained during the cruises in January 1999. The MASNUM wave-tide-circulation coupled model is then employed to simulate the hydrography of the ECS. Comparisons between the simulations and observations show that the model performance is satisfactory. On the basis of successful simulation, four numerical experiments are conducted to investigate the upwelling mechanisms. The results suggest that the density (or salinity) front, which separates the inshore Low Salinity Coastal Water and the offshore Taiwan Warm Current (TWC), is the primary inducement for the upwelling. Owing to strong density gradient, the baroclinic pressure gradient force (PGF) is quite large near the frontal zone, and this PGF elicits an upwelling branch along the topography slope. Wind, TWC, and tide affect the density front in extension and intensity, thus exerting subsidiary influences on the upwelling. According to Ekman's theory, the northerly monsoon is downwelling favorable. However, the net effects of wind on the upwelling off the ECS coast in winter are positive because it drives the Changjiang River Diluted Water (CDW) flowing southward and forms the density front. Similarly, the resultant effects of TWC on the upwelling are negative for obstructing the pathway of CDW. Tide contributes to the upwelling because tidal mixing facilitates the expansion of CDW.

  12. Ice-forming nuclei over the East China Sea

    NASA Astrophysics Data System (ADS)

    Rosinski, J.; Nagamoto, C. T.; Zhou, M. Y.

    Ice-forming nucleus (IFN) population was determined for aerosol particles collected on filters over the East China Sea. The mode of ice nucleation studied was condensation-followed-by-freezing; experiments were performed in a dynamic chamber at a constant temperature and with continuous cooling at Sw=0.3%. Ratios of IFN concentrations determined at a constant temperature to those determined during continuous cooling simulating an updraft were close to one (35%) and larger than one (65%). Ratios close to one indicate the absence of any deactivation of IFN during the growth of droplets; for ratios larger than one the dilution takes place during the entire cooling process, thus producing more dilute solutions of water-soluble salts in droplets and apparently deactivating some ice nucleating sites. IFN concentration maxima were found at 0600 and 1800 local time. Concentrations of IFN were found to be inversely proportional to the amount of air pollutants, but at a very high SO 42- ion concentration IFN concentrations increased.

  13. The distribution and diversity of sea cucumbers in the coral reefs of the South China Sea, Sulu Sea and Sulawesi Sea

    NASA Astrophysics Data System (ADS)

    Woo, Sau Pinn; Yasin, Zulfigar; Ismail, Siti Hasmah; Tan, Shau Hwai

    2013-11-01

    A study on the distribution and diversity of sea cucumbers in the coral reefs of the South China Sea, Sulu Sea and Sulawesi Sea was carried out in July 2009. The survey was done using wandering transect underwater with SCUBA. Twelve species of sea cucumber were found from four different families and nine genera. The most dominant family was Holothuriidae (five species), followed by Stichopodidae (three species), Synaptidae (three species) and Cucumariidae with only one species. The most dominant species found around the island was Pearsonothuria graffei, which can be found abundantly on substrate of dead corals in a wide range of depth (6-15 m). The Sulawesi Sea showed a higher diversity of sea cucumber with seven different species compared to the South China Sea with only six different species and Sulu Sea with only two species. Ordination by multidimensional scaling of Bray-Curtis similarities clustered the sampling locations to three main clusters with two outgroups. Previous studies done indicated a higher diversity of sea cucumber as compared to this study. This can be indication that the population and diversity of sea cucumbers in the reef is under threat.

  14. Seasonal distribution of suspended sediment in the Bohai Sea, China

    NASA Astrophysics Data System (ADS)

    Wang, Houjie; Wang, Aimei; Bi, Naishuang; Zeng, Xiangming; Xiao, Hehui

    2014-11-01

    Distribution of suspended sediment in the Bohai Sea and its seasonal variability were investigated based on the datasets obtained from four cruises carried out in different seasons in 2010 and 2012. The results indicate that the spatial distribution of suspended sediment in the Bohai Sea was dominated by the river input and coastal resuspension that depends on the type of local surface sediment and hydrodynamics. The suspended sediment was mostly concentrated in the southern Bohai Sea particularly around the Yellow River Delta in the summer season as impacted by the river plume but confined within a very limited area near the river mouth, whereas in winter-spring seasons sediment concentration became much higher as a result of active coastal resuspension induced by energetic wave actions in the shallow water. High sediment concentration was found in Liaodong Bay in winter-spring seasons when dynamics become strong but decrease significantly in summer seasons. The sediment concentration in the southern Bohai Strait was much higher than that in the northern part, suggesting evident sediment export to the Yellow Sea particularly in the winter-spring seasons. Strong seasonal variability of suspended sediment distribution in the Bohai Sea was consistent with the monsoon activity and associated wave actions and coastal currents that are varying seasonally. The dominance of seasonal monsoon signal and associated wave dynamics make the subaqueous Yellow River delta to be a major sink for the terrestrial sediment in the summer seasons, but transiting to a primary source in winter-spring seasons for sediment redistribution in the Bohai Sea and sediment export to the Yellow Sea. The seasonal patterns of suspended sediment distribution in the Bohai Sea and the dominance of monsoon activities may provide a good reference to understanding the sediment transport in the China Shelf Seas where sediment resuspension and coastal circulation are evidently driven by monsoon.

  15. Interannual-to-decadal variability and trends of sea level in the South China Sea

    NASA Astrophysics Data System (ADS)

    Cheng, Xuhua; Xie, Shang-Ping; Du, Yan; Wang, Jing; Chen, Xiao; Wang, Juan

    2016-05-01

    Interannual-to-decadal variability and trends of sea level in the South China Sea (SCS) are studied using altimetric data during 1993-2012 and reconstructed sea level data from 1950-2009. The interannual variability shows a strong seasonality. Surface wind anomalies associated with El Niño-Southern Oscillation explain the sea-level anomaly pattern in the interior SCS, while Rossby waves radiated from the eastern boundary dominate the sea-level variability in the eastern SCS. Decadal variability of sea level in the SCS follows that in the western tropical Pacific, with large variance found west of Luzon Island. Local atmospheric forcing makes a negative contribution to decadal variability in the central SCS, and Rossby waves radiated from the eastern boundary appear to be important. During 1993-2012, decadal sea level averaged in the SCS is significantly correlated with the Pacific Decadal Oscillation (PDO) ( r = -0.96). The decadal variability associated with the PDO accounts for most part of sea-level trends in the SCS in the last two decades.

  16. Paleoceanography of the mid-Pleistocene South China Sea

    NASA Astrophysics Data System (ADS)

    Li, Qianyu; Wang, Pinxian; Zhao, Quanhong; Tian, Jun; Cheng, Xinrong; Jian, Zhimin; Zhong, Guangfa; Chen, Muhong

    2008-06-01

    High-frequency fluctuations in paleoenvironmental proxies from the South China Sea, including stable isotopes and abundance of planktonic foraminifers, nannofossils, radiolarians, and palynomorphs, reveal a dynamic local response to the stepwise development of the mid-Pleistocene climate transition (MPT). These proxies indicate a dramatic drop in sea surface temperature (SST) at about 900 ka, the first largest SST decrease in the region during the Quaternary. Estimated winter SST declined from 24-25 °C to 17-18 °C in the northern and from 26-27 °C to 23-24 °C in the southern South China Sea. Subsequent changes in the thermocline depth and faunal-floral turnovers imply a period of about 300 ka in the final stage of the MPT. Winter monsoons increased at ˜900 ka and reached a maximum strength toward the end of the MPT when summer monsoons also strengthened in interglacials. As a result, thermal gradient between the northern and southern South China Sea increased substantially, with stronger winter monsoon influence in the north and warm and saline conditions in the south especially during glacial periods. These N-S paleoceanographic contrasts indicate an initial establishment of the modern-styled semi-enclosed South China Sea about 900 ka ago when passages in the south started to become completely exposed during glacial lowstands. Coupled with deep water cooling and ventilation, uplift of the sill depth in the Bashi Strait to near the present-2400 m during this period caused sudden decline and extinction of Pacific Deep Water benthic foraminifers in the isolated deep sea basin. Together with data from the oceanic western Pacific, these results further imply a considerable weakening of the western Pacific warm pool during MIS 23-22 and in subsequent glacial periods. While the MPT may have invoked high latitude processes especially an increased ice volume, tropical processes more likely have facilitated the restoration of heat and energy to the western Pacific in

  17. Modern sedimentation and extreme event in the South China Sea

    NASA Astrophysics Data System (ADS)

    Chen, Yu-Huang; Su, Chih-Chieh

    2016-04-01

    The South China Sea is the largest marginal sea of the northwest Pacific. It is situated at the plate boundary of the Eurasian, Philippine Sea, and Indian plates and also on the North Western Pacific corridor of typhoons. The unique tectonic and climatic environment makes it has to face the potential of seafloor destructions, like submarine landslides and slumps, and high sediment discharges which induced by typhoon from Philippine. In this study, we analysis the sediment properties of modern extreme event records in cores and attempt to evaluate the history of extreme events in the South China Sea. Twelve gravity cores were collected in the central South China Sea basin and around Taiping island by using R/V Ocean Research 1 from 2014 to 2015 and a series of analysis including multi-sensor core logger, XRF core scanner (Itrax), core surface images, X-radiographs, bulk density, grain size, Pb-210 chronology and X-ray diffractometer were conducted in this study. On core surface images, an obvious brownish oxidized layer exist in core top with higher Pb-210 activity beneath this oxidized layer, and we speculate this layer is caused by nature hazard. According to the sampling time, we conjecture the oxidized layer might formed by typhoon Haiyan in 2013. In addition, the Itrax data shows high manganese content only exist in this layer which might related to the modern industrial pollution delivered by typhoon induced flooding from Philippine. The sedimentation rate of the non-event years in these cores which derived from Pb-210 chronology method is about 0.02 ~0.03 cm/yr. On contrary, the event layer caused by Haiyan with a recorded maximum 87cm deposits in the South China Sea. This study aims to characterize the typhoon induced deposits in the turbidite layer and use it to identify whether the other event layers recorded in these cores were related to typhoon activities and to reconstruct the strong tropical cyclone history in the western Pacific.

  18. Tracing floating green algae blooms in the Yellow Sea and the East China Sea using Lagrangian transport simulations

    NASA Astrophysics Data System (ADS)

    Park, Young-Gyu; Son, Young Baek; Choi, Byoung-Ju; Kim, Yong Hoon

    2014-05-01

    Lagrangian particle tracking experiments were conducted to understand the pathway of the floating green algae patches observed in the Yellow Sea (YS) and East China Sea (ECS) in summer 2011. The numerical simulation results indicated that dominant southerly winds during June and July 2011 were related to offshore movement of the floating green algae, especially their eastward extension in the YS/ECS. An infrequent and unusual event occurred in June 2011: a severe Tropical Strom MEARI, caused the green algae to detach from the coast and initiated movement to the east. After the typhoon event, sea surface temperature recovered rapidly enough to grow the floating green algae, and wind and local current controlled the movement of the massive floating algae patches (coastal accumulation or offshore advection in the area). Analysis of the floating green algae movement using satellite images during passage of Typhoon MAON in July 2011 revealed that the floating green algae patches were significantly controlled by both ocean currents and enhanced winds. These findings suggest that the floating green algae bloom off Qingdao, China and in the middle of the YS and ECS in the summer of 2011 occurred due to the combined effects of recent rapid expansion of seaweed aquaculture, strong winds, and the wind patterns in blooming regions. Our combined approach, using satellite data and numerical simulations, provides a robust estimate for tracing and monitoring changes in green algae blooms on a regional scale.

  19. Antifouling potentials of eight deep-sea-derived fungi from the South China Sea.

    PubMed

    Zhang, Xiao-Yong; Xu, Xin-Ya; Peng, Jiang; Ma, Chun-Feng; Nong, Xu-Hua; Bao, Jie; Zhang, Guang-Zhao; Qi, Shu-Hua

    2014-04-01

    Marine-derived microbial secondary metabolites are promising potential sources of nontoxic antifouling agents. The search for environmentally friendly and low-toxic antifouling components guided us to investigate the antifouling potentials of eight novel fungal isolates from deep-sea sediments of the South China Sea. Sixteen crude ethyl acetate extracts of the eight fungal isolates showed distinct antibacterial activity against three marine bacteria (Loktanella hongkongensis UST950701-009, Micrococcus luteus UST950701-006 and Pseudoalteromonas piscida UST010620-005), or significant antilarval activity against larval settlement of bryozoan Bugula neritina. Furthermore, the extract of Aspergillus westerdijkiae DFFSCS013 displayed strong antifouling activity in a field trial lasting 4 months. By further bioassay-guided isolation, five antifouling alkaloids including brevianamide F, circumdatin F and L, notoamide C, and 5-chlorosclerotiamide were isolated from the extract of A. westerdijkiae DFFSCS013. This is the first report about the antifouling potentials of metabolites of the deep-sea-derived fungi from the South China Sea, and the first stage towards the development of non- or low-toxic antifouling agents from deep-sea-derived fungi. PMID:24532297

  20. Fungal communities from methane hydrate-bearing deep-sea marine sediments in South China Sea.

    PubMed

    Lai, Xintian; Cao, Lixiang; Tan, Hongming; Fang, Shu; Huang, Yali; Zhou, Shining

    2007-12-01

    To elucidate fungal diversity in methane hydrate-bearing deep-sea marine sediments in the South China Sea, internal transcribed spacer (ITS) regions of rRNA genes from five different sediment DNA samples were amplified and phylogenetically analyzed. Total five ITS libraries were constructed and 413 clones selected randomly were grouped into 24 restriction patterns by Amplified Ribosomal DNA Restriction Analysis (ARDRA). ITS sequences of 44 representative clones were determined and compared with the GenBank database using gapped-BLAST. The phylogenetic analysis showed that the ITS sequences (71-97% similarity) were similar to those of Phoma, Lodderomyces, Malassezia, Cryptococcus, Cylindrocarpon, Hortaea, Pichia, Aspergillus and Candida. The remaining sequences were not associated to any known fungi or fungal sequences in the public database. The results suggested that methane hydrate-bearing deep-sea marine sediments harbor diverse fungi. This is the first report on fungal communities from methane hydrate-bearing deep-sea marine sediments in South China Sea. PMID:18059498

  1. A fall land bird migration across the South China Sea from Indo-China to the Greater Sunda Islands

    USGS Publications Warehouse

    Ellis, D.H.; Kepler, A.K.; Kepler, C.B.

    1994-01-01

    We encountered 150 land birds representing 14 families along the cruise track of the Soviet Oceanographic Research Vessel AKADEMlK KOROLEV in the South China Sea. We saw most of these birds during a 3 -day period in a small area c. 350 km southeast of the southern tip of the Indo-China peninsula. These observations suggest that a significant land bird migration corridor crosses the South China Sea from Viet Nam to Borneo.

  2. Joint Air Sea Interaction (JASIN) experiment, Northwest coast of Scotland

    NASA Technical Reports Server (NTRS)

    Businger, J. A.

    1981-01-01

    The joint air sea interaction (JASIN) experiment took place off the Northwest coast of Scotland. Sea surface and boundary layer parameters were measured. The JASIN data was used as ground truth for various sensors on the SEASAT satellite.

  3. Multimodal structure of baroclinic tides in the South China Sea

    NASA Astrophysics Data System (ADS)

    Vlasenko, V.; Stashchuk, N.; Guo, C.; Chen, X.

    2010-10-01

    The modelling of baroclinic tides generated in the northern South China Sea is studied using a fully-nonlinear non-hydrostatic numerical model. The focus of the modelling efforts was on the vertical structure of internal waves in the vicinity of the Luzon Strait. The barotropic tidal flow interacting with a two-ridge bottom topography in the area of the Luzon Strait produces a complex baroclinic tidal signal. A multimodal baroclinic bore with counter-phase displacement of isopycnals generated over the ridges and propagating westward disintegrates into a series of large-amplitude solitary internal waves. The leading first-mode solitary wave of depression is followed by a second mode solitary wave coupled with a packet of short-scale internal waves riding it. Scrutiny of the characteristics of the both wave forms, i.e. the carrier second-mode solitary wave and the packet of short waves, revealed that the short-scale waves are basically concentrated in the upper 500 m layer and attenuate exponentially below it. The short waves exist only thanks to a specific structure of horizontal velocity produced by the second-mode solitary wave. Having equal phase speeds and propagating together for a long distance, this coupled system produces quite a remarkable signal at the free surface, which can be detected by means of remote sensing technique. It was found in a series of sensitivity experiments that the eastern ridge is responsible for the generation of progressive first-mode tidal waves disintegrated into packets of first-mode ISWs. The western ridge produces quite a strong higher-mode signal. The waves generated over the eastern and western ridges interfere in the near-field, and their nonlinear superposition enhances the multimodal signal in the whole domain.

  4. The South China sea margins: Implications for rifting contrasts

    USGS Publications Warehouse

    Hayes, D.E.; Nissen, S.S.

    2005-01-01

    Implications regarding spatially complex continental rifting, crustal extension, and the subsequent evolution to seafloor spreading are re-examined for the northern and southern-rifted margins of the South China Sea. Previous seismic studies have shown dramatic differences in the present-day crustal thicknesses as the manifestations of the strain experienced during the rifting of the margin of south China. Although the total crustal extension is presumed to be the same along the margin and adjacent ocean basin, the amount of continental crustal extension that occurred is much less along the east and central segments of the margin than along the western segment. This difference was accommodated by the early formation of oceanic crust (creating the present-day South China Sea basin) adjacent to the eastern margin segment while continued extension of continental crust was sustained to the west. Using the observed cross-sectional areas of extended continental crust derived from deep penetration seismics, two end-member models of varying rift zone widths and varying initial crustal thicknesses are qualitatively examined for three transects. Each model implies a time difference in the initiation of seafloor spreading inferred for different segments along the margin. The two models examined predict that the oceanic crust of the South China Sea basin toward the west did not begin forming until sometime between 6-12 my after its initial formation (???32 Ma) toward the east. These results are compatible with crustal age interpretations of marine magnetic anomalies. Assuming rifting symmetry with conjugate margin segments now residing along the southern portions of the South China Sea basin implies that the total width of the zone of rifting in the west was greater than in the east by about a factor of two. We suggest the most likely causes of the rifting differences were east-west variations in the rheology of the pre-rift crust and associated east-west variations in the

  5. Late compressional features, East China Sea Shelf Basin

    SciTech Connect

    Cunningham, A.E.; Prebish, M.R.; Eisenstadt, G. ); Norris, J.W.; Letsch, D.K. )

    1994-07-01

    Many anticlinal folds observed in the East China Sea Shelf Basin are interpreted to result from a change in regional stress from tensional to compressional. This compression is interpreted to have occurred during the late Eocene to Oligocene Yuquan movement. These features were observed most frequently south of the Mingyuefeng 1 well within China's recently offered Fourth Round Acreage. Many of these structures are interpreted to be related to reverse and strike-slip motion along reactivated, Late Cretaceous to late Eocene, synrift, normal faults. An early to middle Miocene regional unconformity truncates the crest of most anticlinal features, and does not appear to be involved in the folding episode. Late Eocene to Oligocene compressional highs present attractive structural targets in the East China Sea Shelf Basin. The deformed sedimentary section thickens toward the rift-basin boundary faults, suggesting synrift sedimentation. Consequently, there is no thinning of the synrift section across the crest of the structural highs formed by postrift compression. The timing of these compressional structural highs, however, must be compared with the hydrocarbon generation and migration history from source rocks in adjacent half grabens to properly assess accumulation potential.

  6. Investigation of the sand sea with the tallest dunes on Earth: China's Badain Jaran Sand Sea

    NASA Astrophysics Data System (ADS)

    Dong, Zhibao; Qian, Guangqiang; Lv, Ping; Hu, Guangyin

    2013-05-01

    China's Badain Jaran Sand Sea features the tallest dunes on Earth and a unique mega-dune-lake landscape. It had been explored little until the 1990s, though early scientific explorations surrounding the sand sea had begun by the early 20th century. Heated debates now focus on the desert environment, and particularly how the mega-dunes and desert lakes develop and evolve. This paper reviews the status of these debates and summarizes the supporting evidences. The environmental research mainly concerns formation and evolution of the sand sea, and its relationship with climate change. The proposed formation time ranges from the Early Pleistocene to the Holocene. Opinions vary about climate change on different time scales. The reconstructed climate change history is shorter than the sand sea's history, with the longest record extending to the Late Pleistocene. The mega-dune research focuses on sediments, dune morphology, and formation processes. It remains unclear whether the mega-dunes result primarily from wind action, control by the underlying topography, or groundwater maintenance. The sources of lake water are also debated, but there are four main hypotheses: atmospheric precipitation, groundwater from nearby areas, precipitation and snowmelt in remote areas such as the Qilian Mountains and the Qinghai-Tibetan Plateau, or paleowater that formed during past periods of wet climate. We believe that the sand sea deserves further study in terms of its dune geomorphology, evolution, and hydrology, and their responses to climate change. Meteorological and hydrological observations and monitoring in the sand sea are particularly necessary.

  7. Pollution from China increases cloud droplet number, suppresses rain over the East China Sea

    SciTech Connect

    Bennartz, Ralph; Fan, Jiwen; Rausch, J; Leung, Lai-Yung R; Heidinger, Andrew K

    2011-05-18

    Rapid economic growth over the last 30 years in China has led to a significant increase in aerosol loading, which is mainly due to the increased emissions of its precursors such as SO2 and NOx. Here we show that these changes significantly affect wintertime clouds and precipitation over the East China Sea downwind of major emission sources. Satellite observations show an increase of cloud droplet number concentration from less than 200 cm-3 in the 1980s to more than 300 cm-3 in 2005. In the same time period, precipitation frequency reported by voluntary ship observers was reduced from more than 30% to less than 20% of the time. A back trajectory analysis showed the pollution in the investigation area to originate from the Shanghai-Nanjing and Jinan industrial areas. A model sensitivity study was performed, isolating the effects of changes in emissions of the aerosol precursors SO2 and NOx on clouds and precipitation using a state-of-the-art mesocale model including chemistry and aerosol indirect effects. Similar changes in cloud droplet number concentration over the East China Sea were obtained when the current industrial emissions in China were reduced to the 1980s levels. Simulated changes in precipitation were somewhat smaller than the observed changes but still significant. Citation: Bennartz, R., J. Fan, J. Rausch, L. R. Leung, and A. K. Heidinger (2011), Pollution from China increases cloud droplet number, suppresses rain over the East China Sea, Geophys. Res. Lett., 38, L09704, doi:10.1029/ 2011GL047235.

  8. A study on the seismic fortification level of offshore platform in Bohai Sea of China

    NASA Astrophysics Data System (ADS)

    Lu, Y.

    2010-12-01

    The Chinese sea areas are important places of offshore petroleum resources, and at the same time they are also seismically active regions. Fixed offshore platforms (OPs) are the fundamental facilities for marine resource exploitation, and usually situated in a complex and severe environment as having to endure many environmental loads in their life span, therefore, the damage to their structures may result in serious disasters. Among these environmental loads the seismic load has tremendous destructive effect and is not predictable. In case of not overly severe wind, wave and current, seismic resistance dominates the strength design of platforms. Furthermore, strong earthquakes have occurred recently or in the history of all the sea areas of oil/gas exploitation in China. Therefore, seismic design of fixed OPs is a very important issue. With the development of marine exploration and earthquake researches in the sea area, extensive studies on the seismotectonic environment and seismicity characteristics of the sea areas of China have been performed, meanwhile, more and more experience and data have been accumulated from OP design practice, which laid a foundation for studying and establishing the seismic design standard of OPs. This paper first gives an overall understanding of the seismic environment of the sea areas of China, then taking the Bohai Sea seismic risk study as an example, introducing a so-called shape factor K to characterize the seismic risk distribution in sub-regions of the Bohai Sea. Based on the seismic design ground motions for 46 platforms in Bohai Sea, a statistic analysis was performed for different peak ground acceleration (PGA) ratios at two different probability levels. In accordance with the two-stage design method, a scheme of two seismic design levels is proposed, and two seismic design objectives are established respectively for the strength level earthquake and ductility level earthquake. By analogy with and comparison to the Chinese

  9. Mapping structures of the South China Sea; a synthesis

    NASA Astrophysics Data System (ADS)

    Pubellier, Manuel; Savva, Dimitri; Aurelio, Mario; Yan, Qiu; Phach Phung, Van; Franke, Dieter; Rahman, Hadi A.; Mansor, Yazid M.; Auxiètre, Jean Luc; Meresse, Florian; Delescluse, Matthias; Pichot, Thibaud; Chan, Lung Sang; Le Gal, Virginie; Xin, Nie

    2015-04-01

    The South China Sea margin has been the focus of scientific interest in the past decade including ODP and IODP drilling, oil and gas exploration, and projects from several international teams onshore and offshore. The South China Sea, because of its narrow V shape oceanic crust, the wide extension of its rifted continental crust, and the various styles of rifting is an interesting playground to study the formation of passive margins. We present a synthesis of the main characteristics of the SCS on a structural map focused on the Late Mesozoic and Cenozoic features. The basement, similar in China, Vietnam and part of the western Philippines is undifferentiated. The Mesozoic location of the area was on the upper plate of a subduction zone, resulting in an impressive coverage of Cretaceous granites sometimes separated by narrow Cretaceous molasse basins. These granitic bodies, widespread offshore in the extended crust conditioned the location of the extension via large detachments and normal faults; later cut by steeper faults. The geometries of the faults vary from E-W to NE-SW indicating that the rifting underwent several stages with different stretching directions and a varying degree of extension which ultimately exhumed the mantle. Some faults are low angle detachments and therefore surround the granitic/metamorphic basement structures with an E-W general trend. Platform and reef carbonates occupy some of the bathymetric highs and developed mainly during Late Oligocene to Mid Miocene times and during Late Miocene times. The map also illustrates the coverage of the different units of the NW Borneo wedge, which actually develops offshore in the SE SCS and shifts to the NW of the Sulu Sea. Onshore Borneo, the sub-aerial conditions for the NW Borneo wedge resulted in intense erosion and deltas formation.

  10. The tectonic evolution of the greater South China Sea

    SciTech Connect

    Hayes, D.E. )

    1990-06-01

    The South China Sea (SCS) basin is composed of two major subbasins. The eastern subbasin was formed by seafloor spreading in the middle Tertiary and is associated with roughly E-W-trending magnetic lineations. The southwestern subbasin of the South China Sea is characterized by NE-SW tectonic and magnetic trends and is considerably narrower than the eastern subbasin. There is no obvious structural discontinuity between the two subbasins; hence the initial opening of the eastern subbasin was likely accommodated to the west by a prolonged period of extension of the continental crust that was not accompanied by the formation of normal oceanic crust. The southwest subbasin was eventually also formed by seafloor spreading processes. Although the sequence of magnetic lineations recorded there is relatively short, these data coupled with heatflow and crustal depth data strongly suggest that the southwestern subbasin was not formed until the early-middle Miocene, coincident with the last phase of spreading in the adjacent eastern subbasin. It is still unclear whether or not a significant change in spreading direction occurred within the SCS basin during the early Miocene. The geometry of the deep SCS basin as defined by the seaward limit of the continent-ocean boundary zone provides important constraints on the east-to-west variations in the total crustal extension manifested in the rifted margins of the South China Sea. The amount of new oceanic crust created by seafloor spreading plus the amount of crustal extension accommodated within the continental crust must be nearly the same for all points along the rifted margins. Because the amount of oceanic crust present is quite variable, it follows that the amount of crustal extension must be similarly variable and in a predictable way.

  11. Temporal and spatial variations of sea surface temperature in the East China Sea

    NASA Astrophysics Data System (ADS)

    Tseng, Chente; Lin, Chiyuan; Chen, Shihchin; Shyu, Chungzen

    2000-03-01

    Sea surface temperature of the East China Sea (ECS) were analyzed using the NOAA/AVHRR SST images. These satellite images reveal surface features of ECS including mainly the Kuroshio Current, Kuroshio Branch Current, Taiwan Warm Current, China coastal water, Changjiang diluted water and Yellow Sea mixed cold water. The SST of ECS ranges from 27 to 29°C in summer; some cold eddies were found off northeast Taiwan and to the south of Changjiang mouth. SST anomalies at the center of these eddies were about 2-5°C. The strongest front usually occurs in May each year and its temperature gradient is about 5-6°C over a cross-shelf distance of 30 nautical miles. The Yellow Sea mixed cold water also provides a contrast from China Coastal waters shoreward of the 50 m isobath; cross-shore temperature gradient is about 6-8°C over 30 nautical miles. The Kuroshio intrudes into ECS preferably at two locations. The first is off northeast Taiwan; the subsurface water of Kuroshio is upwelled onto the shelf while the main current is deflected seaward. The second site is located at 31°N and 128°E, which is generally considered as the origin of the Tsushima Warm Current. More quantitatively, a 2-year time series of monthly SST images is examined using EOF analysis to determine the spatial and temporal variations in the northwestern portion of ECS. The first spatial EOF mode accounts for 47.4% of total spatial variance and reveals the Changjiang plume and coastal cold waters off China. The second and third EOF modes account for 16.4 and 9.6% of total variance, respectively, and their eigenvector images show the intrusion of Yellow Sea mixed cold waters and the China coastal water. The fourth EOF mode accounts for 5.4% of total variance and reveals cold eddies around Chusan Islands. The temporal variance EOF analysis is less revealing in this study area.

  12. Rifting and breakup in the South China Sea

    NASA Astrophysics Data System (ADS)

    Franke, Dieter; Savva, Dimitri; Pubellier, Manuel; Steuer, Stephan; Mouly, Benoit; Auxietre, Jean-Luc; Meresse, Florian; Chamot-Rooke, Nicolas

    2014-05-01

    The magma-poor or intermediate magmatic South China Sea is a natural laboratory for studying rifting and breakup. The basin shows an irregular triangular shape with a SW pointing apex, which manifests a preceding propagating rift. The earliest phase of rifting started in the Early Paleocene when a Mesozoic convergent margin changed to extension. After about 30 Million years of rifting, breakup in the major eastern subbasin of the SCS occurred in the Early Oligocene but rifting continued and subsequent breakup of the southwest subbasin took place in the Late Oligocene. The wide Early Cenozoic South China Sea rift preserves the initial rift architecture at the distal margins. Seismic reflection data imaging conjugate crustal sections at the South China Sea margins result in a conceptual model for rift-evolution at conjugate magma-poor margins in time and space. Most distinct are regular undulations in the crust-mantle boundary. Individual rift basins are bounded to crustal blocks by listric normal faults on either side. Moho uplifts are distinct beneath major rift basins, while the Moho is downbended beneath crustal blocks, with a wavelength of undulations in the crust-mantle boundary that approximately equals the thickness of the continental crust. Most of the basin-bounding faults sole out within the middle crust. At the distal margins, detachment faults are located at a mid-crustal level where a weak zone decouples crust and mantle lithosphere during rifting. The lower crust in contrast is interpreted as being strong. Only in the region within about 50 km from the continent-ocean transition (COT) we suggest that normal faults reach the mantle, enabling potentially a coupling between the crust and the mantle. Here, at the proximal margins detachment fault dip either seaward or landward. This may indicate the presence of exhumed mantle bordering the continental margins. Post-rift shallow-water platform carbonates indicate a delay in subsidence during rifting in the

  13. Fluxes of clay minerals in the South China Sea

    NASA Astrophysics Data System (ADS)

    Schroeder, Annette; Wiesner, Martin G.; Liu, Zhifei

    2015-11-01

    In order to assess dominant settling processes that change the composition of the detrital clay fraction during transport from neighboring estuaries to a deep sea basin, we studied relative clay mineral abundances and absolute clay mineral fluxes of clay-sized sinking particulate matter collected by eight sediment trap systems deployed from shallow to deep water depth in the South China Sea. This is the first basin-wide study on recent sedimentation processes in the western Pacific marginal seas. Annual averages of relative clay mineral abundances at the shallow traps are temporally more variable and regionally more diverse, resembling those of surrounding drainage basins. In contrast, higher fluxes of material reach the deeper traps. Their characteristics trend temporally and spatially towards uniformity and are enriched with smectite in the entire deep basin. Sinking particulate matter that reaches the shallow traps spends less time in pelagic transport and is affected by monsoonal current reversals. The enrichment in smectite in the deeper traps is a result of longer duration in transport at low velocities, which may increase the effect of differential settling during transport. The trend is caused by lateral advection driven by the cyclonic deep circulation, and this is considered as the main transport process in the northern and central deep basin. The high fluxes in the south-western deep basin could be the result of laterally advected re-suspended sediments from the neighboring shelves. The effects on the composition of the detrital clay fraction caused by oceanographic control, which indirectly include those by differential settling, mask the climatic signal from surrounding drainage basins in the deep basin sediments. This strongly affects the interpretation of the clay mineralogical record in sediments deposited under recent conditions in the South China Sea deep basin.

  14. The seasonal cycle and variability of sea level in the South China Sea

    NASA Astrophysics Data System (ADS)

    Amiruddin, A. M.; Haigh, I. D.; Tsimplis, M. N.; Calafat, F. M.; Dangendorf, S.

    2015-08-01

    The spatial and temporal characteristics of the seasonal sea level cycle in the South China Sea (SCS) and its forcing mechanisms are investigated using tide gauge records and satellite altimetry observations along with steric and meteorological data. The coastal mean annual amplitude of the seasonal cycle varies between zero and 24 cm, reaching a maximum between July and January. The maximum mean semiannual amplitude is 7 cm, peaking between March and June. Along the coast, the seasonal cycle accounts for up to 92% of the mean monthly sea level variability. Atmospheric pressure explains a significant portion of the seasonal cycle with dominant annual signals in the northern SCS, the Gulf of Thailand and the north-western Philippines Sea. The wind forcing is dominant on the shelf areas of the SCS and the Gulf of Thailand where a simple barotropic model forced by the local wind shows annual amplitudes of up to 27 cm. In the deep basin of the SCS, the Philippines Sea and the shallow Malacca Strait, the steric component is the major contributor with the maximum annual amplitudes reaching 15 cm. Significant variability in the seasonal cycle is found on a year-to-year basis. The annual and semiannual amplitudes vary by up to 63% and 45% of the maximum values, 15 cm and 11 cm, respectively. On average, stepwise regression analysis of contribution of different forcing factors accounts for 66% of the temporal variability of the annual cycle. The zonal wind was found to exert considerable influence in the Malacca Strait.

  15. Evolution of Nonlinear Internal Waves in China Seas

    NASA Technical Reports Server (NTRS)

    Liu, Antony K.; Hsu, Ming-K.; Liang, Nai K.

    1997-01-01

    Synthetic Aperture Radar (SAR) images from ERS-I have been used to study the characteristics of internal waves of Taiwan in the East China Sea, and east of Hainan Island in the South China Sea. Rank-ordered packets of internal solitons propagating shoreward from the edge of the continental shelf were observed in the SAR images. Based on the assumption of a semidiurnal tidal origin, the wave speed can be estimated and is consistent with the internal wave theory. By using the SAR images and hydrographic data, internal waves of elevation have been identified in shallow water due to a thicker mixed layer as compared with the bottom layer on the continental shelf. The generation mechanism includes the influences of the tide and the Kuroshio intrusion across the continental shelf for the formations of elevation internal waves. The effects of water depth on the evolution of solitons and wave packets are modeled by nonlinear Kortweg-deVries (KdV) type equation and linked to satellite image observations. The numerical calculations of internal wave evolution on the continental shelf have been performed and compared with the SAR observations. For a case of depression waves in deep water, the solitons first disintegrate into dispersive wave trains and then evolve to a packet of elevation waves in the shallow water area after they pass through a turning point of approximately equal layer depths has been observed in the SAR image and simulated by numerical model.

  16. Cenozoic evolution of Xisha carbonate platforms, Northern South China Sea

    NASA Astrophysics Data System (ADS)

    Wu, S.; Ma, Y.; Dong, D.

    2009-12-01

    During the Tertiary, extensive tropical shallow-water carbonates, including reefs, were deposited in the tectonically complex region of the South China Sea (SCS) and adjacent areas. Previous studies show that large quantity reefs and carbonate sediments developed in the Xisha Islands, but no further study, especially the distribution and development model, was blank because lack of enough data. Based on the fine interpretation of seismic data of carbonate platform and different types of reefs in the Xisha Islands, we proposed that the evolution process of the carbonate platform and reef in the Xisha Islands can be divided into four stages: 1. Isolated carbonate platform of initial stage in Early Miocene; 2. Carbonate platforms widely developed in the Middle Miocene and seaward prograding sequence formed; 3. With the rising sea level, some low-lying area was floodied in Late Miocene and the carbonate platforms and reefs in these areas were drowned to death, the carbonate platform in the Xisha Islands became fade; 4. Sea level continued rising and most area of the Xisha Islands was flooded but the carbonate platforms and reefs can develop at high points. Various factors have influenced the development of the Xisha carbonate platform. The two main factors in this regard are basement structure and relative sea-level change. Based on the development and distribution of various facies belts, we now consider the influence of these two factors on the development of the Xisha carbonate platform. One is the Tectonic movements and the other is Eustatic Fluctuation of sea level control on development of carbonate platforms in the Xisha Islands.

  17. Pollution from China increases cloud droplet number, suppresses rain over the East China Sea

    NASA Astrophysics Data System (ADS)

    Bennartz, Ralf; Fan, Jiwen; Rausch, John; Leung, L. Ruby; Heidinger, Andrew K.

    2011-05-01

    Rapid economic growth over the last 30 years in China has led to a significant increase in aerosol loading, which is mainly due to the increased emissions of its precursors such as SO2 and NOx. Here we show that these changes significantly affect wintertime clouds and precipitation over the East China Sea downwind of major emission sources. Satellite observations show an increase of cloud droplet number concentration from less than 200 cm-3 in the 1980s to more than 300 cm-3 in 2005. In the same time period, precipitation frequency reported by voluntary ship observers was reduced from more than 30% to less than 20% of the time. A back trajectory analysis showed the pollution in the investigation area to originate from the Shanghai-Nanjing and Jinan industrial areas. A model sensitivity study was performed, isolating the effects of changes in emissions of the aerosol precursors SO2 and NOx on clouds and precipitation using a state-of-the-art mesocale model including chemistry and aerosol indirect effects. Similar changes in cloud droplet number concentration over the East China Sea were obtained when the current industrial emissions in China were reduced to the 1980s levels. Simulated changes in precipitation were somewhat smaller than the observed changes but still significant.

  18. Summer and winter living coccolithophores in the Yellow Sea and the East China Sea

    NASA Astrophysics Data System (ADS)

    Gu, X. Y.; Feng, Y. Y.; Jin, S. F.; Jiang, W. S.; Jin, H. Y.; Chen, J. F.; Sun, J.

    2013-05-01

    To date, very little information on living coccolithophores species composition and distribution, especially the vertical profile has been reported around the world. This paper tries to fill this gap by descripting on living coccolithophores (LCs) distribution in the Yellow Sea and the East China Sea in summer and winter time in detail, and its relationship among enviromental factors by canonical correspondence analysis (CCA). We carried out the investigations on LC distribution in the Yellow Sea and the East China Sea in July and December 2011. 210 samples from different depths were collected from 44 stations in summer and 217 samples were collected from 45 stations in winter. Totally 20 taxa belonging to coccolithophyceae were identified using a polarized microscope at the 1000 × magnification. The dominant species of the two seasons were Gephyrocapsa oceanica, Emiliania huxleyi, Helicosphaera carteri, and Algirosphaera robusta. In summer the abundance of cells and coccoliths ranged 0 ~ 176.40 cells mL-1, and 0 ~ 2144.98 coccoliths mL-1, with the average values of 8.45 cells mL-1, and 265.42 coccoliths mL-1, respectively. And in winter the abundance of cells and coccoliths ranged 0 ~ 71.66 cells mL-1, and 0 ~ 4698.99 coccoliths mL-1, with the average values of 13.91 cells mL-1 and 872.56 coccoliths mL-1 respectively. In summer the LCs in surface layer were mainly observed on the coastal belt and southern part of the survey area. The highest abundance was found at the bloom station. In winter the LCs in surface layer had high value in the continental shelf area of section P. The comparison among section A, section F, section P and section E indicated lower species diversity and less abundance in the Yellow Sea than those of the East China Sea in both seasons. Temperature and the nitrate concentration may be the major environmental factors controlling the distribution and species composition of LCs in the studying area based on CCA.

  19. Bioavailability of dissolved organic carbon linked with the regional carbon cycle in the East China Sea

    NASA Astrophysics Data System (ADS)

    Gan, Shuchai; Wu, Ying; Zhang, Jing

    2016-02-01

    The regional carbon cycle on continental shelves has created great interest recently due to the enigma of whether these areas are a carbon sink or a source. It is vital for a precise carbon cycle model to take the bioavailability of dissolved organic carbon (DOC) into account, as it impacts the sink and source capacity, especially on dynamic shelves such as the East China Sea. Nine bio-decomposition experiments were carried out to assess differences in the bioavailability of DOC. Samples were collected from different water masses in the East China Sea, such as the Coastal Current, the Taiwan Current, and the Kuroshio Current, as well as from the Changjiang (Yangtze River), the main contributor of terrestrial DOC in the East China Sea. This study aimed to quantify and qualify bioavailable DOC (BDOC) in the East China Sea. Both the degradation constant of BDOC and the carbon output from microorganisms have been quantitatively evaluated. Qualitatively, excitation-emission matrix fluorescence spectra (EEMs) were used to evaluate the intrinsic reasons for BDOC variation. By using EEMs in conjunction with parallel factor analysis (PARAFAC), five individual fluorescent components were identified in this study: three humic-like and two protein-like components (P1, P2). The highest P1 and P2 fluorescence intensities were recorded in the coastal water during a phytoplankton algal bloom, while the lowest intensities were recorded in the Changjiang estuary. Quantitatively, BDOC observed during the incubation ranged from 0 to 26.1 μM. The DOC degradation rate constant varied from 0 to 0.027 (d-1), and was lowest in the Changjiang and highest in algal bloom water and warm shelf water (the Taiwan current). The Taiwan Current and mixed shelf water were the major contributors of BDOC flux to the open ocean, and the East China Sea was a net source of BDOC to the ocean. The results verified the importance of BDOC in regional carbon cycle modeling. Combining the data of BDOC and EEMs

  20. A reanalysis dataset of the South China Sea

    PubMed Central

    Zeng, Xuezhi; Peng, Shiqiu; Li, Zhijin; Qi, Yiquan; Chen, Rongyu

    2014-01-01

    Ocean reanalysis provides a temporally continuous and spatially gridded four-dimensional estimate of the ocean state for a better understanding of the ocean dynamics and its spatial/temporal variability. Here we present a 19-year (1992–2010) high-resolution ocean reanalysis dataset of the upper ocean in the South China Sea (SCS) produced from an ocean data assimilation system. A wide variety of observations, including in-situ temperature/salinity profiles, ship-measured and satellite-derived sea surface temperatures, and sea surface height anomalies from satellite altimetry, are assimilated into the outputs of an ocean general circulation model using a multi-scale incremental three-dimensional variational data assimilation scheme, yielding a daily high-resolution reanalysis dataset of the SCS. Comparisons between the reanalysis and independent observations support the reliability of the dataset. The presented dataset provides the research community of the SCS an important data source for studying the thermodynamic processes of the ocean circulation and meso-scale features in the SCS, including their spatial and temporal variability. PMID:25977803

  1. A reanalysis dataset of the South China Sea.

    PubMed

    Zeng, Xuezhi; Peng, Shiqiu; Li, Zhijin; Qi, Yiquan; Chen, Rongyu

    2014-01-01

    Ocean reanalysis provides a temporally continuous and spatially gridded four-dimensional estimate of the ocean state for a better understanding of the ocean dynamics and its spatial/temporal variability. Here we present a 19-year (1992-2010) high-resolution ocean reanalysis dataset of the upper ocean in the South China Sea (SCS) produced from an ocean data assimilation system. A wide variety of observations, including in-situ temperature/salinity profiles, ship-measured and satellite-derived sea surface temperatures, and sea surface height anomalies from satellite altimetry, are assimilated into the outputs of an ocean general circulation model using a multi-scale incremental three-dimensional variational data assimilation scheme, yielding a daily high-resolution reanalysis dataset of the SCS. Comparisons between the reanalysis and independent observations support the reliability of the dataset. The presented dataset provides the research community of the SCS an important data source for studying the thermodynamic processes of the ocean circulation and meso-scale features in the SCS, including their spatial and temporal variability. PMID:25977803

  2. Heavy metals in sea cucumber juveniles from coastal areas of Bohai and Yellow seas, north China.

    PubMed

    Jiang, Haifeng; Tang, Shizhan; Qin, Dongli; Chen, Zhongxiang; Wang, Jinlong; Bai, Shuyan; Mou, Zhenbo

    2015-05-01

    The study was undertaken to assess the contents of heavy metals (Cu, Zn, Cr, Pb, Cd, As and Hg) in sea cucumber (Apostichopus japonicus) juveniles from coastal areas of Bohai and Yellow seas in northern China. Sea cucumber juveniles were collected from twenty commercial hatcheries distributed in five coastal cities. The mean concentrations obtained for heavy metals in mg/kg were as follows: Cu (0.179), Zn (2.634), Cr (0.108), Pb (0.065), Cd (0.161), As (0.372), Hg (0.034). All the mean concentrations were below the maximum residual limits set by Chinese legislation, but As in 10 % samples exceeded the safety threshold. Significant differences in contents of Cr, Pb and Hg were found among the five investigated areas. Overall, the heavy metal levels in sea cucumber juveniles were relatively low and more attention should be paid to toxic metals Pb, Cd, As and Hg in future routine monitoring program. PMID:25421712

  3. Interannual to decadal variation of spring sea level anomaly in the western South China Sea

    NASA Astrophysics Data System (ADS)

    Qiu, Fuwen; Fang, Wendong; Pan, Aijun; Cha, Jing; Zhang, Shanwu; Huang, Jiang

    2016-04-01

    Satellite observations of sea level anomalies (SLA) from January 1993 to December 2012 are used to investigate the interannual to decadal changes of the boreal spring high SLA in the western South China Sea (SCS) using the Empirical Orthogonal Function (EOF) method. We find that the SLA variability has two dominant modes. The Sea Level Changing Mode (SLCM) occurs mainly during La Niña years, with high SLA extension from west of Luzon to the eastern coast of Vietnam along the central basin of the SCS, and is likely induced by the increment of the ocean heat content. The Anticyclonic Eddy Mode (AEM) occurs mainly during El Niño years and appears to be triggered by the negative wind curl anomalies within the central SCS. In addition, the spring high SLA in the western SCS experienced a quasi-decadal change during 1993-2012; in other words, the AEM predominated during 1993-1998 and 2002-2005, while the La Niña-related SLCM prevailed during 1999-2001 and 2006-2012. Moreover, we suggest that the accelerated sea level rise in the SCS during 2005-2012 makes the SLCM the leading mode over the past two decades.

  4. Impacts of typhoon megi (2010) on the South China Sea

    NASA Astrophysics Data System (ADS)

    Ko, Dong Shan; Chao, Shenn-Yu; Wu, Chun-Chieh; Lin, I.-I.

    2014-07-01

    In October 2010, typhoon Megi induced a profound cold wake of size 800 km by 500 km with sea surface temperature cooling of 8°C in the South China Sea (SCS). More interestingly, the cold wake shifted from the often rightward bias to both sides of the typhoon track and moved to left in a few days. Using satellite data, in situ measurements and numerical modeling based on the East Asian Seas Nowcast/Forecast System (EASNFS), we performed detailed investigations. To obtain realistic typhoon-strength atmospheric forcing, the EASNFS applied typhoon-resolving Weather Research and Forecasting (WRF) model wind field blended with global weather forecast winds from the U.S. Navy Operational Global Atmospheric Prediction System (NOGAPS). In addition to the already known impacts from the slow typhoon translation speed and shallow pre-exiting ocean thermocline, we found the importance of the unique geographical setting of the SCS and the NE monsoon. As the event happened in late October, NE monsoon already started and contributed to the southwestward ambient surface current. Together with the topographicβ effect, the cold wake shifted westward to the left of Megi's track. It was also found that Megi expelled waters away from the SCS and manifested as a gush of internal Kelvin wave exporting waters through the Luzon Strait. The consequential sea level depression lasted and presented a favorable condition for cold dome development. Fission of the north-south elongated cold dome resulted afterward and produced two cold eddies that dissipated slowly thereafter.

  5. The Oceanic Crustal Structure of the Southwestern Subbasin in the South China Sea

    NASA Astrophysics Data System (ADS)

    Wu, Z.; Ruan, A.; Li, J.; Lee, C.

    2012-12-01

    Located at the southwestern part of the South China Sea (SCS) among the Zhongsha Islands(Macclesfield Bank), the east subbasin, the Nansha Islands(Dangerous Ground), the V type southwest subbasin (SWSB) is an unique ocean basin in all the three subbasins of SCS. The crustal structure is one of the key problems to study the formation and evolution of SWSB. During December 2010 to March 2011, Ocean Bottom Seismometers (OBSs) experiment has been carried out in the SWSB to get the deep crustal structure information, especially under the fossil spreading center. Three types of OBS, Sedis IV type, I-4C type and MicrOBS type have been used in the experiment, and the energy source was supplied by 6000 inch3 large volume air-gun. High quality seismic data of four 2D profiles which covered the fossil spreading center of SWSB have been acquired. The data of the experiment can supply evidence for the study of oceanic crustal structure of the SWSB and seafloor spreading course, etc. The profile 1 extended 130 km in length. A total of 8 OBSs were deployed at intervals of 10 or 15 km and 7 OBSs were recovered. The data of the 7 stations of profile 1 have been processed, which shows that the seismic records are clear and seismic phases are abundance, and the air-guns have enough energy supply. The velocity model was obtained by using an interactive trial-and-error 2D ray-tracing method. The crustal structure indicates that the crustal thickness under the SWSB is about 6 km, and the moho depth is about 10km. The results reveal that the crust of SWSB is normal oceanic crust with a thin sedimentary layer on the seamount and shallow moho surface. The crustal velocity under the spreading center is extremely low, which shows the characteristic of the deep crustal structure of the fossil spreading center. Acknowledgements This study was supported by the National Natural Science Foundation of China (Grant No. 91028006, 41106053, 41176046), Scientific Research Fund of the Second Institute

  6. Nitrogen deposition fuels harmful algal blooms in the East China Sea

    NASA Astrophysics Data System (ADS)

    Mackey, K. R.; Kavanaugh, M.; Chien, C. T.; Chen, Y.; Glover, D. M.; Paytan, A.

    2015-12-01

    Chinese marginal seas support vast fisheries and vital economies, but their productivity is threatened by eutrophication and increasing harmful algal blooms (HABs). Here we provide direct experimental evidence that aerosol enrichment shifts seawater chemistry by increasing the ratio of N to phosphorus (N:P) and supports the growth of bloom-forming phytoplankton in the East China Sea. We use a combination of field-based aerosol addition incubation experiments, along with ocean color data on blooms dominated by different taxa to show that HAB forming dinoflagellates are particularly responsive to aerosol inputs. Moreover, we show that the effect of N deposition is strongest in offshore waters further from the Yangtze River outflow, consistent with the large anthropogenic flux of N from this source. This study shows the potential for aerosols to control N:P ratios in offshore waters and to shape the phytoplankton community, contributing to the success of bloom-forming organisms.

  7. The Changing Faces of the South China Sea

    NASA Astrophysics Data System (ADS)

    Pubellier, M. F.; Savva, D.; Franke, D.; Meresse, F.; Steuer, S.; Auxietre, J. L.; Aurelio, M.; Chamot-Rooke, N. R. A.; Chan, L. S.

    2014-12-01

    The South China Sea (SCS) region was situated during Mesozoic on the upper plate of a subduction zone. It later evolved as a collapsed continental basin on the edge of the Yenshanian Andean-type orogeny which has been since then considerably eroded, exposing only granites and relicts of Cretaceous molasse basins. The continental crust rifted from the Paleocene to the Mid Oligocene in the eastern part, and the rifting continued until the Middle Miocene in the SW, in an environment of marginal basin opened in the midst of the lower plate. Both spreading and rifting ceased when the subduction of the Proto South China Sea (PSCS) was blocked. Finally the SCS basin which was previously always open to the NE, became isolated by the docking of the northern Philippine Mobile Belt in Luzon, Mindoro and Taiwan islands, during the Late Miocene. Since then the basin subsided whereas the margins observed various amount of uplift, and subsequent gravity tectonics. We illustrate how these event are interdependent, the Cretaceous active margin opening the PSCS by rifting and oceanic crust developed from magma-poor rifting to subsequent seafloor spreading in the Paleogene. It is not clear how the inherited sub continental mantle played a role in the unusual rifting style of the SCS, whose upper crust was extremely stretched for a large time span and was sustained near sea level during the entire duration of the rifting process. The large Jurassic and Cretaceous granitic bodies conditioned the location of the extension via large detachments and normal faults; so that the present day morphology of the sea floor still reflects the location of the granites on which large reefal platforms developed. The mid Miocene cessation of subduction in the PSCS created shortening which jammed its sediments on the NE margin of Borneo, thus generating sub-aerial conditions for the NW Borneo wedge. The resulting erosion created the large deltas starting from the end of the Early Miocene. Excess of

  8. On the tidally driven circulation in the South China Sea: modeling and analysis

    NASA Astrophysics Data System (ADS)

    Nelko, Varjola; Saha, Abhishek; Chua, Vivien P.

    2014-03-01

    The South China Sea is a large marginal sea surrounded by land masses and island chains, and characterized by complex bathymetry and irregular coastlines. An unstructured-grid SUNTANS model is employed to perform depth-averaged simulations of the circulation in the South China Sea. The model is tidally forced at the open ocean boundaries using the eight main tidal constituents as derived from the OSU Tidal Prediction Software. The model simulations are performed for the year 2005 using a time step of 60 s. The model reproduces the spring-neap and diurnal and semidiurnal variability in the observed data. Skill assessment of the model is performed by comparing model-predicted surface elevations with observations. For stations located in the central region of the South China Sea, the root mean squared errors (RMSE) are less than 10 % and the Pearson's correlation coefficient ( r) is as high as 0.9. The simulations show that the quality of the model prediction is dependent on the horizontal grid resolution, coastline accuracy, and boundary locations. The maximum RMSE errors and minimum correlation coefficients occur at Kaohsiung (located in northern South China Sea off Taiwan coast) and Tioman (located in southern South China Sea off Malaysia coast). This may be explained with spectral analysis of sea level residuals and winds, which reveal dynamics at Kaohsiung and Tioman are strongly influenced by the seasonal monsoon winds. Our model demonstrates the importance of tidally driven circulation in the central region of the South China Sea.

  9. A new evaporation duct climatology over the South China Sea

    NASA Astrophysics Data System (ADS)

    Shi, Yang; Yang, Kunde; Yang, Yixin; Ma, Yuanliang

    2015-10-01

    The climatology of evaporation ducts is important for shipborne electromagnetic system design and application. The evaporation duct climatology that is currently used for such applications was developed in the mid 1980s; this study presents efforts to improve it over the South China Sea (SCS) by using a state-of-the-art evaporation duct model and an improved meteorology dataset. This new climatology provides better evaporation duct height (EDH) data over the SCS, at a higher resolution of 0.312°×0.313°. A comparison between the new climatology and the old one is performed. The monthly average EDH in the new climatology is between 10 and 12 m over the SCS, higher than that in the old climatology. The spatiotemporal characteristics of the evaporation duct over the SCS in different months are analyzed in detail, based on the new climatology.

  10. Anaerobic ammonium oxidation, denitrification and dissimilatory nitrate reduction to ammonium in the East China Sea sediment

    NASA Astrophysics Data System (ADS)

    Song, G. D.; Liu, S. M.; Marchant, H.; Kuypers, M. M. M.; Lavik, G.

    2013-03-01

    Benthic nitrogen transformation pathways were investigated in the sediment of the East China Sea in June of 2010 using the 15N isotope pairing technique. Slurry incubations indicated that denitrification, anammox and dissimilatory nitrate reduction to ammonium (DNRA) as well as nitrate release by nitrate storing organisms occurred in the East China Sea sediments. These four processes did not exist independently, the nitrate release therefore diluted the 15N labeling fraction of NO3-, a part of the 15NH4+ derived from DNRA also formed 30N2 via anammox. Therefore current methods of rate calculations led to over and underestimations of anammox and denitrification respectively. Following the procedure outlined in Thampdrup and Dalsgaard (2002), denitrification rates were slightly underestimated by on average 6% without regard to the effect of nitrate release, while this underestimation could be counteracted by the presence of DNRA. On the contrary, anammox rates calculated from 15NO3- experiment were significantly overestimated by 42% without considering nitrate release. In our study this overestimation could only be compensated 14% by taking DNRA into consideration. In a parallel experiment amended with 15NH4+ + 14NO3-, anammox rates were not significantly influenced by DNRA due to the high background of 15NH4+ addition. Excluding measurements in which bioirrigation was present, integrated denitrification rates decreased from 10 to 4 mmol N m-2 d-1 with water depth, while integrated anammox rates increased from 1.5 to 4.0 mmol N m-2 d-1. Consequently, the relative contribution of anammox to the total N-loss increased from 13% at the shallowest site near the Changjiang estuary to 50% at the deepest site on the outer shelf. This study represents the first time in which anammox has been demonstrated to play a significant role in benthic nitrogen cycling in the East China Sea sediment, especially on the outer shelf. N-loss as N2 was the main pathway

  11. Eddy analysis in the Eastern China Sea using altimetry data

    NASA Astrophysics Data System (ADS)

    Qin, Dandi; Wang, Jianhong; Liu, Yu; Dong, Changming

    2015-12-01

    Statistical characteristics of mesoscale eddies in the Eastern China Sea (ECS) are analyzed using altimetry sea surface height anomaly (SSHA) data from 1993 to 2010. A velocity geometry-based automated eddy detection scheme is employed to detect eddies from the SSHA data to generate an eddy data set. About 1,096 eddies (one lifetime of eddies is counted as one eddy) with a lifetime longer than or equal to 4 weeks are identified in this region. The average lifetime and radius of eddies are 7 weeks and 55 km, respectively, and there is no significant difference between cyclonic eddies (CEs) and anticyclonic eddies (AEs) in this respect. Eddies' lifetimes are generally longer in deep water than in shallow water. Most eddies propagate northeastward along the Kuroshio (advected by the Kuroshio), with more CEs generated on its western side and AEs on its eastern side. The variation of the Kuroshio transport is one of the major mechanisms for eddy genesis, however the generation of AEs on the eastern side of the Kuroshio (to the open ocean) is also subject to other factors, such as the wind stress curl due to the presence of the Ryukyu Islands and the disturbance from the open ocean.

  12. Dissolved Black Carbon in the South China Sea

    NASA Astrophysics Data System (ADS)

    Fang, Z.; Yang, W.; Chen, M.; Ma, H.

    2015-12-01

    Dissolved black carbon (DBC) has been ubiquitously reported in dissolved organic matter (DOM). However, the abundance and provenance of DBC in the ocean are not well understood. Here, DBC in the South China Sea (SCS) was determined at molecular level using the benzenepolycarboxylic acids (BPCAs) method. DBC showed high concentrations in the upper 100 m seawater with the average of 1.13 μmol l-1 (n=55). In the intermediate seawater (200-1500 m), DBC ranged from 0.67 to 0.89 μmol l-1 with the average of 0.78 μmol l-1 (n=9), exhibiting nearly homogeneous distributions. The vertical distribution pattern indicated that DBC significantly degraded in the photic zone, corresponding to an attenuate constant of 12.5±4.9 km-1. The ratios of B6CA/B3CAs increased downward, implying that aromatic condensation degree of DBC increase during transport from surface to deep water. Using the standing crops of DBC in the upper 200 m and the residence time of seawater, atmospheric deposition of DBC was estimated to be 1.94 TgC yr-1, accounting for around 16% of the global BC deposition. Our study highlights that DBC could be an important component of ocean carbon cycling in Pacific Asia Marginal Seas.

  13. Wind-induced currents in the South China Sea

    NASA Astrophysics Data System (ADS)

    Luu, Quang-Hung; Tkalich, Pavel

    2016-04-01

    The South China Sea (SCS) is one of the Earth's largest marginal seas. Located in the transitional region between the Pacific Ocean and the Indian Ocean as well as in the convergent zone of various multi-scale atmospheric and climatic drivers, the wind-induced circulations in the SCS are highly complicated. In this study, we derive the high-resolution seasonal patterns of wind-induced circulations in the SCS using the Semi-implicit Eulerian-Lagrangian Finite-Element (SELFE) model. The complicated bathymetry is mainly resolved by the dataset of the Shuttle Radar Topography Mission (SMRT) with the resolution as fine as 15-arc second. We further improve the topography by merging it with very-fine bathymetry being digitized from satellite images for features and islands the in the middle of the SCS (the Spratly and the Paracels). The model is forced by climatological wind and atmospheric pressure from National Centers for Environmental Prediction (NCEP). High-resolution patterns of wind-induced circulations in the SCS during Northeast (NE) and Southwest (SW) monsoons are presented, zooming at small features in the middle of the SCS. We further discuss the distortions of wind-induced currents during NE and SW seasons by examining two cases: the presence and the absence of tides.

  14. Regulation of South China Sea throughflow by pressure difference

    NASA Astrophysics Data System (ADS)

    Qin, Huiling; Huang, Rui Xin; Wang, Weiqiang; Xue, Huijie

    2016-06-01

    Sea Surface Height (SSH) data from the European Centre for Medium-Range Weather Forecasts-Ocean Reanalysis System 4 (ECMWF-ORAS4) are used to determine the pressure difference in connection with variability of the South China Sea ThroughFlow (SCSTF) from 1958 to 2007. Two branches of SCSTF, the Karimata-Sunda Strait ThroughFlow (KSSTF) and the Mindoro Strait ThroughFlow (MSTF), are examined. Using the ensemble empirical mode decomposition method (EEMD), time series of pressure difference and volume transport are decomposed into intrinsic mode functions and trend functions, with the corresponding variability on different time scales. Pressure difference agrees with the KSSTF volume transport on decadal time scale; while for the MSTF, pressure difference varies similarly with volume transport on interannual time scale. Separating the dynamic height difference into the thermal and haline terms, for the KSSTF more than half of the dynamic height difference (32 cm) is due to the thermal contributions; while the remaining dynamic height difference (23 cm) is due to the haline contributions. For the MSTF, the dynamic height difference (29 cm) is primarily due to the thermal contribution (26 cm).

  15. Impact of sea surface temperature front on stratus-sea fog over the Yellow and East China Seas — a case study with implications for climatology

    NASA Astrophysics Data System (ADS)

    Li, Man; Zhang, Suping

    2013-06-01

    A stratus-sea fog event that occurred over the Yellow and East China Seas on 3 June 2011 is investigated using observations and a numerical model, with a focus on the effects of background circulation and Sea Surface Temperature Front (SSTF) on the transition of stratus into sea fog. Southerly winds of a synoptic high-pressure circulation transport water vapor to the Yellow Sea, creating conditions favorable for sea fog/stratus formation. The subsidence from the high-pressure contributes to the temperature inversion at the top of the stratus. The SSTF forces a secondary circulation within the ABL (Atmospheric Boundary Layer), the sinking branch of which on the cold flank of SSTF helps lower the stratus layer further to reach the sea surface. The cooling effect over the cold sea surface counteracts the adiabatic warming induced by subsidence. The secondary circulation becomes weak and the fog patches are shrunk heavily with the smoothed SSTF. A conceptual model is proposed for the transition of stratus into sea fog over the Yellow and East China Seas. Finally, the analyses suggest that sea fog frequency will probably decrease due to the weakened SSTF and the reduced subsidence of secondary circulation under global warming.

  16. Sedimentation rate control on diagenesis, East China Sea sediments

    NASA Astrophysics Data System (ADS)

    Zheng, Yan; Zheng, Hongbo; Kissel, Catherine; Laj, Carlo

    2011-08-01

    Diagenesis of ferrimagnetic minerals can alter the magnetic properties, erasing partially or entirely the original paleomagnetic and paleoclimatic signals, especially on continental margins where sedimentation rates are usually high. Understanding the mechanisms by which magnetic particles are affected by diagenesis is therefore critical for retrieving paleomagnetic and paleoclimatic information from sediments. High-resolution magnetic analysis was carried out on rapidly deposited (0.4-20 mm/year) Holocene sediments from the East China Sea (ECS) inner continental shelf. The primary magnetic mineral assemblage in the sediment core contains ferrimagnetic minerals, such as magnetite, with minor contributions from hematite. The magnetic properties vary down-core in two steps, due to post-depositional reductive diagenesis. The first occurs at depths of 0.15-1.1 m and is characterized by reduction of both magnetite and hematite in suboxic sediments. The suboxic-sulfate boundary (SSB) is therefore located at 1.1 m. We demonstrate that the depth of the SSB has negative relation to the average sedimentation rate in Chinese marginal seas. The second step change in magnetic properties occurs at 3.2-5.8 m, and contains two intervals with extremely low magnetic mineral content, each corresponding to dissolution fronts associated with the former and present position of the sulfate-methanic transition (SMT). These two intervals correlate well with abrupt changes in sedimentation rate and separate the anoxic zone into two parts: the sulfidic zone and the methanic zone. Our study suggests that sedimentation rate provides a dominant control on magnetic mineral diagenesis, at least in the Chinese marginal seas, which controls not only the type of redox zonation, but also the thicknesses of diagenetic zones.

  17. Wave climatological analysis in the East China Sea

    NASA Astrophysics Data System (ADS)

    Wang, Jin; Dong, Changming; He, Yijun

    2016-06-01

    The ERA-40 and ERA-Interim datasets from ECMWF (European Centre for Medium-Range Weather Forecasts) are used to study the wave and wind climate in the East China Sea (ECS). The temporal and spatial variablities in the wave and wind fields on multiple scales from the intraseasonal to decadal are discussed in detail. The results show that the wave height and the wind speed are highly correlated, especially in winter. For interannual and decadal scale, the wind and wave in the ECS is strongly influenced by the ENSO and PDO with the negative correlation. The trend spatial distributions of the mean state and extreme events are presented with wave height increase by 0.005-0.01 m a-1 in most of the ECS from 1979 to 2014. The influence of typhoon on the extreme wave is significant. Vector empirical orthogonal function (VEOF) methods are used to analyze the primary three modes of wave and wind variability. Because the monthly values are filtered the fluctuation with period shorter than 14 months before VEOF analysis, the three modes presents interannual variations. The first mode is presented as the wind blowing from land to sea or from sea to land. The second mode reflects the asymmetry of winter and summer monsoon for wind and wave. And the third mode presents as a cyclone located near 28°N which caused by a cyclonic eddy existing in the north of the ECS. The waves are further categorized based on quasi-wave age. The wind waves and swell distributions display obvious differences in different seasons. The wind waves are found to be dominated in autumn and winter in the ECS.

  18. Observations of SST diurnal variability in the South China Sea

    NASA Astrophysics Data System (ADS)

    Tu, Qianguang; Pan, Delu; Hao, Zengzhou; Chen, Jianyu

    2015-10-01

    In this study, a 3-hourly time resolution gap free sea surface temperature (SST) analysis is generated to resolve the diurnal cycle in the South China Sea (SCS, 0°-25°N, 100°-125°E).It takes advantage of hourly geostationary satellite MTSAT observations and combines three infrared and two microwave polar satellite observations at different local times. First, all the data are classified into eight SST datasets at 3 hour intervals and then remapped to 0.05°resolution grids. A series of critical quality control is done to remove the outliers.Then bias adjustment is applied to the polar satellite observations with reference to the MTSAT data. Finally, the six satellites SST data are blended by using the optimal interpolated algorithm. The 3-hourly blended SST is compared against buoy measurements. It shows a good agreement that the biases do not exceed 0.2 °C and root mean square errors range from 0.5 to 0.65 °C. A typical diurnal cycle similar to sine wave is observed. The minimum SST occurs at around 0600h and warming peak occurring between 1300h and 1500h local solar time and then decrease in the late afternoon, tapering off at night on March 13, 2008 for example. The frequency of diurnal warming events derived from four years of the blended SST provides solid statistics to investigate the seasonal and spatial distributions of the diurnal warming in the SCS. The sea surface diurnal warming tends to appear more easily in spring, especially in the coastal regions than other seasons and the central regions.

  19. The effect of aerosols and sea surface temperature on China's climate over the late twentieth century

    NASA Astrophysics Data System (ADS)

    Folini, Doris; Wild, Martin

    2015-04-01

    Focusing on China in the second half of the twentieth century, we examine the relative role of aerosols and prescribed, observation based sea surface temperatures (SSTs) for the evolution of surface solar radiation (SSR), surface air temperature (SAT), and precipitation in ensembles of transient (1870 - 2005) sensitivity experiments with the global climate model ECHAM5-HAM. Observations and simulations with transient SSTs and aerosol emissions agree reasonably well in eastern China in terms of SSR dimming (-6 +/- 2 W/m2/decade, 1960 - 2000), statistically non-significant JJA SAT trend (1950 - 2000), and drying in JJA from 1950 to 1990 (-2.5% to -3.5% per decade, essentially via reduction of convective precipitation). Other major observed features are not reproduce by the model, e.g. precipitation increase in the 1990s in the Yangtze valley, the strong warming in winter in northern parts of China and Mongolia, or SSR dimming in western China. For the model results, SO2 emissions are more relevant than emissions of black and organic carbon. Aerosol effects are less pronounced at higher model resolution. Transient SSTs are found to be crucial for decadal scale SAT variability over land, especially the strong warming in the 1990s, and, via SST forced reduction of cloud cover, for the ceasing of SSR dimming around the year 2000. Unforced cloud variability leads to relevant scatter (up to +/- 2 W/m2/decade) of modeled SSR trends at individual observation sites.

  20. Numerical study on the interannual oscillation of sea surface temperature in the South China Sea

    NASA Astrophysics Data System (ADS)

    Wang, Dong-Xiao; Zhou, Fa-Xiu; Fu, Gang; Qin, Zeng-Hao

    1996-03-01

    A two and a half layer oceanic model of wind-driven, thermodynamical general circulation is applied to study the interannual oscillation of sea surface temperature (SST) in the South China Sea (SCS). The model consists of two active layers: the upper mixed layer (UML) and the seasonal thermocline, with the motionless abyss beneath them. The governing equations which include momentum, continuity and sea temperature for each active layer, can describe the physics of Boussinseq approximation, reduced gravity and equatorial β-plane. The formulas for the heat flux at the surface and at the interface between two active layers are designed on the Haney scheme. The entrainment and detrainment at the bottom of the UML induces vertical transport of mass, momentum and heat, and couples of dynamic and thermodynamic effects. Using leap-frog integrating scheme and the Arakawa—C grid the model is forced by a time-dependent wind anomaly stress pattern obtained from category analysis of COADS. The numerical results indicate that there is a kind of oscillation with about 30 months period. The paper supports the opinion that the SST interannual oscillation is the oceanic response to the forcing by monsoon wind anomalies in the SCS.

  1. Response of Biogeochemical Cycles and Ecosystem in the East China Sea to Multi-stressors

    NASA Astrophysics Data System (ADS)

    Zhang, Jing; Huang, Daji; Xiao, Tian; Liu, Su Mei; Fang, Jianguang

    2016-02-01

    This editorial article introduces the research progress of IMBER-China Study on "Sustainability of Marine Ecosystem Production under Multi-stressors and Adaptive Management" (MEcoPAM), funded by the Ministry of Science and Technology of China (MoST-China No. 2011CB409800). There are 12 research articles in this Special Issue of Deep-Sea Research II on the "East China Sea", which provide the reader with snapshots of "Impact of Multi-stressors on the Structure and Function of Marine Ecosystems", one of research foci of MEcoPAM in the period of 2011-2015.

  2. Cross-shelf Water Exchange Between the Kuroshio and the Northern Marginal Seas of China

    NASA Astrophysics Data System (ADS)

    Yuan, D.

    2012-04-01

    Satellite ocean color and sea surface temperature data and satellite-tracked surface drifter trajectories are used to study the shelf circulation in the Yellow and East China Seas. The ocean color images show a significant turbid water plume extending in the southeast direction from the Subei coasts of China to the shelf edge southwest of Cheju during fall-winter, suggesting significant cross-shelf current in the Yellow Sea/East China Sea in winter. The turbid plume grows in fall, reaches its maximum expansion and intensity in winter-spring, and subsides in late spring. Cold sea surface temperature is associated with the cross-shelf currents, suggesting its nearshore origin in winter. The cross-shelf current is also expressed explicitly by the latest surface drifter trajectories released in the Yellow and East China Sea and tracked by the satellite. The dynamics of the cross-shelf current are found to be induced by the divergence of the wind-driven currents over the middle shelf in winter. A southward sea level gradient is set up by the northerly winds through the propagation of topographic Rossby waves, which forces a broad cross-shelf current in the Yellow and East China Seas in winter. Satellite images also suggest that the East China Sea shelf is frequented with the Cross-shelf Penetrating Fronts (CPF), which are direct and large-distance excursions of coastal mean fronts across the shelf for distances usually exceeding 50 km. The CPFs bring nearshore waters to the middle-to-outer shelf of the East China Sea, representing an important path of material transport across the shelf.

  3. Increasing eutrophication in the coastal seas of China from 1970 to 2050.

    PubMed

    Strokal, Maryna; Yang, He; Zhang, Yinchen; Kroeze, Carolien; Li, Lili; Luan, Shengji; Wang, Huanzhi; Yang, Shunshun; Zhang, Yisheng

    2014-08-15

    We analyzed the potential for eutrophication in major seas around China: the Bohai Gulf, Yellow Sea and South China Sea. We model the riverine inputs of nitrogen (N), phosphorus (P) and silica (Si) to coastal seas from 1970 to 2050. Between 1970 and 2000 dissolved N and P inputs to the three seas increased by a factor of 2-5. In contrast, inputs of particulate N and P and dissolved Si, decreased due to damming of rivers. Between 2000 and 2050, the total N and P inputs increase further by 30-200%. Sewage is the dominant source of dissolved N and P in the Bohai Gulf, while agriculture is the primary source in the other seas. In the future, the ratios of Si to N and P decrease, which increases the risk of harmful algal blooms. Sewage treatment may reduce this risk in the Bohai Gulf, and agricultural management in the other seas. PMID:24981103

  4. Submarine sand ridges and sand waves in the eastern part of the China Sea

    NASA Astrophysics Data System (ADS)

    Wu, Ziyin; Li, Shoujun; Shang, Jihong; Zhou, Jieqiong; Zhao, Dineng; Liang, Yuyang

    2016-04-01

    Integrated with multi-beam and single-beam echo sounding data, as well as historical bathymetric data, submarine bathymetric maps of the eastern part of the China Sea, including the Bohai Sea, Huanghai Sea, and East China Sea, are constructed to systematically study submarine sand ridges and sand waves in the eastern part of the China Sea, combined with high-resolution seismic, sub-bottom profile and borehole data. Submarine sand ridges are extraordinarily developed in the eastern part of the China Sea, and 7 sand ridge areas can be divided from north to south, that is, the Laotieshan Channel sand ridge area in the Bohai Sea, the Korea Bay sand ridge area in the southern Huanghai Sea, the sand ridge area in the eastern Huanghai islands and the Huanghai Troughs, the Jianggang sand ridge area in the western Huanghai Sea, the sand ridge area in the East China Sea shelf, and the sand ridge and sand wave area in the Taiwan Strait and Taiwan Banks. The distribution area of the sand ridges and sand waves covers more than 450,000 km2, wherein ~10,000 km2 in the Bohai Bay, ~200,000 km2 in the Huanghai Sea, ~200,000 km2 in the East China Sea shelf, and ~40,000 km2 in the Taiwan Strait and Taiwan Banks, respectively. The great mass of sand ridges are distributed within water depth of 5-160 m, with a total length of over 160 km and a main width of 5-10 km. The inner structure of the sand ridges presents features of high-angle inclined beddings, with main lithology of sands, sand-mud alternations partly visible, and a small number of mud cores. Dating results indicate that the sand ridges in the eastern part of the China Sea are mainly developed in the Holocene. Sea-level variation dominates the sand ridge evolution in the eastern part of the China Sea since the LGM, and the sand ridges developed in the area of < 60m water depth are appeared in bad activity, meanwhile sand ridges with good activity are still developed in large scale.

  5. Application of a sea surface temperature front composite algorithm in the Bohai, Yellow, and East China Seas

    NASA Astrophysics Data System (ADS)

    Ping, Bo; Su, Fenzhen; Meng, Yunshan; Du, Yunyan; Fang, Shenghui

    2016-05-01

    The oceanic front is a narrow zone in which water properties change abruptly within a short distance. The sea surface temperature (SST) front is an important type of oceanic front, which plays a signifi cant role in many fi elds including fi sheries, the military, and industry. Satellite-derived SST images have been used widely for front detection, although these data are susceptible to infl uence by many objective factors such as clouds, which can cause missing data and a reduction in front detection accuracy. However, front detection in a single SST image cannot fully refl ect its temporal variability and therefore, the long-term mean frequency of occurrence of SST fronts and their gradients are often used to analyze the variations of fronts over time. In this paper, an SST front composite algorithm is proposed that exploits the frontal average gradient and frequency more eff ectively. Through experiments based on MODIS Terra and Aqua data, we verifi ed that fronts could be distinguished better by using the proposed algorithm. Additionally through its use, we analyzed the monthly variations of fronts in the Bohai, Yellow, and East China Seas, based on Terra data from 2000 to 2013.

  6. Distributions and sea-to-air fluxes of nitrous oxide in the South China Sea and the West Philippines Sea

    NASA Astrophysics Data System (ADS)

    Tseng, Hsiao-Chun; Chen, Chen-Tung Arthur; Borges, Alberto V.; DelValls, T. Angel; Lai, Chao-Ming; Chen, Ting-Yu

    2016-09-01

    Approximately 600 water samples from the South China Sea (SCS) and 250 water samples from the West Philippines Sea (WPS) were collected during seven cruises from August 2003 to July 2007 to determine nitrous oxide (N2O) distributions between the surface and a maximum depth of 4250 m. In the SCS, the average surface N2O concentration exceeded the atmospheric equilibrium concentration (on average 132±23%); however in the WPS, the surface N2O concentration was lower than the atmospheric equilibrium concentration (on average 90±22%). The N2O concentration reached a maximum (~23 nmol L-1) in the WPS at 800-1000 m, and (~28 nmol L-1) at a shallower depth of around 600-800 m in the SCS, owing to vertical mixing and intensive upwelling in the SCS. In the SCS, the surface N2O concentration was 7.59±1.32 nmol L-1 and the calculated sea-to-air flux was 5.5±3.9 μmol m-2 d-1. The surface N2O concentration in the WPS, 5.19±1.26 nmol L-1, was lower than that in the SCS. The WPS is a sink for N2O and the calculated sea-to-air flux was -1.7±3.9 μmol m-2 d-1. The SCS emitted 19.3×106 mol d-1 N2O to the atmosphere and exported 8.5×106 mol d-1 N2O to the WPS during the wet season.

  7. Sea surface salinity variability in the East China Sea observed by the Aquarius instrument

    NASA Astrophysics Data System (ADS)

    Kim, S.; Lee, J. H.; de Matthaeis, P.; Yueh, S. H.; Hong, C. S.; Pang, I.; Lagerloef, G. S. E.

    2014-12-01

    This study demonstrates that the spaceborne Aquarius instrument is able to monitor the sea surface salinity (SSS) variations in the East China Sea (ECS), where routine observations are difficult. The two geophysical contaminants enter the sidelobes of the Aquarius antenna and bias the coastal SSS low: the emission from the land surface and the radiofrequency interference (RFI). Away from about one Aquarius pixel (150 km) from the coastline, the Aquarius SSS is fairly insensitive (less than about 0.2 psu) to the radiometric details of the method to correct for the land emission. The ascending orbits appear to be affected by unfiltered RFI much less than the descending tracks. The Aquarius SSS along the ascending tracks is low over the ECS by 0.40 to 0.93 psu (with respect to the in situ data during the two separate 7-day periods) and is biased low by 0.41 to 1.07 psu (accuracy, or the time-mean of difference from the regional model along three Aquarius tracks over a 18-month period). The presence of the ascending and descending differences in the Aquarius SSS, and the spatially widespread bias suggest that the bias is attributed to the unfiltered RFI originating from strong point sources (rather than to the land contamination from weak distributed sources, or to other seasonally-varying geophysical contaminants). Despite the bias, the Aquarius data describe well the temporal and spatial variability of the ECS SSS. The temporal trend and magnitude of salinity changes agree remarkably between Aquarius and a regional numerical model, during both the freshwater discharge season from the Yangtze river and the rest of the year. The river discharge rate correlates with the Aquarius SSS with the coefficient of 0.71 on a seasonal scale with the discharge leading the SSS changes. The Aquarius SSS increases away from the coast, in response to the river outflow. The interannual changes in the Aquarius SSS capture the effect of the regional drought in summer 2013. Kim et al., in

  8. The Tectonics and Seafloor Spreading Mode of the Eastern South China Sea

    NASA Astrophysics Data System (ADS)

    Hsu, S. K.; Armada, L. T.; Yeh, Y. C.; Bacolcol, T. C.; Dimalanta, C. B.; Doo, W. B.; Liang, C. W.

    2014-12-01

    The South China Sea could be separated into several sub-basins. Among all, the eastern subbasin of the South China Sea occupies the largest portion. The importance of this basin is that the eastern basin holds the main key of understanding the tectonic evolution of the South China Sea. Besides, its subduction southeastward beneath the Philippine islands along the Manila Trench may generate big earthquakes and/or tsunamis affecting the coastal countries surrounding the South China Sea. To better understand the tectonics of the eastern South China Sea basin and the Manila Trench, we have conducted a marine geophysical survey from June 23 to July 13, 2014. Our results show that the extinct mid-ocean-ridges of the basin are displayed en echelon. The ridge subduction beneath the Luzon Island probably does not occur or is just in the early beginning. For the seafloor spreading of the eastern South China Sea, there was probably no ridge jump in magnetic lineation 7 as suggested by Taylor and Hayes or Briais et al. Based on the analysis of our new reflection seismic profiles, bathymetric and magnetic data, the tectonic evolution of the eastern South China Sea basin could be described in three stages. Before magnetic lineation 7, the oceanic crust spread in N-S direction. Between magnetic lineations 7 (~25Ma) and 6c (~20 Ma), the seafloor spreading was in NW-SE direction. However, the supply of the upwelling magma along the mid-ocean-ridges was increasing during this second stage, especially in the eastern side. The abnormal supply of magma thus caused the fan-shaped seafloor spreading fabrics of the eastern South China Sea. Even after the cessation of the seafloor spreading, a supply of the upwelling magma had continued between 20 and 16 Ma, which caused the disturbed sedimentary layers, mainly in the middle area of the basin.

  9. Black carbon over the South China Sea and in various continental locations in South China

    NASA Astrophysics Data System (ADS)

    Wu, D.; Wu, C.; Liao, B.; Chen, H.; Wu, M.; Li, F.; Tan, H.; Deng, T.; Li, H.; Jiang, D.; Yu, J. Z.

    2013-12-01

    Black carbon (BC) is an important atmospheric constituent as an air pollutant and as a climate forcer. To our knowledge, field measurements of BC have not been reported over the South China Sea. Observations of light-absorption coefficients (σabs) and BC concentrations by Aethalometer were conducted on Yongxing Island in the South China Sea and at five continental sites in the Pearl River delta (PRD) region, South China, in two periods: 16 May-20 June 2008 in the rainy season and 12 December 2008-8 January 2009 in the dry season. At the oceanic site, the daily average BC concentrations varied from 0.28 to 2.14 μg m-3 and variations of BC were small between the two periods (0.67 in the dry season sampling period and 0.54 μg m-3 in the rainy season sampling period). Similarly, little difference in BC level was found at a rural site in PRD between the two sampling periods (2.88 and 2.62 μg m-3). At the PRD urban sites, the daily average concentration of BC ranged from 1.56 to 37.9 μg m-3, higher in the dry season sampling period (12.31 μg m-3) and lower in the rainy season sampling period (6.17 μg m-3). The observed average σabs values in rainy vs. dry season sampling periods are 119 vs. 62 Mm-1 at the PRD urban sites, 29 vs. 26 Mm-1 at the PRD background site, and 8.4 vs. 7.2 Mm-1 at the marine site. At urban/suburban PRD sites, BC was observed to have a diurnal pattern of higher concentrations at night and at the urban sites a small peak in the early morning rush hour.

  10. Predictability of winter temperature in China from previous autumn Arctic sea ice

    NASA Astrophysics Data System (ADS)

    Zuo, Jinqing; Ren, Hong-Li; Wu, Bingyi; Li, Weijing

    2016-01-01

    The potential predictability of winter temperature in China from autumn Arctic sea ice anomalies is studied by examining and statistically modeling the large-scale interannual covariability between them on the basis of singular value decomposition analysis. It is demonstrated that an intimate relationship exists between September and October sea ice anomalies in the Eurasian Arctic and following winter temperature anomalies in China, except in the Tibetan Plateau. When the autumn sea ice anomalies decline in the Eurasian Arctic, above-normal pressure anomalies appear to prevail over the region from the Eurasian Arctic to Eastern Europe and Mongolia, and below-normal anomalies prevail over the mid-latitudes of Asia and Northwestern Pacific in the following winter. Consequently, the winter Siberian High and East Asian trough are both strengthened, favoring the southward invasion of high-latitude cold air masses and thus cold temperature anomalies in China. It is found that the Siberian High plays a crucial role in delivering effects of the autumn Arctic sea ice anomalies on winter temperature variability in China. Based on this evidence, a statistical model is established to examine the potential predictability of winter temperature anomalies in China by taking the autumn Arctic sea ice signals as a predictor. Validation shows considerable skill in predicting winter temperature anomalies over a large part of China, indicating a significant potential for improving winter climate prediction in China.

  11. Observed 3D Structure, Generation, and Dissipation of Oceanic Mesoscale Eddies in the South China Sea

    NASA Astrophysics Data System (ADS)

    Zhang, Zhiwei; Tian, Jiwei; Qiu, Bo; Zhao, Wei; Chang, Ping; Wu, Dexing; Wan, Xiuquan

    2016-04-01

    Oceanic mesoscale eddies with horizontal scales of 50–300 km are the most energetic form of flows in the ocean. They are the oceanic analogues of atmospheric storms and are effective transporters of heat, nutrients, dissolved carbon, and other biochemical materials in the ocean. Although oceanic eddies have been ubiquitously observed in the world oceans since 1960s, our understanding of their three-dimensional (3D) structure, generation, and dissipation remains fragmentary due to lack of systematic full water-depth measurements. To bridge this knowledge gap, we designed and conducted a multi-months field campaign, called the South China Sea Mesoscale Eddy Experiment (S-MEE), in the northern South China Sea in 2013/2014. The S-MEE for the first time captured full-depth 3D structures of an anticyclonic and cyclonic eddy pair, which are characterized by a distinct vertical tilt of their axes. By observing the eddy evolution at an upstream versus downstream location and conducting an eddy energy budget analysis, the authors further proposed that generation of submesoscale motions most likely constitutes the dominant dissipation mechanism for the observed eddies.

  12. Assessment for water quality by artificial neural network in Daya Bay, South China Sea.

    PubMed

    Wu, Mei-Lin; Wang, You-Shao; Gu, Ji-Dong

    2015-10-01

    In this study, artificial neural network such as a self-organizing map (SOM) was used to assess for the effects caused by climate change and human activities on the water quality in Daya Bay, South China Sea. SOM has identified the anthropogenic effects and seasonal characters of water quality. SOM grouped the four seasons as four groups (winter, spring, summer and autumn). The Southeast Asian monsoons, northeasterly from October to the next April and southwesterly from May to September have also an important influence on the water quality in Daya Bay. Spatial pattern is mainly related to anthropogenic activities and hydrodynamics conditions. In spatial characteristics, the water quality in Daya Bay was divided into two groups by chemometrics. The monitoring stations (S3, S8, S10 and S11) were in these area (Dapeng Ao, Aotou Harbor) and northeast parts of Daya Bay, which are areas of human activity. The thermal pollution has been observed near water body in Daya Bay Nuclear Power Plant (S5). The rest of the monitoring sites were in the south, central and eastern parts of Daya Bay, which are areas that experience water exchanges from South China Sea. The results of this study may provide information on the spatial and temporal patterns in Daya Bay. Further research will be carry out more research concerning functional changes in the bay ecology with respect to changes in climatic factor, human activities and bay morphology in Daya Bay. PMID:25847104

  13. Inversion of Oceanic Lithosphere Density Structure in the South China Sea by Satellite Gravity

    NASA Astrophysics Data System (ADS)

    Zhang, S.

    2013-12-01

    In this paper, the satellite altimetry gravity anomaly is used to calculate the Bouguer gravity by Seafloor terrain correction in the South China Sea. The faults distribution and basin boundary is extracted to study the geological structure unit. The 3D density inversion method is applied to invert the oceanic lithosphere density structure. In the 3D density inversion method, the depth weighting function is an experience function derived by the relation between gravity anomaly and depth. It is difficult to artificially choose reasonable values of the weighting factors which have great effect on the inversion result. The power spectrum of the gravity anomaly is used to estimate the depth of the geological body, and the function of the weighting factors and the gravity anomaly is built. The weighting factors can be estimated automatically by the gravity anomaly power spectrum. Therefore, the artificial error can be avoided and the accuracy of inversion is improved. In the density inversion, the Bouguer gravity is firstly decomposed into different scales by wavelet transform method. The gravity anomaly in different scales is related to the density distribution in different depth. Then, the power spectrum is calculated by gravity anomaly in different scales to estimate the weighting factors. Finally, the ocean lithosphere density structure in the South China Sea is inverted and compared with its velocity structure.

  14. Observed 3D Structure, Generation, and Dissipation of Oceanic Mesoscale Eddies in the South China Sea.

    PubMed

    Zhang, Zhiwei; Tian, Jiwei; Qiu, Bo; Zhao, Wei; Chang, Ping; Wu, Dexing; Wan, Xiuquan

    2016-01-01

    Oceanic mesoscale eddies with horizontal scales of 50-300 km are the most energetic form of flows in the ocean. They are the oceanic analogues of atmospheric storms and are effective transporters of heat, nutrients, dissolved carbon, and other biochemical materials in the ocean. Although oceanic eddies have been ubiquitously observed in the world oceans since 1960s, our understanding of their three-dimensional (3D) structure, generation, and dissipation remains fragmentary due to lack of systematic full water-depth measurements. To bridge this knowledge gap, we designed and conducted a multi-months field campaign, called the South China Sea Mesoscale Eddy Experiment (S-MEE), in the northern South China Sea in 2013/2014. The S-MEE for the first time captured full-depth 3D structures of an anticyclonic and cyclonic eddy pair, which are characterized by a distinct vertical tilt of their axes. By observing the eddy evolution at an upstream versus downstream location and conducting an eddy energy budget analysis, the authors further proposed that generation of submesoscale motions most likely constitutes the dominant dissipation mechanism for the observed eddies. PMID:27074710

  15. Observed 3D Structure, Generation, and Dissipation of Oceanic Mesoscale Eddies in the South China Sea

    PubMed Central

    Zhang, Zhiwei; Tian, Jiwei; Qiu, Bo; Zhao, Wei; Chang, Ping; Wu, Dexing; Wan, Xiuquan

    2016-01-01

    Oceanic mesoscale eddies with horizontal scales of 50–300 km are the most energetic form of flows in the ocean. They are the oceanic analogues of atmospheric storms and are effective transporters of heat, nutrients, dissolved carbon, and other biochemical materials in the ocean. Although oceanic eddies have been ubiquitously observed in the world oceans since 1960s, our understanding of their three-dimensional (3D) structure, generation, and dissipation remains fragmentary due to lack of systematic full water-depth measurements. To bridge this knowledge gap, we designed and conducted a multi-months field campaign, called the South China Sea Mesoscale Eddy Experiment (S-MEE), in the northern South China Sea in 2013/2014. The S-MEE for the first time captured full-depth 3D structures of an anticyclonic and cyclonic eddy pair, which are characterized by a distinct vertical tilt of their axes. By observing the eddy evolution at an upstream versus downstream location and conducting an eddy energy budget analysis, the authors further proposed that generation of submesoscale motions most likely constitutes the dominant dissipation mechanism for the observed eddies. PMID:27074710

  16. Modeling underwater transport of oil spilled from deepwater area in the South China Sea

    NASA Astrophysics Data System (ADS)

    Chen, Haibo; An, Wei; You, Yunxiang; Lei, Fanghui; Zhao, Yupeng; Li, Jianwei

    2016-01-01

    Based on a Lagrangian integral technique and Lagrangian particle-tracking technique, a numerical model was developed to simulate the underwater transport of oil from a deepwater spill. This model comprises two submodels: a plume dynamics model and an advection-diffusion model. The former is used to simulate the stages dominated by the initial jet momentum and plume buoyancy of the spilled oil, while the latter is used to simulate the stage dominated by the ambient current and turbulence. The model validity was verified through comparisons of the model predictions with experimental data from several laboratory flume experiments and a field experiment. To demonstrate the capability of the model further, it was applied to the simulation of a hypothetical oil spill occurring at the seabed of a deepwater oil/gas field in the South China Sea. The results of the simulation would be useful for contingency planning with regard to the emergency response to an underwater oil spill.

  17. Winter Cold tongue in the South China Sea

    NASA Astrophysics Data System (ADS)

    Thompson, B.; Tkalich, P.; Rizzoli, P. M.

    2014-12-01

    The South China Sea (SCS) surface circulation is mainly forced by seasonally varying monsoon winds and flow through the Luzon Strait. In winter, positive wind curl (due to the northeasterly winds) in the southern half of SCS drives a cyclonic gyre. The strong western boundary current south off Vietnam on the continental slope separates the Sunda Shelf to the west and deep SCS basin to the east. The advection of cold water due to the slope current results in a unique cold tongue in Sea Surface Temperature (SST) from November to February. The inter-annual variability of this cold-tongue is investigated by analyzing the NCEP OISST version-2 dataset. Dynamics of the evolution, growth and decay of the cold tongue during the period 1982-2012 are addressed using the OISST and ERA-interim surface wind datasets. The role of water mass advection in the inter-annual variability of SCS cold-tongue is also investigated through the analysis of lateral heat fluxes estimated from NCEP-Climate Forecast System Re-analysis dataset. The vertically integrated Ekman transport (i.e., the Sverdrup transport) plays a vital role in the formation this cold tongue. The southward Sverdrup transport brings cold water from the northern parts of the SCS. Inter-annual variations in the cold tongue SST during the northeast monsoon (November to February) are strongly linked to the north-south Sverdrup and zonal Ekman transport anomalies. The positive SST anomalies over the cold-tongue region are associated with positive transport anomalies, reflecting the weakening of the southward and westward advection. The formation and termination of this cold tongue has significant correlation with the El Nino phenomenon in the Pacific Ocean.

  18. Antimony and arsenic biogeochemistry in the East China Sea

    NASA Astrophysics Data System (ADS)

    Ren, Jing-Ling; Zhang, Xu-Zhou; Sun, You-Xu; Liu, Su-Mei; Huang, Daji; Zhang, Jing

    2016-02-01

    The biogeochemical cycles of the metalloid elements arsenic and antimony in the East China Sea (ECS), one of the most important marginal seas for western Pacific, were examined in May 2011. Dissolved inorganic arsenic (As(V) and As(III)) and antimony (Sb(V) and Sb(III)) species were determined by selective hydride generation-atomic fluorescence spectrometry (HG-AFS). Results show that total dissolved inorganic arsenic (TDIAs; [TDIAs]=[As(V)]+[As(III)]) were moderately depleted in the surface water and enriched in the deep water. Arsenite (As(III)) showed different vertical profiles with that of TDIAs, with significant surface enrichment in the middle shelf region where the concentrations of phosphate were extremely low. Speciation of dissolved arsenic was subtly controlled by the stoichiometric molar ratio of arsenate (As(V)) to phosphate. The average As(V)/P ratio for the ECS in spring 2011 was 10.8×10-3, which is higher than previous results and indicates the arsenate stress. The concentrations of total dissolved inorganic antimony (TDISb; [TDISb]=[Sb(V)]+[Sb(III)]) were high near the Changjiang Estuary and the coastal area of Hangzhou Bay and decreased moderately off the coast. TDISb displayed moderate conservative behavior in the ECS that confirms by the correlations with salinity and dissolved aluminum. Different with that of As(III), antimonite (Sb(III)) concentrations were extremely lower in the ECS, with relative higher concentration appeared at the bottom layer which indicates the contribution from sediment-water interface. A preliminary box model was established to estimate the water-mass balance and antimony budgets for the ECS. Compared with other areas in the world, the concentrations of dissolved inorganic arsenic and antimony in the ECS remain at natural levels.

  19. Deep Structures of the Palawan and Sulu Sea and Their Implications for Opening of the South China Sea

    NASA Astrophysics Data System (ADS)

    Liu, W.; Li, C. F.; Li, J.; Fairhead, D.; Zhou, Z.

    2014-12-01

    Compared to the northern South China Sea continental margin, the deep structures and tectonic evolution of the Palawan and Sulu Sea and ambient regions are not well understood so far. However, this part of the southern continental margin and adjacent areas embed critical information on the opening of the South China Sea (SCS). We carry out geophysical investigations using regional magnetic, gravity and reflection seismic data. Analytical signal amplitudes (ASA) of magnetic anomalies are calculated to depict the boundaries of different tectonic units. Curie-point depths are estimated from magnetic anomalies using a windowed wavenumber-domain algorithm. Application of the Parker-Oldenburg algorithm to Bouguer gravity anomalies yields a 3D Moho topography. The Palawan Continental Block (PCB) is defined by quiet magnetic anomalies, low ASA, moderate depths to the top and bottom of the magnetic layer, and its northern boundary is further constrained by reflection seismic data and Moho interpretation. However, the continent-ocean transition zone between the PCB and the SCS is characterized by hyper-extended continental crust intruded with magmatic bodies. The NW Sulu Sea is interpreted as a relict oceanic slice and the geometry and position of extinct trench of the Proto South China Sea (PSCS) is further constrained. With additional age constraints from inverted Moho and Curie-point depths, we confirm that the spreading of the SE Sulu Sea started in the Early Oligocene/Late Eocene due to the subduction of the PSCS, and terminated in the Middle Miocene by the obduction of the NW Sulu Sea onto the PCB. According to the newly constrained age of SE Sulu Sea, we also estimate the approximate extent, spreading rate and subducting rate of original SE Sulu Sea.

  20. Propagated rifting in the Southwest Sub-basin, South China Sea: Insights from 3D analogue modeling

    NASA Astrophysics Data System (ADS)

    Ding, Weiwei; Li, Jiabiao

    2015-04-01

    Most of earth scientists agree that the South China Sea is a rifted marginal sea in the western Pacific. How and when the South China Sea rifted has long been a puzzling question and still debated, especially in the Southwest Sub-basin (SWSB). Analog modeling remains one of the useful tools for testing rift model and process. Here we present and discuss a series of analog modeling experiments designed to investigate the rifting process of the SWSB. Convincing geophysical data were compiled to provide truthful constraints to test the experimental results and interpretations. The results show that rigid tectonic blocks existed in the continental margin, such as the Zhongsha Islands and the Reed Bank, and played an important role in shaping up the continent-ocean boundary (COB) and the coupling between the crust and mantle. Our data suggest that the initial thermal condition and rheologial stratification of the lithosphere under the South China Sea controlled the rifting process of the SWSB. The first-stage seafloor spreading has weakened the lithosphere surrounding the East Sub-basin, and the extension was centered on the deep troughs between the rigid blocks. Rifting bagan in these deep troughs in the east part of the SWSB, and the break-up occurred in localized areas between the rigid blocks. The V-shaped configuration of the SWSB also argues for a propagated rifting model.

  1. Mud Volcanoes from the Beaufort Sea to the South China Sea

    NASA Astrophysics Data System (ADS)

    Lundsten, E. M.; Paull, C. K.; Caress, D. W.; Dallimore, S.; Melling, H.; Liu, C. S.; Anderson, K.; Gwiazda, R.

    2015-12-01

    The detailed morphology of five submarine mud volcanoes were surveyed using an Autonomous Underwater Vehicle (AUV) developed at the Monterey Bay Aquarium Research Institute. Mud volcanoes are constructional features built by extrusion of gas, subsurface fluids and fine-grained sediment. Two surveys covering four submarine mud volcanoes were conducted on the CCGS Sir Wilfred Laurier in the Beaufort Sea in the Canadian Arctic. A survey of one mud volcano was conducted on the Taiwanese Ocean Research V in the South China Sea, SE of Taiwan. The AUV carried a multibeam sonar, a 1-6 kHz chirp sub-bottom profiler, and a110 kHz sidescan, and obtained overlapping multibeam bathymetric coverage at a vertical resolution of 0.15 m with a horizontal footprint of 0.9 m and chirp seismic-reflection profiles with a vertical resolution of 0.11 m. Mud volcanoes were either flat topped or conical. The conical mud volcano off Taiwan had a diameter of ~2 km and 10° side slopes; the conical feature in the Beaufort Sea had a diameter of ~1.5 km and 4° side slopes. The sides of the conical mud volcanoes were smooth, suggesting they were formed by sediment flows that emanate from a vent on their crests. The flanks of the conical mud volcanoes characteristically had very low acoustic reflectivity, but one single high reflectivity trail from the crest of the Beaufort Sea mud volcano indicates a recent flow. Three mud volcanoes in the Beaufort Sea formed circular, flat-topped plateaus that are up to ~1.1 km in diameter and elevated up to 30 m from the surrounding seafloor. The fine scale morphology and reflectivity on these plateaus show low relief, concentric, and ovoid circles that appear to be mud boils probably associated with eruptive events of varying ages at shifting vent sites. The different mud volcano shapes are attributed to variations in the viscosity of the erupting sediment slurries and may represent a sequential morphology, which is altered by shifts in venting position over

  2. Sea surface temperature anomalies in the South China Sea during mature phase of ENSO

    NASA Astrophysics Data System (ADS)

    Qiu, Fuwen; Pan, Aijun; Zhang, Shanwu; Cha, Jing; Sun, Haowei

    2016-05-01

    Based on the 18-year (1993-2010) National Centers for Environmental Prediction optimum interpolation sea surface temperature (SST) and simple ocean data assimilation datasets, this study investigated the patterns of the SST anomalies (SSTAs) that occurred in the South China Sea (SCS) during the mature phase of the El Niño/Southern Oscillation. The most dominant characteristic was that of the outof-phase variation between southwestern and northeastern parts of the SCS, which was influenced primarily by the net surface heat flux and by horizontal thermal advection. The negative SSTA in the northeastern SCS was caused mainly by the loss of heat to the atmosphere and because of the cold-water advection from the western Pacific through the Luzon Strait during El Niño episodes. Conversely, it was found that the anomalous large-scale atmospheric circulation and weakened western boundary current during El Niño episodes led to the development of the positive SSTA in the southwestern SCS.

  3. Impact of two typhoons on the marine environment in the Yellow Sea and East China Sea

    NASA Astrophysics Data System (ADS)

    Fu, Dongyang; Luan, Hong; Pan, Delu; Zhang, Ying; Wang, Li'an; Liu, Dazhao; Ding, Youzhuan; Li, Xue

    2016-07-01

    This study investigated the effects of two typhoons (Nari and Wipha) on sea surface temperature (SST) and chlorophyll- a (Chl- a) concentration. Typhoons Nari and Wipha passed through the Yellow Sea on September 13, 2007 and the East China Sea (ECS) on September 16, 2007, respectively. The SST and Chl- a data were obtained from the Aqua/Terra MODIS and NOAA18, respectively, and the temperature and salinity in the southeast of the study area were observed in situ from Argo. The average SST within the study area dropped from 26.33°C on September 10 to a minimum of 22.79°C on September 16. Without the usual phenomenon of `right bias', the most striking response of SST was in the middle of the typhoons' tracks, near to coastal waters. Strong cooling of the upper layers of the water column was probably due to increased vertical mixing, discharge from the Changjiang River estuary, and heavy rainfall. During the typhoons, average Chl- a increased by 11.54% within the study area and by 21.69% in the offshore area near to the southeast ECS. From September 1 to 13, average Chl- a was only 0.10 mg/m3 in the offshore waters but it reached a peak of >0.17 mg/m3 on September 18. This large increase in Chl- a concentration in offshore waters might have been triggered by strong vertical mixing, upwelling induced by strong typhoons, and sedimentation and nutrient influx following heavy rainfall.

  4. In situ study on photosynthetic characteristics of phytoplankton in the Yellow Sea and East China Sea in summer 2013

    NASA Astrophysics Data System (ADS)

    Li, Junlei; Sun, Xiaoxia; Zheng, Shan

    2016-08-01

    In situ studies on photosynthetic characteristics of phytoplankton were important for the analysis of changes in community structure and for the prediction and control of algal blooms, but such studies of phytoplankton in offshore China were few. In this study, the detailed distribution of photosynthetic characteristics of phytoplankton in the summer of 2013 in the Yellow Sea and East China Sea was measured using Phyto-PAM (Pulse Amplitude Modulation). The phytoplankton community structure and the environmental parameters were also investigated to estimate the relationship between the distribution of the photochemical competence of phytoplankton and ecological factors. The total average Fv/Fm (the potential maximum quantum yield) value of phytoplankton in the Yellow Sea and East China Sea in summer 2013 was less than 0.5, reflecting that the photosynthetic activity of phytoplankton was relatively low. Fv/Fm of phytoplankton in summer was significantly positively associated with nitrate content (NO2-), which reflects relationship between metabolism and photosynthesis of phytoplankton: accompanied by NO2- metabolism, photosynthesis and photosynthetic capacity may be enhanced simultaneously, so the Fv/Fm value would increase with the NO2- released by phytoplankton. Through the in situ study on photosynthetic characteristics of phytoplankton in the Yellow Sea and East China Sea, we come to the conclusion that photosynthetic characteristics and activity of phytoplankton are influenced by its biological characteristics and surrounding ecological factors, such as irradiance, nutrients and phytoplankton community. Meanwhile, the thermally stratified structure and the movement of water masses, such as the Yangtze River diluted water, the Yellow Sea cold water mass and other different water system, also have an important impact on phytoplankton photosynthetic activity and characteristics. Greater understanding of the detailed photosynthetic characteristics of phytoplankton

  5. Investigating Effects of Monsoon Winds on Hydrodynamics in the South China Sea

    NASA Astrophysics Data System (ADS)

    Chua, V. P.

    2013-12-01

    The South China Sea is a large marginal sea surrounded by land masses and island chains, and characterized by complex bathymetry and irregular coastlines. The circulation in South China Sea is subjected to seasonal and inter-annual variations of tidal and meteorological conditions. The effects of monsoon winds on hydrodynamics is investigated by applying spectral and harmonic analysis on surface elevation and wind data at stations located in the South China Sea. The analysis indicates varying responses to the seasonal monsoon depending on the location of the station. At Kaohsiung (located in northern South China Sea off Taiwan coast), tides from the Pacific Ocean and the southwest monsoon winds are found to be dominant mechanisms. The Kota Kinabalu and Bintulu stations, located to the east of South China Sea off Borneo coast, are influenced by low energy complex winds, and the shallow bottom bathymetry at these locations leads to tidal energy damping compared to other stations. The tidal dynamics at Tioman, located in southern South China Sea off Malaysia coast, are most responsive to the effects of the northeast monsoon. The complexity of our problem together with the limited amount of available data in the region presents a challenging research topic. An unstructured-grid SUNTANS model is employed to perform three-dimensional simulations of the circulation in South China Sea. Skill assessment of the model is performed by comparing model predictions of the surface elevations and currents with observations. The results suggest that the quality of the model prediction is highly dependent on horizontal grid resolution and coastline accuracy. The model may be used in future applications to investigate seasonal and inter-annual variations in hydrodynamics.

  6. Can the South China Sea tell us anything about Canada Basin?

    NASA Astrophysics Data System (ADS)

    Stephenson, Randell; Li, Lu

    2016-04-01

    The Canada Basin (a sub-basin within the Amerasia Basin) and the South China Sea both preserve oceanic spreading centres and adjacent passive continental margins characterised by broad continent-ocean transition zones with hyper-extended continental crust. There are indications that hyper-extension in the South China Sea occurred mainly as a result of flow within a weak lower crustal layer and that it occurred both before and after plate break-up and the onset of ocean lithosphere formation at the sea-floor spreading axis. Available geophysical data from Canada Basin permit similar inferences. Both basins are about the same size and the oceanic segment in both is about the same size. Seafloor spreading in the South China Sea took place in the Cenozoic whereas in Canada Basin it is widely believed to have occurred during the Cretaceous. Widespread magmatism expressed as the High Arctic Large Igneous Province (HALIP) may or may not have played an intrinsic, linked, role in Canada Basin formation. No similar LIP is associated with the South China Sea although one mechanism proposed to have driven its formation is ascribed to mantle plume activity in its northernmost part. More conventionally the mechanism of opening of the South China Sea is considered to be "passive" rather than "active", related to plate reconfigurations in the southeast Asia region linked or not linked to the nearby collision of India and Eurasia and/or subduction of a "proto-South China Sea". The driving mechanism for opening of Canada Basin is poorly discussed in the literature but is generally ascribed to paleo-tectonic plate reconfigurations and subduction in the northern Pacific (Eurasia-North America plates) region in the Mesozoic. Can the South China Sea tell us anything about Canada Basin in terms of the pre-existing lithosphere of each and the geodynamic processes leading to its hyper-extension and eventual break-up?

  7. Sea-surface temperature fronts in the Yellow and East China Seas from TRMM microwave imager data

    NASA Astrophysics Data System (ADS)

    Huang, Daji; Zhang, Tao; Zhou, Feng

    2010-06-01

    Swath data from the Tropical Rainfall Measuring Mission microwave imager of sea-surface temperatures (SST) from 1998 to 2005 have been used to analyze the climatology and seasonal variability of the SST fronts in the Yellow and East China Seas (YES). Seven fronts have been identified and placed into three categories, namely, (1) the shelf-break front (Kuroshio Front), (2) the coastal fronts (Zhe-Min, Jiangsu, Shangdong Peninsula, Western Korean, and Western Chejudo Fronts), and (3) the shelf front (Western Yellow Sea Shelf Front). The Kuroshio Front exists from December through May, with the maximum SST gradient and highest frontal probability in April. The five coastal fronts exist year-round, all with their maximum SST gradient and highest frontal probability in February. The shelf front in the western Yellow Sea exists only from January to March. Frontogenesis in winter is due to effects of both air-sea heat exchange and advection by currents. The coastal fronts in the stratified months are expressed as tidal fronts. The coastal frontal zones coincide with the major spawning grounds of fish in the YES. The overwintering fishery ground in the Yellow Sea overlaps with the narrow band of favorable water temperature in the frontal zone. The overwintering grounds in the East China Sea are broad and bounded by fronts.

  8. Wave retrieval from SAR imagery in the East China Sea

    NASA Astrophysics Data System (ADS)

    Lou, Xiulin; Chang, Junfang; Liu, Xiaoyan

    2015-12-01

    Synthetic aperture radar (SAR) plays an important role in measuring directional ocean wave spectra with continuous and global coverage. In this article, satellite SAR images were used to estimate the wave parameters in the East China Sea. The Max-Planck Institut (MPI) method was applied to retrieve directional wave spectra from the SAR imagers with the Simulating WAves Nearshore (SWAN) model data as the first guess wave spectra. In order to validate the SAR retrieved wave spectra, a set of buoy measurements during the SAR imaging times was collected and used. The SAR retrieved significant wave heights (SWHs) were analyzed against the buoy measurements to assess the wave retrieval of this study. The root-mean-square error between the SAR SWHs and the buoy measurements is 0.25 m, which corresponds to a relative error of 12%. The case study here shows that the SWAN model data is a potential first guess wave spectra source to the MPI method to retrieve ocean wave spectra from SAR imagery.

  9. Turbulence in the East China Sea: The summertime stratification

    NASA Astrophysics Data System (ADS)

    Lozovatsky, Iossif; Lee, Jae-Hak; Fernando, H. J. S.; Kang, Sok Kuh; Jinadasa, S. U. P.

    2015-03-01

    A series of 134 microstructure profiles were taken in the central East China Sea from a drifting ship, covering more than 12 miles over the sloping bottom. The water depth z varied in the range 52-62 m; the tidal elevation of semidiurnal component was ±1 m. Prior to the onset of 25 h drift, a hydrographic section consisting of 9 stations, 15 miles apart, was taken in the area. A shallow mixed surface layer (SL) underlain by a diurnal pycnocline (z < 13 m), a sharp thermohalocline (13 < z < 30 m), and about 20 m tall bottom boundary layer (BBL) were the main features of summertime stratification. The splitting of upper pycnocline by a warmer, saltier intrusion led to the generation of turbulent patches at the lower, but not at the upper, density interface of this water body, suggesting asymmetry of mixing across the intrusion. In a limited range of the normalized squared buoyancy frequency, 2(N2/N02>)-3, where ɛm=4×10-6 W/kg and N0=5×10-3 s-1. Measurements in the sharp pycnocline and in lesser-stratified transitional layers between the pycnocline and the SL and BBL show that the cumulative distribution functions CDF(log10ɛ) can be modeled either by the generalized extreme value (GEV) distribution or the lognormal distribution.

  10. South China sea off Viet Nam to see more exploration

    SciTech Connect

    Not Available

    1992-06-15

    British and Japanese operators are posed for exploration campaigns off southern Viet Nam. This paper reports that a 50-50 partnership of Lasmo International Ltd., London, and C. Itoh Exploration Co. of Japan signed a heads of agreement covering Block 04-2, and AEDC Vietnam Oil Development Co. and Teikoku Oil Co. acquired Block 05-3 under a production sharing contract. AEDC is a unit of AOC Energy Development Co., a subsidiary of Arabian Oil Co. (AOC) of Japan. Both tracts are in the Con Son basin in the South China Sea. Site is 15 km north of 500 million bbl Dai Hung (Big Bear) oil field for which state owned Petrovietnam is evaluating bids to place on production. A unit of the Royal Dutch/shell Group acquired a west offset, Block 10, early this year. The Lasmo-C. Itoh acreage is among five blocks offered in Vietnam's second round of offshore licensing. All are in the area that once was reserved entirely for Vietsovpetro, a partnership of Petrovietnam and the former Soviet Union.

  11. Study on the storm surges induced by cold waves in the Northern East China Sea

    NASA Astrophysics Data System (ADS)

    Mo, Dongxue; Hou, Yijun; Li, Jian; Liu, Yahao

    2016-08-01

    Cold wave, a kind of severe weather system, can bring strong wind and induce significant sea level rise to the Northern East China Sea. Based on CFSR data, the study shows the monthly distributions of invaded days and the spatiotemporal distributions of cold-wave wind direction and wind speed. A three-dimensional numerical model (ROMS) was developed to study storm surges induced by cold waves. The role of wind direction, wind speed, wind duration, extratropical cyclone and tide-surge interaction is investigated by conducting different sensitivity experiments. The results indicate that storm surges mainly happen at the coasts perpendicular to the wind directions. Surge range and time lag are related to the geometry of the basin and the continental shelf. The response of the sea-level fluctuations to cold wave indicates that there is a positive correlation between crests and wind speed, a negative correlation between troughs and wind speed, but no obvious correlations to wind duration. Coupled weather cold waves, which yield a larger range and a multi-peak structure of surges, can be classified according to cold wave tracks and extratropical cyclones. The tide-surge interaction has an obvious and different effect on the magnitudes and phases of storm surges for different tidal stages.

  12. Convective Systems Over the South China Sea: Cloud-Resolving Model Simulations

    NASA Technical Reports Server (NTRS)

    Tao, Wei-Kuo; Shie, C.-L.; Johnson, D.; Simpson, J.; Braun, S.; Johnson, R.; Ciesielski, P. E.; Starr, David OC. (Technical Monitor)

    2002-01-01

    The South China Sea Monsoon Experiment (SCSMEX) was conducted in May-June 1998. One of its major objectives is to better understand the key physical processes for the onset and evolution of the summer monsoon over Southeast Asia and southern China. Multiple observation platforms (e.g., upper-air soundings, Doppler radar, ships, wind profilers, radiometers, etc.) during SCSMEX provided a first attempt at investigating the detailed characteristics of convective storms and air pattern changes associated with monsoons over the South China Sea region. SCSMEX also provided rainfall estimates which allows for comparisons with those obtained from the Tropical Rainfall Measuring Mission (TRMM), a low earth orbit satellite designed to measure rainfall from space. The Goddard Cumulus Ensemble (GCE) model (with 1-km grid size) is used to understand and quantify the precipitation processes associated with the summer monsoon over the South China Sea. This is the first (loud-resolving model used to simulate precipitation processes in this particular region. The GCE-model results captured many of the observed precipitation characteristics because it used a fine grid size. For example, the temporal variation of the simulated rainfall compares quite well to the sounding-estimated rainfall variation. The time and domain-averaged temperature (heating/cooling) and water vapor (drying/ moistening) budgets are in good agreement with observations. The GCE-model-simulated rainfall amount also agrees well with TRMM rainfall data. The results show there is more evaporation from the ocean surface prior to the onset of the monsoon than after the on-et of monsoon when rainfall increases. Forcing due to net radiation (solar heating minus longwave cooling) is responsible for about 25% of the precipitation in SCSMEX The transfer of heat from the ocean into the atmosphere does not contribute significantly to the rainfall in SCSMEX. Model sensitivity tests indicated that total rain production is

  13. What depth should deep-sea water be pumped up from in the South China Sea for medicinal research?

    NASA Astrophysics Data System (ADS)

    He, Shan; Liu, Hongbing; Yang, Xue; Li, Chunxia; Guan, Huashi

    2013-03-01

    In this study, seawater was pumped up from 150, 200, 300, 500 and 1000 m in the South China Sea and analyzed to make certain what depth should deep-sea water (DSW) be pumped up for medicinal usage. The pumping depth of DSW was determined on the basis of chemical ingredients. The analyses of inorganic elements and dissolved organic matter (DOM) were performed by inductively coupled plasma mass spectrometry (ICP-MS) and ultra performance liquid chromatography-mass spectrometry (UPLC-MS) respectively. The raw data were used for hierarchical cluster analysis (HCA) and principal component analysis (PCA). The results showed that seawater pumped up from 500 m and 1000 m was similar in their chemical ingredients, and was different from the seawater pumped up from other depths. These results indicated that seawater from more than 500 m depth had relatively stable chemical ingredients and could be used as DSW in the South China Sea.

  14. Spacebased Observations of the Oceanic Responses to Monsoons in South China Sea and Arabian Sea

    NASA Technical Reports Server (NTRS)

    Xie, Xiao-Su; Liu, W. Timothy

    2000-01-01

    A large percentage of the world's population and their agrarian economy must endure the vagaries of the monsoons over the tropical oceans between Africa and the Philippines. We know very little about the oceanic responses to changes of the monsoon in the South China Sea (SCS), which is under the influence of the East Asian Monsoon System, and the Arabian Sea (AS), which is dominated by the Indian Monsoon System; oceanic observations are sparse in both regions. Data from spaceborne microwave scatterometers and radiometers have been used to estimate the two major atmospheric forcing, momentum flux and latent heat flux (LHF), which change with the monsoon winds. Spaceborne sensors also observed the surface signatures of the oceanic response: SST and sea level changes (SLC. Sufficient durations of these data have recently become available to allow the meaningful studies of the annual cycles and interannual anomalies. In SCS, the winter monsoon is strong and steady but the summer monsoon is weak and has large intraseasonal fluctuations. In AS, the summer monsoon is much stronger than the winter monsoon. Significant correlations between LHF and SST tendency, and between curl of wind stress and SLC are found in both oceans. In the north SCS, winds are strong and dry, LHF is high, and ocean cooling is also large in fall; LHF is low and the ocean warms up in spring. In AS, LHF and SST tendency have a semi annual period; LHF is high in summer when the wind is strong and in winter when the wind is dry. Along the coast of Oman, the strong summer southwest monsoon causes intense upwelling, low SST and LHF in summer; such wind-driven SST changes is not as obvious along the Vietnam coast because of the weaker summer monsoon. The negative correlation between curl of wind stress and SLC found in the central basins of both SCS and AS agrees with a simple Ekman pumping scenario. Cyclonic winds drive surface divergence and upwelling in the ocean; the rise of the thermocline causes

  15. Comparison of Late Ordovician epicontinental seas and their relative bathymetry in North American and China

    SciTech Connect

    Johnson, M.E.; Fox, W.T. ); Jia-Yu, Rong )

    1989-02-01

    Six widely separated areas with Upper Ordovician strata in Canada and the United States are compared with six localities in southern China. Cyclic sedimentation, including evaporites, carbonates, and phosphatic black shales, occurred in relatively shallow epicontinental seas of North America. As many as three Ashgill cycles of regionally different styles may have been coeval throughout North America in response to modest changes in sea level. Environments in South China primarily included carbonates and black shales with a far more uniform distribution. Absence of comparable sedimentary cycles confirms that the platform bathymetry of South China was consistently deeper than in North America. The almost complete exposure of North China (Sino-Korean Plate) by Late Ordovician time underscores the fact that independent cratons have different bathymetric histories. By mid-Silurian time, South China also was fully exposed. Such hypsographic variation is critical to the intercontinental correlation of features related to eustasy, water chemistry, and even the patterns of extinctions.

  16. Comparison of the HY-2 Against Envisat Altimeter Data and their Applications in the China Seas

    NASA Astrophysics Data System (ADS)

    Cui, Wei; Yang, Jungang; Zhao, Xinhua; Martinez, Bernat

    2014-11-01

    The Chinese HY-2 satellite was launched on 16 August 2011, and its altimeter worked in orbit nearly six months simultaneously with ESA ENVISAT RA-2 satellite altimeter. In order to verify the observation precision and the application capabilities of HY-2 altimeter, this paper carries out the sea surface height(SSH)and the significant wave height(SWH) comparison of HY-2 and ENVISAT RA-2 altimeter respectively, and illustrates their applications on sea level change and ocean waves distribution in the China Seas. The results show that the SSH and SWH data of HY-2 and ENVISAT RA-2 crossovers is basically conformance, respectively, and the SLA and SWH spatial distributions of HY-2 show good agreement with ENVISAT RA-2 results. Furthermore, based on the two altimeter data during they were in orbit simultaneously sea level change and ocean waves distribution of the China Seas are analyzed for the application capabilities examination of HY-2 altimeter.

  17. Responses of phytoplankton community to the input of different aerosols in the East China Sea

    NASA Astrophysics Data System (ADS)

    Meng, X.; Chen, Y.; Wang, B.; Ma, Q. W.; Wang, F. J.

    2016-07-01

    Atmospheric deposition can affect marine phytoplankton by supplying macronutrients and trace elements. We conducted mesocosm experiments by adding aerosols with different composition (dominated by mineral dust, biomass burning and high Cu, and secondary aerosol, respectively) to the surface seawater of the East China Sea. Chlorophyll a concentrations were found to be the highest and lowest after adding aerosols containing the highest Fe and dissolved inorganic nitrogen (DIN), respectively. The relative abundance of Haptophyceae increased significantly after adding mineral dust, whereas diatom, Dinophyceae and Cryptophyceae reached the maximum accompanied with the highest DIN. Our results suggest that Fe may be more important than DIN in promoting primary productivity in the sampled seawater. The input of mineral dust and anthropogenic aerosols may result in distinct changes of phytoplankton community structure.

  18. Prediction of scour depth around offshore pipelines in the South China Sea

    NASA Astrophysics Data System (ADS)

    Cao, Yonggang; Bai, Yuchuan; Wang, Junqin; Liao, Shizhi; Xu, Dong

    2015-03-01

    Scour depth prediction of offshore pipelines is of great significance to the design and construction of the submarine pipeline projects. In this paper, based on the CFD software package FLUENT and User Defined Function (UDF), an Eulerian two-phase model, which includes an Euler-Euler coupled model for water and sediment phases, and a turbulent model for the fluid phase, is adopted to predict the scour depth around pipelines. The model is verified by observation data obtained from laboratory experiments. On the basis of the simulations, the factors affecting the scour depth, including the effects of incipient velocity, pipe diameter and sediment particle size and so on, were investigated. Meanwhile, according to formulas of incipient velocity of various sediments, approximate calculation on theoretical scour depths is developed for pipelines of seven stations in the South China Sea, where engineering application information is available.

  19. On the recurrent Ulva prolifera blooms in the Yellow Sea and East China Sea

    NASA Astrophysics Data System (ADS)

    Hu, Chuanmin; Li, Daqiu; Chen, Changsheng; Ge, Jianzhong; Muller-Karger, Frank E.; Liu, Junpeng; Yu, Feng; He, Ming-Xia

    2010-05-01

    A massive bloom of the green macroalgae Ulva prolifera (previously known as Enteromorpha prolifera) occurred in June 2008 in the Yellow Sea (YS), resulting in perhaps the largest "green tide" event in history. Using a novel index (Floating Algae Index) and multiresolution remote sensing data from MODIS and Landsat, we show that U. prolifera patches appeared nearly every year between April and July 2000-2009 in the YS and/or East China Sea (ECS), which all originated from the nearshore Subei Bank. A finite volume numerical circulation model, driven by realistic forcing and boundary conditions, confirmed this finding. Analysis of meteorological/environmental data and information related to local aquaculture activities strongly supports the hypothesis that the recurrent U. prolifera in the YS and ECS resulted from aquaculture of the seaweed Porphyra yezoensis (or nori) conducted along the 200 km shoreline of the Subei Bank north of the Changjiang (Yangtze) River mouth. Given the continuous growth in aquaculture efforts in the region, similar macroalgae bloom events, such as the summer 2008 event, are likely to occur in the future, particularly between May and July. This was confirmed by the 2009 bloom event in the same regions and the same period. The profit of the local P. yezoensis aquaculture industry (˜16,000 Ha in 2007) is estimated as U.S. 53 million, yet the cost to manage the impact of the summer 2008 U. prolifera bloom exceeded U.S. 100 million. Therefore, better strategies are required to balance the economic benefit of seaweed aquaculture and the costs of environmental impacts.

  20. Chlorinated and brominated organic pollutants in shellfish from the Yellow Sea and East China Sea.

    PubMed

    Yin, Ge; Asplund, Lillemor; Qiu, Yanling; Zhou, Yihui; Wang, Hua; Yao, Zongli; Jiang, Jianbin; Bergman, Åke

    2015-02-01

    The global contamination with persistent organic pollutants (POPs), or compounds with similar characteristics, is well known. Still there are data gaps for POP concentrations from many areas in the world. The aim of the present study is to assess several legacies POPs and also hexabromocyclododecane (HBCDD) and methoxylated polybrominated diphenyl ethers (MeO-PBDEs) in shellfish from three locations in the Yellow Sea and East China Sea. The sources of the contaminants are discussed. Pooled samples were treated by liquid-liquid extraction and acid and column cleanup prior to analysis by gas chromatogram equipped with electron capture detector (GC-ECD) and gas chromatography-mass spectrometry (GC-MS). The by far most abundant environmental contaminant originates from dichlorodiphenyltrichloroethane (DDT), independent of species analyzed or sampling site. The results indicate ongoing or at least recent discharges of DDT. The second highest concentrations were reported for HBCDD (21-40 ng/g fat) in the shellfish, independent of sampling sites. The two natural products, 6-MeO-BDE-47 and 2'-MeO-BDE-68, were also present in the shellfish (1.3-22 and 1-14 ng/g fat, respectively). The polychlorinated biphenyl (PCB) congener CB-153 (0.8-6.5 ng/g fat), hexachlorobenzene (HCB) (1.1-3.6 ng/g fat), and β-hexachlorocyclohexane (β-HCH) (2.3-4.9 ng/g fat) were all higher than the concentrations of other HCH isomers, β-endosulfan, PBDE congeners, and mirex. Apart from the DDTs and HBCDDs, it is evident that the pollution of shellfish was similar to, or lower than, the contamination of shellfish in other parts of the world. PMID:24958534

  1. Shoaling of internal solitary waves at the ASIAEX site in the South China Sea

    NASA Astrophysics Data System (ADS)

    Warn-Varnas, A.; Lamb, K.

    2012-04-01

    The interaction of barotropic tides with Luzon Strait topography generates westward propagating internal bores and solitary waves trains which eventually shoal and dissipate on the western side of the South China Sea. Numerical simulations of this shoaling process at the site of the Asian Seas International Acoustic Experiment (ASIAEX) have been undertaken in order to investigate the sensitivity of the shoaling process on a variety of environmental factors. The model parameters of the Luzon Strait region are tuned to yield solitary wave trains similar to those observed in the ASIAEX experiments. The sensitivity to details of the stratification, bathymetry, deep water depth and initial wave amplitude as well as the effects of dissipation in a bottom boundary layer are considered. On the slope secondary solitary waves are generated which propagate towards the shelf. In the vicinity of the shelf break a leading square-shaped wave of depression forms which is followed by a series of square-shaped waves of elevation in inviscid simulation. The presence of a bottom boundary significantly modifies the waves trailing the leading depression resulting in the emergence of many more smaller waves. Comparison against the measurements of Orr and Mignerey (2003) are conducted.

  2. Final Rifting and Continental Breakup in the South China Sea

    NASA Astrophysics Data System (ADS)

    Franke, D.; Savva, D.; Pubellier, M. F.; Steuer, S.; Mouly, B.; Auxietre, J. L.; Meresse, F.; Chamot-Rooke, N. R. A.

    2014-12-01

    The magma-poor or intermediate magmatic South China Sea basin shows a triangular shape with a SW pointing apex, which manifests a preceding propagating rift. The earliest phase of rifting started in the Early Paleocene when a Mesozoic convergent margin changed to extension. After about 30 Myrs of rifting, breakup in the major eastern subbasin of the SCS occurred in the Early Oligocene and subsequent breakup of the southwest subbasin took place in the Late Oligocene. Seismic reflection data imaging conjugate crustal sections result in a conceptual model for rift-evolution at conjugate margins in time and space. Distinct are regular undulations in the crust-mantle boundary. Individual rift basins are bounded to crustal blocks by listric normal faults on either side. Moho uplifts are distinct beneath major rift basins, while the Moho is downbended beneath crustal blocks. Most of the basin-bounding faults sole out within the middle crust. At the distal margins, detachment faults are located at a mid-crustal level where a weak zone decouples crust and mantle lithosphere during rifting. The lower crust in contrast is interpreted as being strong. Only in the region within about 50 km from the oceanic domain we suggest that normal faults reach the mantle, enabling potentially a coupling between the crust and the mantle. Here, at the proximal margins detachment fault dip either seaward or landward. Largely symmetric structures result from the initial rifting stage. At the future breakup position either of the rift basin bounding faults subsequently penetrates the entire crust, resulting in asymmetry at this location. However, asymmetric deformation which is controlled by large scale detachment faulting is confined to narrow areas and does not result in a margin-wide simple-shear model. Rather considerable along-margin variations are suggested resulting in alternating "upper and lower plate" margins.

  3. Assessment of satellite ocean color products of MERIS, MODIS and SeaWiFS along the East China Coast (in the Yellow Sea and East China Sea)

    NASA Astrophysics Data System (ADS)

    Cui, Tingwei; Zhang, Jie; Tang, Junwu; Sathyendranath, Shubha; Groom, Steve; Ma, Yi; Zhao, Wei; Song, Qingjun

    2014-01-01

    The validation of satellite ocean-color products is an important task of ocean-color missions. The uncertainties of these products are poorly quantified in the Yellow Sea (YS) and East China Sea (ECS), which are well known for their optical complexity and turbidity in terms of both oceanic and atmospheric optical properties. The objective of this paper is to evaluate the primary ocean-color products from three major ocean-color satellites, namely the Moderate Resolution Imaging Spectroradiometer (MODIS), Medium Resolution Imaging Spectrometer (MERIS), and Sea-viewing Wide Field-of-view Sensor (SeaWiFS). Through match-up analysis with in situ data, it is found that satellite retrievals of the spectral remote sensing reflectance Rrs(λ) at the blue-green and green bands from MERIS, MODIS and SeaWiFS have the lowest uncertainties with a median of the absolute percentage of difference (APDm) of 15-27% and root-mean-square-error (RMS) of 0.0021-0.0039 sr-1, whereas the Rrs(λ) uncertainty at 412 nm is the highest (APDm 47-62%, RMS 0.0027-0.0041 sr-1). The uncertainties of the aerosol optical thickness (AOT) τa, diffuse attenuation coefficient for downward irradiance at 490 nm Kd(490), concentrations of suspended particulate sediment concentration (SPM) and Chlorophyll a (Chl-a) were also quantified. It is demonstrated that with appropriate in-water algorithms specifically developed for turbid waters rather than the standard ones adopted in the operational satellite data processing chain, the uncertainties of satellite-derived properties of Kd(490), SPM, and Chl-a may decrease significantly to the level of 20-30%, which is true for the majority of the study area. This validation activity advocates for (1) the improvement of the atmosphere correction algorithms with the regional aerosol optical model, (2) switching to regional in-water algorithms over turbid coastal waters, and (3) continuous support of the dedicated in situ data collection effort for the validation task.

  4. A Preliminary Study of the Microbial Resources and Their Biological Activities of the East China Sea

    PubMed Central

    Lu, Xiaoling; Liu, Xiaoyu; Long, Cong; Wang, Guoxiang; Gao, Yun; Liu, Junhua; Jiao, Binghua

    2011-01-01

    East China Sea is one of the four sea areas in China, which possesses peculiar ecological environment and many kinds of living creatures, especially the microorganisms. We established the East China Sea microorganism library (during 2006–2010) for the first time, which stored about 30000 strains that covered most kinds of the species. In this paper, 395 pure strains of East China Sea microorganism library which belong to 33 different genera were mainly introduced. Sulfitobacter, Halomonas, Bacillus, Pseudoalteromonas, and Idiomarina were the most dominant species. On the large-scale biological activity screening of the 395 strains, 100 strains possess different biological activities based on different screening models, of which 11.4% strains have antibacterial activities, 15.9% have cytotoxicity activities, and 6.1% have antioxidation activities. Besides, the secondary metabolites of 6 strains with strong biological activities were studied systematically; diketopiperazines and macrocyclic lactones are the active secondary metabolites. The species and the biological activity of microorganisms diversity, the abundant structure type of the secondary metabolites, and their bioactivities all indicate that East China Sea is a potent marine microorganisms-derived developing resource for drug discovery. PMID:21789045

  5. Seismic investigation of an ocean-continent transition zone in the northern South China Sea

    NASA Astrophysics Data System (ADS)

    Zhu, J.; Qiu, X.; Xu, H.; Zhan, W.; Sun, Z.

    2011-12-01

    Rifted continental margins and basins are mainly formed by the lithospheric extension. Thined lithosphere of passive continental margins results in decompression melt of magma and created oceanic crust and thined ocean-continent transition (OCT) zone. Two refraction profiles used ocean bottom seismometers deployed in the broad continental shelf and three multi-channel seismic reflection lines in the northern South China Sea, acquired by the ship "Shiyan 2" of the South China Sea Institute of Oceanology, Chinese Academy of Sciences in 2010, are processed and interpreted in this study. Seismic reflection lines cut through the Dongsha rise, Zhu-1 and Zhu-2 depression within a Tertiary basin, Pear River Mouth basin (called as Zhujiangkou basin). These tectonic features are clear imaged in the seismic reflection records. Numerous normal faults, cutted through the basement and related to the stretch of the northern South China Sea margin, are imaged and interpreted. Reflection characteristics of the ocean-continent transition (OCT) zone are summaried and outlined. The COT zone is mainly divided into the northern syn-rift subsidence zone, central volcano or buried volcano uplift zone and tilt faulted block near the South Chia Sea basin. Compared to the previous seismic reflection data and refraction velocity models, the segmentation range of the OCT zone is outlined, from width of about 225 km in the northeastern South China Sea , of 160 km in the central to of 110 km in the north-central South China Sea. Based on the epicenter distribution of sporadic and large than 6 magnitude earthquakes, it suggests the OCT zone in the northern South China Sea at present is still an active seismic zone.

  6. Air-sea exchange of gaseous mercury in the East China Sea.

    PubMed

    Wang, Chunjie; Ci, Zhijia; Wang, Zhangwei; Zhang, Xiaoshan

    2016-05-01

    Two oceanographic cruises were carried out in the East China Sea (ECS) during the summer and fall of 2013. The main objectives of this study are to identify the spatial-temporal distributions of gaseous elemental mercury (GEM) in air and dissolved gaseous mercury (DGM) in surface seawater, and then to estimate the Hg(0) flux. The GEM concentration was lower in summer (1.61 ± 0.32 ng m(-3)) than in fall (2.20 ± 0.58 ng m(-3)). The back-trajectory analysis revealed that the air masses with high GEM levels during fall largely originated from the land, while the air masses with low GEM levels during summer primarily originated from ocean. The spatial distribution patterns of total Hg (THg), fluorescence, and turbidity were consistent with the pattern of DGM with high levels in the nearshore area and low levels in the open sea. Additionally, the levels of percentage of DGM to THg (%DGM) were higher in the open sea than in the nearshore area, which was consistent with the previous studies. The THg concentration in fall was higher (1.47 ± 0.51 ng l(-1)) than those of other open oceans. The DGM concentration (60.1 ± 17.6 pg l(-1)) and Hg(0) flux (4.6 ± 3.6 ng m(-2) h(-1)) in summer were higher than those in fall (DGM: 49.6 ± 12.5 pg l(-1) and Hg(0) flux: 3.6 ± 2.8 ng m(-2) h(-1)). The emission flux of Hg(0) from the ECS was estimated to be 27.6 tons yr(-1), accounting for ∼0.98% of the global Hg oceanic evasion though the ECS only accounts for ∼0.21% of global ocean area, indicating that the ECS plays an important role in the oceanic Hg cycle. PMID:26975003

  7. Assessment of marine debris in beaches or seawaters around the China Seas and coastal provinces.

    PubMed

    Zhou, Changchun; Liu, Xu; Wang, Zhengwen; Yang, Tiantian; Shi, Linna; Wang, Linlin; You, Suwen; Li, Min; Zhang, Cuicui

    2016-02-01

    Compared with United States of America (USA), Brazil, Chile, Australia, limited attention has been paid to marine debris research in China and few studies have attempted to quantify the abundance and mass of marine debris. In this study, firstly the general status and sources of marine debris in China were assessed in the time period between 2007 and 2014, and secondly marine debris situation was evaluated in three China Sea Areas (the North China Sea, the East China Sea and the South China Sea) from 2009 to 2013, and finally marine debris conditions and sources were analyzed in beaches or seawaters around some coastal provinces of China during 2007-2013. Based on above analysis, the primary conclusions were as follows: (1) The mean number and weight densities of beached marine debris (BMD) and submerged marine debris (SMD) were 4.30, 0.13items/100m(2) and 133.80, 22.60g/100m(2) in China from 2007 to 2014, respectively. The average number density of the large size FMD (LOSFMD) was 0.0024items/100m(2) and that of the small and medium size FMD (SMSFMD) was 0.30items/100m(2), and the mean weight density of the SMSFMD was 1.40g/100m(2) from 2008 to 2014. The SMD and FMD densities were at the low level and the BMD density was at the high level in China. (2) The marine debris primarily was comprised of plastic, Styrofoam, wood, glass, rubber, fabric/fiber and metal, which included almost all major categories of marine debris. (3) Sources of BMD and FMD were as follows: the first source was coastal/recreational activities, followed by other disposal sources, navigation/fishing activities and the activities related smoking, and the least source being those associated with medical/sanitary activities, while the source of SMD remained unknown. (4) The mean number and weight densities of BMD were the biggest in the North China Sea, while those of FMD and SMD were the highest in the northern South China Sea. The results of this study were beneficial to the establishment of

  8. Modelling sea level data from China and Malay-Thailand to estimate Holocene ice-volume equivalent sea level change

    NASA Astrophysics Data System (ADS)

    Bradley, Sarah L.; Milne, Glenn A.; Horton, Benjamin P.; Zong, Yongqiang

    2016-04-01

    This study presents a new model of Holocene ice-volume equivalent sea level (ESL), extending a previously published global ice sheet model (Bassett et al., 2005), which was unconstrained from 10 kyr BP to present. This new model was developed by comparing relative sea level (RSL) predictions from a glacial isostatic adjustment (GIA) model to a suite of Holocene sea level index points from China and Malay-Thailand. Three consistent data-model misfits were found using the Bassett et al. (2005) model: an over-prediction in the height of maximum sea level, the timing of this maximum, and the temporal variation of sea level from the time of the highstand to present. The data-model misfits were examined for a large suite of ESL scenarios and a range of earth model parameters to determine an optimum model of Holocene ESL. This model is characterised by a slowdown in melting at ∼7 kyr BP, associated with the final deglaciation of the Laurentide Ice Sheet, followed by a continued rise in ESL until ∼1 kyr BP of ∼5.8 m associated with melting from the Antarctic Ice Sheet. It was not possible to identify an earth viscosity model that provided good fits for both regions; with the China data preferring viscosity values in the upper mantle of less than 1.5 × 1020 Pa s and the Malay-Thailand data preferring greater values. We suggest that this inference of a very weak upper mantle for the China data originates from the nearby subduction zone and Hainan Plume. The low viscosity values may also account for the lack of a well-defined highstand at the China sites.

  9. First Characterization of Bacterial Pathogen, Vibrio alginolyticus, for Porites andrewsi White Syndrome in the South China Sea

    PubMed Central

    Chaoqun, Hu; Zhixiong, Zhu; Shifeng, Wang; Yongcan, Zhou

    2013-01-01

    Background White syndrome, a term for scleractinian coral disease with progressive tissue loss, is known to cause depressed growth and increased morality of coral reefs in the major oceans around the world, and the occurrence of this disease has been frequently reported in the past few decades. Investigations during April to September in both 2010 and 2011 identified widespread Poritesandrewsi White syndrome (PAWS) in Xisha Archipelago, South China Sea. However, the causes and etiology of PAWS have been unknown. Methodology/Principal Findings A transmission experiment was performed on P. andrewsi in the Qilianyu Subgroup (QLY). The results showed that there was a significant (P ≤ 0.05) difference between test and control groups after 28 days if the invalid replicates were excluded. Rates of tissue loss ranged from 0.90-10.76 cm2 d-1 with a mean of 5.40 ± 3.34 cm2 d-1 (mean ± SD). Bacterial strains were isolated from the PAWS corals at the disease outbreak sites in QLY of the Xisha Archipelago, South China Sea, and included in laboratory-based infection trials to satisfy Koch’s postulates for establishing causality. Following exposure to bacterial concentrations of 105 cells mL-1, the infected colonies exhibited similar signs to those observed in the field. Using phylogenetic 16S rRNA gene analysis, classical phenotypic trait comparison, Biolog automatic identification system, MALDI-TOF mass spectrometry and MALDI Biotyper method, two pathogenic strains were identified as Vibrioalginolyticus. Conclusion/Significance This is the first report of V. alginolyticus as a pathogenic agent of PAWS in the South China Sea. Our results point out an urgent need to develop sensitive detection methods for V. alginolyticus virulence strains and robust diagnostics for coral disease caused by this and Vibrio pathogenic bacterium in the South China Sea. PMID:24086529

  10. Comparison of modern pollen distribution between northern and southern South China Sea

    NASA Astrophysics Data System (ADS)

    Luo, C.; Chen, M.; Xiang, R.; Liu, J.; Zhang, L.; Lu, J.

    2013-12-01

    To understand pollen transport mechanic and terrigenous area is the base to explain pollen data correctly in Southern South China Sea (Fig.1). Based on Palynology analyzing the following preliminary conclusions are listed. 1. Air pollen differences between northern and southern South China Sea 15 air pollen samples were collected from northern part of the South China Sea from August to September 2011. 13 air pollen samples were collected from southern South China Sea in December 2011. It was found that the air pollen are different between northern and southern part of South China Sea: the pollen types in the north are more abundant than in the south, Ulmaceae, Monolete spore, Cyperaceae, Euphorbiaceae, Rubiaceae, Artemisia, Chenopodiaceae, Rosaceae, Labiatae occur only in the north, they do not occur or is just sporadic in the south. The total pollen number and concentration in the north is 10 times of the south, one of the reasons may be that the sampling season in the north is autumn with more flowering plants, the sampling season in the south is winter, with fewer flowering plants; the second reason might be that pollen and spore in autumn and winter are mainly spread by the winter wind, thus they reduce from north to south. 2. Pollen differences of the surface sediments between northern and southern South China Sea 14 samples were collected from surface sediments in the northern part of the South China Sea from August to October, 2011. 12 samples were collected from surface sediments in the southern part of the South China Sea from year 1997 to 2002. The differences of pollen characteristics from the surface sediments between northern and southern part of South China Sea are: pollen types and quantities in the north are richer than in south. There are Trilete spores (35-100%), Pinus (3-65%) in northern of SCS, with pollen concentration of 33-1031grain/g. There are only a small amount of Trilete-spore and Pinus pollen in southern of SCS. Pollen concentration in

  11. Size distributions and source function of sea spray aerosol over the South China Sea

    NASA Astrophysics Data System (ADS)

    Chu, Yingjia; Sheng, Lifang; Liu, Qian; Zhao, Dongliang; Jia, Nan; Kong, Yawen

    2016-08-01

    The number concentrations in the radius range of 0.06-5 μm of aerosol particles and meteorological parameters were measured on board during a cruise in the South China Sea from August 25 to October 12, 2012. Effective fluxes in the reference height of 10 m were estimated by steady state dry deposition method based on the observed data, and the influences of different air masses on flux were discussed in this paper. The number size distribution was characterized by a bimodal mode, with the average total number concentration of (1.50 ± 0.76)×103 cm-3. The two mode radii were 0.099 µm and 0.886 µm, both of which were within the scope of accumulation mode. A typical daily average size distribution was compared with that measured in the Bay of Bengal. In the whole radius range, the number concentrations were in agreement with each other; the modes were more distinct in this study than that abtained in the Bay of Bengal. The size distribution of the fluxes was fitted with the sum of log-normal and power-law distribution. The impact of different air masses was mainly on flux magnitude, rather than the shape of spectral distribution. A semiempirical source function that is applicable in the radius range of 0.06 µm< r 80<0.3 µm with the wind speed varying from 1.00 m s-1 to 10.00 m s-1 was derived.

  12. Land-sea interactions at the east coast of Hainan Island, South China Sea: A synthesis

    NASA Astrophysics Data System (ADS)

    Zhang, Jing; Wang, Dao Ru; Jennerjahn, Tim; Dsikowitzky, Larissa

    2013-04-01

    The structure and function of coastal ecosystems is affected by land-based human activities, including changes in water, sediment and pollutant input, as well as land reclamation in coastal areas. Many coastal areas can be considered over-stressed systems as a whole, the ecosystem services of which are strongly impaired. This is particularly important in tropical regions, where the coastal zone is under the influence of a strong climate variability including monsoons and frequent extreme weather events, such as typhoons. During the past decades the continuous development of Hainan's coastal zone and its hinterland, in combination with episodic natural events (e.g., typhoons), caused environmental changes in its coastal ecosystems. However, little is known on the consequences of environmental changes for the biogeochemistry and ecology and, hence, the natural resources of the Hainan coastal ecosystems. The Sino-German inter-disciplinary LANCET (land-sea interactions along coastal ecosystems of tropical China: Hainan) project was designed to address these issues on a local to regional scale and at the same time, to contribute to the global data base in which this type of information from tropical regions is still under-represented. The results obtained from LANCET have been delivered to the local government for an adaptive management at the ecosystem level, and the knowledge is believed to be relevant to other studies of tropical and coastal regions.

  13. Mapping surface tidal currents and Changjiang plume in the East China Sea from Geostationary Ocean Color Imager

    NASA Astrophysics Data System (ADS)

    Hu, Zifeng; Wang, Dong-Ping; Pan, Delu; He, Xianqiang; Miyazawa, Yasumasa; Bai, Yan; Wang, Difeng; Gong, Fang

    2016-03-01

    The spatial pattern of the semidiurnal M2 tidal currents in the East China Sea (ECS) is mapped from the Geostationary Ocean Color Imager (GOCI), taking advantage of the satellite's unique 8 hourly local daytime sequential images. The GOCI-derived surface M2 tidal currents are validated with a comprehensive set of twenty-eight surface drifters and four mooring observations. The agreement is outstanding with the error variance less than 10% of the total variance. The gridded GOCI-derived tidal currents are also in good agreement with the Oregon State University (OSU) high-resolution regional tidal model of the China Seas. The detided mean flow shows a strong Changjiang plume extending hundreds of kilometers offshore, in agreement with the concurrent satellite sea surface temperature (SST) and sea surface salinity (SSS) distributions. The observed surface currents are compared with the daily mean flows derived from the Japan Coastal Ocean Predictability Experiment (JCOPE2). The model results are consistent with the observations, showing the sensitivity of Changjiang plume to wind forcing. The study clearly demonstrates the utility of geostationary satellite in mapping the surface currents over a wide (˜400 km), tidally dominated continental shelf.

  14. Modeling seasonal and diurnal pCO 2 variations in the northern South China Sea

    NASA Astrophysics Data System (ADS)

    Lu, Zhongming; Gan, Jianping; Dai, Minhan

    2012-04-01

    This paper describes the simulated temporal variation of surface seawater CO 2 partial pressure ( pCO 2) in the northern South China Sea. We produced the simulations with a one-dimensional (1-D) coupled physical-biogeochemical model that had high-frequency, time-dependent atmospheric forcing and that were validated with field observations. We also examined the associated processes that modulate seawater pCO 2 at different time scales, from diurnal to seasonal, using a series of process-oriented experiments. At seasonal time scales, we revealed that the sea-air CO 2 exchange was a primary process that modulated surface pCO 2 and exceeded the role of sea surface temperature (SST) even though the phase of the pCO 2 variation generally followed the strong seasonal cycle of SST. This was because sea-air CO 2 exchange is a slow process and has an accumulative effect on surface water pCO 2 due to the buffering effect of the carbonate system once CO 2 has dissolved in the seawater, which leads to a long equilibration time of CO 2 between the atmosphere and seawater. The mixing effect on pCO 2 induced by total alkalinity and dissolved inorganic carbon variations was, generally, positively correlated with the seasonal evolution of wind speed. Biological processes were the smallest contributors to pCO 2 variations at the seasonal scale because of the oligotrophic characteristic of the region. At diurnal time scales, the dominant pCO 2 controlling factor was mainly associated with the local physical and biological conditions. Temperature and wind-induced vertical mixing played major roles in pCO 2 when the winter heat flux and upward transport of low temperature and high pCO 2 in deep water were intensified. Phytoplankton blooms generally occur after a period of strong wind, as a result, biological metabolism becomes the most important pCO 2 regulator when the surface chlorophyll-a reached its highest level. Unlike that in the seasonal scale, the effect of sea-air CO 2

  15. Energy audit data for a resort island in the South China Sea.

    PubMed

    Basir Khan, M Reyasudin; Jidin, Razali; Pasupuleti, Jagadeesh

    2016-03-01

    The data consists of actual generation-side auditing including the distribution of loads, seasonal load profiles, and types of loads as well as an analysis of local development planning of a resort island in the South China Sea. The data has been used to propose an optimal combination of hybrid renewable energy systems that able to mitigate the diesel fuel dependency on the island. The resort island selected is Tioman, as it represents the typical energy requirements of many resort islands in the South China Sea. The data presented are related to the research article "Optimal Combination of Solar, Wind, Micro-Hydro and Diesel Systems based on Actual Seasonal Load Profiles for a Resort Island in the South China Sea" [1]. PMID:26900590

  16. Data from renewable energy assessments for resort islands in the South China Sea.

    PubMed

    Basir Khan, M Reyasudin; Jidin, Razali; Pasupuleti, Jagadeesh

    2016-03-01

    Renewable energy assessments for resort islands in the South China Sea were conducted that involves the collection and analysis of meteorological and topographic data. The meteorological data was used to assess the PV, wind and hydropower system potentials on the islands. Furthermore, the reconnaissance study for hydro-potentials were conducted through topographic maps in order to determine the potential sites suitable for development of run-of-river hydropower generation. The stream data was collected for 14 islands in the South China Sea with a total of 51 investigated sites. The data from this study are related to the research article "Optimal combination of solar, wind, micro-hydro and diesel systems based on actual seasonal load profiles for a resort island in the South China Sea" published in Energy (Khan et al., 2015) [1]. PMID:26779562

  17. Pet Dogs Benefit Owners' Health: A "Natural Experiment" in China

    ERIC Educational Resources Information Center

    Headey, Bruce; Na, Fu; Zheng, Richard

    2008-01-01

    This paper reports results from a "natural experiment" taking place in China on the impact of dogs on owners' health. Previous Western research has reported modest health benefits, but results have remained controversial. In China pets were banned in urban areas until 1992. Since then dog ownership has grown quite rapidly in the major cities,…

  18. Dynamics of the Water Circulations in the Southern South China Sea and Its Seasonal Transports

    PubMed Central

    Ooi, See Hai; Samah, Azizan Abu; Akbari, Abolghasem

    2016-01-01

    A three-dimensional Regional Ocean Modeling System is used to study the seasonal water circulations and transports of the Southern South China Sea. The simulated seasonal water circulations and estimated transports show consistency with observations, e.g., satellite altimeter data set and re-analysis data of the Simple Ocean Data Assimilation. It is found that the seasonal water circulations are mainly driven by the monsoonal wind stress and influenced by the water outflow/inflow and associated currents of the entire South China Sea. The intrusion of the strong current along the East Coast of Peninsular Malaysia and the eddies at different depths in all seasons are due to the conservation of the potential vorticity as the depth increases. Results show that the water circulation patterns in the northern part of the East Coast of Peninsular Malaysia are generally dominated by the geostrophic currents while those in the southern areas are due solely to the wind stress because of negligible Coriolis force there. This study clearly shows that individual surface freshwater flux (evaporation minus precipitation) controls the sea salinity balance in the Southern South China Sea thermohaline circulations. Analysis of climatological data from a high resolution Regional Ocean Modeling System reveals that the complex bathymetry is important not only for water exchange through the Southern South China Sea but also in regulating various transports across the main passages in the Southern South China Sea, namely the Sunda Shelf and the Strait of Malacca. Apart from the above, in comparision with the dynamics of the Sunda Shelf, the Strait of Malacca reflects an equally significant role in the annual transports into the Andaman Sea. PMID:27410682

  19. Dynamics of the Water Circulations in the Southern South China Sea and Its Seasonal Transports.

    PubMed

    Daryabor, Farshid; Ooi, See Hai; Samah, Azizan Abu; Akbari, Abolghasem

    2016-01-01

    A three-dimensional Regional Ocean Modeling System is used to study the seasonal water circulations and transports of the Southern South China Sea. The simulated seasonal water circulations and estimated transports show consistency with observations, e.g., satellite altimeter data set and re-analysis data of the Simple Ocean Data Assimilation. It is found that the seasonal water circulations are mainly driven by the monsoonal wind stress and influenced by the water outflow/inflow and associated currents of the entire South China Sea. The intrusion of the strong current along the East Coast of Peninsular Malaysia and the eddies at different depths in all seasons are due to the conservation of the potential vorticity as the depth increases. Results show that the water circulation patterns in the northern part of the East Coast of Peninsular Malaysia are generally dominated by the geostrophic currents while those in the southern areas are due solely to the wind stress because of negligible Coriolis force there. This study clearly shows that individual surface freshwater flux (evaporation minus precipitation) controls the sea salinity balance in the Southern South China Sea thermohaline circulations. Analysis of climatological data from a high resolution Regional Ocean Modeling System reveals that the complex bathymetry is important not only for water exchange through the Southern South China Sea but also in regulating various transports across the main passages in the Southern South China Sea, namely the Sunda Shelf and the Strait of Malacca. Apart from the above, in comparision with the dynamics of the Sunda Shelf, the Strait of Malacca reflects an equally significant role in the annual transports into the Andaman Sea. PMID:27410682

  20. International Ocean Discovery Program Expedition 349 and Multidisciplinary Research in the South China Sea

    NASA Astrophysics Data System (ADS)

    Lin, J.; Li, C. F.; Wang, P.; Koppers, A. A. P.; Dadd, K. A.; Kulhanek, D. K.

    2014-12-01

    The South China Sea (SCS) is one of the largest low-latitude marginal seas in the world, serving as a natural laboratory for studying the linkages between complex tectonic, volcanic, and oceanic processes. The last several years have witnessed significant progress in investigation of the SCS through comprehensive research programs using multidisciplinary approaches and enhanced international collaboration. In January-March 2014, International Ocean Discovery Program (IODP) Expedition 349 drilled and cored five sites in the SCS, with three sites located near the relict spreading center in the East and Southwest Subbasins and two sites near the transition zone between the oceanic and continental crust (Expedition 349 Scientists, 2014). The expedition successfully obtained the first basaltic rock samples of the SCS relict spreading center, discovered large and frequent deep-sea turbidity events, and sampled multiple seamount volcaniclastic layers. The Expedition 349 shipboard and shorebased research involves the participation and strong collaboration of scientists from the international community including scientists from countries and regions surrounding the SCS. Meanwhile, major progress in studying the SCS processes has also been made through comprehensive multidisciplinary programs, for example, the "South China Sea Deep" initiative (Wang, 2012). This presentation will highlight the recent multidisciplinary research initiatives in investigation of the SCS and the important role of international collaboration. Expedition 349 Scientists, 2014. South China Sea tectonics: Opening of the South China Sea and its implications for southeast Asian tectonics, climates, and deep mantle processes since the late Mesozoic. International Ocean Discovery Program Preliminary Report, 349. http://dx.doi.org/10.14379/iodp.pr.349.2014. Wang, P., 2012. Tracing the life history of a marginal sea—on "The South China Sea Deep" research program. Chinese Science Bulletin, 57(24), 3093

  1. The rift to drift evolution of the South China Sea

    NASA Astrophysics Data System (ADS)

    Ranero, Cesar R.; Cameselle, Alejandra; Franke, Dieter; Barckhausen, Udo

    2016-04-01

    Re-processing with modern algorithms of multichannel seismic reflection records from the South China Sea provide novel images on the crustal structure of the continental margin and its boundary zone with the oceanic crust (COB). The selected re-processed seismic lines strike perpendicular to the margins' trend and cross the entire basin, providing complementary images of conjugated rift segments of the NW, SW, and E sub-basins. Re-processed sections image the post-rift and syn-rift sediment, and fault-bounded basement blocks, often also intra-crustal fault reflections that together provide detailed information of the tectonic structural style during rifting. Further, the largest imaging improvement has been obtained in the delineation of -very often- clear fairly continuous reflections from the crust-mantle boundary across the continental margin into the oceanic crust. The images show how crustal thickness and structure change in parallel to changes in the tectonic style of the deformation during the evolution of the rift. The interpreted COB occurs in regions where the tectonic style displays the most noticeable changes from segments where extension is dominated by normal faulting to segments where faulting is comparatively minor and the crust shows fairly gentle lateral thickness variations; these latter segments are interpreted as oceanic crust. The identification of the continental and oceanic tectonic domains permits to study the along-strike evolution in rifting processes and rift segmentation. Also, the comparison of the tectonic structure of the conjugated flanks of the continental rift across the ocean basins is used to understand the last stages of rifting and the relative importance of tectonic extension and magmatism in final break up and spreading initiation. Although there is ample evidence of important volcanism in the images, with some spectacular large conical volcanoes formed over continental crust and numerous sill-like reflections in the

  2. Impact of atmospheric wet deposition on phytoplankton community structure in the South China Sea

    NASA Astrophysics Data System (ADS)

    Cui, Dong-Yang; Wang, Jiang-Tao; Tan, Li-Ju; Dong, Ze-Yi

    2016-05-01

    The South China Sea (SCS), which is the largest marginal sea in East Asia, plays a significant role in regional climate change. However, research on the phytoplankton community structure (PCS) response to atmospheric wet deposition remains inadequate. In this study, field incubation experiments were performed to survey the impact of atmospheric wet deposition on the PCS in the SCS in December 2013. Results indicate that the mean dissolved inorganic nitrogen/dissolved inorganic phosphorous (DIN/DIP) ratio in rainwater was 136, which was higher than that in seawater. Under low initial nutrient concentrations, rainwater inputs not only significantly increased total chlorophyll a (Chl a) concentrations but also potentially altered the PCS. The total Chl a concentration increased 1.7-, 1.9-, and 1.6-fold; microphytoplankton increased 2.6-, 3.2-, and 1.7-fold with respect to their initial values in the 5%, 10% addition, and 10% addition (filtered) treatment samples, respectively. Finally, microphytoplankton contributed 61% to the total Chl a concentration in 10% addition treatment samples. Differences in the nutrients induced by atmospheric wet deposition resulted in a shift in the advantage from picophytoplankton to microphytoplankton. Diatoms became the predominant species, accounting for 55% of the total abundance after rainwater addition.

  3. The Levels and Distribution of TN, TP and TOC in the South China Sea

    NASA Astrophysics Data System (ADS)

    Wang, H.; Han, D.

    2012-04-01

    The marine biogeochemistries of carbon, nitrogen and phosphorous have come under increased scrutiny because of their close involvement in climate change and coastal eutrophication. The South China Sea is unique in that located in a subtropical zone, and therefore represents an important regime for biogeochemical studies. However, to our knowledge, few data are available for total nitrogen (TN), total phosphorous (TP) and total organic carbon (TOC) in South Sea, China. The present study aims to contribute to the knowledge of their status through investigating the level and distribution of TN, TP and TOC in South China Sea. A total of 108 seawater samples of 11 sites in south sea, china were collected during August 29- September 4, 2006. An automated and simultaneous method for determination of TN and TOC was applied to all seawater samples. The combined system allowed simultaneous determination for TOC and TN in the same sample using a single injection and provided low detection limits and excellent linear ranges for both TOC and TN. The risk of contamination has been remarkably reduced due to the minimal sample manipulation and automated analyses. And quantitative analyses of TP in seawater were accomplished by a typical chemical method. Concentration ranges of TN and TP were 0.06-0.67, and 0.003-0.071 mg/L, respectively, as well as that of TOC were 0.23-2.51mg/L. The values of TN and TP showed that the status of nutrition is relatively better in south china sea than other marine areas. Moreover, the upright change trend of TN concentration level as well as TP and TOC according to the experimental results at the total 11 sites are simultaneity studied. The concentration of TN initial increases with the increasing of the depth, later the value becomes almost constant. In contrast, the concentration of TOC reduces with the increasing of the depth, later the value becomes almost unchangeable. Compared with the trend of TN and TOC, that of TP appears relatively stable

  4. A new species of Hemichela Stock, 1954 from the South China Sea (Arthropoda, Pycnogonida, Ammotheidae)

    PubMed Central

    Wang, Jianjia; Xia, Zhen; Lin, Rongcheng; Liang, Qianyong; Lin, Heshan; Wang, Jianjun; Zheng, Chengxing

    2015-01-01

    Abstract A new species of pycnogonid collected by the Chinese research vessel, R/V HY IV, during deep sea cruises to the South China Sea in 2013, is described. The new species, Hemichela nanhaiensis, obtained from more than 1300 m depth, is distinguished from the other two species in the genus by the characters of the chela dactylus with 12 denticulations on the inner margin and by the presence of taller tubercles on the lateral processes. PMID:26487821

  5. Nitrate dual isotopic composition in the northern South China Sea and neighboring West Philippine Sea

    NASA Astrophysics Data System (ADS)

    Yang, J.; Xu, M.; Wu, Y.; Dai, M.; Kao, S.

    2013-12-01

    Nitrate nitrogen and oxygen isotopic compositions (δ15NNO3 and δ18ONO3) were used to diagnose nitrate dynamics and the origins of water masses in the northern South China Sea (SCS) and West Philippine Sea (WPS) where water exchanges via the Luzon Strait at different depths. In the SCS, 1-3‰ greater upward increase in δ18ONO3 relative to corresponding δ15NNO3 was just observed in the lower euphotic zone (EZ), indicating a rapid internal cycle of nitrate assimilation and remineralization. Much lower nitrate concentration in the EZ of WPS does not allow us to measure its dual isotopes. From 500 m deep to the base of EZ in the WPS, non-proportional decreases in δ15NNO3 (from 6.4‰ to 2.1-2.6‰) and δ18ONO3 (from 3.0‰ to 1.1‰) accompanying with elevated N:P ratio anomalies (N* from -1.2 μM up to 2 μM), suggest the accumulation of atmospheric-derived N (e.g. N2 fixation and/or N deposition). This allochthonous N signal cumulated in the subsurface of WPS may regulate the δ15NNO3 in the SCS subsurface due to seasonal Kuroshio intrusion, which could supply isotopically light nitrate as newly fixed N source to the SCS. The higher (~0.5‰) δ15NNO3 and δ18ONO3 values, associated with lower N* were detected in the WPS intermediate water (WPS-IW, σθ = 26.5~27.1 kg m-3) around depth of 600-800 m (especially at a southern site) when compared to those of the conventional water source coming from North Pacific Intermediate Water (NPIW). By combining nitrate concentration, N* and δ15NNO3 as constraints, we propose that an additional southerly source other than NPIW may feed into the WPS-IW. On the other hand, the SCS intermediate water (SCS-IW, ~400-700 m), which supposedly sourced from WPS-IW along similar isopycnal levels, showed ~1‰ lower δ15NNO3 and δ18ONO3 values. This reduction in nitrate duel isotopes indicates intense diapycnal mixing primarily due to basin-wide upwelling in the SCS interior. This is the first hand data in the SCS for deep profiles

  6. Sea surface salinity variability in the East China Sea observed by the Aquarius instrument

    NASA Astrophysics Data System (ADS)

    Kim, Seung-bum; Lee, Jae Hak; de Matthaeis, Paolo; Yueh, Simon; Hong, Chang-Su; Lee, Joon-Ho; Lagerloef, Gary

    2014-10-01

    This study demonstrates that the spaceborne Aquarius instrument is able to monitor the sea surface salinity (SSS) variations in the East China Sea (ECS) with the spatial resolution of about 150 km at 7 day interval, where routine observations are difficult. The two geophysical contaminants enter the sidelobes of the Aquarius antenna and bias the coastal SSS low: the emission from the land surface and the radiofrequency interference (RFI). Away from about one Aquarius pixel (150 km) from the coastline, the Aquarius SSS is fairly insensitive (less than about 0.2 psu) to the radiometric details of the method to correct for the land emission. The ascending orbits appear to be affected by unfiltered RFI much less than the descending tracks. The Aquarius SSS along the ascending tracks is low over the ECS by 0.40-0.93 psu (with respect to the in situ data during the two separate 7 day periods) and is biased low by 0.41-1.07 psu (accuracy, or the time-mean of difference from the regional model along three Aquarius tracks over a 18 month period). The presence of the ascending and descending differences in the Aquarius SSS, and the spatially widespread bias suggest that the bias is attributed to the unfiltered RFI originating from strong point sources (rather than to the land contamination from weak distributed sources, or to other seasonally varying geophysical contaminants). Despite the bias, the Aquarius data describe well the temporal and spatial variability of the ECS SSS. The temporal trend and magnitude of salinity changes agree remarkably between Aquarius and a regional numerical model, during both the freshwater discharge season from the Yangtze river and the rest of the year. The precision of the Aquarius observation in the ECS is comparable with the Aquarius mission requirement (0.2 psu one-sigma for a monthly average over the open ocean). The river discharge rate correlates with the Aquarius SSS with the coefficient of 0.71 on a seasonal scale with the discharge

  7. Simulations of Tsunami Hazard from Regional Sources in the South China and Adjoining Seas

    NASA Astrophysics Data System (ADS)

    Kalligeris, N.; Synolakis, C. E.; Okal, E. A.

    2008-12-01

    We examine the tsunami potential from sources located in the South China Sea and its adjoining basins, the Sulu and Sulawezi Seas, by running simulations using the MOST code for a number of scenarios of possible earthquakes at the various local subduction zones. In the Sulawezi Sea, we consider the events of 1918 at the Mindanao subduction zone, and 1996 at the Northern end of the Makassar Strait. In the Sulu Sea, we consider a scenario inspired by the 1948 Panay earthquake (because of the fractured nature of the plate system in those areas, it is not feasible to consider much larger earthquakes). In all three cases, we find that the tsunami is contained within the relevant marginal sea and does not penetrate significantly the greater South China Basin, but could cause significant damage to the Eastern coast of Borneo. Farther North, we consider as worst case scenarios events reaching 10**29 dyn*cm with rupture lengths of 400 km, both off Luzon Island and, under a slightly different geometry, off the Luzon Straits separating the Philippines and Taiwan. Such scenarios carry very significant hazard to all coastlines bordering the South China Sea, including Indochina and Borneo. We will also present models of landslide-generated tsunamis, inspired from the event of 14 February 1934 off the Luzon Strait, and the presumably Holocene Brunei mega-slide.

  8. Tsunami Simulations for Regional Sources in the South China and Adjoining Seas

    NASA Astrophysics Data System (ADS)

    Kalligeris, N.; Okal, E. A.; Synolakis, C. E.

    2009-04-01

    The tsunami potential from sources located in the South China Sea and its adjoining basins, Sulu and Sulawesi Seas, is examined. Tsunami numerical modeling was performed using the MOST code [Titov and Synolakis, 1998] for a number of possible earthquake scenarios at the various local subduction zones. For the Sulawesi Sea, we consider the events of 1918 at the Mindanao subduction zone, and the 1996 at the Northern end of the Makassar Strait. For the Sulu Sea, we consider a scenario inspired by the 1948 Panay earthquake (because of the fractured nature of the plate system in those areas, it is not feasible to consider much larger earthquakes). Tsunami simulations of these events show that the tsunami is contained within the relevant marginal seas and does not penetrate significantly the greater South China Basin. However, tsunami hazard that could cause significant damage was found for the Eastern coast of Borneo. Farther North, we consider as worst case scenarios events reaching 10**29 dyn*cm with rupture lengths of 400 km, both off Luzon Island and, under a slightly different geometry, off the Luzon Straits separating the Philippines and Taiwan. These scenarios show very significant hazard to all coastlines bordering the South China Sea, including Indochina and Borneo. Finally, two landslide-generated tsunami scenarios are presented, inspired from the event of 14 February 1934 off the Luzon Strait, and the presumably Holocene Brunei mega-slide.

  9. A regional ocean reanalysis system for coastal waters of China and adjacent seas

    NASA Astrophysics Data System (ADS)

    Han, Guijun; Li, Wei; Zhang, Xuefeng; Li, Dong; He, Zhongjie; Wang, Xidong; Wu, Xinrong; Yu, Ting; Ma, Jirui

    2011-05-01

    A regional ocean reanalysis system for the coastal waters of China and adjacent seas has been developed by the National Marine Data and Information Service (NMDIS). It produces a dataset package called CORA (China ocean reanalysis). The regional ocean model used is based on the Princeton Ocean Model with a generalized coordinate system (POMgcs). The model is parallelized by NMDIS with the addition of the wave breaking and tidal mixing processes into model parameterizations. Data assimilation is a sequential three-dimensional variational (3D-Var) scheme implemented within a multigrid framework. Observations include satellite remote sensing sea surface temperature (SST), altimetry sea level anomaly (SLA), and temperature/salinity profiles. The reanalysis fields of sea surface height, temperature, salinity, and currents begin with January 1986 and are currently updated every year. Error statistics and error distributions of temperature, salinity and currents are presented as a primary evaluation of the reanalysis fields using sea level data from tidal gauges, temperature profiles, as well as the trajectories of Argo floats. Some case studies offer the opportunity to verify the evolution of certain local circulations. These evaluations show that the reanalysis data produced provide a good representation of the ocean processes and phenomena in the coastal waters of China and adjacent seas.

  10. SST Variability over the Southern South China Sea: Local effects and Remote forcing

    NASA Astrophysics Data System (ADS)

    Thompson, B.; Tkalich, P.

    2012-04-01

    The South China Sea (SCS) is one of the largest semi-enclosed marginal seas in the world ocean. The SCS is connected to the East China Sea through the Taiwan Strait to the northeast and the Pacific Ocean in the east through the Luzon Strait, laying between the Luzon and Taiwan Islands. To the south, SCS is connected to the Indonesian Sea (IS) through the Karimata and Gaspar Straits, and to the Indian Ocean though the Malacca Strait. The large-scale circulation and SST over the SCS is dominantly influenced by the seasonal reversal of the monsoon winds. Beyond the seasonal time scale, the circulation and temperature variability over the SCS demonstrate strong relationship with the El Niño/Southern Oscillation (ENSO) events in the Pacific Ocean. The present study addresses the inter-annual variability of Sea Surface Temperature (SST) over the southern South China Sea with special emphasis on the ENSO and Indian Ocean Dipole (IOD) events during the period 1993 to 2009. Due to its geographical location, the dynamics and thermodynamics of the southern SCS is largely influenced by the anomalous events occurring in the Pacific and Indian Oceans. A high resolution, three-dimensional sigma co-ordinate, regional ocean general circulation model (ROMS) configured for the South China Sea and Bay of Bengal region is used for the analysis. The model has been forced by 12-hourly varying surface wind, air temperature, relative humidity, surface downward solar and longwave radiation and precipitation fields obtained from the ERA-interim re-analysis data set as well as space- and time-dependent lateral fluxes of temperature, salinity, currents and sea level. Detailed analysis has been done to identify the roles of the surface heat fluxes, and the water mass advection from the Java Sea and northern South China Sea in driving the SST variability over the region. The surface heat flux data set (NOC v2.0) developed by the National Oceanography Centre, Southampton, is also used to

  11. Two typical boundary layer structures in sea fog on the coast of southern China

    NASA Astrophysics Data System (ADS)

    Huang, H.; Huang, J.; Mao, W.; Bi, X.

    2013-12-01

    Two kinds of sea fog exist on the coast of southern China according to our observations. The predominant one is advection fog. This kind of sea fog has the typical feature that the surface air temperature (SAT) is higher than the sea surface temperature (SST). The formation mechanism is that the eddy diffusion (mechanical turbulence) transports the upper saturation air and liquid water content to the sea surface. The maintain factor is the warm and moist transportation along the thermal turbulence interface. The other kind is the advection-radiative fog, is familiar to the sea fog on the west coast of USA and the Haar. In this kind of fog, the SAT is lower than the SST. This kind of sea fog is initially cooled by contact with the cold sea via advection, and then the mainly maintain mechanism is the radiation from the top of the sea fog and the evaporation from the sea. These two kinds of sea fog are interacted with the low cloud, and could transform from one to the other kind under certain conditions.

  12. Retrieval of Secchi disk depth in the Yellow Sea and East China Sea using 8-day MODIS data

    NASA Astrophysics Data System (ADS)

    Yu, D. F.; Xing, Q. G.; Lou, M. J.; Shi, P.

    2014-03-01

    Secchi disk depth (SDD), is widely used as an indicator of water clarity. The traditional sampling method is not only time-consuming and labor-intensive but also limited in terms of temporal and spatial coverage. Remote sensing technology may deal with these limitations. In this paper, the applicability of 8-day MODIS-Aqua remote sensing reflectance data with 4 km spatial resolution for estimating water clarity in the Yellow Sea and the East China Sea was investigated. Field data such as Secchi depths were collected from two cruises conducted in the Yellow Sea and the East China Sea from 5 May to 7 June 2009. A three-band algorithm to retrieve SDD was developed based on remote sensing reflectance at bands of 488, 555, and 678 nm, which performed better than single-band model and band ratio algorithm, with a determination coefficient of 0.72 and a mean relative error of 19%. This suggests that 8-day MODIS-Aqua products of remote sensing reflectance could be used to assess water transparency in the study area.

  13. Sedimentation and paleoenvironmental evolution in the China seas since the late Pleistocene

    NASA Astrophysics Data System (ADS)

    Shi, Xuefa; Liu, Yanguang; Liu, Shengfa; Qiao, Shuqing

    2014-05-01

    Chinese seas include the Bohai Sea, Yellow Sea, East China Sea and South China Sea. Systematic investigations on the sedimentary geology of the above-mentioned seas have been carried out during 2004-2011 through the project of "Synthetic Investigation and Research on the Chinese Marginal Seas". Around 21700 surface sediment samples and 1250 sediment cores have been collected for the detailed study. Around 75300 km of seismic profiles and 15220 sites of suspended matter investigation have been completed. Major advances of our study are as follows. 1. Sedimentary distribution map of 1:25 0000 of Chinese shallow seas has been complied, with the special emphasis on the harbor, bay and delta regions at 1:50000 scale. Meanwhile, an atlas of the marine sediments has been published. Several issues related to the sediments partition and variations in suspended matters and their controlling factors have been discussed. The sedimentary classification, provenance, characteristics of mineralogy, geochemistry, microfossils, physical and mechanical characteristics, content and turbidity of suspended matter have also been addressed. 2. We also compiled images of seismic profiles and its interpreted pictures, depth of representative strata boundary for Chinese seas. We have attempted to clarify the characteristics of sequence stratigraphy in these four seas since the Last Deglacial Period. Disaster geological bodies, such as sea-bottom sand waves, shallow gas and buried channel/exposed rock have been delineated. 3. High-resolution Holocene stratigraphy and time series of estuary, subaqueous delta and mud deposits in the inner shelf regions of Chinese seas have been established by using sedimentology, mineralogy, geochemistry and sequence stratigraphy. The possible responses of sea-level variations to environmental changes have also been clarified tentatively. 4. Based on the investigation of sedimentary cores, we have constructed the lithostratigraphy and magnetostratigraphy of the

  14. Spatial distributions of floating seaweeds in the East China Sea from late winter to early spring.

    PubMed

    Mizuno, S; Ajisaka, T; Lahbib, S; Kokubu, Y; Alabsi, M N; Komatsu, T

    2014-01-01

    Floating seaweeds play an important role as a habitat for many animals accompanying or attaching to them in offshore waters. It was in 2000 that the first report described abundant distributions of floating seaweeds in offshore waters in the East China Sea in spring. Young individuals of the yellowtail Seriola quinqueradiata are captured for aquaculture purposes from floating seaweeds in the East China Sea. Therefore, a sound understanding of the distributions of floating seaweeds in the East China Sea is needed. Detailed information is especially important during the late winter to early spring, which corresponds to the juvenile period of the yellowtail. Thus, field surveys using R/V Tansei-Maru were conducted in the Japanese Exclusive Economic Zone in the East China Sea from late winter to early spring in 2010 and 2011. We obtained positions of the vessel by GPS and transversal distances from the vessel to a raft by visual observation. Distance sampling method (Thomas et al. 2010) was applied to estimation of floating seaweed densities (rafts km(-2)). Seaweed rafts were also randomly sampled using nets during the research cruises. In the East China Sea, seaweed rafts were distributed mainly on the continental shelf west of the Kuroshio, especially in waters between 26° N and 30° N. Collected rafts consisted of only one species, Sargassum horneri (Turner) C. Agardh. Taking into account surface currents and geographical distribution of S. horneri, it is estimated that these floating seaweeds originated from natural beds along the coast between mid and south China. Considering the approximate travel times, it is suggested that floating patches are colonized by yellowtails early on during their trips, i.e., close to the Chinese coast. PMID:24771973

  15. Distribution of the East China Sea continental shelf basins and depths of magnetic sources

    NASA Astrophysics Data System (ADS)

    Lin, J.-Y.; Sibuet, J.-C.; Hsu, S.-K.

    2005-11-01

    The acoustic basement map of the East China Sea, established by the Shanghai Offshore Petroleum Bureau with all available industry seismic data, shows the existence of a 30-km-wide, 10-km-deep basin, that we named the Ho Basin. The Ho Basin belongs to a series of elongated deep basins extending over 600 km east of the Taiwan-Sinzi Ridge and flanked to the East by a ridge named the Longwan Ridge in its northern part. This new system of basin and ridge was probably formed during middle Miocene, sometimes in between rifting episodes occurring in the Taipei Basin and Okinawa Trough. It complements the already defined system of five belts of backarc basins and associated arc volcanic ridges in the East China Sea, which are progressively younger from the Mainland China shoreline (late Cretaceous/early Tertiary) to the Okinawa Trough (Present). In order to determine the crustal thickness beneath the East China Sea continental shelf, we used a power spectrum method to calculate the depth of the top (Zt) and the centroid (Zo) of the magnetic basement by fitting a straight line through the high- and low-wave number portions of the power spectrum, respectively. Then, the depth of the base (Zb)is estimated from Zt and Zo. After optimizing the size of the data squares, we demonstrate that, except for basins more than 10 km deep, Zt corresponds to the basement depths and Zb, the depth of the Curie point, to the Moho depth. As wide-angle reflection and refraction data are scarce in the East China Sea, this method provides a way to characterize the crustal thickness of the East China Sea and to compute the theoretical heat flow values.

  16. The impact of atmospheric deposition of cadmium on dominant algal species in the East China Sea

    NASA Astrophysics Data System (ADS)

    Quan, Qiwei; Chen, Ying; Ma, Qingwei; Wang, Fujiang; Meng, Xi; Wang, Bo

    2016-04-01

    Cadmium (Cd) mainly derived from anthropogenic emissions can be transported through atmospheric pathway to marine ecosystem, affecting the phytoplankton community and primary productivity. In this study, we identified the toxicity threshold of Cd for phytoplankton under seawater conditions of the coastal East China Sea (ECS) through both laboratory and in situ mesocosm incubation experiments. The mesocosm experiment showed that Cd in low concentration (0.003 μg per μg chl a) was conducive to the growth of natural community and increased chl a productivity. In high concentration (0.03 μg per μg chl a) Cd acted as an inhibiting factor which decreased the total chl a productivity. The diatom community was found to be more sensitive to Cd toxicity than dinoflagellate, as the low concentration Cd showed toxicity to diatom but enhanced dinoflagellate growth. We noticed that the soluble Cd estimated from atmosphere deposition to the coastal ECS was below the toxicity threshold and the Cd deposition might promote phytoplankton growth in this region. In our laboratory experiments, adding Cd, similar to aerosol deposition, stimulated the growth of both dominant algal species Prorocentrum donghaiense Lu (dinoflagellate) and Skeletonema costatum (diatom). Adding Cd on a higher level inhibited the growth of both the species, but Skeletonema costatum seemed obviously more sensitive to toxicity. This indicates the potential impact of atmospheric deposition Cd on phytoplankton community succession in the ECS.

  17. Comparison of modern pollen distribution between the northern and southern parts of the South China Sea

    NASA Astrophysics Data System (ADS)

    Luo, Chuanxiu; Chen, Muhong; Xiang, Rong; Liu, Jianguo; Zhang, Lanlan; Lu, Jun

    2015-04-01

    The authors conducted a palynological analysis based on different number of air pollen samples for the northern and southern parts of the South China Sea, respectively, in order to give a reference to reconstruct the paleoclimate of the area. (1) Fifteen air pollen samples were collected from the northern part of the South China Sea from August to September 2011, and 13 air pollen samples were collected from the southern part of the South China Sea in December 2011. The pollen types were more abundant in the north than in the south. The total pollen number and concentration in the north was 10 times more than that in the south, which may be because of the sampling season. Airborne pollen types and concentrations have a close relationship with wind direction and distance from the sampling point to the continent. (2) Seventy-four samples were collected from surface sediments in the northern part of the South China Sea in the autumn. Thirty-three samples were collected from surface sediments in the southern part of the South China Sea in the winter. Pollen concentrations in the north were nearly 10 times higher than that in the south. This is because trilete spores are transported by rivers from Hainan Island to the sea and also by the summer monsoon-forced marine current. (3) Ten air pollen samples and 10 surface sediments samples were selected for comparison. The pollen and spores in the air were mainly herbaceous and woody pollen, excluding fern spores, having seasonal pollen characteristics. Pollen in the surface sediments were mainly trilete, Pinus, and herbaceous, and may also show a combination of annual pollen characteristics.

  18. Case studies: Application of SEA in provincial level expressway infrastructure network planning in China - Current existing problems

    SciTech Connect

    Zhou Kaiyi; Sheate, William R.

    2011-11-15

    Since the Law of the People's Republic of China on Environmental Impact Assessment was enacted in 2003 and Huanfa 2004 No. 98 was released in 2004, Strategic Environmental Assessment (SEA) has been officially being implemented in the expressway infrastructure planning field in China. Through scrutinizing two SEA application cases of China's provincial level expressway infrastructure (PLEI) network plans, it is found that current SEA practice in expressway infrastructure planning field has a number of problems including: SEA practitioners do not fully understand the objective of SEA; its potential contributions to strategic planning and decision-making is extremely limited; the employed application procedure and prediction and assessment techniques are too simple to bring objective, unbiased and scientific results; and no alternative options are considered. All these problems directly lead to poor quality SEA and consequently weaken SEA's effectiveness.

  19. Optical properties of sea ice in Liaodong Bay, China

    NASA Astrophysics Data System (ADS)

    Xu, Zhantang; Yang, Yuezhong; Wang, Guifen; Cao, Wenxi; Li, Zhijun; Sun, Zhaohua

    2012-03-01

    Many industrial, agricultural, and residential areas surrounding Liaodong Bay are responsible for much of the particulate matter (PM) and colored dissolved organic matter (CDOM) found in the sea ice in the bay. Understanding the optical properties of "dirty" sea ice is important for analyzing remote sensing data and calculating energy balances. We designed a hyperspectral radiation instrument to observe the optical properties of sea ice. The results show that albedo peaks ranged from 0.3 to 0.85 and that the peaks shifted to a longer wavelength for high PM and CDOM concentrations. The absorption and scattering coefficients for sea ice were obtained. The bulk absorption coefficient shows that bulk absorption is primarily determined by PM and CDOM at shorter wavelengths, while pure ice and brine pockets become more important at longer wavelengths. Scattering coefficients for sea ice ranged from 197 to 1072 m-1, and showed consistent variations with gas bubble and brine pocket concentrations. The effects of PM and CDOM on the bulk absorption coefficient of sea ice were studied. At 440 nm, particulates accounted for 55-98% and CDOM accounted for 2-37% of the bulk absorption. Ratios between particulate absorption and bulk absorption for sea ice were almost constant from 400 to 550 nm, and began to decrease sharply for wavelengths >550 nm. Ratios between CDOM and bulk absorption decreased almost linearly with increasing wavelength.

  20. Time trends of polybrominated diphenyl ethers in East China Seas: Response to the booming of PBDE pollution industry in China.

    PubMed

    Li, Yuanyuan; Lin, Tian; Hu, Limin; Feng, Jialiang; Guo, Zhigang

    2016-01-01

    The East China Seas (ECSs) are the receptors of the land-based persistent organic pollutants (POPs), such as polybrominated diphenyl ethers (PBDEs) mainly from China through atmospheric deposition driven by the East Asian winter monsoon and fluvial discharge (e.g., Yangtze River and Yellow River), making the offshore sediments to be a good proxy to reconstruct history of those pollutants in China. In this work, four well-placed sediment cores were extracted from the mud areas in the ECSs, and the (210)Pb-dated cores were analyzed to yield historical concentration profiles of PBDEs in the area. The results showed that there was a persistent increase from 1970s and almost no clear sign in the decline of PBDEs until recently in China. More importantly, there was a faster increase of PBDEs from 1990s in China; while this period was just shown as gradually leveling off or even declining trends in developed countries. The persistently increasing trend of PBDEs in China since 1990s could be largely due to the booming of the manufacturing industry and unexpectedly transfer of PBDE pollution from developed countries to China. Besides, the relative high concentrations and fluxes of PBDEs in the core from coastal ECS located near a well-known electrical/electronic waste (e-waste) recycling area suggests an important contribution of PBDE emissions from recycling centers of e-waste in China. Although efforts in environmental monitoring of PBDE contamination have been substantially increased over the last decade, China is still lagging behind in terms of nationwide regulation of PBDE usage and treatment of disposal PBDE-containing products. PMID:27179303

  1. Tidal cooling effect on SST and its influence on typhoon simulation over the East China Sea

    NASA Astrophysics Data System (ADS)

    Zong, H.; WU, H.

    2013-12-01

    Each summer, tropical cyclones (including typhoon) frequently travel across the East China Sea (ECS), beating the surrounding regions with massive damages. Therefore, it is very important to predict their intensities and tracks by using numerical models, so as to advise people to evacuate from the possible affected area. Unfortunately, forecasting the typhoon is still a big challenge since a couple of reasons. To numerically predict the typhoons, an atmosphere-ocean coupling model is often required. Researchers have done many efforts on the atmosphere part to improve the accuracy, while the ocean part was often treated simply. For example, many operational forecasting models simply set the SST as climatological values. As the ocean motion is energetic and the sea conditions vary significantly with time, this brief setting could result in some error. Some other models include an ocean model that considering the air-sea exchange of heat and momentum, as well as large-scale ocean motions like circulation. However, in the shallow coastal oceans like the ECS, tidal forcing also plays an important role that modulate the vertical exchange to adjust the SST. So far no atmosphere-ocean coupling model in this region consider the tide. In this study, we have found that 1) Accuracy of SST is essential to correctly predict the intensity and track of typhoons; 2) It is important to include the tide to correctly simulate the SST in the shallow oceans like the ECS. We setup an Advanced Research Hurricane WRF (WRF-AHW) model in the ECS and simulated typhoon Muifa (No. 201109). The 6-hourly data of the NCEP FNL Global Analyses was used as the initial and lateral boundary conditions in the model. Firstly, We run the model only with NCEP FNL Global Analyses data. The simulated track was very similar to China forecasted one, which was more than 200 kilometers far from the Joint Typhoon Warning Center (JTWC) provided typhoon location at 0:00 am, 6 August, 2011. Then, We run the model

  2. Descriptions of three new species of Mitridae (Mollusca: Gastropoda) from South China Sea

    NASA Astrophysics Data System (ADS)

    Li, Baoquan; Zhang, Suping; Li, Xinzheng

    2005-03-01

    Three new species of Family Mitridae (Mollusca: Gastropoda) from the South China Sea are described in the present paper. They are Ziba aglais sp. nov. B. LI & S. ZHANg, Neocancilla daidaleosa sp. nov. B. LI & X. LI, and Mitra holkosa sp. nov. B. LI. Their systematic positions are also discussed.

  3. Preliminary study on pisionids (Annelida: Polychaeta Pisionidae) from Hainan Island coastal waters, South China Sea

    NASA Astrophysics Data System (ADS)

    Wu, Bao-Ling; Ding, Zhi-Hu; Huang, Feng-Peng

    1998-06-01

    Of the four species of Pisione Grube (1856) collected from the coastal waters of Hainan Island, the South China Sea, and described in this paper, Pisione hainanensis n. sp. is new to science; Pisione oerstedii Grube, 1857; Pisione complexa Alikunhi, 1947, and Pisione levisetosa Zhao, Westheide & Wu, 1991 are reported for the first time from this area.

  4. Distribution of nanoflagellates in five water masses of the East China Sea in autumn and winter

    NASA Astrophysics Data System (ADS)

    Lin, Shiquan; Huang, Lingfeng; Zhu, Zhisheng; Xiong, Yuan; Lu, Jiachang

    2016-02-01

    The variations of abundance, biomass and trophic structure of nanoflagellates (NF) among five typical water masses in the East China Sea were investigated in autumn (November 19-December 23, 2006) and winter (February 22-March 11, 2007). It was found that water mass had a significant impact on the distribution of NF. Either in autumn or in winter, the highest abundance and biomass of NF were recorded in the East China Sea Shelf Mixing Water (ECSSMW), and the lowest in the Kuroshio Subsurface Water (KSSW). While in the East China Sea Coastal Water (ECSCW), the abundance and biomass of both heterotrophic nanoflagellates (HNF) and pigmented phototrophic nanoflagellates (PNF) were only slightly higher than that in Taiwan Strait Water (TSW) and Kuroshio Surface Water (KSW). In respect to the seasonal variation, the abundance and biomass of NF in TSW declined in winter, while in other 4 water masses, they showed an increasing trend from autumn to winter, mainly due to the decrease (in TSW) or increase (in ECSCW, ECSSMW, KSW and KSSW) of HNF. The distribution pattern of abundance- or biomass-based PNF/HNF ratio was found to be correlated to the nutrient level of the water mass. Results of Pearson correlation analysis and principle component analysis indicated that PNF was mainly constrained by nutrient supply, and HNF was controlled by food availability in the East China Sea.

  5. The boat people of Vietnam. Rescue on the South China Sea.

    PubMed

    Hayes, T J; Thomas, D; Dewar, E P

    1990-01-01

    Poor economic conditions in Vietnam have encouraged large numbers of people seeking a better life in the West to join the flow of political refugees leaving the country as "boat people". We report the events surrounding one such group of people who were rescued from the South China Sea by the Outback 88 Task Group. PMID:2374108

  6. Illicit drugs and their metabolites in 36 rivers that drain into the Bohai Sea and north Yellow Sea, north China.

    PubMed

    Wang, De-Gao; Zheng, Qiu-Da; Wang, Xiao-Ping; Du, Juan; Tian, Chong-Guo; Wang, Zhuang; Ge, Lin-Ke

    2016-08-01

    Illicit drugs and their metabolites have recently been recognized as an emerging group of contaminants due to their potential ecotoxicological impact in aquatic ecosystems. To date, information on the occurrence of these compounds in the aquatic environment of China remains limited. In this study, we collected surface water samples from 36 rivers in north China that discharge into the Bohai Sea and north Yellow Sea and measured the concentrations of amphetamine-like compounds, ketamines, cocainics, and opioids. The occurrence and spatial patterns of these substances show significant differences between the rivers and regions. Two designer drugs, methamphetamine (METH) and ketamine (KET), were the most abundant compounds detected in the entire set of samples (detection frequency of 92 and 69 %). The concentrations of METH and KET ranged from <0.1 to 42.0 ng L(-1) (mean = 4.53 ng L(-1)) and <0.05 to 4.50 ng L(-1) (mean = 0.49 ng L(-1)), respectively. The high detection frequencies of METH and KET are consistent with the fact that they are the main illicit drugs consumed in China. The high concentrations of these illicit drugs and their metabolites were found in areas that have a high population density. The riverine input of total illicit drugs into the Bohai Sea and north Yellow Sea was estimated to be in the range of 684 to 1160 kg per year. PMID:27167374

  7. In-situ measurements of bottom boundary layer processes in the deep South China Sea

    NASA Astrophysics Data System (ADS)

    Xu, J.; Li, J.; Zhang, Y.; Zhao, Y.; Liu, Z.; Ferreira, J. C. T.; Tate, G.

    2014-12-01

    As part of the South China Sea Deep project, we deployed a free-ascending tripod (FAT) on the sea floor of northern South China Sea at a water depth of 1900 m. During the 5-month deployment, the tripod hosted a suite of acoustic and optical oceanographic instruments that simultaneously measured time-series of 3-D velocity structure of the near bottom flows, temperature and salinity, water turbidity (sediment concentration), and particle size variations. A camera system and an acoustic altimeter closely monitored fine scale changes of the sea floor that could have resulted from either physical processes (erosion/deposition) or biological activities. Our goal of the tripod work, first-ever such study in South China Sea, along with several subsurface moorings that were also collecting flow and sedimentological data in the area, was to investigate the bottom boundary layer (BBL) processes and the regional deep current circulation surrounding a large body of sediment deposit whose formation mechanism and origins of sediment are still unclear. In addition, the tripod instruments were set up to capture the in-situ BBL signature of passing "benthic storms" that are believed to be the most important BBL processes in deep ocean. This presentation also includes a brief description of the technological advances implemented in the FAT deep-water tripod.

  8. Changes in Climate over the South China Sea and Adjacent Regions: Response to and Feedback on Global Climate Change

    NASA Astrophysics Data System (ADS)

    Yang, Song

    2016-04-01

    El Niño-Southern Oscillation and the Asian monsoon have experienced significant long-term changes in the past decades. These changes, together with other factors, have in turn led to large climate change signals over the South China Sea and adjacent regions including Southeast Asia, the western Pacific, and the tropical Indian Ocean. An attribution analysis of the feedback processes of these signals indicate the predominant importance of water vapor and cloud radiative feedbacks. Experiments with multiple earth system models also show that these regional climate change signals exert significant influences on global climate. The increases in atmospheric heating over Southeast Asia and sea surface temperature in the adjacent oceans in the past decades have weakened the Indian and African monsoons, led to a drying effect over East Asia, and generated wave-train patterns in both the northern and southern hemispheres, explaining several prominent climate features in and outside Southeast Asia.

  9. Data from renewable energy assessments for resort islands in the South China Sea

    PubMed Central

    Basir Khan, M. Reyasudin; Jidin, Razali; Pasupuleti, Jagadeesh

    2015-01-01

    Renewable energy assessments for resort islands in the South China Sea were conducted that involves the collection and analysis of meteorological and topographic data. The meteorological data was used to assess the PV, wind and hydropower system potentials on the islands. Furthermore, the reconnaissance study for hydro-potentials were conducted through topographic maps in order to determine the potential sites suitable for development of run-of-river hydropower generation. The stream data was collected for 14 islands in the South China Sea with a total of 51 investigated sites. The data from this study are related to the research article “Optimal combination of solar, wind, micro-hydro and diesel systems based on actual seasonal load profiles for a resort island in the South China Sea” published in Energy (Khan et al., 2015) [1]. PMID:26779562

  10. Energy audit data for a resort island in the South China Sea

    PubMed Central

    Basir Khan, M. Reyasudin; Jidin, Razali; Pasupuleti, Jagadeesh

    2015-01-01

    The data consists of actual generation-side auditing including the distribution of loads, seasonal load profiles, and types of loads as well as an analysis of local development planning of a resort island in the South China Sea. The data has been used to propose an optimal combination of hybrid renewable energy systems that able to mitigate the diesel fuel dependency on the island. The resort island selected is Tioman, as it represents the typical energy requirements of many resort islands in the South China Sea. The data presented are related to the research article “Optimal Combination of Solar, Wind, Micro-Hydro and Diesel Systems based on Actual Seasonal Load Profiles for a Resort Island in the South China Sea” [1]. PMID:26900590

  11. Contrasting behavior of tungsten and molybdenum in the Okinawa Trough, the East China Sea and the Yellow Sea

    SciTech Connect

    Sohrin, Yoshiki; Matsui, Masakazu; Nakayama, Eiichiro

    1999-10-01

    By using catalytic current polarography and high-resolution inductively coupled plasma mass spectrometry, W and Mo in seawater were determined in the Okinawa Trough, a backarc rift, and in the East China Sea and the Yellow Sea. Mo was distributed conservatively throughout the study area, and its salinity-normalized concentration was 104 {+-} 6 nM (n = 105). W was also uniformly distributed south of the Kuroshio Current (56 {+-} 7 pM, n = 51). Anomalous high concentrations of W (maximum 254 pM) were found in the Iheya Graben in the middle Okinawa Trough ({gt}1,000 m depth), which were probably supplied by hydrothermal activity. The concentrations of Mo and W in the East China Sea and the Yellow Sea showed linear correlation with salinity (26 {lt} S {lt} 35). The Mo data can be explained by mixing of seawater and river water of the Changjiang (Mo = 10 nM; Qu et al., 1993). However, the values of W extrapolated to S = 0 were largely different between two cruises (1,200 pM in May-June 1987 and 540 pM in June 1994) and much higher than the reported concentrations of 160 pM for world rivers by Turekian (1969) and 30 pM for unpolluted Japanese rivers by Sohrin et al. (1989). Moreover, significantly high W was observed in the bottom water at stations near the Changjiang River estuary and the western Yellow Sea. While these data may suggest that W is released from the anoxic sediments of the continental shelf, more data are needed to elucidate the mechanism controlling the distribution of W.

  12. Sea Level Rise and Land Subsidence Contributions to the Signals from the Tide Gauges of China

    NASA Astrophysics Data System (ADS)

    Parker, Albert

    2016-06-01

    The tide gauges measure the local oscillations of the sea level vs. the tide gauge instrument. The tide gauge instrument is generally subjected to the general subsidence or uplift of the nearby inland, plus some additional subsidence for land compaction and other localised phenomena. The paper proposes a non-linear model of the relative sea level oscillations including a long term trend for the absolute sea level rise, another term for the subsidence of the instrument, and finally a sinusoidal approximation for the cyclic oscillations of periodicities up to decades. This non-linear model is applied to the tide gauges of China. The paper shows that the limited information available for China does not permit to infer any proper trend for the relative rates of rise, as the tide gauge records are all short or incomplete and the vertical movement of the tide gauge instruments is unassessed. The only tide gauge record of sufficient length that may be assembled for China is obtained by combining the North Point and Quarry Bay tide gauges in Hong Kong (NPQB). This NQPB composite tide gauge record is shown to have similarities with the tide gauge records of Sydney, equally in the West pacific, and San Diego, in the east Pacific, oscillating about the longer term trend mostly determined by the local subsidence. As it is very well known that China generally suffers of land subsidence, and the tide gauge installations may suffer of additional subsidence vs. the inland, it may be concluded from the analysis of the other worldwide tide gauges that the sea levels of China are very likely rising about the same amount of the subsidence of the tide gauges, with the sea level acceleration component still negligible.

  13. Tidal elevation, current, and energy flux in the area between the South China Sea and Java Sea

    NASA Astrophysics Data System (ADS)

    Wei, Zexun; Fang, Guohong; Dwi Susanto, R.; Rameyo Adi, Tukul; Fan, Bin; Setiawan, Agus; Li, Shujiang; Wang, Yonggang; Gao, Xiumin

    2016-04-01

    The South China Sea (SCS) and the Java Sea (JS) are connected through the Karimata Strait, Gaspar Strait, and the southern Natuna Sea, where the tides are often used as open boundary condition for tidal simulation in the SCS or Indonesian seas. Tides, tidal currents, and tidal energy fluxes of the principle constituents K1, O1, Q1, M2, S2, and N2 at five stations in this area have been analyzed using in situ observational data. The results show that the diurnal tides are the dominant constituents in the entire study area. The constituent K1 has the largest amplitude, exceeding 50 cm, whereas the amplitudes of M2 are smaller than 5 cm at all stations. The amplitudes of S2 may exceed M2 in the Karimata and Gaspar straits. Tidal currents are mostly of rectilinear type in this area. The semi-major axes lengths of the diurnal tidal current ellipses are about 10 cm s-1, and those of the semidiurnal tidal currents are smaller than 5 cm s-1. The diurnal tidal energy flows from the SCS to the JS. The semidiurnal tidal energy flows from the SCS to the JS through the Karimata Strait and the eastern part of the southern Natuna Sea but flows in the opposite direction in the Gaspar Strait and the western part of the southern Natuna Sea. Harmonic analysis of sea level and current observation also suggest that the study area is located in the antinodal band of the diurnal tidal waves, and in the nodal band of the semidiurnal tidal waves. Comparisons show that the existing models are basically consistent with the observational results, but further improvements are necessary.

  14. Tidal elevation, current and energy flux in the area between the South China Sea and Java Sea

    NASA Astrophysics Data System (ADS)

    Wei, Z. X.; Fang, G. H.; Susanto, R. D.; Adi, T. R.; Fan, B.; Setiawan, A.; Li, S. J.; Wang, Y. G.; Gao, X. M.

    2015-11-01

    The South China Sea (SCS) and the Java Sea (JS) are connected through the Karimata Strait, Gaspar Strait, and the southern Natuna Sea, where the tides are often used as open boundary condition for tidal simulation in the SCS or Indonesian seas. Tides, tidal currents and tidal energy fluxes of the principle constituents K1, O1, Q1, M2, S2 and N2 at five stations in this area have been analyzed using in-situ observational data. The results show that the diurnal tides are the dominant constituents in the entire study area. The constituent K1 has the largest amplitude, exceeding 50 cm, whereas the amplitudes of M2 are smaller than 5 cm at all stations. The amplitudes of S2 may exceed M2 in Karimata and Gaspar Straits. Tidal currents are mostly of rectilinear type in this area. The major semi axis lengths of the diurnal tidal current ellipses are about 10 cm s-1, and those of the semi-diurnal tidal currents are smaller than 5 cm s-1. The diurnal tidal energy flows from the SCS to the JS. The semi-diurnal tidal energy flows from the SCS to the JS through the Karimata Strait and the eastern part of the southern Natuna Sea but flows in the opposite direction in the Gaspar Strait and the western part of the southern Natuna Sea. Harmonic analysis of sea level and current observation also suggest that the study area is located in the loop band of the diurnal tidal waves, and in the nodal band of the semi-diurnal tidal waves. Comparisons show that the existing models are basically consistent with the observational results, but further improvements are necessary.

  15. Ocean pollution from land-based sources: East China Sea, China.

    PubMed

    Li, Daoji; Daler, Dag

    2004-02-01

    The environment of East China Sea (ECS) has been faced by huge stresses from anthropogenic activities and population growth in the Yangtze River drainage basin and the areas along the coasts. Improper use of natural resources and short-term economic objectives have resulted in severe environmental degradation in a fairly short time frame and the degradation has now reached a level where the health and well being of the coastal populations are threatened. The main pollutants are inorganic nitrogen, phosphate, oil hydrocarbons, organic matters and heavy metals. Nutrients cause eutrophication of the coastal waters and the estuarine area and very often stimulate the occurrence of red tides. The environmental pollution of Yangtze River basin directly impact on the state of the marine environment in the ECS. The ecosystem stability is maintained by a steady water discharge from the river, that mixes with the marine salty water in the estuary, and the sediment loads from the river that balance ocean erosion in the delta and its adjacent coastal area. The large-scale water transfer and dam constructions in the Yangtze River basin will change this basis. For the ECS the challenge is to reverse the negative processes taking place and to restore ecosystem balance. The main challenge is to integrate socioeconomic and environmental decision making in order to promote sustainable development. A better understanding of the driving forces in society that cause these environmental pressures is required in order to overcome these obstacles. International cooperation may be an important contributor to the progress and in particular provide access to financial, technological, scientific and human resource assistance. PMID:15083656

  16. Variability of Cross-shelf Penetrating Fronts in the East China Sea

    NASA Astrophysics Data System (ADS)

    He, Lei; Li, Yao; Zhou, Hui; Yuan, Dongliang

    2010-10-01

    Images of 8-day mean chlorophyll- a concentrations of the Moderate Resolution Imaging Spectroradiometer (MODIS) onboard of Aqua Satellite from 2002 to 2007 and of the Sea-viewing Wide Field-of-view Sensor (SeaWiFS) satellite from 1998 to 2007 are used to study the variability of the cross-shelf penetrating fronts (CPFs) in the East China Sea. The analysis suggests that the generation of the CPFs has strong seasonal-to-interannual variations, with more CPFs in summer and winter than in spring and fall. Each CPF lasts for a few days to a month. The majority of the fronts are triangle-shaped with their broad bases nearby the coast and their sharp heads penetrating into the middle shelf. There are over 40 CPFs with penetrating distances exceeding 100 km over the East China Sea during the past 10 years of the satellite era, with the maximum ones reaching the Kuroshio at the edge of the continental shelf. Of all the low cloud scenes of the satellite images, more than 25% contain at least one CPF. The high-frequency occurrence of the CPFs suggests that the CPFs play an important role in cross-shelf transport of heat, effluent, and land-derived materials in the East China Sea. The generation of the CPF is found to be influenced by winds and by intrinsic oceanic variability. In particular, the collision of wind-forced coastal jet with the Taiwan Warm Current is suggested as one of the mechanisms that generate the CPFs in the East China Sea.

  17. Lymphedema in China--experiences and prospects.

    PubMed

    Liu, N F

    2007-12-01

    The history of prevention and treatment of lymphedema in China is long. Filarial lymphedema was the most common type of the disease in the past with 5 million patients countrywide in the 1950's. Great efforts have gone into controlling filariasis during the past 50 years, and China now has essentially eliminated filariasis. In contrast to the reduction in filarial lymphedema, there has been a trend of increase in secondary lymphedema cases after malignant tumor surgery. Although there are no precise figures on the incidence of lymphedema nationwide, physicians and therapists are in great clinical demand. Traditional Chinese medicine has shown effectiveness for prevention and treatment of inflammation and alleviating swelling. The combination with Western medicine may offer improved methods for lymphedema treatment. PMID:18365528

  18. Dissolved rare earth elements in the South China Sea: Geochemical characterization of the water masses

    NASA Astrophysics Data System (ADS)

    Alibo, Dia Sotto; Nozaki, Yoshiyuki

    2000-12-01

    We have measured the vertical profiles of dissolved rare earth elements (REEs) and yttrium in the South China Sea together with conductivity-temperature-depth and hydrographic measurements to compare with those in the western North Pacific and the SuIu Sea. Although the South China Sea is rapidly flushed by the Pacific through the Luzon Strait with a sill depth of ˜2500 m [Broecker et al., 1986], a unique REE pattern is developed within the sea. The most striking difference exists in the dissolved Ce profiles. Dissolved Ce generally decreases from high values (6-9 pmol/kg) at the surface to a minimum of ˜3 pmol/kg at around 300-500 m where the North Pacific Intermediate Water penetrates. In deepwaters of the North Pacific and the Sulu Sea it remains at a relatively low and nearly constant concentration level of ˜5 pmol/kg throughout the water column, whereas in the South China Sea, it gradually increases with depth to a maximum of 12.9 pmol/kg at ˜2500 m, resembling the "nutrient-like" profiles of other strictly trivalent REEs, and then sharply drops to a constant value of ˜6 pmol/kg in the bottom water below 2900 m. Some lighter REEs like Pr, Nd, and Gd, though to a much lesser extent, also show similar concentration breaks at the sill depth, but the other hydrographic properties like dissolved oxygen, nutrients, pH, and alkalinity do not. Therefore dissolved REEs may best be utilized to characterize the water masses. Two major sources for dissolved REEs in the South China Sea are fluvial and coastal input to the surface ocean and a bottom release into the deep water during the passage over the Luzon Strait. Redox chemistry including reduction of Ce(IV) to Ce(III) in the pore water of hemipelagic sediments and subsequent release of dissolved Ce(III) to the overlying deep water may be involved in the latter. The middle REE-enriched patterns with a significant Gd depression relative to that of the North Pacific Deep Water are characteristic of the South China

  19. Seasonal variation of black carbon over the South China Sea and in various continental locations in South China

    NASA Astrophysics Data System (ADS)

    Wu, D.; Wu, C.; Liao, B.; Li, F.; Tan, H.; Deng, T.; Li, H.; Chen, H.; Jiang, D.; Yu, J. Z.

    2013-07-01

    Black carbon (BC) is an important atmospheric constitute as an air pollutant and as a climate forcer. To our knowledge, field measurements of BC have not been reported over the South China Sea. Observation of light absorption coefficients (σabs) and BC concentrations by Aethalometer were conducted on Yongxing Island in the South China Sea and at five continental sites in the Pearl River Delta (PRD) region, South China during the South China Sea monsoon period (rainy season, 16 May-20 June 2008) and the northeast monsoon period (dry season, 12 December 2008-8 January 2009). At the oceanic site, the daily average BC concentrations vary from 0.28 to 2.14 μg m-3 and seasonal variations of BC were small (0.67 in dry season and 0.54 μg m-3 in rainy season). Similarly, little seasonal difference was found at a background site in PRD (2.88 in dry season and 2.62 μg m-3 in rainy season). At PRD urban sites, the daily average concentration of BC ranges from 1.56 to 37.9 μg m-3, higher in the dry season (12.6 μg m-3) and lower in the rainy season (6.4 μg m-3). The observed average σabs values in rainy vs. dry seasons are 119 vs. 62 Mm-1 at the PRD urban sites, 29 vs. 26 Mm-1 at the PRD background site, and 8.4 vs. 7.2 Mm-1 at the marine site. A bi-peak pattern in diurnal BC variation was observed at all sites while this pattern is the most prominent at the urban sites. The first peak appears in the early morning rush hour and the second peak in early evening, with the evening peak more pronounced in dry season.

  20. Remote sensing of pigment concentration and sea surface temperature on the continental shelf of China

    NASA Astrophysics Data System (ADS)

    Tang, Danling

    The combination of a population of more than 1.2 billion people and the recent rapid industrialization and large-scale infrastructure projects have placed a very heavy burden on the coastal environment in China. Algal blooms and red tides pose a serious threat to public health, fisheries and aquaculture industry. Consequently, a thorough assessment of their impacts on the coastal zone is urgently needed. This research is the first application of the historical satellite remote sensing archive to investigate temporal and spatial patterns of pigment concentrations (PC) and sea surface temperatures (SST) on the entire continental shelf of China. Firstly, I examined the temporal (annual/monthly) and spatial patterns of PC and SST on the continental shelf of China. The image availability for the study area was examined. A total of 2139 scenes were obtained from the study area during the years of the Nimbus-7 satellite mission (from 1978 to 1986), from which 76 monthly and 8 annual composite CZCS images were generated. AVHRR (Advanced Very High Resolution Radiometer) data from NOAA (National Oceanic & Atmospheric Administration) satellites were also examined. A distinctive high PC belt of about 50 km wide existed along the coastline of China, and a large plume of high PC was observed which extended nearly 500 km to the east from the Yangtze River. PC were high in the Yellow Sea (about 1--2 mg m-3 it decreased seawards and southeastwards with a minimum value in the Philippine Sea (about 0.2 mg m-3 ). Annual PC increased from 1979 and reached a peak in 1981; it dropped in 1982 with a strong El Nino. In the northern area (Yellow Sea), there were two peaks of PC in each year (spring and fall). In the southern area (northern South China Sea), PC was relatively low and constant over each year. A basin-wide gyre appeared in the center of the Yellow Sea in April 1986. Secondly, I focused on the Luzon Strait, a channel between the Philippine Sea and the South China Sea. High

  1. Scenarios of local tsunamis in the China Seas by Boussinesq model

    NASA Astrophysics Data System (ADS)

    Zhao, Xi; Liu, Hua; Wang, Ben-long

    2014-06-01

    The Okinawa Trench in the East China Sea and the Manila Trench in the South China Sea are considered to be the regions with high risk of potential tsunamis induced by submarine earthquakes. Tsunami waves will impact the southeast coast of China if tsunamis occur in these areas. In this paper, the horizontal two-dimensional Boussinesq model is used to simulate tsunami generation, propagation, and runup in a domain with complex geometrical boundaries. The temporary varying bottom boundary condition is adopted to describe the initial tsunami waves motivated by the submarine faults. The Indian Ocean tsunami is simulated by the numerical model as a validation case. The time series of water elevation and runup on the beach are compared with the measured data from field survey. The agreements indicate that the Boussinesq model can be used to simulate tsunamis and predict the waveform and runup. Then, the hypothetical tsunamis in the Okinawa Trench and the Manila Trench are simulated by the numerical model. The arrival time and maximum wave height near coastal cities are predicted by the model. It turns out that the leading depression N-wave occurs when the tsunami propagates in the continental shelf from the Okinawa Trench. The scenarios of the tsunami in the Manila Trench demonstrate significant effects on the coastal area around the South China Sea.

  2. Using a video-corer to evaluate hydrocarbon fluxes in the northern South China Sea

    NASA Astrophysics Data System (ADS)

    Hung, C. C.; Wang, C. C.; Chen, H. H.; Lin, Y. S.; Huang, K. H.

    2015-12-01

    Many natural methane seeps exist in the northern South China Sea. Researchers have often used gravity corers or piston corers to collect sediments and bottom seawater for estimating methane fluxes of these seeps. The actual sampling locations of these corers are difficult to match seeping vents detected by scientific echo sounder because of the difficulty in positioning of these corers when sampling at sea,. Thus, the hydrocarbon fluxes of the seeping vents estimated using these corers might not be representative hydrocarbon fluxes of seeping vents in the northern South China Sea. In this study, we used a real-time video multicorer to collect surface sediments and bottom seawater samples. This real-time multicorer can accurately obtain surface sediments and bottom seawater samples on hydrocarbon seeping vents. To estimate hydrocarbon diffusion fluxes of seeps in the northern South China Sea, we analyzed methane concentrations and carbon isotopes of methane in both porewater and bottom seawater. During the cruises conducted from August to December, 2014, methane fluxes in the study area ranged from 3 to 57000 μmol m-2 d-1 which are significantly higher than previously reported values (~160 μmol m-2 d-1). Besides, we have obtained some samples in the study area using real-time multicorer in 2015. These new results will be presented in the meeting. Overall, the observed result in this study suggests that the in-situ multicorer can be a suitable instrument sampling surface sediments and bottom seawater samples on hydrocarbon seeping vents.

  3. Current separation and upwelling over the southeast shelf of Vietnam in the South China Sea

    NASA Astrophysics Data System (ADS)

    Chen, Changsheng; Lai, Zhigang; Beardsley, Robert C.; Xu, Qichun; Lin, Huichan; Viet, Nguyen Trung

    2012-03-01

    The high-resolution, unstructured grid Finite-Volume Community Ocean Model (FVCOM) was used to examine the physical mechanisms that cause current separation and upwelling over the southeast shelf of Vietnam in the South China Sea (SCS). Process-oriented experiments suggest that the southwesterly monsoon wind is a key physical mechanism for upwelling in that area but not a prerequisite to cause current separation. With no wind forcing, current separation in summer can occur as a result of the encounter of a southward along-shelf coastal current from the north and northeastward buoyancy-driven and stratified tidal-rectified currents from the southwest. The southward current can be traced upstream to the Hong River in the Gulf of Tonkin. This current is dominated by semigeostrophic dynamics and is mostly confined to the narrow shelf along the northern Vietnamese coast. The northeastward currents are generated by tidal rectification and are intensified by the Mekong River discharge and southwesterly monsoon wind forcing. The dynamics controlling this current are fully nonlinear, with significant contributions from advection and vertical turbulent mixing. Upwelling in the current separation zone can be produced by a spatially uniform constant wind field and can be explained using simple wind-induced Ekman transport theory. This finding differs from previous theory in which the regional dipole wind stress curl is claimed as a key mechanism for current separation and upwelling in this coastal region. Our SCS FVCOM, driven by the wind stress, river discharge, and tides, is capable of reproducing the location and tongue-like offshore distribution of temperature as those seen in satellite-derived sea surface temperature imagery.

  4. Detrital zircon provenance of the Paleogene syn-rift sediments in the northern South China Sea

    NASA Astrophysics Data System (ADS)

    Shao, Lei; Cao, Licheng; Pang, Xiong; Jiang, Tao; Qiao, Peijun; Zhao, Meng

    2016-02-01

    The early rift sedimentation history of the South China Sea is still not well understood due to restricted borehole coverage of the Paleogene strata and lack of reliable stratigraphic dating. We use detrital zircon U-Pb geochronology to explore the source-to-sink characteristics of syn-rift sequences in the northern South China Sea. The results reveal significant intrabasinal provenances in addition to the well-perceived terrigenous supply from the north. The Dongsha Uplift is considered to account for the dominance of the Early Cretaceous zircons in the Eocene samples. The Lower Oligocene sediments in the Qiongdongnan Basin could have been sourced from Hainan Island and local uplifts, but their distinction cannot be confirmed by the U-Pb age spectra. Contemporary sediments in the northern Pearl River Mouth Basin were most likely transported from southeastern South China with well-rounded zircon grains showing U-Pb age similarity to those from the northeastern tributaries of the Pearl River. By contrast, intrabasinal sources from the west and east are suggested to have contributed the infill of the southern part of the Pearl River Mouth Basin based on generally euhedral zircon shapes. These sedimentary source patterns appear to change very little in the Oligocene northern South China Sea. However, the newly detected Neoproterozoic zircons in the Upper Oligocene sediments from borehole L21 tend to indicate a southern source. The episodic and diachronic nature of rifting and erosion processes in the early South China Sea is the cause of complex patterns in the Paleogene provenance history.

  5. Decline in the species richness contribution of Echinodermata to the macrobenthos in the shelf seas of China

    NASA Astrophysics Data System (ADS)

    Jin, Shaofei; Wang, Yongli; Xia, Jiangjiang; Xiao, Ning; Zhang, Junlong; Xiong, Zhe

    Echinoderms play crucial roles in the structure of marine macrobenthic communities. They are sensitive to excess absorption of CO2 by the ocean, which induces ocean acidification and ocean warming. In the shelf seas of China, the mean sea surface temperature has a faster warming rate compared with the mean rate of the global ocean, and the apparent decrease in pH is due not only to the increased CO2 absorption in seawater, but also eutrophication. However, little is known about the associated changes in the diversity of echinoderms and their roles in macrobenthic communities in the seas of China. In this study, we conducted a meta-analysis of 77 case studies in 51 papers to examine the changes in the contribution of echinoderm species richness to the macrobenthos in the shelf seas of China since the 1980s. The relative species richness (RSR) was considered as the metric to evaluate these changes. Trends analysis revealed significant declines in RSR in the shelf seas of China, the Yellow Sea, and the East China Sea from 1997 to 2009. Compared with the RSR before 1997, no significant changes in mean RSR were found after 1997, except in the Bohai Sea. In addition, relative change in the RSR of echinoderms and species richness of macrobenthos led to more changes (decrease or increase) in their respective biomasses. Our results imply that changes in species richness may alter the macrobenthic productivity of the marine benthic ecosystem.

  6. Internal structures and developing mechanisms of tidal sand ridges in the East China Sea

    NASA Astrophysics Data System (ADS)

    Liu, Z.

    2004-12-01

    *Abstract:* The internal structures of the tidal sand ridges in the East China Sea are characterized by the southwest-dipping beddings and several erosion surfaces, which resulted in young sand ridges overlying old ones and forming a unique multi-layer complex structure. These characteristics reveal the multi-phase development of the tidal sand ridges, and their multi-repetitive forming history of accumulation, erosion and accumulation. There are two mechanisms interpreting the migration and evolution of these sand ridges. One mechanism concerns the evolution tidal sand ridge itself. The tidal current difference along two flanks of a ridge makes the sediments migrate toward the side with lower current speed. This is so-called auto-cyclic process of sand ridge developing. For the tidal sand ridges in the East China Sea, one side is dominated by flood currents in a NW direction, the other side is dominated by ebb current in a SE direction. Due to the influences of topography gradient of the continental shelf and the runoff from Chinese main land, the velocity of the ebb currents is larger than that of the flood currents, so the sediment is transported to southwest continuously, and it is a certainty for the sand ridges migrate toward SW and form the beddings inclining toward SW. The other mechanism is allo-cyclic process, which relates to global or regional hydrodynamic changes, such as sea-level fluctuations or storm waves. The post-glacial sea level rose rapidly in a stepwise pattern caused by the four postglacial melting water pulses (MWP-1A, 1B, 1C, 1D) (Liu et al., 2004) and it should play an important role in this mechanism. Both mechanisms exist in the development of the tidal sand ridges in the East China Sea, so there is some difficulties to distinguish them clearly. It is obvious that the tidal sand ridges of the East China Sea have evolved continuously since the postglacial period; four stages of sand ridges have formed in sequence: younger ridges overlaid

  7. An extreme internal solitary wave event observed in the northern South China Sea

    PubMed Central

    Huang, Xiaodong; Chen, Zhaohui; Zhao, Wei; Zhang, Zhiwei; Zhou, Chun; Yang, Qingxuan; Tian, Jiwei

    2016-01-01

    With characteristics of large amplitude and strong current, internal solitary wave (ISW) is a major hazard to marine engineering and submarine navigation; it also has significant impacts on marine ecosystems and fishery activity. Among the world oceans, ISWs are particular active in the northern South China Sea (SCS). In this spirit, the SCS Internal Wave Experiment has been conducted since March 2010 using subsurface mooring array. Here, we report an extreme ISW captured on 4 December 2013 with a maximum amplitude of 240 m and a peak westward current velocity of 2.55 m/s. To the authors’ best knowledge, this is the strongest ISW of the world oceans on record. Full-depth measurements also revealed notable impacts of the extreme ISW on deep-ocean currents and thermal structures. Concurrent mooring measurements near Batan Island showed that the powerful semidiurnal internal tide generation in the Luzon Strait was likely responsible for the occurrence of the extreme ISW event. Based on the HYCOM data-assimilation product, we speculate that the strong stratification around Batan Island related to the strengthening Kuroshio may have contributed to the formation of the extreme ISW. PMID:27444063

  8. An extreme internal solitary wave event observed in the northern South China Sea

    NASA Astrophysics Data System (ADS)

    Huang, Xiaodong; Chen, Zhaohui; Zhao, Wei; Zhang, Zhiwei; Zhou, Chun; Yang, Qingxuan; Tian, Jiwei

    2016-07-01

    With characteristics of large amplitude and strong current, internal solitary wave (ISW) is a major hazard to marine engineering and submarine navigation; it also has significant impacts on marine ecosystems and fishery activity. Among the world oceans, ISWs are particular active in the northern South China Sea (SCS). In this spirit, the SCS Internal Wave Experiment has been conducted since March 2010 using subsurface mooring array. Here, we report an extreme ISW captured on 4 December 2013 with a maximum amplitude of 240 m and a peak westward current velocity of 2.55 m/s. To the authors’ best knowledge, this is the strongest ISW of the world oceans on record. Full-depth measurements also revealed notable impacts of the extreme ISW on deep-ocean currents and thermal structures. Concurrent mooring measurements near Batan Island showed that the powerful semidiurnal internal tide generation in the Luzon Strait was likely responsible for the occurrence of the extreme ISW event. Based on the HYCOM data-assimilation product, we speculate that the strong stratification around Batan Island related to the strengthening Kuroshio may have contributed to the formation of the extreme ISW.

  9. An extreme internal solitary wave event observed in the northern South China Sea.

    PubMed

    Huang, Xiaodong; Chen, Zhaohui; Zhao, Wei; Zhang, Zhiwei; Zhou, Chun; Yang, Qingxuan; Tian, Jiwei

    2016-01-01

    With characteristics of large amplitude and strong current, internal solitary wave (ISW) is a major hazard to marine engineering and submarine navigation; it also has significant impacts on marine ecosystems and fishery activity. Among the world oceans, ISWs are particular active in the northern South China Sea (SCS). In this spirit, the SCS Internal Wave Experiment has been conducted since March 2010 using subsurface mooring array. Here, we report an extreme ISW captured on 4 December 2013 with a maximum amplitude of 240 m and a peak westward current velocity of 2.55 m/s. To the authors' best knowledge, this is the strongest ISW of the world oceans on record. Full-depth measurements also revealed notable impacts of the extreme ISW on deep-ocean currents and thermal structures. Concurrent mooring measurements near Batan Island showed that the powerful semidiurnal internal tide generation in the Luzon Strait was likely responsible for the occurrence of the extreme ISW event. Based on the HYCOM data-assimilation product, we speculate that the strong stratification around Batan Island related to the strengthening Kuroshio may have contributed to the formation of the extreme ISW. PMID:27444063

  10. Modeling of oil spill beaching along the coast of the Bohai Sea, China

    NASA Astrophysics Data System (ADS)

    Xu, Qing; Cheng, Yongcun; Liu, Bingqing; Wei, Yongliang

    2015-12-01

    On June 4 and 17, 2011, two separate oil spill accidents occurred at platforms B and C of the Penglai 19-3 oilfield located in the Bohai Sea, China. Based on the initial oil spill locations detected from the first available Synthetic Aperture Radar (SAR) image acquired on June 11, 2011, we performed a numerical experiment to simulate the potential oil spill beaching area with the General NOAA Operational Modeling Environment (GNOME) model. The model was driven by ocean surface currents from an operational ocean model (Navy Coastal Ocean Model) and surface winds from operational scatterometer measurements (the Advanced Scatterometer). Under the forcing of wind and ocean currents, some of the oil spills reached land along the coast of Qinhuangdao within 12 days. The results also demonstrate that the ocean currents are likely to carry the remaining oil spills along the Bohai coast towards the northeast. The predicted oil spill beaching area was verified by reported in-situ measurements and former studies based on MODIS observations.

  11. Three new records of deep-water goniasterids (Echinodermata: Asteroidea: Goniasteridae) from China seas

    NASA Astrophysics Data System (ADS)

    Xiao, Ning; Liao, Yulin

    2013-09-01

    In this paper, three deep-water species of the family Goniasteridae, Ceramaster misakiensis (Goto, 1914), Nymphaster arthrocnemis Fisher, 1913 and Pontioceramus grandis Fisher, 1911, are recorded for the first time from Chinese waters based on collections deposited in the Marine Biological Museum, Chinese Academy of Sciences. The specimens examined were collected during the period 1956 to 1978 from the East China and South China Seas at depths of 184 to 472 m. Diagnosis, detailed figures, and the geographic distributions are provided. A revised list of Goniasteridae recorded from Chinese waters is proposed.

  12. A diagnostic model of summer circulation on the northwest shelf of the East China sea

    NASA Astrophysics Data System (ADS)

    Yaochu, Yuan; Jilan, Su; Sangyun, Xia

    Hydrographic data and moored current meter records collected during a cruise of the China-U.S. Joint Study in August 1981 were used to compute the circulation in the East China Sea. A steady state, linear diagnostic model with a constant vertical eddy viscosity was developed. Lateral friction was ignored. The Taiwan Warm Current plays a dominant role in the survey area. Both the Huanghai Warm Current and the cyclonic cold water gyre southwest of Cheju Island are closely related to the Taiwan Warm Current.

  13. Advances in Marine Microbial Symbionts in the China Sea and Related Pharmaceutical Metabolites

    PubMed Central

    Li, Zhiyong

    2009-01-01

    Marine animals and plants such as sponges, sea squirts, corals, worms and algae host diverse and abundant symbiotic microorganisms. Marine microbial symbionts are possible the true producers or take part in the biosynthesis of some bioactive marine natural products isolated from the marine organism hosts. Investigation of the pharmaceutical metabolites may reveal the biosynthesis mechanisms of related natural products and solve the current problem of supply limitation in marine drug development. This paper reviews the advances in diversity revelation, biological activity and related pharmaceutical metabolites, and functional genes of marine microbial symbionts from the China Sea. PMID:19597576

  14. Establishment of trophic continuum in the food web of the Yellow Sea and East China Sea ecosystem: insight from carbon and nitrogen stable isotopes.

    PubMed

    Cai, Deling; Li, Hongyan; Tang, Qisheng; Sun, Yao

    2005-12-01

    Stable carbon and nitrogen isotope ratios (delta (13)C and delta (15)N) are used to study the trophic structure of food web in the Yellow Sea and East China Sea ecosystem. The trophic continuum of pelagic food web from phytoplankton to top preyer was elementarily established, and a trophic structure diagram in the Yellow Sea and East China Sea was outlined in combination with carbon isotopic data of benthic organisms, which is basically consistent with and makes some improvements on the simplified Yellow Sea food web and the trophic structure diagram drawn based on the biomass of main resource population during 1985-1986. This result indicates that the stable isotope method is a potential useful means for further studying the complete marine food web trophic continuum from viruses to top predators and food web stability. PMID:16483132

  15. Did opening of the South China Sea impact development of the Asian Monsoon? Results from Oligocene microfossils, IODP Site U1435, northern South China Sea

    NASA Astrophysics Data System (ADS)

    Kulhanek, Denise K.; Su, Xin; Li, Qianyu; Gregory, Mitch; Warny, Sophie; Clift, Peter D.

    2016-04-01

    Development of the Asian Monsoon is linked to uplift of the Himalayas and Tibetan Plateau in the Cenozoic, with good evidence for a strong monsoon system by the late Oligocene to early Miocene (e.g., Guo et al., 2002; Clift et al., 2008). However, Licht et al. (2014) suggested the presence of an Asian Monsoon in the late Eocene. Recent scientific ocean drilling in the Indian Ocean and surrounding marginal seas gives us the opportunity to test this hypothesis with newly recovered Paleogene sediment cores. International Ocean Discovery Program Expedition 349 to the South China Sea recovered a 30 m section of primarily lower Oligocene nannofossil-rich claystone at Site U1435, located near the northern continent/ocean boundary. A thick sandstone unit devoid of typical marine microfossils underlies the marine claystone. The sandstone is interpreted as a deltaic or restricted marine deposit and is dated to the Eocene based on the presence of organic-walled palynomorphs, suggesting that a hiatus of several million years likely separates the sandstone below from the Oligocene marine claystone. This hiatus is interpreted as the breakup unconformity, with paleodepths in the South China Sea increasing during the Oligocene. Thus, this claystone should record if opening of the South China Sea during the early Oligocene influenced development of the Asian Monsoon. Combined calcareous nannofossil and planktonic foraminifer biostratigraphy indicates that the 30 m section is primarily early Oligocene in age (~33.5-30 Ma) and was deposited on the middle slope, with paleodepths >500 m. Stable oxygen isotopes from planktonic foraminifers become heavier up-hole, suggestive of cooling/deepening in the region, whereas carbon isotopes record variable conditions with no distinct maxima or minima. Calcareous nannoplankton primarily live in the upper 50 m of the ocean and are sensitive to sea-surface temperature and nutrient conditions, thus making them useful recorders of paleoceanographic

  16. The spatial and temporal variability of the seasonal mean sea level cycle in the South China Sea

    NASA Astrophysics Data System (ADS)

    Muhaimin Amiruddin, Abd; Haigh, Ivan; Tsimplis, Mikis; Calafat, Francisco; Dangendorf, Soenke

    2015-04-01

    The seasonal cycle is the most energetic component of mean sea level variability and changes in either its amplitude or phase can seriously impact the risk of coastal flooding. Here, tide gauge records and satellite altimetry observations, along with steric and meteorological data are used to investigate the spatial and temporal variability of the seasonal cycle in the South China Sea (SCS) and its forcing mechanisms. The coastal annual amplitude varies significantly from region to region with values ranging from 2 cm to 24 cm, and generally peaks between July and January. The coastal semi-annual amplitude has maximum values of 7 cm, and it peaks between March and June. Along the coast, the seasonal cycle accounts on average for 60% with maximum values of up to 92% of the mean monthly sea level variability. Atmospheric pressure fluctuations explain a significant portion of the seasonal cycle with dominant annual signals in the northern SCS, the Gulf of Thailand and the north-western Philippines Sea. The wind forcing is dominant on the shelf areas of the SCS and the Gulf of Thailand where a simple barotropic model forced by local wind shows amplitudes of up to 27 cm. In the deep basin of the SCS, the Philippines Sea and the shallow Malacca Strait, the steric component is the major contributor with maximum annual amplitudes of up to 15 cm. Significant variability in the annual and semi-annual cycle is found on a year-to-year basis. The annual and semi-annual amplitudes vary by up to 63% and 45% of the maximum values, 15 cm and 11 cm, respectively. On average, stepwise regression analysis of contribution of different forcing factors accounts for 69% of the temporal variability of the annual cycle. The zonal wind and the cross-shore wind were found to exert considerable influence in the Malacca Strait and the northern SCS respectively.

  17. Enhanced sea-air CO2 exchange influenced by a tropical depression in the South China Sea

    NASA Astrophysics Data System (ADS)

    Sun, Qingyang; Tang, DanLing; Legendre, Louis; Shi, Ping

    2014-10-01

    Ship measurements made 2 days after the passage of a tropical depression (TD) in the South China Sea (SCS, April 2011) showed two contrasted responses of the partial pressure of CO2 at sea surface (pCO2,sw). In low sea-surface salinity (SSS) water, pCO2,sw was low (349 ± 7 μatm), and the area was a carbon sink (-4.7 ± 1.8 mmol CO2 m-2 d-1), whereas in water with high SSS and chlorophyll a and low dissolved oxygen and sea surface temperature, pCO2,sw was higher than for normal SCS water (376 ± 8 versus 362 ± 4 μatm) and the area was a carbon source (1.2 ± 3.1 mmol CO2 m-2 d-1). Satellite data showed two large areas of low SSS before the TD, which were likely influenced by rainfall, and these areas were considered to have low pCO2,sw because of their low SSS. The high pCO2,sw after the TD is explained by the uplifting to the surface of deeper and CO2-rich water, due to winds accompanied by the TD. The difference in sea-air CO2 flux between the TD-affected area and the lower-SSS water was 1.99 + 4.70 = 6.7 mmol CO2 m-2 d-1, indicating a 100% change caused by the TD compared to the average seasonal value in spring in southern SCS (3.3 ± 0.3 mmol CO2 m-2 d-1). Undersaturation of CO2 prior to the TD due to dilution by freshwater and the preexisting cold eddy, and slow translation speed of the TD, are considered to account for the CO2 flux change.

  18. Variations of picoplankton abundances during blooms in the East China Sea

    NASA Astrophysics Data System (ADS)

    Zhao, Yuan; Zhao, Li; Zhang, Wuchang; Sun, Jun; Huang, Lingfeng; Li, Jia; Zhai, Hongchang; Liu, Sumei; Xiao, Tian

    2016-02-01

    The picoplankton distribution in the East China Sea was investigated during bloom events occurred in spring (June) and summer (August) 2011. In spring, there was no significant difference in picoplankton abundances between areas where bloom conditions were or were not established. In the bloom area, Synechococcus, picoeukaryotes and heterotrophic prokaryotes exhibited at only some stations that abundances were higher than those within the non-bloom area. In summer, the abundances of Synechococcus and picoeukaryotes were significantly higher inside the bloom area than outside. Among the picoplankton components, heterotrophic prokaryotes represented the highest carbon biomass. Factors that most influenced picoplankton distribution under bloom conditions in the East China Sea varied with season. In spring, ciliates and salinity tended to be the main factors, whereas in summer, this role was played by temperature and chlorophyll a concentration.

  19. Preliminary evidence for a 1000-year-old tsunami in the South China Sea

    PubMed Central

    Sun, Liguang; Zhou, Xin; Huang, Wen; Liu, Xiaodong; Yan, Hong; Xie, Zhouqing; Wu, Zijun; Zhao, Sanping; Da Shao; Yang, Wenqing

    2013-01-01

    The risk of large, devastating tsunamis in the South China Sea and its surrounding coastal region is commonly underestimated or unrecognized due to the difficulty of differentiating tsunami from storm deposits. As a consequence, few convincing records have documented tsunami deposits in this region. Here we report preliminary evidence from Xisha Islands in the South China Sea for a large tsunami around AD 1024. Sand layers in lake sediment cores and their geochemical characteristics indicate a sudden deposition event around AD 1024, temporally consistent with a written record of a disastrous event characterized by high waves in AD 1076. Heavy coral and shell fossils, which are older than AD 1024, deposited more than 200 meters into the island, further support the occurrence of a high-energy event such as a tsunami or an unusually large storm. Our results underscore the importance of acknowledging and understanding the tsunami hazard in this area. PMID:23575432

  20. A new species of Lophophysema (Porifera, Hexactinellida, Hyalonematidae) from the South China Sea.

    PubMed

    Gong, Lin; Li, Xinzheng; Qiu, Jian-Wen

    2014-01-01

    We describe Lophophysema eversa sp. nov. (Porifera, Hexactinellida, Hyalonematidae) based on a single specimen collected from the South China Sea at a depth of 3683 m. The new species can be distinguished from the three known congeners by its unusual body shape with basalia on the side of the body, the lack of macramphidiscs, the combination of the pinular pentactins having spiny tangential rays and the pinular ray of atrialia longer than dermalia and canalaria. This is the first record of the genus Lophophysema from the South China Sea. We also use a partial sequence of the 16S rRNA gene to confirm the family assignment of the new specimen. PMID:25543807

  1. Numerical simulation of rifting controlled by magmatic underplating in the South China Sea

    NASA Astrophysics Data System (ADS)

    Xu, Hehua

    2016-04-01

    South China Sea is one of the largest basins in the western Pacific marginal sea, which is located in the intersection area of the Eurasia, the India-Australian and the Pacific-Philippines plate. Although the duration of seafloor spreading and the extension mechanism are still controversial.It is widely accepted that the South China Sea was opened by seafloor spreading in the Cenozoic. From the point of its structural development history, South China Sea has its own unique development model, which is formed by the continent rifting and expansion, while the tectonic evolution has close relationship with geological peripheral units. According to the seismic detection and magnetic integrated geophysics, the studies found that high-speed lower crust layers are widespread in the northern South China Sea and the northeast of continental margin, these layers are mainly located in continental slopes and some high-degree tensional continental shelves. Researches suggested that materials of high-speed in lower crustal layers are formed by the bottom magmatic underplating rather than serpentinized mantle peridotite. These layers are formed in Cenozoic and has close relationship with extension. However, in most kinematic and dynamic models of rift formation and evolution, the effects of magmatism have been neglected. This study established a two-dimensional thermal - mechanical coupled finite element model to simulate the role of underplated magmatic bodies in the localization of deformation. We examine the response of the lithosphere to an applied constant boundary velocity at the edge of the model. The mamatic underplating is introduced as a material with an anomalous high temperture and a magic upper mantle composition. The mechanical problem is coupled with the thermal problem through temperature-dependent viscosity. Since extension of lithosphere and underlying mantle is associated with intense and simultaneous viscous and brittle/plastic(faulting) deformations, we use

  2. Characterization and source apportionment of polycyclic aromatic hydrocarbons (PAHs) in Sediments from the Bohai Sea, China

    NASA Astrophysics Data System (ADS)

    Liu, Jihua; Hu, Ningjing; Shi, Xuefa

    2015-04-01

    Characterization and source apportionment of polycyclic aromatic hydrocarbons (PAHs) in Sediments from the Bohai Sea, China Liu Jihua, Hu Ningjing, Shi Xuefa First Institute of Oceanography, State Oceanic Administration, Qingdao 266061, China Polycyclic aromatic hydrocarbons (PAHs) are a class of ubiquitous organic contaminants in the environment. Indeed, 16 PAH compounds have been listed as priority pollutants by the United States Environmental Protection Agency and the European Union because of their potential toxicity to humans and ecosystems. As POPs are released or escape into the environment, their global accumulation in marine sediments generates a complex balance between inputs and outputs. Furthermore, PAHs in coastal sediments can serve as effective tracers of materials transport from land-to-sea (Fang et al., 2009). Hence, investigations of PAHs in sediments can provide useful information for further understanding of environmental processes and material transport. In this study, sixteen polycyclic aromatic hydrocarbons (PAHs) were extracted from a total of 112 surface sediment samples collected across the entire territory of the Bohai Sea. The detectable concentrations of PAHs ranged from 97.2 to 300.7 ng/g across all samples, indicating low contamination levels of PAHs compared with reported values for other coastal sediments in China and developed countries. The highest concentrations were found within three belts in the vicinity of Luan River Estuary-Qinhuangdao Harbor, the Cao River Estuary-Bohai Sea Center, and north of the Yellow River Estuary. The distribution patterns of PAHs and source identification implied that PAH contamination in the Bohai Sea mainly originates from offshore oil exploration, sewage discharge from rivers and shipping activities. Further Principal components analysis (PCA)/multivariate linear regression (MLR) analysis suggested that the contributions of spilled oil products (petrogenic), coal combustion and traffic

  3. New Cembrane-Type Diterpenoids from the South China Sea Soft Coral Sarcophyton ehrenbergi.

    PubMed

    Tang, Gui-Hua; Sun, Zhang-Hua; Zou, Yi-Hong; Yin, Sheng

    2016-01-01

    Chemical investigation on the soft coral Sarcophyton ehrenbergi collected from the Xisha Islands of the South China Sea have led to the isolation of eight cembranoids including five new ones, sarcophytonoxides A-E (1-5). The structures of new cembranoids (1-5) were determined by spectroscopic analysis and comparison of the NMR data with those of related analogues. The cytotoxicities of compounds 1-8 against human ovarian cancer cell line A2780 were also evaluated. PMID:27153054

  4. Numerical assessment of factors affecting nonlinear internal waves in the South China Sea

    NASA Astrophysics Data System (ADS)

    Li, Qiang

    2014-02-01

    Nonlinear internal waves in the South China Sea exhibit diverse characteristics, which are associated with the complex conditions in Luzon Strait, such as the double ridge topography, the Earth’s rotation, variations in stratification and the background current induced by the Kuroshio. These effects are individually assessed using the MITgcm. The performance of the model is first validated through comparison with field observations. Because of in-phased ray interaction, the western ridge in Luzon Strait intensifies the semidiurnal internal tides generated from the eastern ridge, thus reinforcing the formation of nonlinear internal waves. However, the ray interaction for K1 forcing becomes anti-phased so that the K1 internal tide generation is reduced by the western ridge. Not only does the rotational dispersion suppress internal tide generation, it also inhibits nonlinear steepening and consequent internal solitary wave formation. As a joint effect, the double ridges and the rotational dispersion result in a paradoxical phenomenon: diurnal barotropic tidal forcing is dominant in Luzon Strait, but semidiurnal internal tides prevail in the deep basin of the South China Sea. The seasonal variation of the Kuroshio is consistent with the seasonal appearance of nonlinear internal waves in the South China Sea. The model results show that the westward inflow due to the Kuroshio intrusion reduces the amplitude of internal tides in the South China Sea, causing the weakening or absence of internal solitary waves. Winter stratification cannot account for the significant reduction of nonlinear internal waves, because the amplitude growth of internal tides due to increased thermocline tilting counteracts the reduced nonlinearity caused by thermocline deepening.

  5. Two new eunicellin diterpenoids from the East China Sea gorgonian Muricella sp.

    PubMed

    Zhao, Chuan; Wang, Jia; Jin, De-Jun; Duan, Hong-Quan; Xing, Guo-Sheng; Tang, Sheng-An

    2016-09-01

    A phytochemical investigation on gorgonian Muricella sp. from East China Sea resulted in the isolation of eight eunicellin diterpenoids including two new ones, muricellins A-B (1, 2). Chemical structures of these compounds were elucidated by spectroscopic techniques (1D and 2D NMR and MS) and by comparison with data reported in the literature. Anti-rheumatoid arthritis activities of 1, 3, 4, and 6 have been evaluated. PMID:27004724

  6. Three new aaptamine derivatives from the South China Sea sponge Aaptos aaptos.

    PubMed

    Gan, Jian-Hong; Hu, Wen-Zhen; Yu, Hao-Bing; Yang, Fan; Cao, Meng-Xue; Shi, Hua-Jin; Kang, Yong-Feng; Han, Bing-Nan

    2015-01-01

    Three new aaptamine derivatives (1-3), together with six known related compounds (4-9), have been isolated from the South China Sea sponge Aaptos aaptos. The structures of all compounds were unambiguously elucidated on the basis of spectroscopic analyses. Compounds 1, 4, 5, 7, and 9 showed cytotoxic activities against HeLa, K562, MCF-7, and U937 cell lines with IC50 values in the range of 0.90-12.32 μM. PMID:26699877

  7. Basement structures of East and South China Seas and adjacent regions from gravity inversion

    NASA Astrophysics Data System (ADS)

    Guan, Dongliang; Ke, Xiaoping; Wang, Yong

    2016-03-01

    The satellite-derived gravity gives us an opportunity to investigate the basement structures of the East and South China Seas since the satellite gravimetry could provide large scale gravity data with high resolution of 1 arc-min by 1 arc-min. We isolate the residual gravity anomaly corresponding to the basement by subtracting the gravity anomalies of sediments and Moho undulations from satellite-derived free-air gravity anomalies. Two methods, namely gravity inversion method and convolution method based on flexure isostasy model, are used to calculate the Moho undulations in order to guarantee the accuracy of the Moho undulations since it occupies large percentages of the gravity anomalies. We invert the isolated gravity anomaly for the basement depths of East and South China Seas and adjacent areas with resolution of 1 arc-min by 1 arc-min. The basement depths of East and South China Seas range from 0.5 km to 12 km and the Moho depths vary between 6 km and 32 km. The basement topography reveals many tectonic depressions and two spreading axes concealed by the sediments, which are unseen in the bathymetry. The two spreading axes correspond to the spreading ridges derived from magnetic anomaly and the SW-NE oriented spreading axis extends SW much farther than that identified from magnetic anomaly, almost reaching to the Nam Con Son Basin. We also find that the faults constrain the distributions of basement depressions since the faults usually lie along the places where large changes of basement depth take place. Reversely, the basement map could be used to identify the unknown faults. Besides, according to the four profiles in the East and South China Seas, the mirror-image relation was found between the basement topography and the underlying Moho undulations that when the basement depth increases or decreases, the corresponding Moho depth decreases or increases.

  8. A numerical study on the relationships of the variations of volume transport around the China seas

    NASA Astrophysics Data System (ADS)

    Zhu, Xueming; Liu, Guimei; Wang, Jia; Wang, Hui; Bao, Xianwen; Hu, Wei

    2015-05-01

    Three dimensional oceanic circulations in the North Pacific Ocean are simulated using the Regional Ocean Model System (ROMS). The model very well reproduces the main oceanic circulation patterns and the hydrodynamic structures in the North Pacific Ocean, especially in the China seas. Eight transects around the China seas are selected to analyze volume transport and their relationships. The simulated mean volume transport and their standard deviations are in good agreement with previous studies and observations in the Taiwan Strait (TWS, 1.79 ± 0.96 Sv, 1 Sv ≡ 106 m3/s), East of Taiwan (PCM, 20.03 ± 5.19 Sv), Tokara Strait (TKS, 19.22 ± 3.22 Sv), Tsushima Strait (TUS, 2.14 ± 0.47 Sv), Luzon Strait (LUS, 4.57 ± 4.13 Sv), Karimata Strait (KMS, 1.28 ± 0.65 Sv), East of Luzon Island (ELI, 13.93 ± 5.31 Sv), and 137°E across the North Equatorial Current from 10°N to 20°N (137E, 44.0 ± 9.90 Sv). Three kinds of time scale variations (seasonal, sub-seasonal, intra-seasonal) were found in the volume transport through these transects with over the 95% significance level. The power spectrum density of the seasonal variation was almost one order of magnitude larger than the others for transects around the China seas. Coherency relationships among the volume transport through transects were analyzed. The results indicate that the seasonal time scale variations in volume transport around the China seas were dominated by the monsoon winds, but the Kuroshio along its pathway was relatively stable with small seasonal variation; the sub-seasonal time scale variations were associated with strong monsoon reversal winds; and the intra-seasonal variations were complex and weak, associating with local small scale winds and mesoscale eddy activities along the Kuroshio.

  9. Stability of submarine slopes in the northern South China Sea: a numerical approach

    NASA Astrophysics Data System (ADS)

    Zhang, Liang; Luan, Xiwu

    2013-01-01

    Submarine landslides occur frequently on most continental margins. They are effective mechanisms of sediment transfer but also a geological hazard to seafloor installations. In this paper, submarine slope stability is evaluated using a 2D limit equilibrium method. Considerations of slope, sediment, and triggering force on the factor of safety (FOS) were calculated in drained and undrained ( Φ=0) cases. Results show that submarine slopes are stable when the slope is <16° under static conditions and without a weak interlayer. With a weak interlayer, slopes are stable at <18° in the drained case and at <9° in the undrained case. Earthquake loading can drastically reduce the shear strength of sediment with increased pore water pressure. The slope became unstable at >13° with earthquake peak ground acceleration (PGA) of 0.5 g; whereas with a weak layer, a PGA of 0.2 g could trigger instability at slopes >10°, and >3° for PGA of 0.5 g. The northern slope of the South China Sea is geomorphologically stable under static conditions. However, because of the possibility of high PGA at the eastern margin of the South China Sea, submarine slides are likely on the Taiwan Bank slope and eastern part of the Dongsha slope. Therefore, submarine slides recognized in seismic profiles on the Taiwan Bank slope would be triggered by an earthquake, the most important factor for triggering submarine slides on the northern slope of the South China Sea. Considering the distribution of PGA, we consider the northern slope of the South China Sea to be stable, excluding the Taiwan Bank slope, which is tectonically active.

  10. Major mid-late Holocene cooling in the East China Sea revealed by an alkenone sea surface temperature record

    NASA Astrophysics Data System (ADS)

    Zhao, Meixun; Ding, Ling; Xing, Lei; Qiao, Shuqing; Yang, Zuosheng

    2014-12-01

    Although the mid-late Holocene cold and dry event about 4000 years ago (the 4 ka event) has been observed almost globally, it was most prominent in terrestrial climate proxies from the lower latitudes. Here we evaluate the oceanic response to this event in terms of a Holocene sea surface temperature (SST) record reconstructed using the U37K' index for Core B3 on the continental shelf of the East China Sea. The record reveals a large temperature drop of about 5°C from the mid-Holocene (24.7°C at 5.6 ka) to the 4 ka event (19.2°C at 3.8 ka). This mid-late Holocene cooling period in Core B3 correlated with (i) decreases in the East Asia summer monsoon intensity and (ii) the transition period with increased El Niño/Southern Oscillation activities in the Equatorial Pacific. Our SST record provides oceanic evidence for a more global nature of the mid-late Holocene climate change, which was most likely caused by a southward migration of the Intertropical Converge Zone in response to the decreasing summer solar insolation in the Northern Hemisphere. However, the large SST drop around Core B3 indicates that the mid-late Holocene cooling was regionally amplified by the initiation/strengthening of eddy circulation/cold front which caused upwelling and resulted in additional SST decrease. Upwelling during the mid-late Holocene also enhanced with surface productivity in the East China Sea as reflected by higher alkenone content around Core B3.

  11. Upward Continuation Apply Newly to Process Gravity Anomaly Data in the East China Sea

    NASA Astrophysics Data System (ADS)

    Han, Bo; Zhang, Xunhua; Jiang, Jinyu

    2014-05-01

    The research area lies in the East China Sea and its adjacent area and the concrete is between 120-130 degree of east longitude and 20-30 degree of north latitude and it also lies between Eurasian Plate and Pacific Plate. The structures of the area transform differently and they are namely Uplifted Zone of Zhejiang-Fujian, East China Sea Shelf Basin, Okinawa Trough Back-arc Basin, Ryukyu Arc, Ryukyu trench and Philippine Sea from west to east. Bouguer gravity anomaly can reflect deep structure characters and it is help to judge deep structures. The bouguer gravity anomalies of the area change differently from west to east. The anomalies increase gradually from land to the middle of Okinawa trough and near land anomaly contour strike accords with coastline and the middle of Okinawa trough reflect the highest anomalies in this area. Gravity anomalies re-increase from Ryukyu fore-arc basin to trench and Ryukyu island arc appears the low anomalies. Philippine Sea appears high gravity anomalies background. Upward continuation method has been used to process original gravity anomaly as a common method and its destination is to weaken local anomaly and at last strengthen deep anomaly and it's important to deep structure study. Upward 5 km, 10 km and 20 km have been used to process data and the results been compared. However, the research area is very large and the deep structure is complex, it isn't suitable to use single height to upward continuation processing bouguer gravity anomaly. Then we propose multiple upward heights continuation to process gravity data respectively in different area. We use upward 20km to process data in the area from land to the slope and upward 10km from Okinawa trough to Ryukyu island arc and upward 5km from Ryukyu trench to Philippine Sea. At last we obtain multiple upward height result and the calculated result confirms that it is fit to use this method. Gravity anomalies contours become smoother than before and the deep structures become

  12. The possible physical barrier and coastal dispersal strategy for Japanese grenadier anchovy, Coilia nasus in the East China Sea and Yellow Sea: evidence from AFLP markers.

    PubMed

    Han, Zhi-Qiang; Han, Gang; Wang, Zhi-Yong; Gao, Tian-Xiang

    2015-01-01

    In order to ascertain the taxonomic status of the Ariake Sea population of Japanese grenadier anchovy, Coilia nasus, and assess the contemporary possible genetic barrier between the west and east coastal waters of the East China Sea, we used amplified fragment length polymorphism (AFLP) markers to detect the genetic structure of C. nasus, in the East China Sea and Yellow Sea. Eighty-one individuals of C. nasus were collected from five locations and 12 individuals of Coilia mystus were sampled from the Yangtze River Estuary. A total of 371 loci were detected by five primer combinations, 310 of which were polymorphic (83.56%). Analysis of molecular variation (AMOVA) and pairwise fixation index (FST) revealed significant genetic differentiation among five samples, indicating limited gene flow among populations. The dendrogram for populations by neighbor-joining (NJ) cluster analysis provided evidence of a clear relationship between genetic and geographic patterns, supporting significant genetic differentiation between China coastal populations and Ariake Sea populations. Compared to the genetic divergence between C. nasus and C. mystus, the level of genetic differentiation between China and the Ariake Sea populations of C. nasus is obvious below the species level, indicating isolated populations of C. nasus in the Ariake Sea. Isolation by distance analysis revealed that direct ocean distance with deep-water at the continental slope and high salinity between west and east coastal waters of the East China Sea served as major physical barrier to C. nasus, supporting the coastal dispersal pattern in this estuarine species, and rejecting offshore dispersal strategy. PMID:25654225

  13. Professional Experience Reform in China: Key Issues and Challenges

    ERIC Educational Resources Information Center

    Campbell, Anne; Hu, Xiuwei

    2010-01-01

    This study investigates the attitudes of teacher educators in China toward recent reforms in professional experience for pre-service teachers proposed by the Chinese Ministry of Education and their perception of the challenges facing the implementation of the proposed reforms. An analysis of data from an online survey and semi-structured…

  14. A General Music Experience in China: Reflections and Lesson Ideas

    ERIC Educational Resources Information Center

    Whitcomb, Rachel; Berger, Linda M.; Schmidt, Catherine

    2011-01-01

    In this article, the authors share their recent experiences with a fourth grade general music classroom in China as members of the "People-to-People Ambassador Program". They provide a description of the types of musical activities they observed at Aiju Primary School in Shanghai in December 2009 by sharing the content of one specific lesson. The…

  15. An estimate of the cross-frontal transport at the shelf break of the East China Sea with the Finite Volume Coastal Ocean Model

    NASA Astrophysics Data System (ADS)

    Isobe, Atsuhiko; Beardsley, Robert C.

    2006-03-01

    The Finite Volume Coastal Ocean Model (FVCOM) is used to estimate the onshore cross-frontal transport at the shelf break of the East China Sea. Boundary conditions of FVCOM are provided by the Princeton Ocean Model simulating ocean currents in the Yellow Sea and East China Sea realistically. One advantage of this study is that the unstructured triangular cell grid of FVCOM resolves complex bottom topography that may trigger Kuroshio frontal waves. It is anticipated that these nonlinear frontal waves enhance the exchange of seawater between the Kuroshio and shelf regions. Kuroshio frontal waves in the model are excited around the location where the bottom slope changes abruptly, and have the phase speed and amplitude consistent with those observed in the East China Sea. In addition, the model reproduces the onshore transport associated with growing frontal waves in the upper and lower layers. On the basis of passive tracer experiments, the annually averaged onshore-transport integrated along the shelf break is estimated to be 0.85 × 106 m3/s.

  16. Tsunami Simulations for Regional Sources in the South China and Adjoining Seas

    NASA Astrophysics Data System (ADS)

    Okal, Emile A.; Synolakis, Costas E.; Kalligeris, Nikos

    2011-06-01

    We present 14 scenarios of potential tsunamis in the South China Sea and its adjoining basins, the Sulu and Sulawezi Seas. The sources consist of earthquake dislocations inspired by the the study of historical events, either recorded (since 1900) or described in historical documents going back to 1604. We consider worst-case scenarios, where the size of the earthquake is not limited by the largest known event, but merely by the dimension of the basin over which a coherent fault may propagate. While such scenarios are arguably improbable, they may not be impossible, and as such must be examined. For each scenario, we present a simulation of the tsunami's propagation in the marine basin, exclusive of its interaction with the coastline. Our results show that the South China, Sulu and Sulawezi Seas make up three largely independent basins where tsunamis generated in one basin do not leak into another. Similarly, the Sunda arc provides an efficient barrier to tsunamis originating in the Indian Ocean. Furthermore, the shallow continental shelves in the Java Sea, the Gulf of Thailand and the western part of the South China Sea significantly dampen the amplitude of the waves. The eastern shores of the Malay Peninsula are threatened only by the greatest—and most improbable—of our sources, a mega-earthquake rupturing all of the Luzon Trench. We also consider two models of underwater landslides (which can be triggered by smaller events, even in an intraplate setting). These sources, for which there is both historical and geological evidence, could pose a significant threat to all shorelines in the region, including the Malay Peninsula.

  17. Trend and Variability of China Precipitation in Spring and Summer: Linkage to Sea Surface Temperatures

    NASA Technical Reports Server (NTRS)

    Yang, Fanglin; Lau, K.-M.

    2004-01-01

    Observational records in the past 50 years show an upward trend of boreal-summer precipitation over central eastern China and a downward trend over northern China. During boreal spring, the trend is upward over southeastern China and downward over central eastern China. This study explores the forcing mechanism of these trends in association with the global sea-surface temperature (SST) variations on the interannual and inter-decadal timescales. Results based on Singular Value Decomposition analyses (SVD) show that the interannual variability of China precipitation in boreal spring and summer can be well defined by two centers of actions for each season, which are co-varying with two interannual modes of SSTs. The first SVD modes of precipitation in spring and summer, which are centered in southeastern China and northern China, respectively, are linked to an ENSO-like mode of SSTs. The second SVD modes of precipitation in both seasons are confined to central eastern China, and are primarily linked to SST variations over the warm pool and Indian Ocean. Features of the anomalous 850-hPa winds and 700-Wa geopotential height corresponding to these modes support a physical mechanism that explains the causal links between the modal variations of precipitation and SSTs. On the decadal and longer timescale, similar causal links are found between the same modes of precipitation and SSTs, except for the case of springtime precipitation over central eastern China. For this case, while the interannual mode of precipitation is positively correlated with the interannual variations of SSTs over the warm pool and Indian Ocean; the inter-decadal mode is negatively correlated with a different SST mode, the North Pacific mode. The later is responsible for the observed downward trend of springtime precipitation over central eastern China. For all other cases, both the interannual and inter-decadal variations of precipitation can be explained by the same mode of SSTs. The upward trend

  18. Two new species of Sternaspis Otto, 1821 (Polychaeta: Sternaspidae) from China seas.

    PubMed

    Wu, Xuwen; Salazar-Vallejo, Sergio I; Xu, Kuidong

    2015-01-01

    Two species of Sternaspidae, Sternaspis chinensis sp. nov. and S. liui sp. nov., are described based on historic material and recently collected specimens in the sea areas of China. Sternaspis chinensis is abundantly distributed from the Bohai Sea southwards to the East China Sea. It has been frequently misidentified as the nominally cosmopolitan species S. scutata (Ranzani, 1817) in China since the 1950s. However, S. chinensis differs from the latter by possessing concentric bands on the shield (vs. absent) and crenulated posterior margin reaching or slightly expanded beyond the posterolateral corners (vs. posterior margin smooth and markedly expanded beyond the posterolateral corners). Sternaspis chinensis most resembles the NE Pacific species S. affinis Stimpson, 1864, but differs distinctly by its markedly concentric bands decorated from margin to center (vs. mainly restricted in the marginal area). Sternaspis liui is characterized within the genus by its slightly soft shield with firmly adhered sediment particles, which gives it a superficial resemblance to species of Caulleryaspis Sendall & Salazar-Vallejo, 2013. However, the shields of the latter are remarkably soft and poorly developed, without ribs and concentric lines, while in Sternaspis liui both the ribs and concentric lines are well defined. Variations of both species with remarks on juvenile shield development are provided. PMID:26701437

  19. Population genetics of Thamnaconus hypargyreus (Tetraodontiformes: Monacanthidae) in the South China Sea.

    PubMed

    Li, Yufang; Chen, Guobao; Yu, Jie; Wu, Shuiqing; Xiong, Dan; Li, Xia; Cui, Ke; Li, Yongzhen

    2016-01-01

    Knowledge of population structure is particularly important for long-term fisheries management and conservation. Lesser-spotted leatherjacket Thamnaconus hypargyreus is an economically important fish species in the South China Sea. Fish specimens (totally 158 individuals) used in this study were collected from five geographical locations in the north of the South China Sea and the southwestern Nansha Islands. The results were as follows: a total of 636 nucleotides of the mitochondrial DNA (mtDNA) control region (CR) of T. hypargyreus were amplified by polymerase chain reaction (PCR) technology. Both 103 mutations of nucleotide acids without inserting or deleting one and 91 haplotypes were found among the examined CR fragment. High haplotype diversity (0.9419 ± 0.0151) and nucleotide diversity (0.0095 ± 0.00506) relatively together with a recent and sudden population expansion which characterizes the genetic population structure of this species. Analysis of molecular variance (AMOVA) and the fixation indices (Fst) of five groups showed that the genetic variance mainly came from individuals within groups, and there was no genetic differentiation between groups. The phylogenetic trees including maximum likelihood (ML) and Bayesian inference (BI) proved no phylogeographic differentiation structure in five groups. The mtDNA marker suggested the five groups should be genetic homogeneity, which implied T. hypargyreus in the north and southwest continental shelf of the South China Sea belongs to one population. PMID:24865897

  20. Full-fit reconstruction of the South China Sea conjugate margins

    NASA Astrophysics Data System (ADS)

    Bai, Yongliang; Wu, Shiguo; Liu, Zhan; Müller, R. Dietmar; Williams, Simon E.; Zahirovic, Sabin; Dong, Dongdong

    2015-10-01

    Although the South China Sea margins have been well-studied, there are no full-fit reconstructions that document the complex rifting history in a regional geodynamic context. We restored conjugate margins to their original Late Cretaceous unstretched geometries, and generated the first full-fit reconstructions of the South China Sea conjugate margins. The impact of magmatic underplating on restoration and full-fit reconstruction was estimated quantitatively. The full-fit reconstruction model includes restoration uncertainties and results in minimum gaps and overlaps between the restored conjugate margin geometries. Based on our restoration, the full-fit reconstruction and the continental basement thickness distribution, we estimate that there was more extension of continental basement on the western part of the conjugate margins compared with the eastern margin prior to the initiation of seafloor spreading. Therefore, the mid ocean ridge initially formed in the east and propagated westward to open the South China Sea. Seafloor spreading propagated along the Xisha Trough during NW Sub-basin formation, but continental breakup occurred along the southern side of the Zhongsha-Xisha Islands where the lithosphere was probably weaker than along the Xisha Trough, consistent with the geometry and evolution of the NW Sub-basin and the southward jump of the mid oceanic ridge.

  1. [Water environment adaptability and ecological groups of hydroidomedusae in East China Sea].

    PubMed

    Xu, Zhao-li

    2009-01-01

    Based on the data of four seasonal oceanographic censuses in East China Sea (23 degrees 30' - 33 degrees 00' N, 118 degrees 30' - 128 degrees 00' E) in 1997-2000, the optimal water temperature and salinity and the ecological groups of Hydroidomedusae were studied by curve fitting, mathematical model forming, and geographic distribution analyzing. The results showed that Hydroidomedusae could live in the waters with different temperature and salinity. 15 species of Hydroidomedusae had an optimal water temperature of <20 degrees C, 8 species at 20 degrees C - 25 degrees C, 12 species at 22.5 degrees C - 25 degrees C, and 17 species at > or =25 degrees C. 32 species of Hydroidomedusae had an optimal salinity of 32-34, 13 species at 34, 6 species at 30-32, and only 2 species at <30. The weak adaptability of most Hydroidomedusae species to the variation of water salinity made them have low density and limited distribution in East China Sea. Sugiura chengshanense and Clytia hemisphaerica were of nearshore warm temperate water species, Cunina octonaria and other 12 species were of offshore warm temperate water species, 8 species represented by Ectopleura latitaeniata were of nearshore subtropical water species, 5 species represented by Aglaura hemistoma showed some oceanic tropical features, while 25 species represented by Liriope tetraphylla were of offshore subtropical species. Some Hydroidomedusae species could be used as an important bio-indicator of water mass in East China Sea. PMID:19449583

  2. A new version of regional ocean reanalysis for coastal waters of China and adjacent seas

    NASA Astrophysics Data System (ADS)

    Han, Guijun; Li, Wei; Zhang, Xuefeng; Wang, Xidong; Wu, Xinrong; Fu, Hongli; Zhang, Xiaoshuang; Zhang, Lianxin; Li, Dong

    2013-07-01

    A new regional ocean reanalysis over multiple decades (1958-2008) for the coastal waters of China and adjacent seas has been completed by the National Marine Data and Information Service (NMDIS) under the CORA (China Ocean ReAnalysis) project. Evaluations were performed on three aspects: (1) the improvement of general reanalysis quality; (2) eddy structures; and (3) decadal variability of sea surface height anomalies (SSHAs). Results showed that the quality of the new reanalysis has been enhanced beyond ˜40% (39% for temperature, 44% for salinity) in terms of the reduction of root mean squared errors (RMSEs) for which the reanalysis values were compared to observed values in the observational space. Compared to the trial version released to public in 2009, the new reanalysis is able to reproduce more detailed eddy structures as seen in satellite and in situ observations. EOF analysis of the reanalysis SSHAs showed that the new reanalysis reconstructs the leading modes of SSHAs much better than the old version. These evaluations suggest that the new CORA regional reanalysis represents a much more useful dataset for the community of the coastal waters of China and adjacent seas.

  3. Molecular Approach to the Identification of Fish in the South China Sea

    PubMed Central

    Zhang, Junbin; Hanner, Robert

    2012-01-01

    Background DNA barcoding is one means of establishing a rapid, accurate, and cost-effective system for the identification of species. It involves the use of short, standard gene targets to create sequence profiles of known species against sequences of unknowns that can be matched and subsequently identified. The Fish Barcode of Life (FISH-BOL) campaign has the primary goal of gathering DNA barcode records for all the world's fish species. As a contribution to FISH-BOL, we examined the degree to which DNA barcoding can discriminate marine fishes from the South China Sea. Methodology/Principal Findings DNA barcodes of cytochrome oxidase subunit I (COI) were characterized using 1336 specimens that belong to 242 species fishes from the South China Sea. All specimen provenance data (including digital specimen images and geospatial coordinates of collection localities) and collateral sequence information were assembled using Barcode of Life Data System (BOLD; www.barcodinglife.org). Small intraspecific and large interspecific differences create distinct genetic boundaries among most species. In addition, the efficiency of two mitochondrial genes, 16S rRNA (16S) and cytochrome b (cytb), and one nuclear ribosomal gene, 18S rRNA (18S), was also evaluated for a few select groups of species. Conclusions/Significance The present study provides evidence for the effectiveness of DNA barcoding as a tool for monitoring marine biodiversity. Open access data of fishes from the South China Sea can benefit relative applications in ecology and taxonomy. PMID:22363454

  4. Comparison and validation of global and regional ocean forecasting systems for the South China Sea

    NASA Astrophysics Data System (ADS)

    Zhu, Xueming; Wang, Hui; Liu, Guimei; Régnier, Charly; Kuang, Xiaodi; Wang, Dakui; Ren, Shihe; Jing, Zhiyou; Drévillon, Marie

    2016-07-01

    In this paper, the performance of two operational ocean forecasting systems, the global Mercator Océan (MO) Operational System, developed and maintained by Mercator Océan in France, and the regional South China Sea Operational Forecasting System (SCSOFS), by the National Marine Environmental Forecasting Center (NMEFC) in China, have been examined. Both systems can provide science-based nowcast/forecast products of temperature, salinity, water level, and ocean circulations. Comparison and validation of the ocean circulations, the structures of temperature and salinity, and some mesoscale activities, such as ocean fronts, typhoons, and mesoscale eddies, are conducted based on observed satellite and in situ data obtained in 2012 in the South China Sea. The results showed that MO performs better in simulating the ocean circulations and sea surface temperature (SST), and SCSOFS performs better in simulating the structures of temperature and salinity. For the mesoscale activities, the performance of SCSOFS is better than MO in simulating SST fronts and SST decrease during Typhoon Tembin compared with the previous studies and satellite data; but model results from both of SCSOFS and MO show some differences from satellite observations. In conclusion, some recommendations have been proposed for both forecast systems to improve their forecasting performance in the near future based on our comparison and validation.

  5. Winter sea surface temperature reflected by the TEX86 proxy in core sediments from the coastal northern South China Sea

    NASA Astrophysics Data System (ADS)

    Wei, Y.; Wang, P.; Zhao, M.; Zhang, C.

    2013-12-01

    Although TEX86 is widely used as a sea surface temperature proxy for the open ocean, the validity of TEX86 in the coastal seas has yet to be tested. In this study, three sediment cores from the coastal northwestern South China Sea (SCS) (water depth 33 m for core A9, 73 m for core, and 102 m for core A9, respectively) were analyzed using lipid biomarker approaches. The distribution of archaeal core lipids varied in core A9 and A7 but remained constant in A5. TEX86-based temperature according to Kim et al. (2010) averaged 17.2 × 0.4 οC (n=30), 20.9 × 0.3 οC (n=19) and 23.0 × 0.3 οC(n=16) in core A9, A7 and A5, respectively. These results show that temperature changed little with sediment depth at each location and increased by about 3 οC between the two adjacent locations. These are lower than the annual SST (24.5-25.7 οC) and much lower than the summer SST (>28 οC), indicating that organisms producing the TEX86-related compounds mostly lived in the winter season.

  6. Summer carbonate chemistry dynamics in the Southern Yellow Sea and the East China Sea: Regional variations and controls

    NASA Astrophysics Data System (ADS)

    Qu, Baoxiao; Song, Jinming; Yuan, Huamao; Li, Xuegang; Li, Ning; Duan, Liqin; Chen, Xin; Lu, Xi

    2015-12-01

    Surface partial pressure of CO2 (pCO2) and pertinent parameters (i.e., pH, total alkalinity, dissolved oxygen, chlorophyll a) were investigated in the southern Yellow Sea (SYS) and the East China Sea (ECS) basing on two surveys conducted in June and August of 2013. The results suggested carbonate chemistry dynamics and related controlling factors were provided with significant temporal and spatial variations in different subregions of these two continental shelf seas. The western of SYS (SYSW) was CO2-undersaturated both in June and August, with the average FCO2 -1.88 mmol m-2 d-1 and -3.72 mmol m-2 d-1, respectively. The phytoplankton initiated CO2-absorption and the suspended sediment induced CO2-emission jointly controlled the air-sea CO2 exchange there. The center of SYS (SYSC) also behaved as an obvious CO2 sink (-1.57 mmol m-2 d-1and -3.99 mmol m-2 d-1 in June and August, respectively), probably due to elevated TA/DIC ratio and the subsequent effects of spring bloom. As for the Yangtze River estuary (YRE), it changed from an obvious CO2 sink (-1.28 mmol m-2 d-1) in June into a very weak CO2 source (0.04 mmol m-2 d-1) in August. This change was probably associated with the rising of seawater temperature and monthly variation of Yangtze River discharge. The inner shelf of ECS (ECSS) experienced obvious air-sea CO2 flux changes during from June (-8.88 mmol m-2 d-1) to August (-0.36 mmol m-2 d-1) as well. Biological DIC consumption in the upper layer and DIC regenerated from respiration in the subsurface jointly controlled this pCO2 variation. As a whole, the SYS and ECS acted as an obvious CO2 sink during summer and could absorb atmospheric CO2 with the average air-sea flux (FCO2) -2.68 mmol m-2 d-1. The summary of air-sea CO2 flux in the ECS and SYS during recent two decades indicated the ECS served as quite a stable CO2 sink, whereas the SYS experienced obvious change. Discharge of Yangtze River and anthropogenic nutrients loading could profoundly affect the

  7. Species characteristics of lead in sea foods collected from coastal water of Fujian, Southeastern of China.

    PubMed

    He, Ye; Chen, Zhiqiang; Mo, Fan; Huang, Limei; Xu, LiangJun; Wu, Yongning; Xue, Zhimin; Fu, FengFu

    2016-01-01

    Various sea foods including fish, shellfish and shrimp were collected from different coastal areas of Fujian in China, and their Pb species characteristics were investigated in detail. The results indicated that there are two different species characteristics of Pb existing in sea food samples. About half of samples were detected to have only Pb(2+), and another half of samples were detected to have both Pb(2+) and trimethyl lead (TML). The results also revealed that Pb species characteristics in the sea foods rather depend on the species of sea food than the sampling area. In comparison with shellfish/shrimp samples, fish samples have higher concentrations of TML and Pb(2+). Especially, the average concentration of TML in the TML-detected fish samples is about 3 times of that in the TML-detected shellfish/shrimp samples, indicating that fish has stronger ability to uptake and accumulate TML. The concentrations of total lead in all samples are lower than the maximum allowable limit of national standard, suggesting that the sea foods collected from Fujian are safe for consumption. By considering that TAL has more toxicity than Pb(2+), the effect of TML in sea foods on the human health should be paid more attention in the future. PMID:27624560

  8. Subsatellite experiments in a coastal region of the Black sea

    NASA Astrophysics Data System (ADS)

    Bakhanov, V.; Bogatov, N.; Ermoshkin, A.; Kazakov, V.; Kemarskaya, O.; Lobanov, V.; Repina, I.; Titov, V.; Troitskaya, Yu.; Zuikova, E.

    2009-04-01

    The results of field experiments carried out in 2007, 2008 in a north-east part of the Black sea in region of city Gelendzhik, are given. Experiments targeted the development of a bottom topography remote (radar and optical) diagnostics. Experimental area is characterized by abrupt depth dumping (fall 50 - 1250 m), and irregularity of a bank vault (numerous canyons). Such bottom topography in the presence of alongshore current creates favorable conditions for hydrodynamic perturbations on thermocline and corresponding anomalies on sea surface and in atmospheric surface layer characteristics. The simultaneous measurement of atmospheric near-surface layer, sea surface and sea bulk parameters synchronously with reception of the radar image from the satellite ENVISAT was feature of the given experiment. The ground-based measurements were carried out simultaneously from high coast by means of X-band radar and from R/V "Aquanaut" (Institute of Oceanology RAS). The meteorological conditions during observations varied considerably. The wind velocity changed from 0 up to 10 m/c, heaving - from 0 up to 4 balls. The short-term atmospheric precipitations were observed. The bottom topography was measured by echo-sounder. Investigation of the hydrological characteristics was carried out by combined SVP-CTD probe. The current field was measured by ADCP. The surface wave characteristics in length range 4 mm - 1 m were measured by X and Ka radar and two-dimensional optical spectrum analyzer. Air temperature, relative humidity, atmospheric pressure, wind velocity and direction were measured. Sonic anemometer-thermometer for recording horizontal and vertical components of the wind and temperature fluctuations in the surface layer was used. The connection of current field heterogeneities with a bottom configuration in region of depth dumping is investigated. The correlation of radar signal with current speed in near-surface region is observed also. For example, the slicks are observed

  9. The Fourth SeaWiFS HPLC Analysis Round-Robin Experiment (SeaHARRE-4)

    NASA Technical Reports Server (NTRS)

    Hooker, Stanford B.; Thomas, Crystal S.; van Heukelem, Laurie; Schlueter, louise; Russ, Mary E.; Ras, Josephine; Claustre, Herve; Clementson, Lesley; Canuti, Elisabetta; Berthon, Jean-Francois; Perl, Jason; Normandeau, Claire; Cullen, John; Kienast, Markus; Pinckney, James L.

    2010-01-01

    Ten international laboratories specializing in the determination of marine pigment concentrations using high performance liquid chromatography (HPLC) were intercompared using in situ samples and a mixed pigment sample. Although prior Sea-viewing Wide Field-of-view Sensor (SeaWiFS) High Performance Liquid Chromatography (HPLC) Round-Robin Experiment (SeaHARRE) activities conducted in open-ocean waters covered a wide dynamic range in productivity, and some of the samples were collected in the coastal zone, none of the activities involved exclusively coastal samples. Consequently, SeaHARRE-4 was organized and executed as a strictly coastal activity and the field samples were collected from primarily eutrophic waters within the coastal zone of Denmark. The more restrictive perspective limited the dynamic range in chlorophyll concentration to approximately one and a half orders of magnitude (previous activities covered more than two orders of magnitude). The method intercomparisons were used for the following objectives: a) estimate the uncertainties in quantitating individual pigments and higher-order variables formed from sums and ratios; b) confirm if the chlorophyll a accuracy requirements for ocean color validation activities (approximately 25%, although 15% would allow for algorithm refinement) can be met in coastal waters; c) establish the reduction in uncertainties as a result of applying QA procedures; d) show the importance of establishing a properly defined referencing system in the computation of uncertainties; e) quantify the analytical benefits of performance metrics, and f) demonstrate the utility of a laboratory mix in understanding method performance. In addition, the remote sensing requirements for the in situ determination of total chlorophyll a were investigated to determine whether or not the average uncertainty for this measurement is being satisfied.

  10. Spatial distribution of Rastrelliger kanagurta (Cuvier 1817) in the South China Sea Exclusive Economic Zone (EEZ)

    NASA Astrophysics Data System (ADS)

    Razib, N. A.; Mustapha, M. A.

    2013-11-01

    Rastrelliger kanagurta inhabits the South China Sea, where it is the most abundant commercial fish. Understanding distribution of this species is important. Objective of this study is to describe the relationship between spatial distribution of R. kanagurta and its local environmental factors. Chlorophyll-a distribution and sea surface temperature was obtained from Aqua MODIS satellite image. Fisheries data of 2007 to 2010 were obtained from the Southeast Asean Fisheries Department Center (SEAFDEC). These data were analyzed in relation to physical and environmental factors to establish the spatial-temporal distribution of the species. Catch per unit effort (CPUE) was calculated from the fisheries data and used as abundance index. Kernel Density maps of the abundance were created. The result showed that the abundance generated by Kernel Density analysis at 10.0 to 12.0 were associated with chlorophyll-a concentration of 0.4 ± 0.1 mg/m3 and sea surface temperature of 27.0 ± 1.0 °C at offshore of Pahang coast. The density maps showed that the increase of R. kanagurta abundance was occurred in October. The environmental factors in South China Sea played an important role on R. kanagurta's density patterns. This study indicated the capability of GIS and satellite image to indicate aggregation area of R. kanagurta.

  11. Four newly recorded free-living marine nematodes (Comesomatidae) from the East China Sea

    NASA Astrophysics Data System (ADS)

    Hua, Er; Zhang, Zhinan

    2007-01-01

    Three species in genus Sabatieria and one in genus Cervonema from the East China Sea were recorded. S. breviseta is characterized by uniformly punctuated coarse dots, large amphids of 5.5 turns (♂) and prominent gubernaculum median piece. The characters of S. breviseta agree quite well with the European original descriptions and only differ in the male amphid turns (5.5 vs. 4.0 turns) and unmodified preanal supplements (5-7 vs. 6). S. pulchra can be recognized by amphid 2.75 turns, irregularly arranged lateral dots, and the first three supplements anterior to the anus, which are more widely spaced than the following ones. The excretory system of S. breviseta and S. pulchra shows sexual dimorphism. S. celtica is defined by amphids 2.00-2.25 turns, weakly developed pharyngeal bulb, curved apophyses and 12-13 conspicuous supplements. C. deltensis is characterized by amphids 4.75 turns, ovate pharyngeal posterior bulb, sperm dimorphism, 7 thin preanal supplements, and long tail cylindrical portion (50%-53% of tail length). All the three Sabatieria species are for the first time recorded in Chinese waters. C. deltensis was originally isolated from the Bohai Sea and Yellow Sea and newly recorded in the East China Sea.

  12. Spatial Diversity of Bacterioplankton Communities in Surface Water of Northern South China Sea

    PubMed Central

    Li, Fuchao; Zou, Tao; Yu, Shuxian; Wang, Yinchu; Qin, Song; Wang, Guangyi

    2014-01-01

    The South China Sea is one of the largest marginal seas, with relatively frequent passage of eddies and featuring distinct spatial variation in the western tropical Pacific Ocean. Here, we report a phylogenetic study of bacterial community structures in surface seawater of the northern South China Sea (nSCS). Samples collected from 31 sites across large environmental gradients were used to construct clone libraries and yielded 2,443 sequences grouped into 170 OTUs. Phylogenetic analysis revealed 23 bacterial classes with major components α-, β- and γ-Proteobacteria, as well as Cyanobacteria. At class and genus taxon levels, community structure of coastal waters was distinctively different from that of deep-sea waters and displayed a higher diversity index. Redundancy analyses revealed that bacterial community structures displayed a significant correlation with the water depth of individual sampling sites. Members of α-Proteobacteria were the principal component contributing to the differences of the clone libraries. Furthermore, the bacterial communities exhibited heterogeneity within zones of upwelling and anticyclonic eddies. Our results suggested that surface bacterial communities in nSCS had two-level patterns of spatial distribution structured by ecological types (coastal VS. oceanic zones) and mesoscale physical processes, and also provided evidence for bacterial phylogenetic phyla shaped by ecological preferences. PMID:25402458

  13. A parabolic model of drag coefficient for storm surge simulation in the South China Sea

    NASA Astrophysics Data System (ADS)

    Peng, Shiqiu; Li, Yineng

    2015-10-01

    Drag coefficient (Cd) is an essential metric in the calculation of momentum exchange over the air-sea interface and thus has large impacts on the simulation or forecast of the upper ocean state associated with sea surface winds such as storm surges. Generally, Cd is a function of wind speed. However, the exact relationship between Cd and wind speed is still in dispute, and the widely-used formula that is a linear function of wind speed in an ocean model could lead to large bias at high wind speed. Here we establish a parabolic model of Cd based on storm surge observations and simulation in the South China Sea (SCS) through a number of tropical cyclone cases. Simulation of storm surges for independent Tropical cyclones (TCs) cases indicates that the new parabolic model of Cd outperforms traditional linear models.

  14. Eddy-entrained Pearl River plume into the oligotrophic basin of the South China Sea

    NASA Astrophysics Data System (ADS)

    He, Xianqiang; Xu, Dongfeng; Bai, Yan; Pan, Delu; Chen, Chen-Tung Arthur; Chen, Xiaoyan; Gong, Fang

    2016-08-01

    The South China Sea (SCS) is the world's largest tropical marginal sea with an oligotrophic basin. In June 2015, a rare large phytoplankton bloom, which is ~500 km long, 100 km wide and lasting more than 19 days, was captured in the northern SCS basin by satellite daily chlorophyll images. Water within the bloom area had a feature of low salinity and high temperature measured by an accidental-passing cruise. Meanwhile, satellite sea level anomaly images and drifter trajectory proved there was a cyclonic eddy nearby. No typhoon and heavy rain happened in this period, so we believed the bloom was triggered by the injection of nutrient-rich Pearl River plume driven by eddy. This is the first report on eddy-entrained Pearl River plume into the SCS, which would raise a new view on irregular transportation of nutrient and carbon and its related biogeochemical influence on the oligotrophic ocean.

  15. A parabolic model of drag coefficient for storm surge simulation in the South China Sea.

    PubMed

    Peng, Shiqiu; Li, Yineng

    2015-01-01

    Drag coefficient (Cd) is an essential metric in the calculation of momentum exchange over the air-sea interface and thus has large impacts on the simulation or forecast of the upper ocean state associated with sea surface winds such as storm surges. Generally, Cd is a function of wind speed. However, the exact relationship between Cd and wind speed is still in dispute, and the widely-used formula that is a linear function of wind speed in an ocean model could lead to large bias at high wind speed. Here we establish a parabolic model of Cd based on storm surge observations and simulation in the South China Sea (SCS) through a number of tropical cyclone cases. Simulation of storm surges for independent Tropical cyclones (TCs) cases indicates that the new parabolic model of Cd outperforms traditional linear models. PMID:26499262

  16. A parabolic model of drag coefficient for storm surge simulation in the South China Sea

    PubMed Central

    Peng, Shiqiu; Li, Yineng

    2015-01-01

    Drag coefficient (Cd) is an essential metric in the calculation of momentum exchange over the air-sea interface and thus has large impacts on the simulation or forecast of the upper ocean state associated with sea surface winds such as storm surges. Generally, Cd is a function of wind speed. However, the exact relationship between Cd and wind speed is still in dispute, and the widely-used formula that is a linear function of wind speed in an ocean model could lead to large bias at high wind speed. Here we establish a parabolic model of Cd based on storm surge observations and simulation in the South China Sea (SCS) through a number of tropical cyclone cases. Simulation of storm surges for independent Tropical cyclones (TCs) cases indicates that the new parabolic model of Cd outperforms traditional linear models. PMID:26499262

  17. Social Work Experience and Development in China

    ERIC Educational Resources Information Center

    Sibin, Wang

    2013-01-01

    This article presents the experience and limitations of government-run social work and the nonprofessional nature of social work, and suggests that the rapid development of social work and its professionalization are the inevitable results of the reform in the system. The author maintains that under market socialism, social work requires the…

  18. Retrieval of diffuse attenuation coefficient in the China seas from surface reflectance.

    PubMed

    Qiu, Zhongfeng; Wu, Tingting; Su, Yuanyuan

    2013-07-01

    Accurate estimation of the diffuse attenuation coefficient is important for our understanding the availability of light to underwater communities, which provide critical information for the China seas ecosystem. However, algorithm developments and validations of the diffuse attenuation coefficient in the China seas have been seldom performed before and therefore our knowledge on the quality of retrieval of the diffuse attenuate coefficient is poor. In this paper optical data at 306 sites collected in coastal waters of the China seas between July 2000 and February 2004 are used to evaluate three typical existing Kd(490) models. The in situ Kd(490) varied greatly among different sites from 0.029 m(-1) to 10.3 m(-1), with a mean of 0.92 ± 1.59 m(-1). Results show that the empirical model and the semi-analytical model significantly underestimate the Kd(490) value, with estimated mean values of 0.24 m(-1) and 0.5 m(-1), respectively. The combined model also shows significant differences when the in situ Kd(490) range from 0.2 m(-1) to 1 m(-1). Thus, the present study proposes that the three algorithms cannot be directly used to appropriately estimate Kd(490) in the turbid coastal waters of the China seas without a fine tuning for regional applications. In this paper, new Kd(490) algorithms are developed based on the semi-analytical retrieval of the absorption coefficient a(m(-1)) and the backscattering coefficient bb(m(-1)) from the reflectance at two wavelengths, 488 and 667 nm for the Moderate Resolution Imaging Spectroradiometer (MODIS) and 490 and 705 nm for the Medium Resolution Imaging Spectrometer (MERIS) applications, respectively. With the new approaches, the mean ratio and the relative percentage difference are 1.05 and 4.6%, respectively, based on an independent in situ data set. Furthermore, the estimates are reliable within a factor of 1.9 (95% confidence interval). Comparisons also show that the Kd(490) derived with the new algorithms are well correlated

  19. A reconstruction of late Pleistocene relative sea level in the south Bohai Sea, China, based on sediment grain-size analysis

    NASA Astrophysics Data System (ADS)

    Yi, Liang; Yu, Hongjun; Ortiz, Joseph D.; Xu, Xingyong; Qiang, Xiaoke; Huang, Haijun; Shi, Xuefa; Deng, Chenglong

    2012-12-01

    Future anthropogenic sea-level rise and its impact on coastal regions is an important issue facing human civilizations. Due to the short nature of the instrumental record of sea-level change, development of proxies for sea-level change prior to the advent of instrumental records is essential to reconstruct long-term background sea-level changes on local, regional and global scales. Here, we employ numerical methods to partition sediment grain size using a combined database of marine surface and core samples, and to quantitatively reconstruct sea-level variation since the late Pleistocene in the south Bohai Sea, China. Our sea-level reconstruction indicates that relative sea-level changes in the southern Bohai Sea track global sea-level variation for the duration of the record. The results also indicate substantial regression from 70 to 30 cal kyr BP, and potentially subarial exposure from 38 to 20 cal kyr BP. Our results document the feasibility of reconstructing relative sea-level change by numerical partitioning of sediment grain size data, demonstrating the potential for future applications.

  20. Biweekly Sea Surface Temperature over the South China Sea and its association with the Western North Pacific Summer Monsoon

    NASA Astrophysics Data System (ADS)

    Vaid, B. H.

    2015-10-01

    The association of the biweekly intraseasonal (BWI) oscillation in the Sea Surface Temperature (SST) over the South China Sea (SCS) and the Western North Pacific Summer Monsoon is authenticated using version 4 the Tropical Rainfall Measuring Mission Microwave Imager data (SST and rain) and heat fluxes from Ocean Atmosphere Flux project data during 1998-2012. The results suggest that the SCS involves ocean-atmosphere coupling on biweekly timescales. The positive biweekly SST anomalies lead the rain anomalies over the SCS by 3 days, with a significant correlation coefficient (r = 0.6, at 99 % significance levels) between the SST-rain anomalies. It is evident from lead/lag correlation between biweekly SST and zonal wind shear that warm ocean surface induced by wind shear may contribute to a favorable condition of the convective activity over the SCS. The present study suggests that ocean-to-atmospheric processes induced by the BWI oscillation in the SCS SST results in enhanced sea level pressure and surface shortwave radiation flux during the summer monsoon. Besides, it is observed that the SCS BWI oscillation in the changes of SST causes a feedback in the atmosphere by modifying the atmospheric instability. This suggests that the active/break biweekly cycle of the SST over the SCS is related by sea level pressure, surface heat fluxes and atmospheric instability. The potential findings here indicate that the biweekly SST over the SCS play an important role in the eastward and the southward propagation of the biweekly anomalies in the Western North Pacific.

  1. Assessing changes in extreme sea levels along the coast of China

    NASA Astrophysics Data System (ADS)

    Feng, Jianlong; von Storch, Hans; Jiang, Wensheng; Weisse, Ralf

    2015-12-01

    Hourly tide-gauge data along the coast of China are used to evaluate changes in extreme water levels in the past several decades. Mean sea level, astronomical tide, nontidal component and the tide-surge interaction was analyzed separately to assess their roles in the changes of extreme sea levels. Mean sea level at five tide gauges, Kanmen, Keelung, Zhapo, Xiamen and Quarrybay, show significant increasing trends during the past decades (1954-2013) with a rate of about 1.4-3.5 mm/yr. At Keelung, Kaohsiung and Quarrybay the mean high waters increased during 1954-2013 with a rate from 0.6 to 1.8 mm/yr, while the annual mean tidal range rose at the same time by 0.9 to 3.8 mm/yr. In terms of storm surge intensities, there is interannual variability and decadal variability but five tide gauges show significant decreasing trends, and three gauges, at Keelung, Xiamen and Quarrybay, exhibited significant increases of extreme sea levels with trends of 1.5-6.0 mm/yr during 1954-2013. Significant tide-surge interactions were found at all 12 tide gauges, but no obvious change was found during the past few decades. The changes in extreme sea levels in this area are strongly related to the changes of mean sea levels (MSL). At gauges, where the tide-surge interaction is large, the astronomic tides are also an important factor for the extreme sea levels, whereas tide gauges with little tide-surge interaction, the changes of wind driven storm surge component adds to the change of the extreme sea levels.

  2. Numerical modeling of Late Miocene tectonic inversion in the Xihu Sag, East China Sea Shelf Basin, China

    NASA Astrophysics Data System (ADS)

    Dai, Liming; Li, Sanzhong; Lou, Da; Liu, Xin; Suo, Yanhui; Yu, Shan

    2014-06-01

    The East China Sea Shelf Basin is an important oil- and gas-bearing basin in the West Pacific continental margin. This region was affected by subduction of the Pacific Plate and the Philippine Plate in Cenozoic and experienced multi-stage tectonic inversions. This paper presents results from a numerical simulation by finite element method to the Xihu Sag in the East China Sea Shelf Basin and neighboring areas in an attempt to evaluate the WNW-directed compression on the sag during Late Miocene. Based on comprehensive structural analysis of a large number of seismic profiles, we determine the structural geometry of the sag, including the basement of the basin, the sedimentary cover, and 29 major faults in the Xihu Sag. Simulation results show that under continuous WNW-directed compression, tectonic inversion occurred firstly in the Longjing and Yuquan tectonic zones in the sag. Based on quantitative analysis of vertical displacement field of the Xihu Sag and peripheral areas and its stress intensity evolution, we identify a compressional regime in the Longjing Anticline Zone with a gradually propagated uplifting from south to north; whereas the propagation of uplifting in the Yuquan Anticline Zone is from north to south. The inversion intensity decreases from north to south. The formation of the tectonic inversion zone in the Xihu Sag is not only correlated to the direction of compression and fault patterns in the basin, but also closely related to the spatial configuration of fault surfaces of the Xihu-Jilong Fault in the Xihu Sag.

  3. The SOLAS air-sea gas exchange experiment (SAGE) 2004

    NASA Astrophysics Data System (ADS)

    Harvey, Mike J.; Law, Cliff S.; Smith, Murray J.; Hall, Julie A.; Abraham, Edward R.; Stevens, Craig L.; Hadfield, Mark G.; Ho, David T.; Ward, Brian; Archer, Stephen D.; Cainey, Jill M.; Currie, Kim I.; Devries, Dawn; Ellwood, Michael J.; Hill, Peter; Jones, Graham B.; Katz, Dave; Kuparinen, Jorma; Macaskill, Burns; Main, William; Marriner, Andrew; McGregor, John; McNeil, Craig; Minnett, Peter J.; Nodder, Scott D.; Peloquin, Jill; Pickmere, Stuart; Pinkerton, Matthew H.; Safi, Karl A.; Thompson, Rona; Walkington, Matthew; Wright, Simon W.; Ziolkowski, Lori A.

    2011-03-01

    The SOLAS air-sea gas exchange experiment (SAGE) was a multiple-objective study investigating gas-transfer processes and the influence of iron fertilisation on biologically driven gas exchange in high-nitrate low-silicic acid low-chlorophyll (HNLSiLC) Sub-Antarctic waters characteristic of the expansive subpolar zone of the southern oceans. This paper provides a general introduction and summary of the main experimental findings. The release site was selected from a pre-voyage desktop study of environmental parameters to be in the south-west Bounty Trough (46.5°S 172.5°E) to the south-east of New Zealand and the experiment was conducted between mid-March and mid-April 2004. In common with other mesoscale iron addition experiments (FeAX's), SAGE was designed as a Lagrangian study, quantifying key biological and physical drivers influencing the air-sea gas exchange processes of CO 2, DMS and other biogenic gases associated with an iron-induced phytoplankton bloom. A dual tracer SF 6/ 3He release enabled quantification of both the lateral evolution of a labelled volume (patch) of ocean and the air-sea tracer exchange at tenths of kilometer scale, in conjunction with the iron fertilisation. Estimates from the dual-tracer experiment found a quadratic dependency of the gas exchange coefficient on windspeed that is widely applicable and describe air-sea gas exchange in strong wind regimes. Within the patch, local and micrometeorological gas exchange process studies (100 m scale) and physical variables such as near-surface turbulence, temperature microstructure at the interface, wave properties and windspeed were quantified to further assist the development of gas exchange models for high-wind environments. There was a significant increase in the photosynthetic competence ( Fv/ Fm) of resident phytoplankton within the first day following iron addition, but in contrast to other FeAX's, rates of net primary production and column-integrated chlorophyll a concentrations had

  4. Continuous surface seawater surveillance on poly aromatic hydrocarbons (PAHs) and mutagenicity of East and South China Seas

    NASA Astrophysics Data System (ADS)

    Ren, Huifeng; Kawagoe, Tsubasa; Jia, Huijuan; Endo, Hideaki; Kitazawa, Akira; Goto, Sumio; Hayashi, Tetsuhito

    2010-02-01

    Poly aromatic hydrocarbons (PAHs) and mutagenic compounds were adsorbed on Blue Rayon (BR) to monitor the pollution level of the surface seawater of the East and South China Seas by continuous sampling of seawater along the ship lane of our research and training vessel Umitaka-Maru. Eluted PAHs from BR were quantitatively determined by HPLC and their total amount in each sample ranged between 30.40 and 120.29 ng per liter of seawater, showing a difference of about 4 times among 8 samples. Acenaphthylene, naphthalene, and benz(a)anthracene were the most common PAHs found in the East and South China Seas, however, no big difference was observed in the concentrations of PAHs distributed throughout those two closed seas. Mutagenicity was detected as pseudo-positive from three samples. Among them, one sample collected along the east edge of the East China Sea showed a strong direct cytotoxicity which interrupted the mutagenicity test.

  5. Seismic anisotropy beneath South China Sea: using SKS splitting to constrain mantle flow

    NASA Astrophysics Data System (ADS)

    Xue, M.; Le, K.; Yang, T.

    2011-12-01

    The evolution of South China Sea is under debate and several hypotheses have been proposed: (1) The collision of India plate and Eurasia plate; (2) the backward movement of the Pacific subduction plate; (3) mantle upwelling; and (4) combinations of above hypotheses. All these causal mechanisms emphasize the contributions of deep structures to the evolution of South China Sea. In this study we use earthquake data recorded by seismic stations surrounding South China Sea to constrain mantle flow beneath. To fill the vacancy of seismic data in Viet Nam, we deployed 4 seismic stations (VT01-VT04) in a roughly north - south orientation in Viet Nam in Nov. 2009. We combine the VT dataset with the AD and MY datasets from IRIS and select 81 events for SKS splitting analysis. Measurements were made at 11 stations using Wolfe and Silver (1998)'s multi-event stacking procedure. Our observed splitting directions in Vietnam are generally consistent with those of Bai et. al. (2009) . In northern Vietnam, the splitting times are around 1 sec and the fast directions are NWW-SEE, parallel to the absolute plate motion as well as the motion of the Earth surface, implying the crust and the mantle are coupled in this region and is moving as a result of the collision of India and China. While in southern Vietnam and Malaya, the fast directions are NE-SW, almost perpendicular to the absolute plate motion as well as the surface motion of Eurasia plate. However, the observed NE-SW is parallel to the subduction direction of the Australian plate, which might be caused by the mantle flow along NE-SW induced by the subduction.

  6. Agricultural water consumption decreasing nutrient burden at Bohai Sea, China

    NASA Astrophysics Data System (ADS)

    Tong, Yindong; Wang, Xuejun; Zhen, Gengchong; Li, Ying; Zhang, Wei; He, Wei

    2016-02-01

    In this study, we discussed the impacts of human water consumption to the nutrient burden in a river estuary, and used Huanghe River as a case study. The agricultural water consumption from the Huanghe River has significantly decreased the natural water flows, and the amount of water consumption could be almost twice as high as the water entering into the estuary. According to our calculation, agricultural water usage decreased TN outflows by 6.5 × 104 Mg/year and TP outflows by 2.0 × 103 Mg/year. These account for 74% and 77% of the total output loads. It has been widely reported that the majority of the rivers in northern China were severely polluted by nutrients. Its implication on the budget of nutrient in the estuary ecosystem is not well characterized. Our study showed that the discharge of nutrients in the coast waters from polluted rivers was over concerned. Nutrients in the polluted rivers were transported back to the terrestrial systems when water was drawn for human water consumption. The magnitudes of changes in riverine nutrient discharges even exceed the water-sediment regulation trails in the Huanghe River. It has non-negligible impact on estimating the nutrient burden in costal water ecosystem.

  7. Tiny Sea Anemone from the Lower Cambrian of China

    PubMed Central

    Han, Jian; Kubota, Shin; Uchida, Hiro-omi; Stanley, George D.; Yao, Xiaoyong; Shu, Degan; Li, Yong; Yasui, Kinya

    2010-01-01

    Background Abundant fossils from the Ediacaran and Cambrian showing cnidarian grade grossly suggest that cnidarian diversification occurred earlier than that of other eumetazoans. However, fossils of possible soft-bodied polyps are scanty and modern corals are dated back only to the Middle Triassic, although molecular phylogenetic results support the idea that anthozoans represent the first major branch of the Cnidaria. Because of difficulties in taxonomic assignments owing to imperfect preservation of fossil cnidarian candidates, little is known about forms ancestral to those of living groups. Methods and Findings We have analyzed the soft-bodied polypoid microfossils Eolympia pediculata gen. et sp. nov. from the lowest Cambrian Kuanchuanpu Formation in southern China by scanning electron microscopy and computer-aided microtomography after isolating fossils from sedimentary rocks by acetic acid maceration. The fossils, about a half mm in body size, are preserved with 18 mesenteries including directives bilaterally arranged, 18 tentacles and a stalk-like pedicle. The pedicle suggests a sexual life cycle, while asexual reproduction by transverse fission also is inferred by circumferential grooves on the body column. Conclusions The features found in the present fossils fall within the morphological spectrum of modern Hexacorallia excluding Ceriantharia, and thus Eolympia pediculata could be a stem member for this group. The fossils also demonstrate that basic features characterizing modern hexacorallians such as bilateral symmetry and the reproductive system have deep roots in the Early Cambrian. PMID:20967244

  8. On the warm/cold regime shift in the South China Sea: Observation and modeling study

    NASA Astrophysics Data System (ADS)

    Swapna, P.; Gan, Jianping; Lau, Alexis; Fung, Jimmy

    2009-07-01

    Remote sensing data sets and a high-resolution three-dimensional regional ocean model were utilized to investigate the shifting of warm/cold regime and the associated sea level variation in the South China Sea (SCS) during 2000-2003. Both the altimetry data and the model results showed an increase in the sea level (warm phase) followed by an abrupt decrease (cold phase) in the SCS during 2000-2003. Heat budget calculations performed with the model revealed excess heat advection from the western Pacific warm pool into the SCS during the warm phase than the cold phase. The warm phase, which occurred during La Niña episodes, resulted from the intrusion of abnormally warmer western Pacific water that increased the heat content and thus sea level in the SCS. The cold phase, which occurred during El Niño episodes, was triggered by a reduction in the net atmospheric heat flux followed by cold water advection into the SCS. Decrease in the rate of precipitation minus evaporation ( P-E) also accounted for the falling of sea level during cold phase. The present study integrated the available remote sensing data and advanced numerical model to identify the time-dependent three-dimensional dynamic and thermodynamic forcing that are important in governing the warm/cold regime shift in the SCS.

  9. Validation and Variation of Upper Layer Thickness in South China Sea from Satellite Altimeter Data

    PubMed Central

    Lin, Chun-Yi; Ho, Chung-Ru; Zheng, Zhe-Wen; Kuo, Nan-Jung

    2008-01-01

    Satellite altimeter data from 1993 to 2005 has been used to analyze the seasonal variation and the interannual variability of upper layer thickness (ULT) in the South China Sea (SCS). Base on in-situ measurements, the ULT is defined as the thickness from the sea surface to the depth of 16°C isotherm which is used to validate the result derived from satellite altimeter data. In comparison with altimeter and in-situ derived ULTs yields a correlation coefficient of 0.92 with a slope of 0.95 and an intercept of 6 m. The basin averaged ULT derived from altimeter is 160 m in winter and 171 m in summer which is similar to the in-situ measurements of 159 m in winter and 175 m in summer. Both results also show similar spatial patterns. It suggests that the sea surface height data derived from satellite sensors are usable for study the variation of ULT in the semi-closed SCS. Furthermore, we also use satellite derived ULT to detect the development of eddy. Interannual variability of two meso-scale cyclonic eddies and one anticyclonic eddy are strongly influenced by El Niño events. In most cases, there are highly positive correlations between ULT and sea surface temperature except the periods of El Niño. During the onset of El Niño event, ULT is deeper when sea surface temperature is lower.

  10. Study on the seasonal variation of the suspended sediment distribution and transportation in the East China Seas based on SeaWiFS data

    NASA Astrophysics Data System (ADS)

    Wang, Wenjuan; Jiang, Wensheng

    2008-11-01

    The monthly mean suspended sediment concentration in the upper layer of the East China Seas was derived from the retrieval of the monthly binned SeaWiFS Level 3 data during 1998 to 2006. The seasonal variation and spatial distribution of the suspended sediment concentration in the study area were investigated. It was found that the suspended sediment distribution presents apparent spatial characteristics and seasonal variations, which are mainly affected by the resuspension and transportation of the suspended sediment in the study area. The concentration of suspended sediment is high inshore and low offshore, and river mouths are generally high concentration areas. The suspended sediment covers a much wider area in winter than in summer, and for the same site the concentration is generally higher in winter. In the Yellow and East China Seas the suspended sediment spreads farther to the open sea in winter than in summer, and May and October are the transitional periods of the extension. Winds, waves, currents, thermocline, halocline, pycnocline as well as bottom sediment feature and distribution in the study area are important influencing factors for the distribution pattern. If the 10 mg L-1 contour line is taken as an indicator, it appears that the transportation of suspended sediment can hardly reach 124°00'E in summer or 126°00'E in winter, which is due to the obstruction of the Taiwan Warm Current and the Kuroshio Current in the southern Yellow Sea and the East China Sea.

  11. Air-sea exchange of gaseous mercury in the tropical coast (Luhuitou fringing reef) of the South China Sea, the Hainan Island, China.

    PubMed

    Ci, Zhijia; Zhang, Xiaoshan; Wang, Zhangwei

    2016-06-01

    The air-sea exchange of gaseous mercury (mainly Hg(0)) in the tropical ocean is an important part of the global Hg biogeochemical cycle, but the related investigations are limited. In this study, we simultaneously measured Hg(0) concentrations in surface waters and overlaying air in the tropical coast (Luhuitou fringing reef) of the South China Sea (SCS), Hainan Island, China, for 13 days on January-February 2015. The purpose of this study was to explore the temporal variation of Hg(0) concentrations in air and surface waters, estimate the air-sea Hg(0) flux, and reveal their influencing factors in the tropical coastal environment. The mean concentrations (±SD) of Hg(0) in air and total Hg (THg) in waters were 2.34 ± 0.26 ng m(-3) and 1.40 ± 0.48 ng L(-1), respectively. Both Hg(0) concentrations in waters (53.7 ± 18.8 pg L(-1)) and Hg(0)/THg ratios (3.8 %) in this study were significantly higher than those of the open water of the SCS in winter. Hg(0) in waters usually exhibited a clear diurnal variation with increased concentrations in daytime and decreased concentrations in nighttime, especially in cloudless days with low wind speed. Linear regression analysis suggested that Hg(0) concentrations in waters were positively and significantly correlated to the photosynthetically active radiation (PAR) (R (2) = 0.42, p < 0.001). Surface waters were always supersaturated with Hg(0) compared to air (the degree of saturation, 2.46 to 13.87), indicating that the surface water was one of the atmospheric Hg(0) sources. The air-sea Hg(0) fluxes were estimated to be 1.73 ± 1.25 ng m(-2) h(-1) with a large range between 0.01 and 6.06 ng m(-2) h(-1). The high variation of Hg(0) fluxes was mainly attributed to the greatly temporal variation of wind speed. PMID:26931659

  12. Toxicological studies of Karlodinium micrum (Dinophyceae) isolated from East China Sea.

    PubMed

    Zhou, Chengxu; Fernández, Nuria; Chen, Haiming; You, Yurong; Yan, Xiaojun

    2011-01-01

    Karlodinium micrum (Strain NMBjah047) was isolated from the water samples of East China Sea (ECS). The hemolytic, ichthyotoxic, and cytotoxic activities of the algae was characterized. Embryotoxicity of both intra and extracellular extracts were also tested on a local sea urchin species. The algal intracellular hemolytic toxicity averaged about 87.5% at different algal growth phases. However, extracellular hemolytic activity depended on the population growth phase. The toxicity increased with the increase in the population size, reaching the highest hemolytic activity during the stationary phase, and maintained a relatively high activity even when the population declined. Time and density dependent ichthyotoxicity to Lateolabrax maculates juveniles was also detected. The LD(50) in 24 h was 1.1 × 10(5) cells/mL. Inhibition of the fertilized egg hatching was also observed and estimated the IC(50) in 40 h with 3.5 × 10(4) cells/mL. Extracellular extracts of K. micrum dense culture also showed significant cytotoxic activity on HUVEC (IC(50) = 70.8 μg/mL). A dose dependent acute toxicity to embryos of sea urchin was also determined. The algal intracellular and extracellular extracts delayed or even restricted the embryological development of the sea urchin, illustrating the potential toxicity of K. micrum not only to vertebrates, but also to marine invertebrates. The hemolytic compounds in the ECS strain were extracted and analyzed. At least two fractions had significant hemolytic activities. A lipid-like compound, named Digalactosyldiacylglycerol (DGDG), was suggested to be responsible for the hemolytic activity in one of these fractions. From the results of the present studies, this strain of K. micrum isolated from the East China Sea might be considered a toxic strain with hemolytic activity, ichthyotoxicity, cytotoxicity and embryotoxicity. PMID:20858509

  13. Mechanistic controls on diverse fates of terrestrial organic components in the East China Sea

    NASA Astrophysics Data System (ADS)

    Zhu, Chun; Wagner, Thomas; Talbot, Helen M.; Weijers, Johan W. H.; Pan, Jian-Ming; Pancost, Richard D.

    2013-09-01

    Terrestrial carbon transferred from the land to sea is a critical component of the global carbon cycle. A range of geochemical proxies has been developed to fingerprint the fate of terrestrial organic matter (TOM) in marine sediments. However, discrepancies among different proxies limit our ability to quantify and interpret the terrestrial signals in marine sediments, with consequences for the investigation of both the modern carbon cycle and past environmental change. To mechanistically understand these discrepancies, we examined the distributions of a range of terrestrial proxies and their aquatic counterparts (i.e. marine proxies) in the Yangtze river-East China Sea (YR-ECS) shelf system, where TOM experiences extensive modification during transport and burial. TOM proxies in the YR-ECS system collectively fit a power-law model but with distinct attenuation rates (the a∗ values) for individual molecular proxy groups. Among a range of TOM proxies, the modeled a∗ values decrease in the order: soil-marker BHPs > triterpenols > lignin > HMW n-alkanols > branched GDGTs > HMW n-alkanes for biomarkers; and Rsoil > BIT > %TOMiso for proxies tracing %TOM. Rapid loss of TOM components through dissociation in the narrow estuary, followed by oxidation over the wide open shelf, are best described by power curves. Inherent chemical reactivity (i.e. the number of functional groups), responses to hydraulic sorting, and in situ production regulate the individual attenuation rates. Of them, chemical reactivity plays the most important role on proxy behavior, supported by a strong correlation between a∗ values and standard molal Gibbs energies. Both, physical protection and chemical reactivity fundamentally control the overall behavior of TOM components, with the relative importance being setting-dependant: The former is relatively important in the estuary, whereas the later is the primary control over the open shelf. Moreover, regional variation of different marine

  14. Factors controlling the CCN number concentrations at north of East China Sea in spring 2005

    NASA Astrophysics Data System (ADS)

    Koike, M.; Kuwata, M.; Kondo, Y.; Miyazaki, Y.; Kodama, D.; Yum, S. S.; Tanimoto, H.; Matsueda, H.

    2006-12-01

    Ground based measurement of Cloud Condensation Nuclei (CCN) was made at Gosan station on Jeju Island, Korea, which is located at north of East China Sea during the Atmospheric Brown Cloud/East Asian Regional Experiment 2005 (ABC/EAREX2005) campaign conducted in March/April 2005. An averaged CCN number concentration was 3600 cm-3 at super-saturation S = 1.0%, which is higher than previously-reported CCN concentrations in the maritime (less than 1000 cm-3) and continental (about 2000 cm-3) air, and is as high as the CCN concentration measured in air influenced by large- scale biomass burning in southern Africa and Amazon. When air parcels which had been strongly affected by anthropogenic emissions over Asian continent were transported, CCN concentrations increased by a factor of 2-6. While the CCN concentrations at S = 1.0 and 0.6% are primarily explained by the temporal change in aerosol total number concentrations, the aerosol size distribution becomes more important for the CCN concentration at S = 0.3 and 0.1%. For S = 1.0%, in addition to transport of anthropogenic aerosols from over the Asian continent, the new particle formation resulted from anthropogenic precursor gases and their subsequent growth are likely important to increase CCN number concentrations. For S = 0.1%, CCN number concentration generally correlated with CO concentration, and more than 80% of these aerosols contained refractory-core, suggesting that many of these CCN had been transported from over the Asian continent. These aerosols are considered to grow to the critical dry diameter of 130 nm through condensation of precursor gases and/or coagulation of aerosols.

  15. Case study of absorption aerosol optical depth closure of black carbon over the East China Sea

    NASA Astrophysics Data System (ADS)

    Koike, M.; Moteki, N.; Khatri, P.; Takamura, T.; Takegawa, N.; Kondo, Y.; Hashioka, H.; Matsui, H.; Shimizu, A.; Sugimoto, N.

    2014-01-01

    aerosol optical depth (AAOD) measurements made by sun-sky photometers are currently the only constraint available for estimates of the global radiative forcing of black carbon (BC), but their validation studies are limited. In this paper, we report the first attempt to compare AAODs derived from single-particle soot photometer (SP2) and ground-based sun-sky photometer (sky radiometer, SKYNET) measurements. During the Aerosol Radiative Forcing in East Asia (A-FORCE) experiments, BC size distribution and mixing state vertical profiles were measured using an SP2 on board a research aircraft near the Fukue Observatory (32.8°N, 128.7°E) over the East China Sea in spring 2009 and late winter 2013. The aerosol extinction coefficients (bext) and single scattering albedo (SSA) at 500 nm were calculated based on aerosol size distribution and detailed BC mixing state information. The calculated aerosol optical depth (AOD) agreed well with the sky radiometer measurements (2 ± 6%) when dust loadings were low (lidar-derived nonspherical particle contribution to AOD less than 20%). However, under these low-dust conditions, the AAODs obtained from sky radiometer measurements were only half of the in situ estimates. When dust loadings were high, the sky radiometer measurements showed systematically higher AAODs even when all coarse particles were assumed to be dust for in situ measurements. These results indicate that there are considerable uncertainties in AAOD measurements. Uncertainties in the BC refractive index, optical calculations from in situ data, and sky radiometer retrieval analyses are discussed.

  16. A Preliminary Study on the Lithosphere-Asthenosphere Boundary beneath the South China Sea

    NASA Astrophysics Data System (ADS)

    Lee, T. T. Y.; Chen, C. W.

    2014-12-01

    The lithosphere-asthenosphere boundary (LAB) is an important boundary at which the rigid lithosphere translates coherently upon the viscous asthenosphere. New observations have been made on LAB through detailed seismic analysis, especially that from receiver functions. Previous studies have found LAB depth varies significantly, systematically getting shallower from continental to oceanic lithosphere. In smaller scale, the depth and sharpness of LAB also differ from region to region, suggesting the effects of a combination of thermal and compositional origins. In this study, we investigate the LAB beneath the South China Sea, a region poorly instrumented that conventional seismological are less effective and impractical. The South China Sea is on the Sunda Plate, which is considered to be once the southeastern part of the Eurasia Plate before separating with a distinct moving direction from that of India-Eurasia continental collision. The South China Sea is Phanerozoic in age and continental in nature, but the striped magnetic anomalies observed from the sea floor have suggested multiple spreading events since early Miocene, indicating the presence of latter formed oceanic lithosphere. Previous seismic studies of this region focused mainly on shallow basin structure pertaining to petroleum exploration. The lithospheric structure, particularly the LAB, remains elusive, while it provides important insight into the complex tectonic history in this region. To image the LAB, we use the precursor of SS phase. The precursor bounces at the LAB discontinuity at depth would appear before the SS and presents a signal amenable to analysis for depth and properties. We collect seismic waveform data recorded mainly at Japan and Cocos Islands of corresponding teleseismic events from Southern Sumatera and Japan, with SS and potential precursors bouncing beneath the South China Sea. We employ an analysis technique, velocity spectral analysis (vespagrams), to identify precursory

  17. Spatio-temporal distribution of dissolved sulfide in China marginal seas

    NASA Astrophysics Data System (ADS)

    Wu, Xiaodan; Wu, Bin; Song, Jinming; Li, Xuegang

    2014-09-01

    With sulfide increasingly recognized as an important parameter to assess the oxidation-reduction level in aqueous environment, research on its geochemical behavior is becoming important. Water samples collected in Bohai Sea (1-19 August, 2010), Yellow Sea (20-30 November, 2010) and East China Sea (3-17 June, 2010 and 1-10 November, 2010) were used to determine the occurrence and distribution of dissolved sulfide by methylene blue spectrophotometric method. Results show that: (1) horizontally, concentration of dissolved sulfide significantly varied from the coastal region to the open sea and profoundly influenced by physical processes. High values occurred in the river-sea boundary zone "marginal filter" due to rich riverine input, frequent upwelling and active exchange in shelf edge. Terrestrial input from adjacent rivers and the current cycling contributed to the high sulfide appeared in western Bohai Sea, eastern Shandong Peninsula, and northeast of Changjiang (Yangtze) River estuary. Especially, relative higher sulfide values occurred in Yellow Sea, which is consistent with the variation of salinity largely due to the hydrodynamic feature; (2) vertically, measurement of dissolved sulfide in bottom water was higher and more variable than that in surface water caused by the wind-induced resuspension and dissimilatory sulfate reduction. Moreover, nutrient-type profile clearly identified that oxidation plays a major role in the biogeochemistry cycle of sulfide in water; (3) seasonally, investigation for East China Sea in June and November reflected seasonal variation of Changjiang River Diluted Water, Kuroshio Current, and Taiwan Warm Current. Concentration in June was much higher than that sampled in November at most stations. Mean concentration of dissolved sulfide varied seasonally from 2.26 μg/L (June) to 1.16 μg/L (November) in surface and 3.00 μg/L (June) to 1.56 μg/L (November) in bottom. Progress in the field is slow and more effort is needed to ensure

  18. Formation of the modern current system in the East China Sea since the early Holocene and its relationship with sea level and the monsoon system

    NASA Astrophysics Data System (ADS)

    Zheng, Xufeng; Li, Anchun; Wan, Shiming; Jiang, Fuqing; Yin, Xueming; Lu, Jian

    2015-07-01

    The Okinawa Trough is a natural laboratory for the study of air-sea interaction and paleoenvironmental change. It has been demonstrated that present offshore export of particles in the bottom nepheloid layer occur primarily with downwelling from the northeast winter monsoon, which is inhibited by a transverse circulation pattern in summer. This current system was very different during the Last Glacial Maximum owing to low sea level (-120 m) and exposure of a large shelf area. We collected sediment core Oki01 from the middle Okinawa Trough during 2012 using R/V Kexue No. 1 to elucidate the timing and cause of the current system transition in the East China Sea. Clay mineral, dry density, and elemental (Ti, Ca) composition of core Oki01 was analyzed. The results indicate that clay minerals derived mainly from the Huanghe (Yellow) and the Changjiang (Yangtze) Rivers during 16.0-11.6 ka, and the modern current system in the East China Sea formed beginning in the early Holocene. Therefore, mixing of East China Sea continental shelf, Changjiang River and partially Taiwan Island sediment are the major contributors. The decrease of log(Ti/Ca) and alternating provenance since the early Holocene indicate less sediment from the East China in summer because of resistance of the modern current system, i.e., a "water barrier" and upwelling. Conversely, sediment delivery persists in winter and log(Ti/Ca) indicates the winter monsoon signal since the early Holocene. Our evidence also suggests that sediment from Taiwan Island could be transported by the Kuroshio Current to the middle Okinawa Trough, where it mingles with winter monsoon-induced export of sediment from the Changjiang River and East China Sea continental shelf. Although the present research advances understanding of the evolutionary history of paleoenvironmental change in the Okinawa Trough, more sediment cores should be retrieved over wide areas to construct a larger scenario.

  19. Genetic type of natural gas in Ya13-1 gas field, South China Sea

    SciTech Connect

    Zhang Gang

    1995-08-01

    Ya13-1 is one of the largest gas field ever found in China in recent years. Studying on the genetic type of natural gas in the field is one of the key factors to determine the regional hydrocarbon potential--Qiongdongnan Basin and Yinggerhaii Basin, northwest part of South China Sea. Series of geochemical methods have been undertook including the analysis of the chemical composition of the natural gas and their isotopic ratio discussed in this paper. Other related studied including geological settings, gas-source correlations, geochemistry of the condensates and extractable compounds of source rocks, and thermal simulation and evaluation of the marine shales provides further informations. It is noticeable that the higher content of mercury (44000 ng/cubic meter) and aromatics such as benzene and toluene may be related to the joint of condensates, which derived from coal-bearing Oligocene shales in the adjacent Qingdingnan Basin. Studies show that the natural gas in Ya13-1 gas field belong to high to post mature non-associated gas derived in marine source rocks, and mainly come from Oligocene to Pliocene marine shales in Yinggerhai Basin. This is quite different with the former studies, which believe the gas derived from Oligocene coal-bearing strata of Yacheng formation, Qiongdongnan Basin. The new results of the studies make sure further a pretty good potential of gas resources in the northwest part ofSouth China Sea.

  20. Unusual distribution of floating seaweeds in the East China Sea in the early spring of 2012.

    PubMed

    Komatsu, Teruhisa; Mizuno, Shizuha; Natheer, Alabsi; Kantachumpoo, Attachai; Tanaka, Kiyoshi; Morimoto, Akihiko; Hsiao, Sheng-Tai; Rothäusler, Eva A; Shishidou, Hirotoshi; Aoki, Masakazu; Ajisaka, Tetsuro

    2014-01-01

    Floating seaweeds play important ecological roles in offshore waters. Recently, large amounts of rafting seaweed have been observed in the East China Sea. In early spring, juveniles of commercially important fish such as yellowtail accompany these seaweed rafts. Because the spatial distributions of seaweed rafts in the spring are poorly understood, research cruises were undertaken to investigate them in 2010, 2011, and 2012. Floating seaweed samples collected from the East China Sea during the three surveys contained only Sargassum horneri. In 2010 and 2011, seaweed rafts were distributed only in the continental shelf and the Kuroshio Front because they had become trapped in the convergence zone of the Kuroshio Front. However, in 2012, seaweed was also distributed in the Kuroshio Current and its outer waters, and massive strandings of seaweed rafts were observed on the northern coast of Taiwan and on Tarama Island in the Ryukyu Archipelago. Environmental data (wind, currents, and sea surface height) were compared among the surveys of 2010, 2011, and 2012. Two factors are speculated to have caused the unusual distribution in 2012. First, a continuous strong north wind produced an Ekman drift current that transported seaweed southwestward to the continental shelf and eventually stranded seaweed rafts on the coast of Taiwan. Second, an anticyclonic eddy covering northeast Taiwan and the Kuroshio Current west of Taiwan generated a geostrophic current that crossed the Kuroshio Current and transported the rafts to the Kuroshio Current and its outer waters. Such unusual seaweed distributions may influence the distribution of fauna accompanying the rafts. PMID:24771974

  1. Geotechnical properties of surface and near-surface deposits in the East China Sea

    NASA Astrophysics Data System (ADS)

    Keller, George H.; Yincan, Ye

    Shelf deposits in the East China Sea are primarily relict sands with overlying fine-grained cohesive deposits occurring along the innermost shelf and as a more or less isolated deposit on the midshelf. Considering these surface and near-surface (0 to 1.5 m) cohesive deposits as a unit, the innermost shelf sediments are slightly coarser (more silt) than those of the midshelf which commonly contain more clay-size material. The inner shelf sediments also display higher mean wet bulk densities (1.48 to 1.88 mg m -3) and shear strengths (4.0 to 9.8 kPa), but lower water contents (64 to 81%) and porosities (62 to 66%) than those found associated with the midshelf deposits. Available data indicate that the midshelf mud deposit is primarily derived from the reworking of Huanghe (Yellow River) coastal deposits that were laid down at a time when the river debouched into the Yellow Sea to the north of the Changjiang. Some portion of the midshelf mud may be derived from the Changjiang. These midshelf 'fines' apparently are caught up in a large circulation gyre over the shelf which accounts for their isolated nature. Strong bottom and near-bottom currents, as well as winter storm wave activity, are primary mechanisms resulting in both suspended sediment and bedload transport on the shelf of the East China Sea.

  2. The distribution of dissolved aluminum in the Yellow and East China Seas

    NASA Astrophysics Data System (ADS)

    Li, Jianbing; Ren, Jingling; Zhang, Jing; Liu, Sumei

    2008-02-01

    Water samples containing dissolved aluminum were collected from the Yellow and East China Seas in October-November 2000. The average concentrations of dissolved Al in the Yellow Sea (YS) and East China Sea (ECS) were 0.042 and 0.056 μmolL-1, respectively. The concentration of dissolved aluminum decreased gradually across the continental shelf. The lower concentrations appeared in the YS cold water center and in the bottom layer at the shelf edge of the ECS, where they were 0.016 and 0.011 μmolL-1, respectively. The distribution of dissolved Al was controlled by physical mixing processes rather than biological uptake processes. The impact of different water masses along the PN transect was calculated based on the mass balance model. The results show that the impact of the Changjiang River was mainly concentrated on the coastal area and the top thermocline water on the ECS shelf, where the impact percentage decreased from 12.6% to 1.1% in the surface water, while the contribution of the Kuroshio water was dominant on the ECS shelf in this survey, increasing from 77.6% to 97.8% along the PN transect from the Changjiang River Estuary to the Ryukyu Islands. It is concluded that aluminum can serve as a proper tracer for studying the impact of Changjiang terrestrial matter on the ECS shelf water.

  3. The Sea Surface Temperature Variation during the Spring Tide and Neap Tide in the South China Sea

    NASA Astrophysics Data System (ADS)

    Huang, Shih-Jen; Kuo, Nan-Jung; Ho, Chung-Ru; Lo, Yao-Tsai

    2016-04-01

    The sea surface temperature (SST) data of MODIS/Terra (Moderate-resolution Imaging Spectroradiometer) are used to analyze the SST difference between the spring tide and the neap tide in the South China Sea (SCS) from 2001 to 2013. The 4 stations from north to south in the SCS are used to investigate the variation of SST. The results show the lowest SST found on January and the highest SST found on June. The standard deviation of SST in shallow regions (St. 1 and St. 4) are larger than the deep regions (St. 2 and St. 3). During the winter and spring the standard deviation of SST at the neap tide are greater than the spring tide period. From the later winter to early summer, the SST during the neap tide period is greater than the spring tide period. They are more obvious in the shallow regions. Meanwhile the influence of tide action in the shallow regions is greater than it in the deep regions.

  4. Alkylphenols in surface sediments of the Yellow Sea and East China Sea inner shelf: occurrence, distribution and fate.

    PubMed

    Duan, Xiao-yong; Li, Yan-xia; Li, Xian-guo; Zhang, Da-hai; Gao, Yi

    2014-07-01

    Alkylphenols (APs) have been found as ubiquitous environmental pollutants with reproductive and developmental toxicity. In this study, APs in surface sediments of the Yellow Sea (YS) and East China Sea (ECS) inner shelf were analyzed to assess influences of riverine and atmospheric inputs of pollutants on the marine environment. NP concentrations ranged from 349.5 to 1642.8 ng/g (average 890.1 ng/g) in the YS sediments and from 31.3 to 1423.7 ng/g (average 750.1 ng/g) in the ECS inner shelf sediments. NP distribution pattern was mainly controlled by the sedimentary environment. OP concentration was 0.8-9.3 ng/g (average 4.7 ng/g) in the YS sediments and 0.7-11.1 ng/g (average 5.1 ng/g) in the ECS sediments. Assessment of the influence of distances from land on OP concentrations provided evidence for the predominance of coastal riverine and/or atmospheric inputs rather than long-range transport. And the biological pump may play an important role for sequestration of OP in the nearshore area. PMID:24411839

  5. Summer Surface Layer Thermal Response to Surface Gravity Waves in the Yellow Sea and the East China Sea

    NASA Astrophysics Data System (ADS)

    Zhang, X.; Han, G.; Deng, Z.; Wang, X.

    2010-12-01

    A three-dimensional ocean model is applied to study the summer surface layer thermal response to surface gravity waves in the Yellow sea and the East China Sea(YES).The parameterization schemes of wave breaking developed by Mellor and Blumberg(2004) and Langmuir circulation developed by Kantha and Clayson(2004) are both included in the Mellor-Yamada turbulence closure model(Mellor and Yamada, 1982). Numerical results show that both surface wave breaking and Langmuir circulation determine the depth of surface boundary layer of temperature in the YES in summer. Langmuir circulation is able to obtain the turbulent kinetic energy injected by breaking waves near the surface and transport it downward to greater depths. A diagnostic analysis of the momentum balance shows that surface gravity waves can decrease the velocity near the surface and make the flow near the surface more homogeneous vertically in the YES. In addition, a diagnostic analysis of the temperature equation has been done for studying the heat budget. Diagnostic results show that more heat that is brought from surface in the YES can been transferred into the deeper layer owing to the surface gravity waves, which can induce local temperature there increase more rapidly. Besides, diagnostic results also suggest that surface gravity waves are likely to decrease upwelling near the bank in the region.

  6. Construction and preliminary analysis of a deep-sea sediment metagenomic fosmid library from Qiongdongnan Basin, South China Sea.

    PubMed

    Hu, Yongfei; Fu, Chengzhang; Yin, Yeshi; Cheng, Gong; Lei, Fang; Yang, Xi; Li, Jing; Ashforth, Elizabeth Jane; Zhang, Lixin; Zhu, Baoli

    2010-11-01

    Preliminary characterization of the microbial phylogeny and metabolic potential of a deep-sea sediment sample from the Qiongdongnan Basin, South China Sea, was carried out using a metagenomic library approach. An effective and rapid method of DNA isolation, purification, and library construction was used resulting in approximately 200,000 clones with an average insert size of about 36 kb. End sequencing of 600 individual clones from the fosmid library generated 1,051 sequences with an average sequence length of 619 bp. Phylogenetic ascription indicated that this library was dominated by Bacteria, predominantly Proteobacteria, though Planctomycetes were also relatively abundant. Sulfate-reducing and anaerobic ammonium-oxidizing bacteria, which play important roles in the cycling of sedimentary nutrients, were abundant in the library. Cluster of orthologous groups category analysis showed that most of the genes contained in the end sequences were related to metabolism, and with cellular processes and signaling. Functional groups assigned by SEED (subsystems-based annotations) highlighted the existence of 'one-carbon' metabolism within this community as well as identifying functional genes involved in methanogenesis. Furthermore, diverse genes involved in the biodegradation of xenobiotics were found using Kyoto Encyclopedia of Genes and Genomes metabolic pathway analysis. PMID:20514504

  7. Macrobenthic community structure and species composition in the Yellow Sea and East China Sea in jellyfish bloom

    NASA Astrophysics Data System (ADS)

    Peng, Songyao; Li, Xinzheng; Wang, Hongfa; Zhang, Baolin

    2014-05-01

    To understand the characteristics of macrobenthic structures and the relationship between environment and benthic assemblages in jellyfish bloom, we studied the macrobenthos and related environmental factors in the coastal waters of the Yellow Sea and East China Sea. Data were collected during two seasonal cruises in April and August of 2011, and analyzed with multivariate statistical methods. Up to 306 macrobenthic species were registered from the research areas, including 115 species of Polychaeta, 78 of Crustacea, 61 of Mollusca, 30 of Echinodermata, and 22 of other groups. Nine polychaete species occurred at frequencies higher than 25% from the sampling stations: Lumbrineris longifolia, Notomastus latericeus, Ninöe palmata, Ophelina acuminata, Nephtys oligobranchia, Onuphis geophiliformis, Glycera chirori, Terebellides stroemii, and Aricidea fragilis. Both the average biomass and abundance of macrobenthos are higher in August (23.8 g/m2 and 237.7 ind./m2) than those in April (11.3 g/m2 and 128 ind./m2); the dissimilarity of macrobenthic structures among stations is as high as 70%. In terms of the dissimilarity values, we divided the stations into four clusters in spring and eight in summer. The ABC curve shows that the macrofauna communities in high jellyfish abundance were not changed. Canonical correspondence analysis showed that depth, temperature, median grain size, total organic carbon of sediment and total nitrogen in sediment were important factors affecting the macrozoobenthic community in the study area.

  8. Simulation of 1986 South China Sea Monsoon with a Regional Climate Model

    NASA Technical Reports Server (NTRS)

    Tao, W. -K.; Lau, W. K.-M.; Jia, Y.; Juang, H.; Wetzel, P.; Qian, J.; Chen, C.

    1999-01-01

    A Regional Land-Atmosphere Climate Simulation System (RELACS) project is being developed at NASA Goddard Space Flight Center. One of the major goals of RELACS is to use a regional scale model with improved physical processes and in particular land-related processes, to understand the role of the land surface and its interaction with convection and radiation as well as the water/energy cycles in the IndoChina/South China Sea (SCS) region. The Penn State/NCAR MM5 atmospheric modeling system, a state of the art atmospheric numerical model designed to simulate regional weather and climate, has been successfully coupled to the Parameterization for Land-Atmosphere-Cloud Exchange (PLACE) land surface model. The original MM5 model (without PLACE) includes the option for either a simple slab soil model or a five-layer soil model (MRF) in which the soil moisture availability evolves over time. However, the MM5 soil models do not include the effects of vegetation, and thus important physical processes such as evapotranspiration and interception are precluded. The PLACE model incorporates vegetation type and has been shown in international comparisons to accurately predict evapotranspiration and runoff over a wide variety of land surfaces. The coupling of MM5 and PLACE creates a numerical modeling system with the potential to more realistically simulate atmosphere and land surface processes including land-sea interaction, regional circulations such as monsoons, and flash flood events. In addition, the Penn State/NCAR MM5 atmospheric modeling system has been: (1) coupled to the Goddard Ice Microphysical scheme; (2) coupled to a turbulent kinetic energy (TKE) scheme; (3) modified to ensure cloud budget balance; and (4) incorporated initialization with the Goddard EOS data sets at NASA/Goddard Laboratory for Atmospheres. The improved MM5 with two nested domains (60 and 20 km horizontal resolution) was used to simulate convective activity over IndoChina and the South China Sea

  9. Primary Analysis of Shear-Wave Splitting Aroundbohai Sea Area in North China

    NASA Astrophysics Data System (ADS)

    Tai, L.; Gao, Y.; Shi, Y.; Sun, J.

    2012-12-01

    Bohai Sea area locates at eastern China, including 3 provinces ( Hebei, Liaoning and Shandong ) and 2 metropolitan cities ( Beijing and Tianjin ). There are 5 tectonic units (Yanshan uplift, Taihang uplift, Liaodong uplift, Luxi uplift and Jizhong depression), where is within North China (in short, NC). Zhangjiakou-Bohai seismic belt, an important seismotectonic zone in eastern China and Tanlu fault, the largest fault in eastern China, intersect in this zone, so that the tectonics are complicated. Earthquake activity is very strong in this zone, which is famous of earthquakes with large magnitude and high frequency. This study used a system analysis method of shear-wave splitting, namely SAM method (GAO et al, 2004). It includes mainly three aspects, i.e., calculation of cross-correlation function, elimination of time delay and check of polarization analysis. Preliminarily, we obtained the 378 seismic data within shear-wave window recorded by 27 stations around Bohai Sea area. The polarizations of fast shear-waves show different local features so that we divide the studied zone into 3 different areas, west of Bohai Sea gulf (including Beijing, Tianjin and Hebei province), north of Bohai Sea gulf (Liaoning province) and south of Bohai Sea gulf (Shandong province). In the west of Bohai Sea gulf, we divided the area into 3 parts. In south of Zhangjiakou-Bohai seismic belt, the predominant polarizations of fast shear-waves are a little scattered, lots of stations strike to nearly E-W, consistent with the direction of the in situ principal stress, consistent with the direction of regional tectonic stress in north part of NC, which strikes to nearly WNW or E-W, while some stations strike to NNE or NW, different from the direction of the regional principal stress field. It may be influenced by local tectonics or shallow crust structure. Within Zhangjiakou-Bohai seismic belt, the predominant polarizations of fast shear-waves are in direction of nearly E-W, consistent with

  10. Floating production platforms and their applications in the development of oil and gas fields in the South China Sea

    NASA Astrophysics Data System (ADS)

    Zhang, Dagang; Chen, Yongjun; Zhang, Tianyu

    2014-03-01

    This paper studies the current available options for floating production platforms in developing deepwater oil fields and the potential development models of future oil and gas exploration in the South China Sea. A detailed review of current deepwater platforms worldwide was performed through the examples of industry projects, and the pros and cons of each platform are discussed. Four types of platforms are currently used for the deepwater development: tension leg platform, Spar, semi-submersible platform, and the floating production system offloading. Among these, the TLP and Spar can be used for dry tree applications, and have gained popularity in recent years. The dry tree application enables the extension of the drilling application for fixed platforms into floating systems, and greatly reduces the cost and complexity of the subsea operation. Newly built wet tree semi-submersible production platforms for ultra deepwater are also getting their application, mainly due to the much needed payload for deepwater making the conversion of the old drilling semi-submersible platforms impossible. These platforms have been used in different fields around the world for different environments; each has its own advantages and disadvantages. There are many challenges with the successful use of these floating platforms. A lot of lessons have been learned and extensive experience accumulated through the many project applications. Key technologies are being reviewed for the successful use of floating platforms for field development, and potential future development needs are being discussed. Some of the technologies and experience of platform applications can be well used for the development of the South China Sea oil and gas field.

  11. China's soil and groundwater management challenges: Lessons from the UK's experience and opportunities for China.

    PubMed

    Coulon, Frédéric; Jones, Kevin; Li, Hong; Hu, Qing; Gao, Jingyang; Li, Fasheng; Chen, Mengfang; Zhu, Yong-Guan; Liu, Rongxia; Liu, Ming; Canning, Kate; Harries, Nicola; Bardos, Paul; Nathanail, Paul; Sweeney, Rob; Middleton, David; Charnley, Maggie; Randall, Jeremy; Richell, Martin; Howard, Trevor; Martin, Ian; Spooner, Simon; Weeks, Jason; Cave, Mark; Yu, Fang; Zhang, Fang; Jiang, Ying; Longhurst, Phil; Prpich, George; Bewley, Richard; Abra, Jonathan; Pollard, Simon

    2016-05-01

    There are a number of specific opportunities for UK and China to work together on contaminated land management issues as China lacks comprehensive and systematic planning for sustainable risk based land management, encompassing both contaminated soil and groundwater and recycling and reuse of soil. It also lacks comprehensive risk assessment systems, structures to support risk management decision making, processes for verification of remediation outcome, systems for record keeping and preservation and integration of contamination issues into land use planning, along with procedures for ensuring effective health and safety considerations during remediation projects, and effective evaluation of costs versus benefits and overall sustainability. A consequence of the absence of these overarching frameworks has been that remediation takes place on an ad hoc basis. At a specific site management level, China lacks capabilities in site investigation and consequent risk assessment systems, in particular related to conceptual modelling and risk evaluation. There is also a lack of shared experience of practical deployment of remediation technologies in China, analogous to the situation before the establishment of the independent, non-profit organisation CL:AIRE (Contaminated Land: Applications In Real Environments) in 1999 in the UK. Many local technology developments are at lab-scale or pilot-scale stage without being widely put into use. Therefore, a shared endeavour is needed to promote the development of technically and scientifically sound land management as well as soil and human health protection to improve the sustainability of the rapid urbanisation in China. PMID:26970591

  12. The First SeaWiFS HPLC Analysis Round-Robin Experiment (SeaHARRE-1)

    NASA Technical Reports Server (NTRS)

    Hooker, Stanford B. (Editor); Firestone, Elaine R. (Editor); Claustre, Herve; Ras, Josephine; VanHeukelem, Laurie; Berthon, Jean-Francois; Targa, Cristina; vanderLinde, Dirk; Barlow, Ray; Sessions, Heather

    2001-01-01

    Four laboratories, which had contributed to various aspects of SeaWiFS calibration and validation activities, participated in the first SeaWiFS HPLC Analysis Round-Robin Experiment (SeaHARRE-1): Horn Point Laboratory (USA), the Joint Research Centre (Italy), the Laboratoire de Physique et Chimie Marines (France), and the Marine and Coastal Management group (South Africa). The analyses of the data are presented in Chapter 1 and the individual methods of the four groups are presented in Chapters 2-5. The average (or overall) conclusions of the round-robin are derived from 12 in situ stations occupied during a cruise in the Mediterranean Sea, although, only 11 stations are used in the analyses. The data set is composed of 12 replicates taken during each sampling opportunity with 3 replicates going to each of the 4 laboratories. The average (or overall) results from the intercomparison of 15 pigments or pigment associations are as follows (in some cases, data subsets that exclude pigments which were not analyzed by all the laboratories, or that had unusually large variances, are used to exclude a variety of problematic pigments): a) the accuracy of the four methods in determining the concentration of total chlorophyll a is 7.9%, (one method did not separate mono- and divinyl chlorophyll a, and if the samples containing significant divinyl chlorophyll a concentrations are ignored, the four methods have an accuracy of 6.7%); b) the accuracy in determining the full set of pigments is 19.1%; c) there is a reduction in accuracy of approximately - 12.2% for every decade (factor of 10) decrease in concentration (based on a data subset); d) the precision of the four methods using a subset data is 8.617( 6.2% for an edited subset); e) the repeatability of the four methods using the subset data is 9.2% (7.2%; for an edited subset, and f) the reproducibility of the four methods using the subset data is 21.31% (15.0% for an edited subset).

  13. Convective Systems during the South China Sea Monsoon Onset and Post-Onset Simulated by a Cloud Resolving Model Using SCSMEX Data

    NASA Technical Reports Server (NTRS)

    Shie, C.-L.; Tao, W.-K.; Johnson, D.; Simpson, J.; Braun, S.; Wang, J.-J.; Johnson, R.; Ciesielski, E.; Starr, David O'C. (Technical Monitor)

    2002-01-01

    South China Sea Monsoon Experiment (SCSMEX, 1998), one of several major TRMM field experiments, has successfully obtained a wealth of information and observational data on the summer monsoon onset and evolution in the South China Sea region. The primary goal of the experiment is to provide a better understanding of the key physical processes for the onset and maintenance of the monsoon over Southeast Asia and southern China leading to improved predictions. In this paper, our objective is to investigate the major physical and microphysical processes involved in the convective systems that developed during the onset and post-onset of the South China Sea monsoon - for both the similarities and differences between these two phases. There are two episodes simulated in this study, one of the onset period (May 18-26, 1998) and one of the post-onset period (June 2-11, 1998). The focus of this paper is to study four major aspects between these two different episodes. First, characteristics of rainfall such as rainfall amount and occurrence in the convective and stratiform regions are investigated, as well as the propagation of convective systems. The numerical precipitation fields are also validated against both the TRMM Microwave Imager (TMI) soundings and Precipitation Radar (PR) observations. Second, the domain-averaged heat and moisture budgets are analyzed to comprehend the essential roles played by physical processes such as the large-scale forcing and latent heat flux. Third, the microphysical processes associated with warm rain or ice are also closely examined during these two episodes. Finally, vertical distributions of Q1 and Q2 budgets are presented to perform a detailed discussion on the energy and moisture cascade in the vertical direction.

  14. A Numerical Study of Sea Breeze and Spatiotemporal Variation in the Coastal Atmospheric Boundary Layer at Hainan Island, China

    NASA Astrophysics Data System (ADS)

    Huang, Qian-Qian; Cai, Xu-Hui; Song, Yu; Kang, Ling

    2016-06-01

    Numerical simulations of sea breezes and the coastal atmospheric boundary layer (ABL) at Hainan Island, China during summer and winter are discussed. The different behaviour of sea breezes and the ABL on the leeward and windward sides of the island are examined, and it is found that offshore flows are more likely to create a strong sea-breeze signature, whereas the process of sea-breeze development under onshore flows is difficult to capture. At the location where the sea-breeze signal is remarkable, the height of the coastal ABL displays an abnormal decrease, corresponding to a transitional point from a continental ABL to a thermal internal boundary layer (TIBL) formed under sea-breeze conditions. This is corroborated by the sudden increase in the water vapour mixing ratio and/or wind speed, indicating the arrival of the sea breeze. Regarding the spatial distribution, the TIBL height decreases abruptly just ahead of the sea-breeze front, and above the cold air mass. When the sea-breeze front occurs with a raised head, a cold air mass is separated from the sea-breeze flow and penetrates inland. This separation is attributed to the interaction between the sea breeze and valley breeze, while the dry airflow entraining to the sea-breeze flow may also partially contribute to this air mass separation.

  15. Healthcare reform in China: making sense of a policy experiment?

    PubMed

    Millar, Ross; Jian, Weiyan; Mannion, Russell; Miller, Robin

    2016-05-16

    Purpose - The purpose of this paper is to explore recent healthcare reform in China. Reflecting on the current literature, the viewpoint argues that greater attention should be paid to healthcare reform in China as a public policy process, particularly one that is built on policy experimentation. Design/methodology/approach - The viewpoint argues that while recent efforts to understand the impact of reform have brought significant understanding of key issues and processes, such interest tends to focus on pragmatic concerns rather than pose wider theoretical and methodological questions about the nature and pace of reform. Findings - The authors suggest that the lens of public policy is particular relevant and insightful given what has been documented elsewhere regarding China's unique policy process characterised by "policy experimentation". The authors discuss how a policy experiment perspective can provide a useful heuristic for understanding healthcare reform in China. Originality/value - The viewpoint concludes by outlining possible applications of this approach and looks forward at the emerging research agenda in this area. PMID:27119389

  16. Influence of small river derived sediment on the Northeastern South China Sea sedimentation processes in the last 40 K years

    NASA Astrophysics Data System (ADS)

    Cheng, Wan-Yen; Lin, Saulwood; Lou, Jiann-Yuh; Wei, Kuo-Yen; Liu, CharShine; Chen, Shing-Li; Wang, Yun-Shuen

    2015-04-01

    Small rivers derived particles are major source of sediment to the ocean in the present time. Small rivers in Taiwan are subjected to fast tectonic activity, high precipitation rate and erosion rate. The combined annual river particle load from small rivers on the Island of Taiwan is higher than that of the Mississippi River. A large fraction of those rivers particle may finding its way into the surrounding seas and ocean, e.g. South China Sea, East China Sea, and the Philippine Sea. Furthermore, due to the nature of particle transportation off rivers from Taiwan were connected by a number of canyon systems close by the river mouth, majority of those river particles were facilitated in delivering and deposited later further into the South China Sea deep basin. The objectives of this study are to understand spatial variations in sedimentation rates and to resolve the temporal differences in sedimentation in the Northeastern South China Sea region, and to evaluate influence of small river particles to the marginal sea. A set of cores was collected in overlying water depth within 1600 - 3300 m for mutilsensor core logging of magnetic susceptibility, density, and porosity. Foraminifera (G. sacculifer, G. conglobatus, O. universa) were picked and AMS C14 analyses for age determination. Grain size, organic carbon, carbonate and biogenic silica content were measured. The results show that large sedimentation rates difference existed in the study area. Earlier studies on sedimentation rate in the region west of our study area were in range of about 10 cm/kyr while our rates are about 20-40 cm/kyr and much higher near Taiwan. Bulk sedimentation rate were higher during the transition period between LGM and Holocene and lower during Holocene. Our results demonstrated that large quantity of particles from small rivers in Taiwan are and were major source of particle and are the dominating factor in controlling sediment deposition in the northeastern South China Sea.

  17. From orogenic collapse to rifting ; structures of the South China Sea

    NASA Astrophysics Data System (ADS)

    Pubellier, M.; Chan, L. S.; Chamot Rooke, N.; Shen, W.; Ringenbach, J. C.

    2009-04-01

    The opening of the South China Sea has been a matter of debate for many years because of its internal structure, the differences between the conjugate margins and the variations of rifting and spreading directions. Although it is considered as being a back-arc basin, it is not sitting directly above a subduction zone, and the rifting process lasted for an unusually long duration. Among the specific characteristics is the early phase of rifting which took place early in place of the former Yanshanian andean-type mountain range. This stage is marked by narrow basins filled with deformed conglomerate, and initiated around 70My ago within a framework where the oblique subduction marked by igneous activity and ductile wrench faults, was replaced by orogenic collapse. The rifting stage is marked by Eocene syntectonic normal faults and occasional volcanics centres and has proceeded from NW-SE to NS extension. The NW stretching created at least two aborted basins which remained at rift stage. Extension was followed by spreading from 33 to ~20 Ma in the South China Sea. The ocean floor spreading also changed direction to NW-SE with a propagator inside the Sunda shelf from 20 to 17My ago. However the propagator opening implies that deformation is also taken by rifting around a southern wedge which in turn created strain inside the thinned crust. Another extension parallel to the margin is also observed althought the spreading was in process. The southward motion of the southern conjugate margin was later accommodated by its subduction beneath the NW Borneo wedge until completion of the Proto South China Sea subduction. Variations of rifting spreading through time and variations of structural styles are discussed in terms of boundary forces acting to the SE.

  18. A Preliminary Study in the Spratly, Southern Part of the South China Sea

    NASA Astrophysics Data System (ADS)

    Lee, C.

    2005-12-01

    From 20 June to 1 August (a total of 44 days) this year, a group of 8 scientists conducted a preliminary geological and geophysical study from the Taiping reef island, also called as the Ita Abu, owned by Taiwan. Since the Taiping Island is the biggest island (1,300 m in length, 400 m in width) in these some 102 reef islands, atolls, and sand bars in the southern part of the South China Sea. It is also the only island having the ground water and a hospital in a radius of 1,000 km of this tropical reef islands. Before the cruise, we requested the satellite images from the Taiwan-owned FORMOSA satellite in this region. During the survey, we acquired the echo sounding and side scan sonar data in the lagoon in order to give us a first topographical expression of the seafloor and to identify the dredge sites. Inside the wave break reef and beach site, we drilled several series of 30-cm cores, about 30 sites. Outside the wave break, we had a wonderful time to conduct many underwater photography and investigations. All of these efforts are aiming to get a better understanding of early rifting of the South China Sea and the evolution of reef growth in this tropical environment. Since the corals are the doctors of their living ecological system; they record the temperature, salinity, storm events, and El Nino. Our preliminary survey will provide a first glance of the last hundred and thousand years of our climate change. We will continue with our adventures. We also understand the political conflicts in this region. However, the Spratly islands hold the major key to reveal the sciences of the South China Sea, such as the early continental rifting, reef evolution, coral ecosystem, fishery resource and possible energy resource. We intend to open the Taiping Island as an International Marine Science Observatory.

  19. Effects of Kuroshio intrusions on nonlinear internal waves in the South China Sea during winter

    NASA Astrophysics Data System (ADS)

    Park, Jae-Hun; Farmer, David

    2013-12-01

    During winter the Kuroshio tends to cross Luzon Strait, penetrating the northeastern South China Sea where it forms energetic mesoscale structures. Luzon Strait is also a site where westward-propagating large-amplitude internal waves are generated. We describe observations of these waves acquired in the deep basin of the South China Sea during the winter of 2010-2011, with the goal of assessing the influence of mesoscale variability on their properties. Combining tidal current simulations with an internal wave generation and evolution model, we obtain time series of deviations between our observations and the model simulations. These deviations are analyzed in terms of mesoscale variability based on the data-assimilated HYbrid Coordinate Ocean Model (HYCOM) simulations. We find that simplified models of nonlinear internal wave response to changes in horizontal stratification gradients and vertical shear provide at best weak simulations of amplitude modulation. In contrast to these results, deviations of internal wave arrival time, occurring up to 2 h early during Kuroshio inflows, are quite well simulated when derived from integration of the first internal mode phase speed along two-dimensional ray-traced paths using HYCOM simulations of velocity and density fields together with bathymetry. Refraction of the internal waves by Kuroshio intrusions can lead to substantial distortion of the paths, sufficient to provide a potential explanation for the apparent suppression of waves during previous winter measurements. Our results suggest that the internal wave field can be a sensitive indicator of mesoscale variability in Luzon Strait and the northeastern South China Sea.

  20. Crustal structure and extension mode in the northwestern margin of the South China Sea

    NASA Astrophysics Data System (ADS)

    Gao, Jinwei; Wu, Shiguo; McIntosh, Kirk; Mi, Lijun; Liu, Zheng; Spence, George

    2016-06-01

    Combining multi-channel seismic reflection and gravity modeling, this study has investigated the crustal structure of the northwestern South China Sea margin. These data constrain a hyper-extended crustal area bounded by basin-bounding faults corresponding to an aborted rift below the Xisha Trough with a subparallel fossil ridge in the adjacent Northwest Sub-basin. The thinnest crust is located in the Xisha Trough, where it is remnant lower crust with a thickness of less than 3 km. Gravity modeling also revealed a hyper-extended crust across the Xisha Trough. The postrift magmatism is well developed and more active in the Xisha Trough and farther southeast than on the northwestern continental margin of the South China Sea; and the magmatic intrusion/extrusion was relatively active during the rifting of Xisha Trough and the Northwest Sub-basin. A narrow continent-ocean transition zone with a width of ˜65 km bounded seaward by a volcanic buried seamount is characterized by crustal thinning, rift depression, low gravity anomaly and the termination of the break-up unconformity seismic reflection. The aborted rift near the continental margin means that there may be no obvious detachment fault like that in the Iberia-Newfoundland type margin. The symmetric rift, extreme hyper-extended continental crust and hotter mantle materials indicate that continental crust underwent stretching phase (pure-shear deformation), thinning phase and breakup followed by onset of seafloor spreading and the mantle-lithosphere may break up before crustal-necking in the northwestern South China Sea margin.

  1. Recent organic carbon sequestration in the shelf sediments of the Bohai Sea and Yellow Sea, China

    NASA Astrophysics Data System (ADS)

    Hu, Limin; Shi, Xuefa; Bai, Yazhi; Qiao, Shuqing; Li, Li; Yu, Yonggui; Yang, Gang; Ma, Deyi; Guo, Zhigang

    2016-03-01

    This study provides an extensive depiction of regional scale sedimentary total organic carbon (TOC) sequestration in the Bohai Sea (BS) and Yellow Sea (YS), marginal system of the western Pacific Ocean. The spatial pattern of the sediment mass accumulation rate (MAR) in the BS and YS was summarized based on a 100-year timescale. The relatively higher MAR (3 - 7 g/cm2/y) in the Yellow River estuary, compared to the adjacent areas, indicate a predominant impact of river discharge on the modern sedimentation process in the BS. Relatively stable sedimentary environment in the offshore mud deposits of the BS and YS was also identified based on the along-core sediment composition and radionuclides profiles. The corresponding spatial pattern of grain size and TOC content suggest a hydrodynamic constraint on the sedimentary TOC accumulation. Moreover, in spite of the various TOC sources revealed by the bulk organic matter (OM) proxies (C/N ratio and δ13C), the restriction of these bulk parameters with potential masking of the signature of terrigenous OM was also identified. The average burial flux of TOC (15.3 g C/m2/y) was finally obtained with a total sequestration of 5.6 × 106 t C/y, suggesting that the BS and YS serve as a significant repository of sedimentary TOC. The overall organic carbon storage capacity of the BS and YS is mainly sustained by the fluvial/land-based OM input, high phytoplankton primary productivity, convergent hydrodynamic and stable depositional settings.

  2. Impact of atmospheric nitrogen deposition on phytoplankton productivity in the South China Sea

    NASA Astrophysics Data System (ADS)

    Kim, Tae-Wook; Lee, Kitack; Duce, Robert; Liss, Peter

    2014-05-01

    The impacts of anthropogenic nitrogen (N) deposition on the marine N cycle are only now being revealed, but the magnitudes of those impacts are largely unknown in time and space. The South China Sea (SCS) is particularly subject to high anthropogenic N deposition, because the adjacent countries are highly populated and have rapidly growing economies. Analysis of data sets for atmospheric N deposition, satellite chlorophyll-a (Chl-a), and air mass back trajectories reveals that the transport of N originating from the populated east coasts of China and Indonesia, and its deposition to the ocean, has been responsible for the enhancements of Chl-a in the SCS. We found that atmospheric N deposition contributed approximately 20% of the annual biological new production in the SCS. The airborne contribution of N to new production in the SCS is expected to grow considerably in the coming decades.

  3. Monitoring the burst-out of Enteromorpha prolifera in the Yellow Sea of China

    NASA Astrophysics Data System (ADS)

    Li, Haiying; Peng, Hongchun; Zhang, Hui; Huang, Chunlin

    2012-10-01

    In the eve of the Beijing Olympics Games, Qingdao in China, as the host city of OSC of Beijing 2008 Olympic Games, was surrounded by Enteromorpha prolifera, which was followed with interest by whole China and the world. The Enteromorpha often comes from other ocean, monitoring the drifting path of the Enteromorpha will become very important.The Study area is mainly the Yellow Sea. And the data sources are Terra MODIS 1B images from 2000-2010 years. The data preprocessing include BOW-TIE processing, image registration, clip, merge, and masking. And the NDVI was selected as the index of derived Enteromorpha prolifera information, to get the range of Enteromorpha prolifera, and get that of dynamic change with time, and monitor the drifting path of the Enteromorpha.

  4. Sediment deformation related to the submarine failure in northeastern South China Sea continental margin

    NASA Astrophysics Data System (ADS)

    Chiu, J.

    2012-12-01

    In northeastern South China Sea continental margin, geological structure is complex due to the passive continental margin meets the Taiwan mountain belt. Submarine slope failures, turbidity flows and so on are the main sedimentary processes in this continental slope, but these processes play different roles along the passive continental slope. So Chirp subbottom profiles, include analog and digital data, and cores collected in this region were analyzed to study the difference of sedimentation of the Late Quaternary. We found that more sediment deformations near seafloor, e.g. sediment layer pulled by sliding block and formed a shape like "pinch-out", were observed in the west region of the study area. This phenomenon could be related to finer sediments from mainland China, comparing with coarser sediments from Taiwan mountain belt deposited in the east region of the study area.

  5. Evidence for a fall raptor migration pathway across the South China Sea

    USGS Publications Warehouse

    Ellis, D.H.; Kepler, A.K.; Kepler, C.B.

    1990-01-01

    While conducting seabird surveys along the cruise track of the Soviet oceanographic Research Vessel Akademlk Korolev in the South China Sea in late October, 1988, we encountered about 150 land birds, including about 40 raptors. Most of the raptors were small accipiters, but we also recorded small numbers of Peregrine Falcons (Falco peregrinus) and Oriental Scops Owls (Otus sunia). We saw most of the raptors during a 3-day period in a restricted area ca 350 km southeast of the southern tip of the Indo-China Peninsula. The observations suggest that a significant raptor migration corridor exists between Viet Nam and Borneo. The behavior and body condition of the diurnal raptors suggest that they were in good health and were making extensive use of the ship for perching, roosting, and hunting.

  6. Spatial variation, fractionation and sedimentary records of mercury in the East China Sea.

    PubMed

    Duan, Li-Qin; Song, Jin-Ming; Yu, Yu; Yuan, Hua-Mao; Li, Xue-Gang; Li, Ning

    2015-12-15

    Surface and core sediments were collected to study distributions, phases and potential environmental risk of Hg and to reconstruct anthropogenic Hg change over the past one hundred years in the East China Sea (ECS). Hg contents in surface sediments displayed a decreasing gradient from the Changjiang Estuary to the outer sea. Sequential extraction analysis showed that Hg mainly existed as residual fraction (70.18% of total), and while organic matter fraction (22.96% of total) was the main component of labile fraction, indicating the strong adsorption of organic matters on Hg. Enrichment factor and sediment quality guidelines suggested that Hg in sediments of ECS were at minor enrichment and low adverse effect. Temporal distributions of total Hg content, labile fraction, burial flux and anthropogenic Hg flux showed that anthropogenic Hg input increased since the 1960s, which was related to riverine input and atmospheric transport. PMID:26475021

  7. Microphysical characteristics of sea fog over the east coast of Leizhou Peninsula, China

    NASA Astrophysics Data System (ADS)

    Zhao, Lijuan; Niu, Shengjie; Zhang, Yu; Xu, Feng

    2013-07-01

    Microphysical properties of sea fog and correlations of these properties were analyzed based on the measurements from a comprehensive field campaign carried out from 15 March to 18 April 2010 on Donghai Island (21°35″N, 110°32'5″E) in Zhanjiang, Guangdong Province, China. There were four types of circulation pattern in favor of sea fog events in this area identified, and the synoptic weather pattern was found to influence the microphysical properties of the sea fogs. Those influenced by a warm sector in front of a cold front or the anterior part of low pressure were found to usually have a much longer duration, lower visibility, greater liquid water content, and bigger fog droplet sizes. A fog droplet number concentration of N⩽1 cm-3 and liquid water content of L⩽0.001 g m-3 can be used to define sea fogs in this area. The type of fog droplet size distribution of the sea fog events was mostly monotonically-decreasing, with the spectrum width always being >20 μm. The significant temporal variation of N was due in large part to the number concentration variation of fog droplets with radius <3 μm. A strong collection process appeared when droplet spectrum width was >10 μm, which subsequently led to the sudden increase of droplet spectrum width. The dominant physical process during the sea fog events was activation with subsequent condensational growth or reversible evaporation processes, but turbulent mixing also played an important role. The collection process occurred, but was not vital.

  8. Decadal variability of chlorophyll a in the South China Sea: a possible mechanism

    NASA Astrophysics Data System (ADS)

    Liu, Fenfen; Chen, Chuqun; Zhan, Haigang

    2012-11-01

    Four climatologies on a monthly scale (January, April, May and November) of chlorophyll a within the South China Sea (SCS) were calculated using a Coastal Zone Color Scanner (CZCS) (1979-1983) and the Sea-viewing Wide Field-of-view Sensor (SeaWiFS) (1998-2002). We analyzed decadal variability of chlorophyll a by comparing the products of the two observation periods. The relationships of variability in chlorophyll a with sea surface wind speed (SSW), sea surface temperature (SST), wind stress (WS), and mixed layer depth (MLD) were determined. The results indicate that there is obvious chlorophyll a decadal variability in the SCS. The decadal chlorophyll a presents distinct seasonal variability in characteristics, which may be as a result of various different dynamic processes. The negative chlorophyll a concentration anomaly in January was associated with the warming of SST and a shallower MLD. Generally, there were higher chlorophyll a concentrations in spring during the SeaWiFS period compared with the CZCS period. However, the chlorophyll a concentration exhibits some regional differences during this season, leading to an explanation being diffi cult. The deepened MLD may have contributed to the positive chlorophyll a concentration anomalies from the northwestern Luzon Island to the northeastern region of Vietnam during April and May. The increases of chlorophyll a concentration in northwestern Borneo during May may be because the stronger SSW and higher WS produce a deeper mixed layer and convective mixing, leading to high levels of nutrient concentrations. The higher chlorophyll a off southeastern Vietnam may be associated with the advective transport of the colder water extending from the Karimata Strait to southeastern Vietnam.

  9. A 1400-year terrigenous dust record on a coral island in South China Sea

    PubMed Central

    Liu, Yi; Sun, Liguang; Zhou, Xin; Luo, Yuhan; Huang, Wen; Yang, Chengyun; Wang, Yuhong; Huang, Tao

    2014-01-01

    We present analyses of a lacustrine sediment core (DY6) on Dongdao Island, which provides high-resolution paleoclimate records for the South China Sea (SCS). Results of element analyses indicate that the concentrations of Ti and Al in DY6 are much higher than the background on the island. Morphological characteristics of acidic insoluble particles are similar to aeolian in East China. Sr and Nd isotope compositions in these particles are consistent with those in Asian aeolian dust. We inferred that dust in DY6 may have been transported by East Asian Winter Monsoon (EAWM) from inland Asia. The continuous dust records for the past 1400 years in North SCS were presented based on the measured Ti flux, which revealed an opposite trend to the variations in the EAWM for the past 50 years. A comparison of wind fields between cold and warm years shows that north surface wind in southeast China was stronger in cold years. However, 850 hPa wind vector along the east coast of China, the key level of wind for long-distance dust transmission, weakened in cold years. We conclude that differences in the EAWM records can be attributed to the 850 hPa wind pattern in different areas. PMID:24845372

  10. Acoustic mode coupling due to subaqueous sand dunes in the South China Sea.

    PubMed

    Chiu, Linus Y S; Reeder, D Benjamin

    2013-08-01

    The large subaqueous sand dunes on the upper continental slope of the South China Sea are expected to couple acoustic propagating normal modes. In this letter, the criterion of adiabatic invariance is extended to the case of a waveguide possessing bedforms. Using the extended criterion to examine mode propagation over the bedforms observed in the sand dune field in 2012, results demonstrate that bedforms increase mode coupling strength such that the criterion for adiabatic propagation is exceeded for waveguides with small bedform amplitude to water depth ratios; increasing bedform amplitude enhances mode coupling. Numerical simulations confirm the extended criterion parameterization. PMID:23927225

  11. Cytotoxic Bryostatin Derivatives from the South China Sea Bryozoan Bugula neritina.

    PubMed

    Yu, Hao-Bing; Yang, Fan; Li, Yan-Yun; Gan, Jian-Hong; Jiao, Wei-Hua; Lin, Hou-Wen

    2015-05-22

    Four new macrocyclic lactones, bryostatin 21 (1) and 9-O-methylbryostatins 4, 16, and 17 (2-4), together with three known related compounds, bryostatins 4, 16, and 17 (5-7), have been isolated from an extract of the South China Sea bryozoan Bugula neritina. The structures of all compounds were unambiguously elucidated using detailed spectroscopic analysis. Structurally, the presence of a single methyl group at C-18 in compound 1 has not been observed before for known bryostatins. The isolated macrolides exhibited inhibitory effects against a small panel of human cancer cell lines. PMID:25932671

  12. A new species of Amphictene (Annelida, Pectinariidae) from the northern South China Sea.

    PubMed

    Zhang, Jinghuai; Zhang, Yanjie; Qiu, Jian-Wen

    2015-01-01

    Pectinariids are a family of polychaetes commonly found in shallow coastal waters around the world, but their diversity is poorly known along the coasts of Asia. Here we describe Amphictene alata sp. n. (Pectinariidae), based on 15 specimens collected from the coastal waters of Guangdong in the northern South China Sea. This new species can be distinguished from all other 13 described species and one described subspecies of Amphictene by having a pair of dorsolateral lobes on segment 3, a pair of large lateral lobes on segment 21, and more scaphal hooks (26 to 37 pairs). PMID:26798291

  13. A new species of Eunice (Polychaeta: Eunicidae) from Hainan Island, South China Sea

    NASA Astrophysics Data System (ADS)

    Wu, Xuwen; Sun, Ruiping; Liu, Ruiyu

    2013-01-01

    A taxonomic survey of benthic marine animals from coastal regions of Hainan Island, South China Sea, revealed specimens of a new species of Eunice (Polychaeta: Eunicida: Eunicidae), Eunice uschakovi n. sp., collected from the intertidal zone. The species belongs to the group of Eunice that has yellow tridentate subacicular hooks and branchiae scattered over an extensive region of the body. It resembles E. miurai and E. havaica in having both bidentate and tridentate falcigers, but can be readily distinguished by branchial features. Comparisons between E. uschakovi and the two related species are presented.

  14. Implications of IODP Expedition 349 Age Results for the Spreading History of the South China Sea

    NASA Astrophysics Data System (ADS)

    Briais, Anne

    2016-04-01

    The International Ocean Discovery Program (IODP) Expedition 349 in the South China Sea drilled three sites (U1431, U1433, and U1434) into the basaltic crustal basement near the fossil spreading center in the East and Southwest Subbasins. These results provided age constraints on the termination of seafloor spreading in the South China Sea (SCS) basin. Shipboard biostratigraphic analysis of microfossils from the sediment immediately above or between flows in the basaltic basement indicates early Miocene ages: 16.7-17.6 Ma for Site U1431 in the East Subbasin, ~18-21 Ma for Site U1433 in the Southwest Subbasin. Since Expedition 349, Ar/Ar dating of basalt samples from these two sites have confirmed these ages in the east, and have provided an age of 17 Ma in the Southwest. The similarity in crustal age between sites suggests that the last stages of spreading have been coeaval in both the East and Southwest Subbasins, forming a single mid-ocean ridge system with a series of transform faults and discontinuities between the two subbasins. Expedition 349 also drilled Site U1435 on a bathymetric high along the northwestern continent-ocean boundary. Onboard core description, biostratigraphy and magnetostratigraphy revealed that sediment at this site shows a sharp discontinuity at about 33 Ma, interpreted to represent the breakup unconformity and date the beginning of seafloor spreading in the East Subbasin. The results of IODP Exp. 349, as well as results from deep-towed magnetic surveys, thus imply that oceanic seafloor spreading in the SCS, from 33 to ~16-18 Ma, is coeval with a large part of the left-lateral motion along the Ailao Shan-Red River Fault Zone (dated 34 to 17 Ma). This episode of the extension of the South China Sea basin is therefore more likely driven by the extrusion of the Indochina tectonic block resulting from the collision of India with Eurasia than by the subduction of a proto-South China Sea to the south.

  15. New record of Lobophora rosacea (Dictyotales; Phaeophyceae) from the South China Sea

    NASA Astrophysics Data System (ADS)

    Sun, Zhongmin; Wang, Yongqiang; Yan, Pengcheng; Guo, Hui; Yao, Jianting; Tanaka, Jiro; Kawai, Hiroshi

    2016-04-01

    Lobophora rosacea C.W. Vieira, Payri et De Clerck is reported from the South China Sea for the first time. Our specimens are very similar to L. rosacea recently described from New Caledonia, not only in morphology but also in rbcL and cox3 gene sequences. The fan-shaped thallus grows erectly, attaching to the substrate by a basal holdfast. The thallus is composed of a single layer of large medullary cells and three to four layers of cortical cells on both sides of the medulla. Mature sporophytes are detected, with sporangium sori scattered on both surfaces of the thallus.

  16. Resonant interaction of acoustic waves with subaqueous bedforms: Sand dunes in the South China Sea.

    PubMed

    Chiu, Linus Y S; Chang, Andrea Y Y; Reeder, D Benjamin

    2015-12-01

    The large subaqueous sand dunes in the South China Sea are expected to produce the coupling of energy between acoustic normal modes. In this letter, resonant interaction between acoustic propagating modes and subaqueous bedforms are numerically investigated as a function of bedform wavelength, acoustic frequency and bedform packet length. The results demonstrate that bedform wavelength impacts acoustic mode coupling behavior, with the principal transfer of energy occurring between acoustic modes whose eigenvalue difference is equal to the peak value in the bedform wavenumber spectrum. The observed effect of wavelength is greater than that of acoustic frequency and bedform packet length. PMID:26723360

  17. Atmospheric Transport and Deposition of Nitrogen Compounds From the Asian Continent Over the East China Sea

    NASA Astrophysics Data System (ADS)

    Uematsu, M.; Nakamura, T.; Endo, M.; Narita, Y.

    2004-12-01

    The growth of economy and population is rapid among in the east Asian countries. Within two decades, emission from east Asia could roughly account for half of the nitrogen released to the atmosphere from all anthropogenic sources worldwide. The Asia/western Pacific region has a unique mixture of aerosols and trace gases because of these distinctive patterns of emissions in combination with the local meteorological conditions affecting the region. Continental outflows can alter bilogical and chemical processes along the coastal Asia and, therefore, modify biogeochemical fluxes and feedbacks that may have serious implications to human health and climate implications. We made atmospheric measurements on board R/V Hakuho Maru over the western North Pacific and the East China Sea from 26 September to 9 October 2002 (the KH02-3 Cruise) in the autumn and from 4 to 20 March 2004 (the KH04-1 Cruise) in the spring. The atmospheric deposition fluxes of nitrogen compounds (ammonium, nitrate, and organic N) to the marine environment were investigated as a part of the IGBP/SOLAS project. Size segregated ambient aerosols (d<2.5μ m and d>2.5μ m) were collected at every 4-12 hours intervals on a PTFE fiber filter by using a high-volume dichotomous virtual impactor air sampler. Atmospheric average total ammonium concentration over the East China Sea was 2.3 μ g N m-3, and that of nitrate was 0.48 μ g N m-3. However, >90 percent of paticulate ammonium occurred in the fine fraction whereas >80 percent of particulate nitrate was in the coarse fraction. By using empirical dry deposition velocities for two size categories, we estimated the ammonium and nitrate dry deposition fluxes over the East China Sea to be 160 Gg N yr-1 and 270 Gg N yr-1, respectively. Our results clearly show that particle size is critical for different components and flux estimation. The atmospheric inputs of the nitrogen compounds to the East China Sea are found to be comparable to their fluxes of 190 Gg N yr

  18. A new species of Amphictene (Annelida, Pectinariidae) from the northern South China Sea

    PubMed Central

    Zhang, Jinghuai; Zhang, Yanjie; Qiu, Jian-Wen

    2015-01-01

    Abstract Pectinariids are a family of polychaetes commonly found in shallow coastal waters around the world, but their diversity is poorly known along the coasts of Asia. Here we describe Amphictene alata sp. n. (Pectinariidae), based on 15 specimens collected from the coastal waters of Guangdong in the northern South China Sea. This new species can be distinguished from all other 13 described species and one described subspecies of Amphictene by having a pair of dorsolateral lobes on segment 3, a pair of large lateral lobes on segment 21, and more scaphal hooks (26 to 37 pairs). PMID:26798291

  19. A new species of Praebebalia (Crustacea: Brachyura: Leucosiidae) from East China Sea

    NASA Astrophysics Data System (ADS)

    Chen, Hui-Lian; Fang, Shao-Hua

    2000-12-01

    A new species of the genus Praebebalia from the East China Sea, belonging to the subfamily Ebaliinae Stimpson, 1871, is described. It is characterized by carapace being broader than long, the dorsal surface without sharp granules near borders, the median part of anterolateral borders with a notch, the junction of anterolateral and posterolateral borders with a tubercle, the posterior border with a triangular tubercle on each side, the propodi of anterior 3 pairs of ambulatory legs with a tubercle and the fingers of chelipeds being longer than palm.

  20. Polychlorinated biphenyl (PCB) congeners in Mussel and other mollusc from Da Chen Island, East China Sea

    SciTech Connect

    Chu, S.G.; Xi, Z.Q.; Xu, X.B

    1995-11-01

    Polychlorinated biphenyls (PCBs) are among the most persistent and toxic pollutants in environment. Determination of these contaminants in fish, shellfish and other mollusc is very important, not only because these aquatics are important food for mankind, but also because they can bioconcentrate contaminants preferentially in their adipose tissue, and serve as biomarker of the aquatic pollution. Mussels and oysters have been widely used to monitor the pollution in the coastal environment. The aim of the study was to investigate the concentrations and the main source of PCBs in mussels and other mollusca from the coastal areas of East China Sea. 10 refs., 3 figs., 2 tabs.

  1. New evidence from the South China Sea for an abrupt termination of the last glacial period

    NASA Technical Reports Server (NTRS)

    Broecker, W. S.; Klas, M.; Andree, M.; Bonani, G.; Wolfli, W.

    1988-01-01

    Results demonstrating an abrupt change in the rate and character of sedimentation in the South China Sea at the close of the last glacial period are presented. Radiocarbon dating and its position in the oxygen isotope shift suggest that this change may be coincident with the abrupt change in climatic conditions seen at high latitudes in the North Atlantic and the Antarctic at 13 kyr BP. These results support the contention that a major global climatic change occurred between 14 and 13 kyr BP.

  2. A new species of Lataxiena Jousseaume, 1883 (Gastropoda: Muricidae) from the East and South China Seas

    NASA Astrophysics Data System (ADS)

    Zhang, Suping; Zhang, Shuqian

    2015-03-01

    A new muricid gastropod species, Lataxiena lutescena sp. nov., is described and illustrated. The new species was recognized during reidentification of the Muricidae collection in the Marine Biological Museum, Chinese Academy of Sciences, Qingdao. The specimens of the new species were collected from the East and South China Seas off Fujian, Guangdong, and Hainan Provinces. Lataxiena lutescena sp. nov. is similar to Lataxiena blosvillei (Deshayes, 1832) in general shape, but can be distinguished from the latter by the shell sculpture and radular characteristics. Lataxiena lutescena sp. nov. also resembles Lataxiena bombayana (Melvill, 1893), but differs from that species in the shell shape and anal notches and in lacking short spines on the shell.

  3. The presence of natural radioactivity and 137Cs in the South China Sea bordering peninsular Malaysia.

    PubMed

    Amin, Y M; Mahat, R H; Nor, R M; Khandaker, Mayeen Uddin; Takleef, Ghazwa Hatem; Bradley, D A

    2013-10-01

    The presence of natural radioactivity and (137)Cs has been investigated in fresh media obtained from South China Sea locations off the coast of peninsular Malaysia. The media include seafood, sea water and sediment. The samples were collected some weeks prior to the devastating 2011 Tōhoku earthquake and associated tsunami, the occurrence of which precipitated the Fukushima incident. All samples showed the presence of naturally occurring (226)Ra, (228)Ra and primordial (40)K, all at typically prevailing levels. The concentrations of natural radioactivity in molluscs were found to be greater than that of other marine life studied herein, the total activity ranging from 337 to 393 Bq kg(-1) dry weight. The total activity in sea water ranged from 15 to 88 Bq l(-1). Sediment samples obtained at deep sea locations more than 20 km offshore further revealed the presence of (137)Cs. The activity of (137)Cs varied from ND to 0.5 Bq kg(-1) dry weight, the activity increasing with offshore distance and depth. The activity concentrations presented herein should be considered useful in assessing the impact of any future radiological contamination to the marine environment. PMID:23584496

  4. An analysis of the current deflection around Dongsha Islands in the northern South China Sea

    NASA Astrophysics Data System (ADS)

    Wang, Dongxiao; Wang, Qiang; Zhou, Weidong; Cai, Shuqun; Li, Li; Hong, Bo

    2013-01-01

    Based on the in situ data and ADCP observation in fall, it is found that a northeastward current at inter-middle level flows on the Northern South China Sea (NSCS) continental shelf. This current flows almost along the isobaths, and it deflects from the isobaths veering toward deep water when flowing over the Dongsha Islands. Geographic currents derived from the climatologic hydrography data (WOA01) and absolute dynamic topography (ADT) data confirm the deflection of the northeastward current on NSCS continent. A fine resolution regional ocean model which can well reproduce the large scale circulation in the NSCS is used to analyze the dynamic about the deflection. The vorticity term balances shows that JEBAR (Joint Effect of Baroclinicity and Relief) drives the water column to depart from the isobaths. To the east of the Dongsha Islands, the isopycnal is almost orthogonal to the isobaths. The joint effect of the topographic and the baroclinic effect supplies negative vorticity and drives the water column to deflect from the isobaths and veer to deeper water. Momentum analysis along the stream line shows that, when the sea water flows around the Dongsha islands, the pressure gradient along the isobath pushes the sea water to accelerate, and then the Coriolis force orthogonal to the isobath increases and overcomes the corresponding pressure gradient, which drives the water deflected from the isobath toward the deep sea.

  5. Empirical prediction of the onset dates of South China Sea summer monsoon

    NASA Astrophysics Data System (ADS)

    Zhu, Zhiwei; Li, Tim

    2016-05-01

    The onset of South China Sea summer monsoon (SCSSM) signifies the commencement of the wet season over East Asia. Predicting the SCSSM onset date is of significant importance. In this study, we establish two different statistical models, namely the physical-empirical model (PEM) and the spatial-temporal projection model (STPM) to predict the SCSSM onset. The PEM is constructed from the seasonal prediction perspective. Observational diagnoses reveal that the early onset of the SCSSM is preceded by (a) a warming tendency in middle and lower troposphere (850-500 hPa) over central Siberia from January to March, (b) a La Niña-like zonal dipole sea surface temperature pattern over the tropical Pacific in March, and (c) a dipole sea level pressure pattern with negative center in subtropics and positive center over high latitude of Southern Hemisphere in January. The PEM built on these predictors achieves a cross-validated reforecast temporal correlation coefficient (TCC) skill of 0.84 for the period of 1979-2004, and an independent forecast TCC skill of 0.72 for the period 2005-2014. The STPM is built on the extended-range forecast perspective. Pentad data are used to predict a zonal wind index over the South China Sea region. Similar to PEM, the STPM is constructed using 1979-2004 data. Based on the forecasted zonal wind index, the independent forecast of the SCSSM onset dates achieves a TCC skill of 0.90 for 2005-2014. The STPM provides more detailed information for the intraseasonal evolution during the period of the SCSSM onset (pentad 25-35). The two models proposed herein are expected to facilitate the real-time prediction of the SCSSM onset.

  6. Impacts of earthquake on atoll in Nansha Islands, South China Sea

    NASA Astrophysics Data System (ADS)

    Guo, Lei; Zhan, Wenhuan; Xiong, Lijia; Chen, Wujin; Yao, Yantao; Li, Jian

    2016-04-01

    Coral reef is a kind of rock soil masses. It is a special marine geotechnical medium, which are made up of the reef coral debris undergo very long geological age. Atoll is the predominant type of coral reefs in South China Sea. In recent years, there are more and more construction projects on the reef flat in Nansha Islands, South China Sea. Therefore, it is very important to estimate the stability of coral reefs, especially the atolls. According to the geological structure characters of atoll in Nansha Islands, a model of reef body is presented in this paper to study the influence of earthquake. Meanwhile, Geostudio, which is a popular geotechnical engineering simulation software, is used to stimulate the stress and deformation situation of reef body under different six kinds of earthquake intensity. The factor of safety can be calculated by the limit equilibrium method. And the possible scenario of earthquake-induced landslides and sliding scale can be defined through the Newmark sliding block method. The stress distribution and deformation behavior are studied. The main relations between atoll and earthquake are analyzed as follows: (1) the safety factor of reef slope exceeds 1.993 under self-gravity state; (2) It may cause slope's instability and bring slumping when the safety factor is less than one. The factor of safety decreases with increased earthquake intensity and it may fluctuate around a particular value when earthquake intensity continues to increase; (3) The smaller shallow landslide as new developed part of the reef is subject to collapse under earthquake action and the bigger slope of reef is more stable. The results show that it is feasible to evaluate the stability of coral reef by using geotechnical engineering simulation method, which can help to provide some information for construction on coral reefs in South China Sea. In the meantime,the authers wish to thank the National Natural Science Foundation of China (NO.41376063)and the National

  7. Distribution and Sea-to-air Flux of Nitrous Oxide in the East China Sea during the Summer of 2013

    NASA Astrophysics Data System (ADS)

    Wang, Lan; Zhang, Guiling; Zhu, Zhuoyi; Li, Jia; Liu, Sumei; Ye, Wangwang; Han, Yu

    2016-07-01

    Dissolved nitrous oxide (N2O) at different depths of 73 stations in the Changjiang (Yangtze River) Estuary and the East China Sea (ECS) were determined from August 4 to 31 of 2013, and the sea-to-air fluxes of N2O were also estimated in this study. N2O concentrations in the surface waters ranged from 6.33 to 44.40 nmol L-1 with an average of (9.27±4.30) nmol L-1 and the values in the bottom waters ranged from 5.19 to 26.98 nmol L-1 with an average of (11.87±3.71) nmol L-1. The concentrations of N2O decreased with distance from the Changjiang Estuary to the open sea. The vertical distributions of N2O indicated great spatial variations. A region of significant bottom-water hypoxia, with oxygen concentration less than 1.5 mg L-1, occurred at the north of the ECS, and increased bottom N2O concentrations was observed. Frequent vertical mixing may enhance the emission of N2O from this hypoxic area. N2O in the surface waters of all stations were over-saturated, and the N2O saturations ranged from 106% to 658%, with an average of (149±62)%. We estimated the sea-to-air fluxes of N2O as (30.6±59.1) μmol m-2 d-1 from the Changjiang Estuary, (9.8±8.8) μmol m-2 d-1 from the coastal and shelf, and (21.0±12.7) μmol m-2 d-1 from the continental slope using the Wanninkhof 1992 equation, (24.9±47.2) μmol m-2 d-1, (8.0±6.7) μmol m-2 d-1 and (16.5±9.6) μmol m-2 d-1 using the Nightingale 2000 equation, respectively. N2O emission from the ECS was estimated to be about (8.2-16.0)×10-2 Tg-N2O yr-1, suggesting that the ECS was a significant net source of atmospheric N2O.

  8. Observation of Directional Ocean Wave Spectra in China Seas and Northwest Pacific Ocean Using SAR Retrieval Software

    NASA Astrophysics Data System (ADS)

    Liu, Xiaoyan; Zeng, Kan; He, Mingxia

    2014-11-01

    A software to retrieve directional ocean wave spectra from SAR images has been developed for China seas and northwest Pacific. The software, written with C programming language, is based on the MPI method proposed by Hasselmann. It is designed to support the wave mode SAR data of ERS, Envisat, Sentinel and so on. The directional ocean wave spectra produced by this software are validated with buoy data in global ocean area, northwest Pacific and China seas and the retrieved significant wave height (SWH) errors are 5.2%, 4.9% and 9.3% respectively. About 15,000 directional ocean wave spectra are obtained with the software from the wave mode data of Envisat/ASAR over the China seas and northwest Pacific during the period between Jan 2003 and Jan 2012. The preliminary analysis is presented.

  9. SEAS: Student Experiments At Sea - An Education Outreach Pilot Program Sponsored by the Ridge2000 Program

    NASA Astrophysics Data System (ADS)

    Goehring, L.

    2004-12-01

    SEAS is a pilot program for middle and high school students who want to learn science by doing science. SEAS students study the deep sea hydrothermal vent environment and learn to ask questions about this exciting, relatively unexplored world, just as researchers do. SEAS students also learn how to answer their own questions through the process of scientific investigation. With the SEAS program, students have the opportunity to participate in the actual discovery process, along side deep-sea researchers. SEAS builds upon the successes of programs like Dive&Discover and Extreme2000, which demonstrated the capability deep-sea scientists have in engaging students with live research. SEAS extends this concept by inviting students to participate in deep-sea research through formal proposal and report competitions. SEAS challenges students to higher levels of achievement. A curriculum, developed by teachers expert in the translation of scientific inquiry in the classroom, prepares students to participate. SEAS was concept-tested during the 2003-2004 school year, with 14 pilot teachers and approximately 800 students. Twenty Ridge2000 scientists contributed their time and expertise to the SEAS program in its first year. Five student proposals were selected and conducted at sea in April during a Ridge2000 research cruise to the East Pacific Rise. All results were posted to the SEAS website (http://www.ridge2000.org/SEAS/) during the cruise, and students were invited to analyze data for their final reports. Final student reports, along with scientists comments were also posted. During the 2004-2005 school year, SEAS will be evaluated for its impact on student learning and attitudes toward science. The benefits of SEAS to the Ridge2000 scientific community are many. Scientists are invited to contribute in a variety of ways, all of which help satisfy the requirement of NSFs Broader Impacts Criterion. They may contribute time and expertise by answering student questions and

  10. Anammox, denitrification and dissimilatory nitrate reduction to ammonium in the East China Sea sediment

    NASA Astrophysics Data System (ADS)

    Song, G. D.; Liu, S. M.; Marchant, H.; Kuypers, M. M. M.; Lavik, G.

    2013-11-01

    Benthic nitrogen transformation pathways were investigated in the sediment of the East China Sea (ECS) in June of 2010 using the 15N isotope pairing technique. Slurry incubations indicated that denitrification, anammox and dissimilatory nitrate reduction to ammonium (DNRA) as well as intracellular nitrate release occurred in the ECS sediments. These four processes did not exist independently, nitrate release therefore diluted the 15N labeling fraction of NO3-, and a part of the 15NH4+ derived from DNRA also formed 30N2 via anammox. Therefore, current methods of rate calculations led to over and underestimations of anammox and denitrification respectively. Following the procedure outlined in Thamdrup and Dalsgaard (2002), denitrification rates were slightly underestimated by an average 6% without regard to the effect of nitrate release, while this underestimation could be counteracted by the presence of DNRA. On the contrary, anammox rates calculated from 15NO3- experiment were significantly overestimated by 42% without considering nitrate release. In our study, this overestimation could only be compensated 14% by taking DNRA into consideration. In a parallel experiment amended with 15NH4++14NO3-, anammox rates were not significantly influenced by DNRA due to the high background of 15NH4+ addition. The significant correlation between potential denitrification rate and sediment organic matter content (r = 0.68, p < 0.001, Pearson) indicated that denitrification was regulated by organic matter, while, no such correlations were found for anammox and DNRA. The relative contribution of anammox to the total N-loss increased from 13% at the shallowest site near the Changjiang estuary to 50% at the deepest site on the outer shelf, implying the significant role of anammox in benthic nitrogen cycling in the ECS sediments, especially on the outer shelf. N-loss as N2 was the main pathway, while DNRA was also an important pathway accounting for 20-31% of benthic nitrate

  11. Double SST fronts observed from MODIS data in the East China Sea off the Zhejiang-Fujian coast, China

    NASA Astrophysics Data System (ADS)

    He, Shuangyan; Huang, Daji; Zeng, Dingyong

    2016-02-01

    We report a double coastal front system off the Zhejiang (Zhe) and Fujian (Min) Provinces in the East China Sea in winter. In addition to the well-known Zhe-Min offshore coastal front along 50 m isobath, a secondary near-shore coastal thermal front along 20 m isobath is also apparent in December and January. The fronts were observed by Moderate Resolution Imaging Spectroradiometer (MODIS) at monthly mean nighttime sea surface temperature (SST) during 2000-2013 in terms of SST gradients. Our results showed temporal and spatial variations of the two fronts as follows: (1) both offshore front and near-shore front often co-exist between 26.5°N and 29.5°N in December and between 28.0°N and 29.5°N in January. However, only the offshore front is apparent in November and February. (2) The near-shore front is narrow (4-16 km), while the offshore front is three to four times wider (16-48 km). (3) In contrast to the well-known offshore front which exists throughout the winter with a strong intensity, the near-shore front has a shorter lifetime with a weak intensity, and has been overlooked by previous studies. Finally, we proposed that the bottom bathymetric gradients may play an important role in the frontogenesis of the double fronts.

  12. Multi-Scale Interactions Associated with the Monsoon Onset Over South China Sea and Adjacent Regions during SCSMEX-98

    NASA Technical Reports Server (NTRS)

    Lau, William K. M.; Li, X.; Wu, H.-T.

    1999-01-01

    Using data collected during The South China Sea Monsoon Experiment (SCSMEX) (1998) as well as from the TRMM Microwave-Imager (TMI) and precipitation radar (PR), we have studied the multi-scale interactions (meso-synoptic-intraseasonal) associated with monsoon onset over South China Sea (SCS) and its subsequent evolution. Results show that the monsoon onset (defined by development of steady wind direction and heavy precipitation) over the northern SCS occurred around May 15 -17. Prevailing southerlies and southwesterlies developed over the central SCS after May 20. Shortly after, monsoon convection developed over the whole SCS region around May 23-27. The entire onset process appeared to be delayed by about a week to 10 days compared with climatology. During late spring of 1998, mid-latitude frontal systems were particularly active. These systems strongly impacted the northern SCS convection and may have been instrumental in triggering the onset of the SCS monsoon. The Tropical Oceans and Global Atmosphere (TOGA) and Bureau of Meteorology Research Centre (BMRC) radar showed a wide variety of convective systems over the Intensive Flux Array, from frontal bands to shear-banded structure, deep convection, pop-corn type shallow convection, slow moving "fine lines" to water spout. Analysis of SSM/I wind and moisture data suggested that the delayed convective activity over the SCS may be linked to the weakened northward propagation of monsoon rain band, hence contributing to a persistence of the rainband south of the Yangtze River and the disastrous flood that occurred over this region during mid to late June, 1998.

  13. Seismic ambient noise around the South China Sea: seasonal and spatial variations, and implications for its climate and surface circulation

    NASA Astrophysics Data System (ADS)

    Huo, Da; Yang, Ting

    2013-12-01

    With its strong seasonal variation in wave climate and various bathymetric features due to the complex tectonics, the South China Sea (SCS) provides a natural laboratory to study the microseism. We collected data from seismic stations around the SCS and calculated their noise spectra, through which seasonal and spatial variations of microseism, as well as the general feature of seismic ambient noise in this marginal sea were revealed. Microseism seasonal variations in general reflect influences of the East Asian monsoon in winter and the Indian monsoon in summer, respectively. The two microseism components, the single frequency microseism (SFM) and the double frequency microseism (DFM), show striking alternating variation patterns both seasonally and spatially. These variation patterns, along with the bathymetric feature near the stations, indicate SFM and DFM are generated through different physical mechanisms. More interestingly, seasonal and spatial variations of DFM appear to be consistent with the basin-scale surface circulation model of the SCS, in which the upper SCS experiences cyclonic in winter and anti-cyclonic in summer. These consistencies provide observational evidence for the hypothesis that the cyclonic depression is a favorable condition to generate DFM.

  14. Physical-biological oceanographic coupling influencing phytoplankton and primary production in the South China Sea

    NASA Astrophysics Data System (ADS)

    Ning, X.; Chai, F.; Xue, H.; Cai, Y.; Liu, C.; Shi, J.

    2004-10-01

    Two cruises were carried out in the summer and winter of 1998 to study coupled physical-chemical-biological processes in the South China Sea and their effects on phytoplankton stock and production. The results clearly show that the seasonal distributions of phytoplankton were closely related to the coupled processes driven by the East Asian Monsoon. Summer southwesterly monsoon induced upwelling along the China and Vietnam coasts. Several mesoscale cyclonic cold eddies and anticyclonic warm pools were identified in both seasons. In the summer, the upwelling and cold eddies, both associated with rich nutrients, low dissolved oxygen (DO), high chlorophyll a (Chl a) and primary production (PP), were found in the areas off the coast of central Vietnam, southeast of Hainan Island and north of the Sunda shelf, whereas in the winter they form a cold trough over the deep basin aligning from southwest to northeast. The warm pools with poor nutrients, high DO, low Chl a, and PP were found in the areas southeast of Vietnam, east of Hainan, and west of Luzon during the summer, and a northwestward warm jet from the Sulu Sea with properties similar to the warm pools was encountered during the winter. The phytoplankton stock and primary production were lower in summer due to nutrient depletion near the surface, particularly PO4. This phosphorus depletion resulted in phytoplankton species succession from diatoms to dinoflagellates and cyanophytes. A strong subsurface Chl a maximum, dominated by photosynthetic picoplankton, was found to contribute significantly to phytoplankton stocks and production.

  15. Structural evolution of the northern East China Sea Shelf Basin interpreted from cross-section restoration

    NASA Astrophysics Data System (ADS)

    Cukur, Deniz; Horozal, Senay; Lee, Gwang H.; Kim, Dae C.; Han, Hyun C.; Kang, Moo H.

    2011-09-01

    The northern East China Sea Shelf Basin consists of three depressions (the Domi, Jeju, and Socotra Depressions), separated by basement highs or rises. Reconstruction of depth-converted seismic reflection profiles from these depressions reveals that the northern East China Sea Shelf Basin experienced two phases of rifting, followed by regional subsidence. Initial rifting in the Late Cretaceous was driven by the NW-SE crustal stretching of the Eurasian plate, caused by the subduction of the Pacific plate beneath the plate margin. Major extension (~15 km) took place during the early phase of basin formation. The initial rifting was terminated by regional uplift in the Late Eocene-Early Oligocene, which was probably due to reorganization of plate boundaries. Rifting resumed in the Early Oligocene; the magnitude of extension was mild (<1 km) during this period. A second phase of uplift in the Early Miocene terminated the rifting, marking the transition to the postrift phase of regional subsidence. Up to 2,600 m of sediments and basement rock were removed by erosion during and after the second phase of uplift. An inversion in the Late Miocene interrupted the postrift subsidence, resulting in an extensive thrust-fold belt in the eastern part of the area. Subsequent erosion removed about 900 m of sediments. The regional subsidence has dominated the area since the Late Miocene.

  16. Benthic fluxes of dissolved organic carbon from gas hydrate sediments in the northern South China Sea

    NASA Astrophysics Data System (ADS)

    Hung, Chia-Wei; Huang, Kuo-Hao; Shih, Yung-Yen; Lin, Yu-Shih; Chen, Hsin-Hung; Wang, Chau-Chang; Ho, Chuang-Yi; Hung, Chin-Chang; Burdige, David J.

    2016-07-01

    Hydrocarbon vents have recently been reported to contribute considerable amounts of dissolved organic carbon (DOC) to the oceans. Many such hydrocarbon vents widely exist in the northern South China Sea (NSCS). To investigate if these hydrocarbon vent sites release DOC, we used a real-time video multiple-corer to collect bottom seawater and surface sediments at vent sites. We analyzed concentrations of DOC in these samples and estimated DOC fluxes. Elevated DOC concentrations in the porewaters were found at some sites suggesting that DOC may come from these hydrocarbon vents. Benthic fluxes of DOC from these sediments were 28 to 1264 μmol m‑2 d‑1 (on average ~321 μmol m‑2 d‑1) which are several times higher than most DOC fluxes in coastal and continental margin sediments. The results demonstrate that the real-time video multiple-corer can precisely collect samples at vent sites. The estimated benthic DOC flux from the methane venting sites (8.6 × 106 mol y‑1), is 24% of the DOC discharge from the Pearl River to the South China Sea, indicating that these sediments make an important contribution to the DOC in deep waters.

  17. Rifting of the north-western South China Sea Basin from MCS images

    NASA Astrophysics Data System (ADS)

    Ranero, Cesar R.; Cameselle, Alejandra L.; Franke, Dieter; Barckhausen, Udo

    2014-05-01

    We have reprocessed about 2250 km of multichannel seismic reflection data collected during cruise Sonne 49 across the NW South China Sea. We present images across four regional lines that cross the outer continental shelf and slope, and extend into the deep-water basin. The seismic images are of high quality and show the crustal structure from clear base-of-the-crust reflections to continuous top-of-basement reflections and a well imaged syn-rift and post rift stratigraphy and intrusive magmatic layering. In addition, fault reflections in the basement are also common. The crystalline basement and sediment strata display a series of structures that change laterally from the continental shelf to the deep-water basin and that have been used to define a continental domain, an abrupt continent to ocean transition and an oceanic domain. Existing wide-angle data coincident with our lines support our interpretation. The style of continental extension, the structures defining the continent to ocean transition, and the distribution of oceanic crust in the basin has been used to propose a tectonic model of the formation of the NW South China Sea continental margin. The data document the three-dimensional temporal evolution of the interplay between rifting processes and seafloor spreading leading to the current structural configuration.

  18. Acceleration of modern acidification in the South China Sea driven by anthropogenic CO₂.

    PubMed

    Liu, Yi; Peng, Zicheng; Zhou, Renjun; Song, Shaohua; Liu, Weiguo; You, Chen-Feng; Lin, Yen-Po; Yu, Kefu; Wu, Chung-Che; Wei, Gangjian; Xie, Luhua; Burr, George S; Shen, Chuan-Chou

    2014-01-01

    Modern acidification by the uptake of anthropogenic CO2 can profoundly affect the physiology of marine organisms and the structure of ocean ecosystems. Centennial-scale global and regional influences of anthropogenic CO2 remain largely unknown due to limited instrumental pH records. Here we present coral boron isotope-inferred pH records for two periods from the South China Sea: AD 1048-1079 and AD 1838-2001. There are no significant pH differences between the first period at the Medieval Warm Period and AD 1830-1870. However, we find anomalous and unprecedented acidification during the 20th century, pacing the observed increase in atmospheric CO2. Moreover, pH value also varies in phase with inter-decadal changes in Asian Winter Monsoon intensity. As the level of atmospheric CO2 keeps rising, the coupling global warming via weakening the winter monsoon intensity could exacerbate acidification of the South China Sea and threaten this expansive shallow water marine ecosystem. PMID:24888785

  19. Benthic fluxes of dissolved organic carbon from gas hydrate sediments in the northern South China Sea

    PubMed Central

    Hung, Chia-Wei; Huang, Kuo-Hao; Shih, Yung-Yen; Lin, Yu-Shih; Chen, Hsin-Hung; Wang, Chau-Chang; Ho, Chuang-Yi; Hung, Chin-Chang; Burdige, David J.

    2016-01-01

    Hydrocarbon vents have recently been reported to contribute considerable amounts of dissolved organic carbon (DOC) to the oceans. Many such hydrocarbon vents widely exist in the northern South China Sea (NSCS). To investigate if these hydrocarbon vent sites release DOC, we used a real-time video multiple-corer to collect bottom seawater and surface sediments at vent sites. We analyzed concentrations of DOC in these samples and estimated DOC fluxes. Elevated DOC concentrations in the porewaters were found at some sites suggesting that DOC may come from these hydrocarbon vents. Benthic fluxes of DOC from these sediments were 28 to 1264 μmol m−2 d−1 (on average ~321 μmol m−2 d−1) which are several times higher than most DOC fluxes in coastal and continental margin sediments. The results demonstrate that the real-time video multiple-corer can precisely collect samples at vent sites. The estimated benthic DOC flux from the methane venting sites (8.6 × 106 mol y−1), is 24% of the DOC discharge from the Pearl River to the South China Sea, indicating that these sediments make an important contribution to the DOC in deep waters. PMID:27432631

  20. Eutrophication-Driven Hypoxia in the East China Sea off the Changjiang Estuary.

    PubMed

    Wang, Hongjie; Dai, Minhan; Liu, Jinwen; Kao, Shuh-Ji; Zhang, Chao; Cai, Wei-Jun; Wang, Guizhi; Qian, Wei; Zhao, Meixun; Sun, Zhenyu

    2016-03-01

    Coastal hypoxia is an increasingly recognized environmental issue of global concern to both the scientific community and the general public. We assessed the relative contributions from marine and terrestrially sourced organic matter that were responsible for oxygen consumption in a well-studied seasonal coastal hypoxic zone, the East China Sea off the Changjiang Estuary. Our fieldwork was conducted in August 2011 during reinstatement of a subsurface hypoxia, when we observed a continuous decline of dissolved oxygen along with production of dissolved inorganic carbon resulting from organic carbon remineralization. On the basis of a three end-member mixing model and determinations of the stable isotopic compositions of dissolved inorganic carbon (δ(13)CDIC), the end product of particulate organic carbon (POC) degradation, we quantified the δ(13)C value of the remineralized organic carbon (δ(13)COCx), which was -18.5 ± 1.0‰. This isotopic composition was very similar to the δ(13)C of marine sourced POC produced in situ (-18.5 ± 0.3‰) rather than that of the terrestrially sourced POC (-24.4 ± 0.2‰). We concluded that marine-sourced organic matter, formed by eutrophication-induced marine primary production, was the dominant oxygen consumer in the subsurface hypoxic zone in the East China Sea off the Changjiang Estuary. PMID:26824328

  1. DDTs and HCHs in sediment cores from the coastal East China Sea.

    PubMed

    Lin, Tian; Nizzetto, Luca; Guo, Zhigang; Li, Yuanyuan; Li, Jun; Zhang, Gan

    2016-01-01

    Four sediment cores were collected along the Yangtze-derived sediment transport pathway in the inner shelf of the East China Sea (ECS) for OCP analysis. The sediment records of HCHs and DDTs in estuarine environment reflected remobilization of chemicals from enhanced soil erosion associated to extreme flood events or large scale land use transformation. The sediment records in the open sea, instead, reflected long-term historical trends of OCP application in the source region. Unlike the so-called mud wedge distribution of sediment, inventories of HCHs and DDTs slightly increased from the mouth of Yangtze River alongshore toward south, suggesting the sediment deposition rate was one of factors on the exposure of chemicals within the inner shelf of the ECS. Re-suspension and transport of the Yangtze-derived sediment and consequent fractionation in grain size and TOC were also responsible for the spatial variation of inventories of catchment derived OCPs in a major repository area of the Yangtze suspended sediment. The total burdens of HCHs and DDTs in the inner shelf of the ECS were 35tons and 110tons, respectively. After 1983 (year of the official ban in China), those values were 13tons and 50tons, respectively. It appears that the Yangtze still delivers relatively high inputs of DDTs more than 30years after the official ban. High proportions of DDD+DDE and β-HCH suggested those OCPs mainly originated from historical usage in the catchment recent years. PMID:26372941

  2. Detecting the red tide based on remote sensing data in optically complex East China Sea

    NASA Astrophysics Data System (ADS)

    Xu, Xiaohui; Pan, Delu; Mao, Zhihua; Tao, Bangyi; Liu, Qiong

    2012-09-01

    Red tide not only destroys marine fishery production, deteriorates the marine environment, affects coastal tourist industry, but also causes human poison, even death by eating toxic seafood contaminated by red tide organisms. Remote sensing technology has the characteristics of large-scale, synchronized, rapid monitoring, so it is one of the most important and most effective means of red tide monitoring. This paper selects the high frequency red tides areas of the East China Sea as study area, MODIS/Aqua L2 data as the data source, analysis and compares the spectral differences in the red tide water bodies and non-red tide water bodies of many historical events. Based on the spectral differences, this paper develops the algorithm of Rrs555/Rrs488> 1.5 to extract the red tide information. Apply the algorithm on red tide event happened in the East China Sea on May 28, 2009 to extract the information of red tide, and found that the method can determine effectively the location of the occurrence of red tide; there is a good corresponding relationship between red tide extraction result and chlorophyll a concentration extracted by remote sensing, shows that these algorithm can determine effectively the location and extract the red tide information.

  3. Acceleration of modern acidification in the South China Sea driven by anthropogenic CO2

    NASA Astrophysics Data System (ADS)

    Liu, Yi; Peng, Zicheng; Zhou, Renjun; Song, Shaohua; Liu, Weiguo; You, Chen-Feng; Lin, Yen-Po; Yu, Kefu; Wu, Chung-Che; Wei, Gangjian; Xie, Luhua; Burr, George S.; Shen, Chuan-Chou

    2014-06-01

    Modern acidification by the uptake of anthropogenic CO2 can profoundly affect the physiology of marine organisms and the structure of ocean ecosystems. Centennial-scale global and regional influences of anthropogenic CO2 remain largely unknown due to limited instrumental pH records. Here we present coral boron isotope-inferred pH records for two periods from the South China Sea: AD 1048-1079 and AD 1838-2001. There are no significant pH differences between the first period at the Medieval Warm Period and AD 1830-1870. However, we find anomalous and unprecedented acidification during the 20th century, pacing the observed increase in atmospheric CO2. Moreover, pH value also varies in phase with inter-decadal changes in Asian Winter Monsoon intensity. As the level of atmospheric CO2 keeps rising, the coupling global warming via weakening the winter monsoon intensity could exacerbate acidification of the South China Sea and threaten this expansive shallow water marine ecosystem.

  4. Acceleration of modern acidification in the South China Sea driven by anthropogenic CO2

    PubMed Central

    Liu, Yi; Peng, Zicheng; Zhou, Renjun; Song, Shaohua; Liu, Weiguo; You, Chen-Feng; Lin, Yen-Po; Yu, Kefu; Wu, Chung-Che; Wei, Gangjian; Xie, Luhua; Burr, George S.; Shen, Chuan-Chou

    2014-01-01

    Modern acidification by the uptake of anthropogenic CO2 can profoundly affect the physiology of marine organisms and the structure of ocean ecosystems. Centennial-scale global and regional influences of anthropogenic CO2 remain largely unknown due to limited instrumental pH records. Here we present coral boron isotope-inferred pH records for two periods from the South China Sea: AD 1048–1079 and AD 1838–2001. There are no significant pH differences between the first period at the Medieval Warm Period and AD 1830–1870. However, we find anomalous and unprecedented acidification during the 20th century, pacing the observed increase in atmospheric CO2. Moreover, pH value also varies in phase with inter-decadal changes in Asian Winter Monsoon intensity. As the level of atmospheric CO2 keeps rising, the coupling global warming via weakening the winter monsoon intensity could exacerbate acidification of the South China Sea and threaten this expansive shallow water marine ecosystem. PMID:24888785

  5. Vertical distribution and indications of lipids biomarkers in the sediment core from East China Sea

    NASA Astrophysics Data System (ADS)

    Wang, Rui; Wang, Jiangtao; Li, Feng; Yang, Shu; Tan, Liju

    2016-07-01

    To study the distribution and indications of lipids biomarkers in the mud areas of the East China Sea shelf, a sediment core was collected. Lipids were determined to find the origination of different organic matter (fatty acids and sterols) inputs. The results demonstrated that the distribution of fatty acids and sterols indicated the organic matter derived from the mixed allochthonous and autochthonous sources, but mainly autochthonous. The total fatty acids concentrations ranged from 29.08 μg g-1 to 303.92 μg g-1 and exhibited unimodal distribution with the predominance of C16-fatty acid. Neutral lipid concentrations ranged from 1.77 μg g-1 to 4.65 μg g-1. Furthermore, the distribution patterns of sterols varied with depth, and were dominated by C27-sterol and C29-sterol in the top and bottom sediments respectively. Although bacterial lipids were recruited during diagenesis, the refractory terrestrial lipids were usually preferentially preserved. This records dated from the 1980s suggested that the phytoplankton community was mainly influenced by eutrophication in the East China Sea and this variation may be recorded by lipid biomarkers deposited in the sediment.

  6. Actinomycetes from the South China Sea sponges: isolation, diversity, and potential for aromatic polyketides discovery

    PubMed Central

    Sun, Wei; Zhang, Fengli; He, Liming; Karthik, Loganathan; Li, Zhiyong

    2015-01-01

    Marine sponges often harbor dense and diverse microbial communities including actinobacteria. To date no comprehensive investigation has been performed on the culturable diversity of the actinomycetes associated with South China Sea sponges. Structurally novel aromatic polyketides were recently discovered from marine sponge-derived Streptomyces and Saccharopolyspora strains, suggesting that sponge-associated actinomycetes can serve as a new source of aromatic polyketides. In this study, a total of 77 actinomycete strains were isolated from 15 South China Sea sponge species. Phylogenetic characterization of the isolates based on 16S rRNA gene sequencing supported their assignment to 12 families and 20 genera, among which three rare genera (Marihabitans, Polymorphospora, and Streptomonospora) were isolated from marine sponges for the first time. Subsequently, β-ketoacyl synthase (KSα) gene was used as marker for evaluating the potential of the actinomycete strains to produce aromatic polyketides. As a result, KSα gene was detected in 35 isolates related to seven genera (Kocuria, Micromonospora, Nocardia, Nocardiopsis, Saccharopolyspora, Salinispora, and Streptomyces). Finally, 10 strains were selected for small-scale fermentation, and one angucycline compound was detected from the culture extract of Streptomyces anulatus strain S71. This study advanced our knowledge of the sponge-associated actinomycetes regarding their diversity and potential in producing aromatic polyketides. PMID:26483773

  7. Spatial and Vertical Variability in Bacterial Community Structure in the Sediment of the South China Sea

    NASA Astrophysics Data System (ADS)

    Wang, P.; Xie, W.; Chen, S.; Zhang, C. L.

    2014-12-01

    The ocean subsurface contains one of the largest pools of reactive carbon and nitrogen on earth, and thus serves as the largest realm for microbial life. However, the microbial communities that drive deep-subsurface geochemical processes are vastly unexplored. In this study, the bacterial community structure in the subsurface of the South China Sea were examined using sediment cores collected from shelf (water depth 667 m) to slope (water depth 3840 m). High-throughput sequencing of the bacterial 16S rRNA genes from the sediment samples resulted in a total of 270,000 sequences with each sample averaging about 10,000 sequences. In all sediment cores, the 16S rRNA gene copies of bacteria were highest in the surface sediment and decreased with the core depth. The bacterial community was dominated by Proteobacteria, Bacteroidetes, Actinobacteria, and Firmicutes. In most of the sediment cores, Proteobacteria dominated surface sediment samples and decreased with depth. The community structure showed no significant difference among the stations at different water depths, which indicates that bacterial distribution in the sediment is not influenced by the water column above. However, stations along the transect from Pearl River canyon to the deep basin were grouped together by cluster analysis, which indicates that bacterial community structure at these stations may bear the same consequence of sedimentary processes of the deep South China Sea.

  8. Spatio-temporal variations in the siphonophore community of the northern South China Sea

    NASA Astrophysics Data System (ADS)

    Li, Kaizhi; Yin, Jianqiang; Huang, Liangmin; Lian, Shumin; Zhang, Jianlin

    2013-03-01

    To understand how hydrological and biological factors affect near- to off-shore variations in the siphonophore community, we sampled zooplankton at 82 stations in the northern South China Sea during summer, winter, and spring. Forty-one species of siphonophore were collected by vertical trawling. The species richness of siphonophores increased from the nearshore to offshore regions in all three seasons of investigation, with maximum richness in summer and minimum richness in winter. The abundance of siphonophores was also higher in summer than in spring and winter, concentrated in the nearshore region in the warm season and scattered in the offshore region in the cold season. Four siphonophore groups were classified according to the frequency of occurrence: nearshore, near-offshore, offshore, and tropical pelagic. Among them, the nearshore group had higher abundance nearshore compared with the offshore. The tropical pelagic group had higher species number offshore than nearshore. Spatial and temporal fluctuations in taxonomic composition and abundance of siphonophores were due to the influence of the coastal upwelling and surface ocean currents of the South China Sea, driven by the East Asia monsoonal system.

  9. Benthic fluxes of dissolved organic carbon from gas hydrate sediments in the northern South China Sea.

    PubMed

    Hung, Chia-Wei; Huang, Kuo-Hao; Shih, Yung-Yen; Lin, Yu-Shih; Chen, Hsin-Hung; Wang, Chau-Chang; Ho, Chuang-Yi; Hung, Chin-Chang; Burdige, David J

    2016-01-01

    Hydrocarbon vents have recently been reported to contribute considerable amounts of dissolved organic carbon (DOC) to the oceans. Many such hydrocarbon vents widely exist in the northern South China Sea (NSCS). To investigate if these hydrocarbon vent sites release DOC, we used a real-time video multiple-corer to collect bottom seawater and surface sediments at vent sites. We analyzed concentrations of DOC in these samples and estimated DOC fluxes. Elevated DOC concentrations in the porewaters were found at some sites suggesting that DOC may come from these hydrocarbon vents. Benthic fluxes of DOC from these sediments were 28 to 1264 μmol m(-2 )d(-1) (on average ~321 μmol m(-2 )d(-1)) which are several times higher than most DOC fluxes in coastal and continental margin sediments. The results demonstrate that the real-time video multiple-corer can precisely collect samples at vent sites. The estimated benthic DOC flux from the methane venting sites (8.6 × 10(6 )mol y(-1)), is 24% of the DOC discharge from the Pearl River to the South China Sea, indicating that these sediments make an important contribution to the DOC in deep waters. PMID:27432631

  10. Impacts of South East Biomass Burning on local air quality in South China Sea

    NASA Astrophysics Data System (ADS)

    Wai-man Yeung, Irene; Fat Lam, Yun; Eniolu Morakinyo, Tobi

    2016-04-01

    Biomass burning is a significant source of carbon monoxide and particulate matter, which is not only contribute to the local air pollution, but also regional air pollution. This study investigated the impacts of biomass burning emissions from Southeast Asia (SEA) as well as its contribution to the local air pollution in East and South China Sea, including Hong Kong and Taiwan. Three years (2012 - 2014) of the Hybrid Single Particle Lagrangian-Integrated Trajectory (HYSPLIT) with particles dispersion analyses using NCEP (Final) Operational Global Analysis data (FNL) data (2012 - 2014) were analyzed to track down all possible long-range transport from SEA with a sinking motion that worsened the surface air quality (tropospheric downwash from the free troposphere). The major sources of SEA biomass burning emissions were first identified using high fire emissions from the Global Fire Emission Database (GFED), followed by the HYSPLIT backward trajectory dispersion modeling analysis. The analyses were compared with the local observation data from Tai Mo Shan (1,000 msl) and Tap Mun (60 msl) in Hong Kong, as well as the data from Lulin mountain (2,600 msl) in Taiwan, to assess the possible impacts of SEA biomass burning on local air quality. The correlation between long-range transport events from the particles dispersion results and locally observed air quality data indicated that the background concentrations of ozone, PM2.5 and PM10 at the surface stations were enhanced by 12 μg/m3, 4 μg/m3 and 7 μg/m3, respectively, while the long-range transport contributed to enhancements of 4 μg/m3, 4 μg/m3 and 8 μg/m3 for O3, PM2.5 and PM10, respectively at the lower free atmosphere.

  11. Air-sea CO2 fluxes in the East China Sea based on multiple-year underway observations

    NASA Astrophysics Data System (ADS)

    Guo, X.-H.; Zhai, W.-D.; Dai, M.-H.; Zhang, C.; Bai, Y.; Xu, Y.; Li, Q.; Wang, G.-Z.

    2015-09-01

    This study reports the most comprehensive data set thus far of surface seawater pCO2 (partial pressure of CO2) and the associated air-sea CO2 fluxes in a major ocean margin, the East China Sea (ECS), based on 24 surveys conducted in 2006 to 2011. We showed highly dynamic spatial variability in sea surface pCO2 in the ECS except in winter, when it ranged across a narrow band of 330 to 360 μatm. We categorized the ECS into five different domains featuring with different physics and biogeochemistry to better characterize the seasonality of the pCO2 dynamics and to better constrain the CO2 flux. The five domains are (I) the outer Changjiang estuary and Changjiang plume, (II) the Zhejiang-Fujian coast, (III) the northern ECS shelf, (IV) the middle ECS shelf, and (V) the southern ECS shelf. In spring and summer, pCO2 off the Changjiang estuary was as low as < 100 μatm, while it was up to > 400 μatm in autumn. pCO2 along the Zhejiang-Fujian coast was low in spring, summer and winter (300 to 350 μatm) but was relatively high in autumn (> 350 μatm). On the northern ECS shelf, pCO2 in summer and autumn was > 340 μatm in most areas, higher than in winter and spring. On the middle and southern ECS shelf, pCO2 in summer ranged from 380 to 400 μatm, which was higher than in other seasons (< 350 μatm). The area-weighted CO2 flux on the entire ECS shelf was -10.0 ± 2.0 in winter, -11.7 ± 3.6 in spring, -3.5 ± 4.6 in summer and -2.3 ± 3.1 mmol m-2 d-1 in autumn. It is important to note that the standard deviations in these flux ranges mostly reflect the spatial variation in pCO2 rather than the bulk uncertainty. Nevertheless, on an annual basis, the average CO2 influx into the entire ECS shelf was 6.9 ± 4.0 mmol m-2 d-1, about twice the global average in ocean margins.

  12. Air-sea CO2 fluxes in the East China Sea based on multiple-year underway observations

    NASA Astrophysics Data System (ADS)

    Guo, X.-H.; Zhai, W.-D.; Dai, M.-H.; Zhang, C.; Bai, Y.; Xu, Y.; Li, Q.; Wang, G.-Z.

    2015-04-01

    This study reports thus far a most comprehensive dataset of surface seawater pCO2 (partial pressure of CO2) and the associated air-sea CO2 fluxes in a major ocean margin, the East China Sea (ECS) based on 24 surveys conducted in 2006 to 2011. We showed highly dynamic spatial variability of sea surface pCO2 in the ECS except in winter when it ranged in a narrow band of 330 to 360 μatm. In this context, we categorized the ECS into five different domains featured with different physics and biogeochemistry to better characterize the seasonality of the pCO2 dynamics and to better constrain the CO2 flux. The five domains are (I) the outer Changjiang estuary and Changjiang plume, (II) the Zhejiang-Fujian coast, (III) the northern ECS shelf, (IV) the middle ECS shelf, and (V) the southern ECS shelf. In spring and summer, pCO2 off the Changjiang estuary was as low as < 100 μatm, while it was up to > 400 μatm in fall. pCO2 along the Zhejiang-Fujian coast was low in spring, summer and winter (300 to 350 μatm) but was relatively high in fall (> 350 μatm). In the northern ECS shelf, pCO2 in summer and fall was > 340 μatm in most areas, higher than in winter and spring. In the middle and southern ECS shelf, pCO2 in summer ranged from 380 to 400 μatm, which was higher than in other seasons (< 350 μatm). The area-weighted CO2 flux in the entire ECS shelf was -10.0 ± 2.0 mmol m-2 d-1 in winter, -11.7 ± 3.6 mmol m-2 d-1 in spring, -3.5 ± 4.6 mmol m-2 d-1 in summer and -2.3 ± 3.1 mmol m-2 d-1 in fall. It is important to note that the standard deviations in these flux ranges mostly reflect the spatial variation of pCO2, which differ from the spatial variance nor the bulk uncertainty. Nevertheless, on an annual basis, the average CO2 influx into the entire ECS shelf was -6.9 ± 4.0 mmol m-2 d-1, about twice the global average in ocean margins.

  13. Sequence stratigraphy and continental margin development of the northwestern shelf of the South China Sea

    SciTech Connect

    Chen, P.P.H. ); Zhi Yuong Chen; Qi Min Zhang )

    1993-05-01

    Based on the sequence stratigraphic analyses of the Tertiary in the northwestern continental margin of the South China Sea, this paper summarizes the regional tectonics and their influences on the basin developments and discusses the systems tract distributions through the continental margin growth. The study area is underlain by two Tertiary basins separated by a major basin boundary fault across which two distinctly different basin structural styles developed. The Qiongdongnan basin shows characteristic rift structures and is closely related to the opening of the South China Sea. The Yinggehai basin is filled with thick Neogene monoclines overlying basement without apparent rift structures. The Yinggehai's genesis has been linked to the tectonism along the Red River suture zone. The margin development is characterized by depositional environments of sediment influx constantly exceeding accommodation space. Under these environments, the highstand deltas frequently developed near shelf edges, where vertically stacked shallow water sands of both highstand deltas and lowstand wedges/deltas could produce favorable exploration targets. High rates of sedimentation in the study area allow the identification of fourth-order cyclicity in the Quaternary. Regional sequence stratigraphic correlations suggest that many sequence boundaries appear to be synchronous, but not all boundaries exist in all basins along the eastern and southern continental margins of mainland China. The margin evolved through the repeated development of lowstand fans, lowstand wedges, transgressive systems tracts, and highstand deltas. Prior to the Pliocene, the shelf was sourced both from Vietnam and Hainan Island and, as a result, two shelf margins developed. The southwestern margin stopped growing in the late Miocene, and the northern margin continued to prograde with possible additional sediment inputs through the Red River system in the Quaternary. 29 refs., 22 figs.

  14. Regime shift of the South China Sea SST in the late 1990s

    NASA Astrophysics Data System (ADS)

    Thompson, Bijoy; Tkalich, Pavel; Malanotte-Rizzoli, Paola

    2016-05-01

    Decadal variability of the South China Sea (SCS) sea surface temperature (SST) during 1982-2014 is investigated using observations and ocean reanalysis datasets. The SCS SST shows an abrupt transition from a cold-to-warm regime in the late 1990s. Based on the long-term SST variability two epochs are defined, 1982-1996 and 2000-2014 as cold and warm regimes respectively, spanning on either side of the 1997-1999 SCS warming. Despite the occurrence of strong El Nino induced warming events, the SST anomalies tend to be negative in the cold regime. Conversely during the warm regime, the positive SST anomalies have dominated over the La Nina driven cooling events. The cold (warm) SST regime is marked by net heat gain (loss) by the SCS. The long-term variations of net surface heat flux are mainly driven by the latent heat flux anomalies while the short wave flux plays a secondary role. Low-frequency variability of the South China Sea throughflow (SCSTF) appears to be closely related to the SCS SST regime shift. The SCSTF shows reversing trends during the cold and warm epochs. The weakened SCSTF in the warm regime has promoted the SCS warming by limiting the outward flow of warm water from the SCS. Meanwhile, enhanced SCSTF during the cold regime acts as a cooling mechanism and lead to persistent negative SST anomalies. The change in trend of the SCSTF and SST regime shift coincides with the switching of pacific decadal oscillation from a warm to cold phase in the late 1990s.

  15. Tides and Their Dynamics over the Sunda Shelf of the Southern South China Sea.

    PubMed

    Daryabor, Farshid; Ooi, See Hai; Abu Samah, Azizan; Akbari, Abolghasem

    2016-01-01

    A three-dimensional Regional Ocean Modelling System is used to study the tidal characteristics and their dynamics in the Sunda Shelf of the southern South China Sea. In this model, the outer domain is set with a 25 km resolution and the inner one, with a 9 km resolution. Calculations are performed on the inner domain. The model is forced at the sea surface by climatological monthly mean wind stress, freshwater (evaporation minus precipitation), and heat fluxes. Momentum and tracers (such as temperature and salinity) are prescribed in addition to the tidal heights and currents extracted from the Oregon State University TOPEX/Poseidon Global Inverse Solution (TPXO7.2) at the open boundaries. The results are validated against observed tidal amplitudes and phases at 19 locations. Results show that the mean average power energy spectrum (in unit m2/s/cph) for diurnal tides at the southern end of the East Coast of Peninsular Malaysia is approximately 43% greater than that in the East Malaysia region located in northern Borneo. In contrast, for the region of northern Borneo the semidiurnal power energy spectrum is approximately 25% greater than that in the East Coast of Peninsular Malaysia. This implies that diurnal tides are dominant along the East Coast of Peninsular Malaysia while both diurnal and semidiurnal tides dominate almost equally in coastal East Malaysia. Furthermore, the diurnal tidal energy flux is found to be 60% greater than that of the semidiurnal tides in the southern South China Sea. Based on these model analyses, the significant tidal mixing frontal areas are located primarily off Sarawak coast as indicated by high chlorophyll-a concentrations in the area. PMID:27622552

  16. Contrasting Photophysiological Characteristics of Phytoplankton Assemblages in the Northern South China Sea.

    PubMed

    Jin, Peng; Gao, Guang; Liu, Xin; Li, Futian; Tong, Shanying; Ding, Jiancheng; Zhong, Zhihai; Liu, Nana; Gao, Kunshan

    2016-01-01

    The growth of phytoplankton and thus marine primary productivity depend on photophysiological performance of phytoplankton cells that respond to changing environmental conditions. The South China Sea (SCS) is the largest marginal sea of the western Pacific and plays important roles in modulating regional climate and carbon budget. However, little has been documented on photophysiological characteristics of phytoplankton in the SCS. For the first time, we investigated photophysiological characteristics of phytoplankton assemblages in the northern South China Sea (NSCS) using a real-time in-situ active chlorophyll a fluorometry, covering 4.0 × 105 km2. The functional absorption cross section of photosystem II (PSII) in darkness (σPSII) or under ambient light (σPSII') (A2 quanta-1) increased from the surface to deeper waters at all the stations during the survey period (29 July to 23 August 2012). While the maximum (Fv/Fm, measured in darkness) or effective (Fq'/Fm', measured under ambient light) photochemical efficiency of PSII appeared to increase with increasing depth at most stations, it showed inverse relationship with depth in river plume areas. The functional absorption cross section of PSII changes could be attributed to light-adapted genotypic feature due to niche-partition and the alteration of photochemical efficiency of PSII could be attributed to photo-acclimation. The chlorophyll a fluorometry can be taken as an analog to estimate primary productivity, since areas of higher photochemical efficiency of PSII coincided with those of higher primary productivity reported previously in the NSCS. PMID:27195824

  17. Contrasting Photophysiological Characteristics of Phytoplankton Assemblages in the Northern South China Sea

    PubMed Central

    Liu, Xin; Li, Futian; Tong, Shanying; Ding, Jiancheng; Zhong, Zhihai; Liu, Nana; Gao, Kunshan

    2016-01-01

    The growth of phytoplankton and thus marine primary productivity depend on photophysiological performance of phytoplankton cells that respond to changing environmental conditions. The South China Sea (SCS) is the largest marginal sea of the western Pacific and plays important roles in modulating regional climate and carbon budget. However, little has been documented on photophysiological characteristics of phytoplankton in the SCS. For the first time, we investigated photophysiological characteristics of phytoplankton assemblages in the northern South China Sea (NSCS) using a real-time in-situ active chlorophyll a fluorometry, covering 4.0 × 105 km2. The functional absorption cross section of photosystem II (PSII) in darkness (σPSII) or under ambient light (σPSII’) (A2 quanta-1) increased from the surface to deeper waters at all the stations during the survey period (29 July to 23 August 2012). While the maximum (Fv/Fm, measured in darkness) or effective (Fq’/Fm’, measured under ambient light) photochemical efficiency of PSII appeared to increase with increasing depth at most stations, it showed inverse relationship with depth in river plume areas. The functional absorption cross section of PSII changes could be attributed to light-adapted genotypic feature due to niche-partition and the alteration of photochemical efficiency of PSII could be attributed to photo-acclimation. The chlorophyll a fluorometry can be taken as an analog to estimate primary productivity, since areas of higher photochemical efficiency of PSII coincided with those of higher primary productivity reported previously in the NSCS. PMID:27195824

  18. Five Sarsiellidae ostracods (Crustacea: Myodocopida) from the South Coast of Korea (East China Sea).

    PubMed

    Karanovic, Ivana; Soh, Ho-Young

    2015-01-01

    The East China Sea is part of the Warm Temperate Northwest Pacific zoogeographic province and, as such, has a high biodiversity and many tropical and subtropical biotic elements. Nevertheless, many invertebrate groups from this area remain poorly studied. Ostracods are one of them, especially those belonging to the subclass Myodocopa. In this paper we provide the first data on a diverse myodocopid family, Sarsiellidae, not only for the East China Sea, but also for Korea. Five species are reported in this paper from three Korean islands (Jeju, Chuja, and Maemul), and they are only a part of the ostracods collected during this study, indicating a high diversity of the group in this region. Three new species, Eurypylus koreanus sp. nov., Eusarsiella hanguk sp. nov., and Sarsiella nereis sp. nov., clearly stand apart from their respective congeners, mostly by prominent shell characters but also by details of the soft part morphology. Their affinity though clearly indicates a close connection of the region with the more southern zoogeographical realms, especially Central Indo Pacific and partly Temperate Australasia. Two species previously known from Japan (north part of the Sea of Japan and southeastern part of the Pacific Coast of Japan), Sarsiella japonica Hiruta, 1977 and S. misakiensis Kajiyama, 1912, are redescribed. Based on 11 newly obtained COI sequences we construct a preliminary phylogenetic tree, which supports previous hypotheses based on the morphological data, that Eusarsiella Cohen & Kornicker, 1975 is a polyphyletic taxon. With the maps of species distribution provided for each of the three genera, we give an overview of their current zoogeography, and clearly indicate areas that have no data, mostly due to the lack of investigation. PMID:25947749

  19. Seasonal migration of Cnaphalocrocis medinalis (Lepidoptera: Crambidae) over the Bohai Sea in northern China.

    PubMed

    Fu, X-W; Li, C; Feng, H-Q; Liu, Z-F; Chapman, J W; Reynolds, D R; Wu, K-M

    2014-10-01

    The rice leaf roller, Cnaphalocrocis medinalis (Guenée), is a serious insect pest of rice with a strong migratory ability. Previous studies on the migration of C. medinalis were mostly carried out in tropical or subtropical regions, however, and what the pattern of seasonal movements this species exhibits in temperate regions (i.e. Northern China, where they cannot overwinter) remains unknown. Here we present data from an 11-year study of this species made by searchlight trapping on Beihuang Island (BH, 38°24'N; 120°55'E) in the centre of the Bohai Strait, which provides direct evidence that C. medinalis regularly migrates across this sea into northeastern agricultural region of China, and to take advantage of the abundant food resources there during the summer season. There was considerable seasonal variation in number of C. medinalis trapped on BH, and the migration period during 2003-2013 ranged from 72 to 122 days. Some females trapped in June and July showed a relatively higher proportion of mated and a degree of ovarian development suggesting that the migration of this species is not completely bound by the 'oogenesis-flight syndrome'. These findings revealed a new route for C. medinalis movements to and from Northeastern China, which will help us develop more effective management strategies against this pest. PMID:24901755

  20. [Levels and sources of gaseous polybrominated diphenyl ethers in air over the northern South China Sea].

    PubMed

    Li, Qi-lu; Li, Jun; Liu, Xiang; Xu, Wei-hai; Zhang, Gan

    2012-08-01

    A total of 32 air samples collected during a Shiyan III voyage over the northern South China Sea (SCS) were analyzed for polybrominated diphenyl ethers (PBDEs) by gas chromatography/mass spectrometry. The concentrations of sigma 7 PBDEs ranged from 0.07 to 35.9 pg x m(-3). The sigma 7 PBDEs were dominated by tetra-(BDE-47) and penta-(BDE-99 and -100) components, which accounted for 51.5% and 36.9%, respectively. This result indicated that the widely used commercial penta-BDE product was the original source. The higher concentrations of PBDEs were monitored close to the coastline of the South China and Philippine, while the lower concentrations were found over the SCS adjacent to central coast of Vietnam. Back trajectory analysis showed that the high PBDE concentrations observed in air over the northern SCS may be related to the continental pollutant outflows from the southeast coast of China, especially the Pearl River Delta, Taiwan and Philippine, by prevailing northeast wind transport. PMID:23213869

  1. Tsunami hazards along Chinese coast from potential earthquakes in South China Sea

    NASA Astrophysics Data System (ADS)

    Liu, Yingchun; Santos, Angela; Wang, Shuo M.; Shi, Yaolin; Liu, Hailing; Yuen, David A.

    2007-08-01

    The pair of earthquakes off Taiwan on December 26, 2006 and the subsequent disruption of the Internet traffic have called attention to the potential destructive hazards along the Chinese coast from tsunamis. Historical records show past tsunami earthquakes in this region. Using GPS, earthquake focal mechanisms and geological evolution, we have delineated the dangerous zones in the Philippine Sea plate where major earthquakes may occur. The Manila Trench is identified as being most susceptible to future major earthquakes. We have obtained the local Gutenberg-Richter relationship for five sections along the Philippine Sea plate boundary and use this information for determining the probability distribution for tsunami waves of various heights to impinge on various Chinese cities. We devise a new method called the probabilistic forecast of tsunami hazard (PFTH), which determines this probability distribution by direct numerical simulation of the waves excited by hypothetical earthquakes in these zones. We have employed the linear shallow-water equations over the South China Sea. We have also compared them with results from the nonlinear version and found that the linear treatment serves our purpose sufficiently well. In the next century the probability of a wave with a height of over 2.0 m to hit near-coast ocean of Hong Kong and Macau is about 10%. Cities in Taiwan are less vulnerable than those on the mainland coast.

  2. [Monitoring "green tide" in the Yellow Sea and the East China Sea using multi-temporal and multi-source remote sensing images].

    PubMed

    Xing, Qian-Guo; Zheng, Xiang-Yang; Shi, Ping; Hao, Jia-Jia; Yu, Ding-Feng; Liang, Shou-Zhen; Liu, Dong-Yan; Zhang, Yuan-Zhi

    2011-06-01

    Landsat-TM (Theme Mapper) and EOS (Earth Observing System)-MODIS (MODerate resolution Imaging Spectrora-diometer) Terra/Aqua images were used to monitor the macro-algae (Ulva prolifera) bloom since 2007 at the Yellow Sea and the East China Sea. At the turbid waters of Northern Jiangsu Shoal, there is strong spectral mixing behavior, and satellite images with finer spatical resolution are more effective in detection of macro-algae patches. Macro-algae patches were detected by the Landsat images for the first time at the Sheyang estuary where is dominated by very turbid waters. The MODIS images showed that the macro-algae from the turbid waters near the Northern Jiangsu Shoal drifted southwardly in the early of May and affected the East China Sea waters; with the strengthening east-asian Summer Monsoon, macro-algae patches mainly drifted in a northward path which was mostly observed at the Yellow Sea. Macro-algae patches were also found to drift eastwardly towards the Korea Peninsular, which are supposed to be driven by the sea surface wind. PMID:21847950

  3. A Numerical Study on Kuroshio Frontal Eddies at the Shelf Edge of the East China Sea Using a Finite Volume Coastal Ocean Model

    NASA Astrophysics Data System (ADS)

    Isobe, A.; Beardsley, R. C.

    2005-05-01

    Cross-frontal transports of seawater and materials are induced by nonlinear frontal eddies as they grow from baroclinically unstable frontal waves. It is difficult to measure these transports based on field observations and/or analyses of archived datasets because of intense spatiotemporal variability of frontal waves. In order to evaluate cross-frontal transports induced by frontal eddies quantitatively, it is therefore reasonable to use a numerical model approach that includes realistic bathymetric irregularities that may trigger frontal waves and eddies. The Finite Volume Coastal Ocean Model (FVCOM; Chen et al., 2003) is useful because this model features an unstructured grid that can resolve complex bottom topography. In this study, FVCOM is used with the Princeton Ocean Model (POM) to study Kuroshio frontal eddies in the East China Sea. First, the large-scale circulation in the Yellow and East China Seas is simulated using POM with inflow-outflow conditions of ocean currents (i.e., Kuroshio, Taiwan and Tsushima Currents), heat and freshwater fluxes through the sea surface, and the Changjiang river run-off. These conditions vary in time with an annual period. The model reaches a stable state with an annual cycle after seven years of spinup. The seventh-year POM results are then used as boundary conditions to drive FVCOM in a limitted area along the shelf break where the Kuroshio frontal eddies are frequently detected by field measurements and satellite infrared images. FVCOM reproduces frontal eddies with a folded-wave pattern, which is a characteristic of a mature frontal eddy. In addition, modeled eddies have wavelengths of 100-200 km and periods of 10-20 days, which are consistent with those observed in this area. Model results are compared with the temperature time series observed at a Japan Meteorological Agency buoy located at East China Sea shelf break, and are used for the quantitative evaluation of the cross-frontal transport in conjunction with

  4. Bottom-up and top-down controls on picoplankton in the East China Sea

    NASA Astrophysics Data System (ADS)

    Guo, C.; Liu, H.; Zheng, L.; Song, S.; Chen, B.; Huang, B.

    2013-05-01

    Dynamics of picoplankton population distribution in the East China Sea (ECS), a marginal sea in the western North Pacific Ocean, were studied during two "CHOICE-C" cruises in August 2009 (summer) and January 2010 (winter). Dilution experiments were conducted during the two cruises to investigate the growth and grazing among picophytoplantkon populations. Picoplankton accounted for an average of ~29% (2% to 88%) of community carbon biomass in the ECS on average, with lower percentages in plume region than in shelf and kuroshio regions. Averaged growth rates (μ) for Prochlorococcus (Pro), Synechococcus (Syn) and picoeukaryotes (peuk) were 0.36, 0.89, 0.90 d-1, respectively, in summer, and 0.46, 0.58, 0.56 d-1, respectively, in winter. Seawater salinity and nutrient availability exerted significant controls on picoplankton growth rate. Averaged grazing mortality (m) were 0.46, 0.63, 0.68 d-1 in summer, and 0.22, 0.32, 0.22 d-1 in winter for Pro, Syn and peuk respectively. The three populations demonstrated very different distribution patterns regionally and seasonally affected by both bottom-up and top-down controls. In summer, Pro, Syn and peuk were dominant in Kuroshio, transitional and plume regions respectively. Protist grazing consumed 84%, 78%, 73% and 45%, 47%, 57% of production for Pro, Syn and peuk in summer and winter respectively, suggesting more significant top-down controls in summer. In winter, all three populations tended to distribute in offshore regions, although the area of coverage was different (peuk > Syn > Pro). Bottom-up factors can explain as much as 91.5%, 82% and 81.2% of Pro, Syn and peuk abundance variance in winter, while only 59.1% and 43.7% for Pro and peuk in summer. Regionally, Yangtze River discharge plays a significant role in affecting the intensity of top-down control, indicated by significant and negative association between salinity and grazing mortality of all three populations and higher grazing mortality to growth rate ratio

  5. Relation between oceanic conditions in the South China Sea and water levels within and along the Vietnamese Mekong River Delta

    NASA Astrophysics Data System (ADS)

    Uehara, K.; Tanaka, A.; Saito, Y.; Tamura, T.; Nguyen, V. L.; Ta, T. K.

    2013-12-01

    Seasonal water level change within and around the Vietnamese Mekong River Delta (MRD) has been analyzed to understand the impact of climate change in the South China Sea on river flooding within the MRD. It was found that the sea level variability along the deltaic coast has high coherence with the strength of offshore oceanic currents which seasonally reverse their direction under the SE Asian monsoon climate, indicating that the coastal sea level is linked with offshore currents through a geostrophic relation. It was also suggested that the temporal pattern of water levels in the middle reaches of the MRD, 80-100km apart from the river mouth, was influenced not only by upstream information but also by the downstream sea level change. These results indicates that the climatic change in the oceanic current field may influence the occurrence of flooding within the MRD especially during the NE monsoon season when the sea level is high.

  6. Bacterial Community Composition of South China Sea Sediments through Pyrosequencing-Based Analysis of 16S rRNA Genes

    PubMed Central

    Zhu, Daochen; Tanabe, Shoko-Hosoi; Yang, Chong; Zhang, Weimin; Sun, Jianzhong

    2013-01-01

    Background Subseafloor sediments accumulate large amounts of organic and inorganic materials that contain a highly diverse microbial ecosystem. The aim of this study was to survey the bacterial community of subseafloor sediments from the South China Sea. Methodology/Principal Findings Pyrosequencing of over 265,000 amplicons of the V3 hypervariable region of the 16S ribosomal RNA gene was performed on 16 sediment samples collected from multiple locations in the northern region of the South China Sea from depths ranging from 35 to 4000 m. A total of 9,726 operational taxonomic units (OTUs; between 695 and 2819 unique OTUs per sample) at 97% sequence similarity level were generated. In total, 40 bacterial phyla including 22 formally described phyla and 18 candidate phyla, with Proteobacteria, Firmicutes, Planctomycetes, Actinobacteria and Chloroflexi being most diverse, were identified. The most abundant phylotype, accounting for 42.6% of all sequences, belonged to Gammaproteobacteria, which possessed absolute predominance in the samples analyzed. Among the 18 candidate phyla, 12 were found for the first time in the South China Sea. Conclusions This study provided a novel insight into the composition of bacterial communities of the South China Sea subseafloor. Furthermore, abundances and community similarity analysis showed that the compositions of the bacterial communities are very similar at phylum level at different depths from 35-4000 m. PMID:24205246

  7. Phenotypic and genetic characterization of bacteria isolated from diseased cultured sea cucumber (Apostichopus japonicus) in Northeastern China

    Technology Transfer Automated Retrieval System (TEKTRAN)

    During the winter–spring from 2004 to 2006 in northeastern China cultured Japanese sea cucumber Apostichopus japonicus suffered from a serious disease. Clinical signs included swollen mouth, skin ulceration and massive mortality. Clinical samples taken during this period were studied. Thirty-one bac...

  8. Observed drag coefficients in high winds in the near offshore of the South China Sea

    DOE PAGESBeta

    Bi, Xueyan; Liu, Yangan; Gao, Zhiqiu; Liu, Feng; Song, Qingtao; Huang, Jian; Huang, Huijun; Mao, Weikang; Liu, Chunxia

    2015-07-14

    This paper investigates the relationships between friction velocity, 10 m drag coefficient, and 10 m wind speed using data collected at two offshore observation towers (one over the sea and the other on an island) from seven typhoon episodes in the South China Sea from 2008 to 2014. The two towers were placed in areas with different water depths along a shore-normal line. The depth of water at the tower over the sea averages about 15 m, and the depth of water near the island is about 10 m. The observed maximum 10 min average wind speed at a heightmore » of 10 m is about 32 m s⁻¹. Momentum fluxes derived from three methods (eddy covariance, inertial dissipation, and flux profile) are compared. The momentum fluxes derived from the flux profile method are larger (smaller) over the sea (on the island) than those from the other two methods. The relationship between the 10 m drag coefficient and the 10 m wind speed is examined by use of the data obtained by the eddy covariance method. The drag coefficient first decreases with increasing 10 m wind speed when the wind speeds are 5–10 m s⁻¹, then increases and reaches a peak value of 0.002 around a wind speed of 18 m s⁻¹. The drag coefficient decreases with increasing 10 m wind speed when 10 m wind speeds are 18–27 m s⁻¹. A comparison of the measurements from the two towers shows that the 10 m drag coefficient from the tower in 10 m water depth is about 40% larger than that from the tower in 15 m water depth when the 10 m wind speed is less than 10 m s⁻¹. Above this, the difference in the 10 m drag coefficients of the two towers disappears.« less

  9. Observed drag coefficients in high winds in the near offshore of the South China Sea

    SciTech Connect

    Bi, Xueyan; Liu, Yangan; Gao, Zhiqiu; Liu, Feng; Song, Qingtao; Huang, Jian; Huang, Huijun; Mao, Weikang; Liu, Chunxia

    2015-07-14

    This paper investigates the relationships between friction velocity, 10 m drag coefficient, and 10 m wind speed using data collected at two offshore observation towers (one over the sea and the other on an island) from seven typhoon episodes in the South China Sea from 2008 to 2014. The two towers were placed in areas with different water depths along a shore-normal line. The depth of water at the tower over the sea averages about 15 m, and the depth of water near the island is about 10 m. The observed maximum 10 min average wind speed at a height of 10 m is about 32 m s⁻¹. Momentum fluxes derived from three methods (eddy covariance, inertial dissipation, and flux profile) are compared. The momentum fluxes derived from the flux profile method are larger (smaller) over the sea (on the island) than those from the other two methods. The relationship between the 10 m drag coefficient and the 10 m wind speed is examined by use of the data obtained by the eddy covariance method. The drag coefficient first decreases with increasing 10 m wind speed when the wind speeds are 5–10 m s⁻¹, then increases and reaches a peak value of 0.002 around a wind speed of 18 m s⁻¹. The drag coefficient decreases with increasing 10 m wind speed when 10 m wind speeds are 18–27 m s⁻¹. A comparison of the measurements from the two towers shows that the 10 m drag coefficient from the tower in 10 m water depth is about 40% larger than that from the tower in 15 m water depth when the 10 m wind speed is less than 10 m s⁻¹. Above this, the difference in the 10 m drag coefficients of the two towers disappears.

  10. Initial insights into the age and origin of the Kubuqi sand sea of northern China

    NASA Astrophysics Data System (ADS)

    Yang, Xiaoping; Forman, Steven; Hu, Fangen; Zhang, Deguo; Liu, Ziting; Li, Hongwei

    2016-04-01

    The Kubuqi Desert is the only active sand sea in the semiarid regions of northern China and occurs along the southern margin of the Yellow River. Little is known about the age and origin of this large (17,000 km2) sand sea with a present annual precipitation of 200-480 mm. Sand drift potentials indicated net capable winds for aeolian transport are from the northwest, though winds are stronger to north beyond the dune field than within the sand sea. Geomorphic and stratigraphic observations indicate that Holocene aeolian sand often drapes over bedrock and river terraces as a palimpsest landscape. Field investigations identified four stratigraphic sections with multiple aeolian sand units and palaeosols, with age control by optically stimulated luminescence (OSL) dating of quartz grains. Palaeosols are weakly developed, mostly accumulative A horizon with organic carbon content < 1% and reflect sand sheet deposition possibly in a steppe environment. Although sediments near river channels or former lakes might give old ages, the initial formation and age of the Kubuqi sand sea should be judged from the occurrence of the sandy palimpsest of the landscape that is OSL dated to the Holocene in general. The latest period of aeolian reactivation may be related to human activity associated with grazing and farming from lost cities in the Kubuqi Desert during the Han (206 B.C. - A.D. 220) and the Tang (A.D. 608 - 907) Dynasties. Also, variable discharge of the Yellow River with local diversions for irrigation and throughout the catchment resulted in possibly an increased supply of aeolian particles for dune field expansion in the past 2 ka.

  11. The world's largest macroalgal bloom in the Yellow Sea, China: Formation and implications

    NASA Astrophysics Data System (ADS)

    Liu, Dongyan; Keesing, John K.; He, Peimin; Wang, Zongling; Shi, Yajun; Wang, Yujue

    2013-09-01

    The world's largest trans-regional macroalgal blooms during 2008-2012 occurred in the Yellow Sea, China. This review addresses the causes, development and future challenges in this unique case. Satellite imagery and field observations showed that the macroalgal blooms in the Yellow Sea originated from the coast of Jiangsu province and that favorable geographic and oceanographic conditions brought the green macroalgae from the coast offshore. Optimal temperature, light, nutrients and wind contributed to the formation and transport of the massive bloom north into the Yellow Sea and its deposition onshore along the coast of Shandong province. Morphological and genetic evidence demonstrated that the species involved was Ulva prolifera, a fouling green commonly found growing on structures provided by facilities of Porphyra aquaculture. Large scale Porphyra aquaculture (covering >20,000 ha) along the Jiangsu coast thus hypothetically provided a nursery bed for the original biomass of U. prolifera. Porphyra growers remove U. prolifera from the mariculture rafts, and the cleaning releases about 5000 wet weight tonnes of green algae into the water column along the coast of Jiangsu province; the biomass then is dispersed by hydrographic forcing, and takes advantage of rather high nutrient supply and suitable temperatures to grow to impressive levels. Certain biological traits of U. prolifera —efficient photosynthesis, rapid growth rates, high capacity for nutrient uptake, and diverse reproductive systems— allowed growth of the original 5000 tonnes of U. prolifera biomass into more than one million tonnes of biomass in just two months. The proliferation of U. prolifera in the Yellow Sea resulted from a complex contingency of circumstances, including human activity (eutrophication by release of nutrients from wastewater, agriculture, and aquaculture), natural geographic and hydrodynamic conditions (current, wind) and the key organism's biological attributes. Better

  12. Do indicators influence communication in SEA? — Experience from the Chinese practice

    SciTech Connect

    Gao, Jingjing Kørnøv, Lone Christensen, Per

    2013-11-15

    Indicators have become one of the primary tools for Strategic Environmental Assessment (SEA) in the Chinese context, but what does this use of indicators mean for communication within the SEA processes? This article explores how the selection and use of indicators influence the communication between different stakeholders involved in SEA. The article provides a conceptual communication model covering directions and level of communication. Using this model on empirical findings from interviews with two specific SEA cases and from general experience collected through an online survey, the results suggest that indicators are used mainly in internal communication although a change of approach, with more external communication and stakeholder engagement, is taking place as a consequence of working with indicators in the SEA. However, the external communication mainly involves the experts and other relevant sectors (planning, energy, land use, forestry, etc.), the involvement of the public and NGOs is still not well implemented in Chinese SEA practice, and the direction of communication is mainly one-way channel of providing information rather than a two-way channel of dialogue and participation. Highlights: • Exploring indicators' influence on the communication in SEA with Chinese experience. • Providing a conceptual model covering directions and level of communication in SEA. • Empirical findings from two specific SEA cases and collected general experience. • The external communication mainly involves the experts and other sectors. • More one-way information provision than two-way dialogue and participation.

  13. Experiments in Reconstructing Twentieth-Century Sea Levels

    NASA Technical Reports Server (NTRS)

    Ray, Richard D.; Douglas, Bruce C.

    2011-01-01

    One approach to reconstructing historical sea level from the relatively sparse tide-gauge network is to employ Empirical Orthogonal Functions (EOFs) as interpolatory spatial basis functions. The EOFs are determined from independent global data, generally sea-surface heights from either satellite altimetry or a numerical ocean model. The problem is revisited here for sea level since 1900. A new approach to handling the tide-gauge datum problem by direct solution offers possible advantages over the method of integrating sea-level differences, with the potential of eventually adjusting datums into the global terrestrial reference frame. The resulting time series of global mean sea levels appears fairly insensitive to the adopted set of EOFs. In contrast, charts of regional sea level anomalies and trends are very sensitive to the adopted set of EOFs, especially for the sparser network of gauges in the early 20th century. The reconstructions appear especially suspect before 1950 in the tropical Pacific. While this limits some applications of the sea-level reconstructions, the sensitivity does appear adequately captured by formal uncertainties. All our solutions show regional trends over the past five decades to be fairly uniform throughout the global ocean, in contrast to trends observed over the shorter altimeter era. Consistent with several previous estimates, the global sea-level rise since 1900 is 1.70 +/- 0.26 mm/yr. The global trend since 1995 exceeds 3 mm/yr which is consistent with altimeter measurements, but this large trend was possibly also reached between 1935 and 1950.

  14. Variation of phytoplankton absorption coefficients in the northern South China Sea during spring and autumn

    NASA Astrophysics Data System (ADS)

    Wu, J.; Hong, H.; Shang, S.; Dai, M.; Lee, Z.

    2007-05-01

    We examined the temporal and spatial variabilities of phytoplankton absorption coefficients (αphλ)) and their relationships with physical processes in the northern South China Sea from two cruise surveys during spring (May 2001) and late autumn (November 2002). A large river plume induced by heavy precipitation in May stimulated a phytoplankton bloom on the inner shelf, causing significant changes in the surface water in αph values and B/R ratios (αph(440)/αph(675)). This was consistent with the observed one order of magnitude elevation of chlorophyll α and a shift from a pico/nano dominated phytoplankton community to one dominated by micro-algae. At the seasonal level, enhanced vertical mixing due to strengthened northeast monsoon in November has been observed to result in higher surface αph(675) (0.002-0.006 m-1 higher) and less pronounced subsurface maximum on the outer shelf/slope in November as compared that in May. Measurements of αph and B/R ratios from three transects in November revealed a highest surface αph(675) immediately outside the mouth of the Pearl River Estuary, whereas lower αph(675) and higher B/R ratios were featured in the outer shelf/slope waters, demonstrating the respective influence of the Pearl River plume and the oligotrophic nature of South China Sea water. The difference in spectral shapes of phytoplankton absorption (measured by B/R ratios and bathochromic shifts) on these three transects infers that picoprocaryotes are the major component of the phytoplankton community on the outer shelf/slope rather than on the inner shelf. In addition, a regional tuning of the phytoplankton absorption spectral model (Carder et al., 1999) demonstrated a greater spatial variation than seasonal variation in the lead parameter a0(λ). These results suggest that phytoplankton absorption properties in a coastal region such as the northern South China Sea are complex and region-based parameterization is mandatory in order for remote sensing

  15. Evidence of the observed change in the atmosphere-ocean interactions over the South China Sea during summer in a regional climate model

    NASA Astrophysics Data System (ADS)

    Jang, Hye-Yeong; Yeh, Sang-Wook; Chang, Eun-Chul; Kim, Baek-Min

    2016-01-01

    The South China Sea plays a key role to change the precipitation variability in East Asia by influencing the northward moisture transport. Previous study found that there exist changes in atmosphere-ocean interactions over the South China Sea (SCS) before and after the late 1990s during boreal summer (June-July-August) in the observations. This study further supports such changes using two simulations of the atmospheric regional climate model (RCM) forced by historical sea surface temperature (SST). The control run is forced by historical SSTs, which are prescribed in the entire domain in the RCM. In addition to the control run, an additional idealized experiment is conducted, i.e., the historical SSTs are prescribed in the SCS only and the climatological SST is prescribed outside the SCS to examine the changes in the atmosphere-ocean interactions in the SCS. It is found that the simultaneous correlation coefficient between SST and precipitation changes significantly over the SCS before and after the late 1990s. This result supports the notion that there are significant changes in atmosphere-ocean interactions over the SCS before and after the late 1990, which affects the ability of the RCM to simulate precipitation variability accurately relative to observation. This result implies that the simulations of atmospheric circulation model results forced by observed SST before the late 1990 should be cautiously interpreted because the observed SST anomalies are forced by the atmosphere.

  16. Hydroclimate implications of thermocline variability in the southern South China Sea over the past 180,000 yr

    NASA Astrophysics Data System (ADS)

    Dong, Liang; Li, Li; Li, Qianyu; Wang, Hui; Zhang, Chuanlun L.

    2015-03-01

    Based on core-top calibration, the TEX 86H-derived temperature has been considered as representing subsurface sea temperature (SSST), and the difference between the U37K‧-derived sea-surface temperature (SST) and the TEX 86H-derived SSST can be used to reflect the depth of thermocline (DOT) in the South China Sea region (Jia et al., 2012). We evaluated the DOT dynamics in late Quaternary records using this approach on paired analysis of samples from core MD05-2896/7 in the southern South China Sea. The reconstructed DOT over the last 180,000 yr (180 ka) displays a shoaling trend in glacial periods, which may be attributed to the strengthened cyclonic gyre by the enhanced East Asian winter monsoon and Walker circulation with prominent La Niña-like state, and vice versa in interglacial periods corresponding to reduced winter monsoon with enhanced El Niño-like state. These upper-water thermal variations testify that enhanced winter monsoon was the direct cause of an uplifted local thermocline during glacial or La Niña-like states with strengthened cyclonic gyre due to positive wind stress curl in the southern South China Sea. Our results provide insights into the relationship between monsoon and ENSO on both glacial and millennial time scales.

  17. Effect of model error representation in the Yellow and East China Sea modeling system based on the ensemble Kalman filter

    NASA Astrophysics Data System (ADS)

    Kwon, Kyung Man; Choi, Byoung-Ju; Lee, Sang-Ho; Kim, Young Ho; Seo, Gwang-Ho; Cho, Yang-Ki

    2016-02-01

    To increase the accuracy of ocean predictions in the Yellow and East China Sea (YES), the satellite-borne sea surface temperature (SST) data have been assimilated to an operational ocean modeling system by applying an ensemble Kalman filter (EnKF). As the observed SST was assimilated continuously into the model with time, the ensemble spread decreased and the efficiency of data assimilation degenerated. To increase liability of the system and the ensemble spread, model uncertainties were represented stochastically by perturbing the model tendency parameters such as eddy viscosity, bottom drag coefficient, light attenuation depth, as well as atmospheric forcing. Data assimilation experiments were performed with forcing from a regional atmospheric model from September 2011 to February 2012. The assimilation results with and without the stochastically perturbed model parameters and atmospheric forcing were compared. The ensemble with the perturbations has larger spread and smaller root-mean-square deviation (RMSD) in temperature compared with the ensemble without the perturbations. The SST RMSD relative to anther supplementary SST dataset was reduced from 0.91 to 0.81 °C over the YES. The assimilation of the SST data improved the simulated SST compared with the observation at the ocean buoy stations, and also made the subsurface temperature profiles closer to the observed ones. The assimilation experiments showed that a stochastic representation of the model errors by the perturbations of the model parameters and atmospheric forcing increases the spread of the ensemble and improves the structure of background error covariance, which enhances the performance of the ensemble modeling system in the YES.

  18. Using stable isotopes to determine the submarine groundwater discharge in the East China Sea

    NASA Astrophysics Data System (ADS)

    Lian, E.; Yang, S.; Yang, C.; Li, C.

    2013-12-01

    Over the last decade the flux of submarine groundwater discharge (SGD) to global ocean has been well investigated, which reaches 12, 000km3/yr, about 10~50% of the total riverine discharge into the ocean. The large uncertainty of the estimation of SGD flux lies in poor data in large river deltas and adjoining coastal areas. As a typical river-dominated epicontinental sea, the East China Sea is characterized by wide continental shelf and huge terrestrial input mostly from the Changjiang (Yangtze River). The Changjiang River exerts a significant role on sedimentological and biogeochemical processes in the East China Sea by delivering an enormous amount of dissolved and particulate materials. In this contribution, the riverwater and seawater samples were collected in dry and flood seasons in 2012 and 2013 for the measurements of stable H-O isotopes, with a major aim to examine the contribution of SGD off the Changjiang Estuary and on the coastal shelf. The results show that the values of δD and δ18O exhibit regular variations with seasons, controlled by the monsoon-induced rainfall and anthropogenic activities in the large Changjiang catchment. The δD and δ18O values in the groundwater samples from the boreholes in the Changjiang Delta fluctuate between -48.0 and -51.5‰ and between -5.9 and -7.55‰, respectively, while relatively positive values were observed in the seawater samples, ranging from -2.82 to 0.16‰ for δD and -0.54 to -0.26‰ for δ18O. Some of the offshore samples (about 50 km off the coast, 11-15 m below the sea surface) bear relatively negative isotopic values (δD: -11.21~ -3.25‰; δ18O: -1.55 ~ -0.23‰). The H-O isotopic compositions of these samples fall on a mixing line between those of groundwater and seawater samples, which probably reflects the SGD contribution. Based on the isotopic equilibrium calculation, it is estimated that about 18.7~23.1% of fresh groundwater resource flowing into the Changjiang estuarine and shelf areas is

  19. Teacher at Sea: Bringing Hands-on Experience to the Classroom

    ERIC Educational Resources Information Center

    National Oceanic and Atmospheric Administration, 2007

    2007-01-01

    Since its inception in 1990, National Oceanic and Atmospheric Administration's (NOAA) Teacher at Sea program has enabled more than 460 teachers to gain first-hand experience of science and life at sea. By participating in this program, it becomes possible for teachers to enrich their classroom curricula with a depth of understanding made possible…

  20. A fine grid two-dimensional M{sub 2} tidal model of the East China Sea

    SciTech Connect

    Han, K.M.; Choi, B.H.

    1993-12-31

    The previous two-dimensional non-linear tidal model of the East China Sea (Chung, 1986) has been further refined to resolve the flow over the continental shelf in more detail. The mesh resolution of the present finite-difference grid system used is 4 minutes latitude by 5 minutes longitude over the entire shelf. The developed fine grid two-dimensional model was utilized to reproduce the M{sub 2} tide and M{sub 4} tide for the East China Sea continental shelf. There is general agreement between the model results and the current observation made in the Eastern Yellow Sea, which supports the calculated tidal regime over the shelf. Some preliminary results on maximum bottom stress and tidally-induced residual current were also examined and discussed.

  1. Riding over the Kuroshio from the South to the East China Sea: Mixing and transport of DIC

    NASA Astrophysics Data System (ADS)

    Sheu, David D.; Chou, Wen-Chen; Chen, C. T. Arthur; Wei, Ching-Ling; Hsieh, Hsiu-Ling; Hou, Wei-Ping; Dai, Minhan

    2009-04-01

    Export of dissolved inorganic carbon (DIC) to adjoining oceans enhances the potential of CO2 sequestration in marginal seas. By using a series of measured DIC depth profiles and reported flow transports, we estimated that the intermediate outflow (100-600 m) from the South China Sea is capable of transporting 6.5 ± 4.1 Tg (1 Tg = 1012g) of biologically mediated carbon (DICbio) annually to the East China Sea (ECS) via the northwardly flowing Kuroshio current. The mixing and transport of these DIC-rich waters would raise 3% and 16% of DIC/TA ratio and the Revelle factor of the adjoining seawaters, respectively. Upon upwelling onto the ECS shelf, these DIC-rich waters would counteract the potential of CO2 uptake of shelf waters that might have been enhanced by the accompanying increase in nutrient inputs, thus complicating assessment of the ECS as a net CO2 source or sink.

  2. Aerosol direct radiative forcing at the top of atmosphere based on satellite remote sensing over China Seas: a preliminary study

    NASA Astrophysics Data System (ADS)

    Hao, Zengzhou; Pan, Delu; Gong, Fang

    2010-09-01

    Radiative forcing as an index of climate change can reflect the relative effect of climate factors. To understand climatic implications of aerosols over the China Seas, the aerosol direct radiative forcing at the top of atmosphere (TOA) is computed using three-year collocated Clouds and the Earth's Radiant Energy System (CERES) radiation fluxes and Moderate Resolution Imaging Spectroradiometer (MODIS) aerosol optical thickness data on the platform Terra. The upward radiation flux for clear skies is a key for the aerosol radiative forcing at the TOA. A linear relationship is found between the solar radiation fluxes at the TOA from CERES and the aerosol optical thickness is at 550 nm from MODIS over the China Seas. In a linear regression Eq., the intercept for zero aerosol optical thickness is the radiation flux at the TOA for clear skies. Based on the definition of the aerosol direct radiative forcing at TOA and the diurnal correction factor from a simulated radiative forcing using radiation transfer model, the daily averaged aerosol direct radiative forcing at the TOA is estimated and its seasonal variations over the cloud-free China Seas are presented. In total, the aerosol radiative forcing over the China Seas is negative. It implies that the aerosol over the China Seas is mainly a cooling effect on climate change, which is opposite to the greenhouse effect. The largest aerosol radiative forcing is found in spring, while the smallest is in summer. The aerosol radiative forcing over the coastal region is always more than that in the open ocean in four seasons. The method in the study can be used for evaluation of the aerosols impact on global or region climate from satellite measurements.

  3. Magnetic Properties of the Rivers Feeding the South China Sea: a Critical Step for Understanding the Paleo-Marine Records.

    NASA Astrophysics Data System (ADS)

    Kissel, C.; Liu, Z.; Wandres, C.

    2014-12-01

    In order to use the magnetic properties of marine sediments as a tracer for past changes in the precipitation rate on land and in oceanic water masses transport and exchanges in the South China Sea, we identify and characterize the different sources of the detrital fraction among which the magnetic particles. This work is presently conducted in the framework of the Franco-Chinese LIA-MONOCL Thanks to the Westpac project, we had access to sediments collected in the deltas of the main rivers feeding the South China Sea from about 25°N to the equator. This is represented on the Asian continent by the Pearl river, the Red River, the Mekong river, by Malaysia, Sumatra and Borneo regions with minor rivers but also contributing to the South China Sea, and finally by Luzon and Taiwan. The geological formations contributing to the river sediment discharges are different from one catchment basin to another as well as the present climatic conditions. The magnetic analyses consist in the analysis of low-field magnetic susceptibility, ARM acquisition and decay, IRM acquisition and decay, back-field acquisition, thermal demagnetization of 3-axes IRM, hysteresis parameters, and FORC diagrams. The obtained parameters all together allow us to define the nature of the magnetic grains and their grain size distribution when magnetite is dominant. Some degree of variability is observed at the river mouths, illustrating different geological sources at the local/regional scale. As an average, it appears that the Southern basin of the South China Sea is surrounded by regions richer in high coercivity magnetic minerals than the northern basin. This mineral is identified as hematite while magnetites (and sulfides) are more abundant in the north. These results are complementary to the clay mineral assemblages previously determined on the same samples. The first steps of a similar study conducted on marine core-tops well distributed in the South China Sea will also be illustrated.

  4. Deep-water sediment transport processes in the northeastern South China Sea: Mooring and shipboard-based observations

    NASA Astrophysics Data System (ADS)

    Liu, Z.; Zhao, Y.; Zhang, Y.; Li, J.; Li, X.; Wang, W.; Xu, J.

    2013-12-01

    Six moorings equipped with acoustic doppler current profiler (ADCP), recording current meter (RCM), and sediment trap have been deployed in the northeastern South China Sea at water depths ranging from 1700-3900 m to collect time-series data that can hopefully help better characterize the bottom current system and transport process in the region. Shipboard-based measurements including CTD, transmissometer, optical backscatter (OBS), and in-situ layered suspended particle sampling using large volume pump (LVP) were undertaken along three deep-water transects in the region during two cruises in the spring of 2012 and 2013. Preliminary results show for the first time the presence of continuous and relative stable contour currents and widespread deep-water nepheloid layers in the deep South China Sea. The contour currents flow southwestwards with average speeds of 2-4 cm/s (occasionally up to 11 cm/s) along lower slope of the northern South China Sea at depths of 1700-2500 m. The large-scale sediment waves recorded by high-resolution multibeam bathymetry appear to be related to activities of the contour currents. Intermediate and bottom nepheloid layers with an average suspended particle concentration of 0.6 mg/l are extended from the lower slope to the deep basin of the South China Sea. The intermediate nepheloid layers in depths ranging from 900 to 1100 m are thought to be controlled mainly by the interaction between the North Pacific Intermediate Water and the Pacific Deep Water masses. A sedimentary core (MD01-2905) previously collected on the sediment drift of ODP Site 1144, where three of the mooring systems are located, indicates that 60% of total fine-grained terrigenous sediment budget since the last glacial time have sourced from Taiwan. Our data suggest that the observed contour currents are the major carrier for transporting Taiwan-derived sediments to the northern slope of the South China Sea.

  5. Modeled connectivity of Acropora millepora populations from reefs of the Spratly Islands and the greater South China Sea

    NASA Astrophysics Data System (ADS)

    Dorman, Jeffrey G.; Castruccio, Frederic S.; Curchitser, Enrique N.; Kleypas, Joan A.; Powell, Thomas M.

    2016-03-01

    The Spratly Island archipelago is a remote network of coral reefs and islands in the South China Sea that is a likely source of coral larvae to the greater region, but about which little is known. Using a particle-tracking model driven by oceanographic data from the Coral Triangle region, we simulated both spring and fall spawning events of Acropora millepora, a common coral species, over a 46-yr period (1960-2005). Simulated population biology of A. millepora included the acquisition and loss of competency, settlement over appropriate benthic habitat, and mortality based on experimental data. The simulations aimed to provide insights into the connectivity of reefs within the Spratly Islands, the settlement of larvae on reefs of the greater South China Sea, and the potential dispersal range of reef organisms from the Spratly Islands. Results suggest that (1) the Spratly Islands may be a significant source of A. millepora larvae for the Palawan reefs (Philippines) and some of the most isolated reefs of the South China Sea; and (2) the relatively isolated western Spratly Islands have limited source reefs supplying them with larvae and fewer of their larvae successfully settling on other reefs. Examination of particle dispersal without biology (settlement and mortality) suggests that larval connectivity is possible throughout the South China Sea and into the Coral Triangle region. Strong differences in the spring versus fall larval connectivity and dispersal highlight the need for a greater understanding of spawning dynamics of the region. This study confirms that the Spratly Islands are likely an important source of larvae for the South China Sea and Coral Triangle region.

  6. Coastal SAR Altimetry: An Experiment in the Northern Caspian Sea

    NASA Astrophysics Data System (ADS)

    Dinardo, Salvatore; Lucas, Bruno; Benveniste, Jerome

    2013-04-01

    backscattered power distribution vs. Doppler beam angle as achieved integrating the SAR STACK's power echoes. This RMSS parameter is an indicator of how much specular or diffusive is the surface illuminated by the radar. The RMSS parameter will be hence fed as input in the SAMOSA Physical Model in order to adapt the model itself automatically to the changed water scenario conditions, turning the model's classic long-tail SAR waveform into a very peaky waveform. THE SAMOSA model will be implemented in its full analytical formulation (zero-order and first-order term), neglecting only the effect of the water surface skewness. The benefit of this methodology is that we use either for open ocean conditions either for coastal still water conditions the same model and re-tracker scheme, avoiding hence any bias or discontinuity in height, typically occurring when one swaps waveform model or re-tracker scheme during the same pass. The experiment will be run at the wetlands of the Volga's Delta in the Northern Caspian Sea in summer time. CryoSat-2 is covering the area in SAR mode and along the passes, the instrument is facing an abrupt transition from diffusive open sea condition to very specular water conditions over the Volga's Delta wetlands. Hence, this seems to be the ideal environment where to test the proposed methodology.

  7. Seismic scattering and velocity structure near the Earth's core-mantle boundary beneath the South China Sea and north Indonesia

    NASA Astrophysics Data System (ADS)

    Yao, J.; Wen, L.

    2013-12-01

    We constrain seismic scatterers near the Earth's core-mantle boundary beneath the South China Sea and north Indonesia using the observed PKP precursory energy and velocity structure in the region using the travel time of the core-reflected phases. The PKP precursor data are collected from the seismic data recorded in the USArray and the core-reflected seismic data include ScS and ScP phases recorded in the China National Digital Seismographic Network, the F-net in Japan, the Global Seismographic Network and several regional arrays. Migration of PKP precursory energy reveals crescent-shaped scatterers distributed from the middle of the South China Sea to the north of Sulawesi Island. ScSH-SH differential-travel-times suggest a complex shear-velocity structure near the core-mantle boundary, changing from a low-velocity patch to a high shear-velocity patch and to another low shear-velocity patch from east to west beneath the middle of the South China Sea. ScP-P differential travel-time residuals reveal a low-velocity patch in northeast of Sulawesi Sea, a high-velocity patch in north of Sulawesi Sea, another low-velocity patch in the middle of Sulawesi Sea and another high-velocity patch in north of the Kalimantan Island. Overall, the seismic structure in the region can be characterized by alternative presence of high- and low-velocity patches near the core-mantle boundary, with the abrupt shear-wave velocity changes between the patches being the source of seismic scattering in the region.

  8. Interpreting the South China Sea (SCS) spreading history through tectonic analysis of the Nansha-Dangerous Ground

    NASA Astrophysics Data System (ADS)

    Sun, Z.; Zhou, D.; Li, J.; Zhao, Z.

    2011-12-01

    Constrained by drilling data, long profiles across the Nansha-Dangerous Ground were interpreted to reconstruct the evolutionary history of the Southern South China Sea. Two important sequence boundaries were identified, Breakup Unconformity (B.U.) related to the SCS spreading and Collision Unconformity(C.U.) caused by Nansha-Borneo collision. In the western part of Nansha, B.U. is same as C.U. and dated at Mid-Miocene around 16Ma through the post-rift draping sediments. Mild folding, uplifting and erosion were seen in the strata of early Miocene. To the east, B.U. is proved to be located at early Miocene, while the C.U. still occurred around mid-Miocene. We can conclude that the B.U. is diachronous from middle Miocene in the west to early Miocene in the east. From the B.U. age of the basins and the spreading pattern, we conclude that Liyue basin should break apart from Zhongsha (Macclesfield) along with the spreading of the SW sub sea basin. From topography simulation, we see that the forearc uplift of Nansha decreases from SW to NE, which might suggest that the cessation of seafloor spreading in the South China Sea propagate northeastward, that's why the central sub sea basin has a wider floor area near the ridge than its western counterpart. Combined with the remnant Mesozoic oceanic crust under the northeastern margin of the South China Sea, we can see that the present South China Sea were formed through breakup of Mesozoic oceanic crust in the eastern part.

  9. The abundance, composition and sources of marine debris in coastal seawaters or beaches around the northern South China Sea (China).

    PubMed

    Zhou, Peng; Huang, Chuguang; Fang, Hongda; Cai, Weixu; Li, Dongmei; Li, Xiaomin; Yu, Hansheng

    2011-09-01

    The abundance and composition of marine debris including floating marine debris (FMD), seafloor marine debris (SMD) and beached marine debris (BMD) were investigated in coastal seawaters/beaches around the northern South China Sea during 2009 and 2010. The FMD density was 4.947 (0.282-16.891) items/km², with plastics (44.9%) and Styrofoam (23.2%) dominating. More than 99.0% of FMD was small or medium size floating marine debris. The SMD and BMD densities of were 0.693 (0.147-5.000) and 32.82 (2.83-375.00) items/km², respectively. SMD was composed of plastics (47.0%), wood (15.2%), fabric/fiber (13.6%) and glass (12.1%), while BMD was composed of plastics (42.0%) and wood (33.7%). More than 90% of FMD, 75% of SMD and 95% of BMD were not ocean-based sources but land-based sources, mostly attributed to coastal/recreational activity, because of the effect of human activities in the areas. PMID:21764082

  10. The rift architecture and extensional tectonics of the South China Sea

    NASA Astrophysics Data System (ADS)

    Cameselle, Alejandra L.; Ranero, César R.; Barckhausen, Udo; Franke, Dieter

    2016-04-01

    Non-volcanic rifted continental margins are classically described as the product of lithospheric stretching and breakup leading to mantle exhumation, and subsequent seafloor spreading. However, recent studies question this model and indicate a wider range of structural evolutions, that challenge the existing model (e.g. Australia-Antarctic Rift System (Direen et al. 2007, 2011); the Tyrrhenian basin (Prada et al., 2014) or the South China Sea (Cameselle et al. 2015)). Rifting in the South China Sea developed from a series of extensional events, from early Eocene to Late Oligocene, resulting in a V-shape oceanic basin affected by the occurrence of several spreading centers, ridges, transform faults and post-spreading volcanism. In recent years, this marginal basin - the largest in East Asia - has increasingly become one of the key sites for the study of rifting and continental break-up. Its relative small size - compared to many classic, Atlantic-type continental margin settings - allows to easily match conjugated rifted margins and its relative youth promotes the preservation of its original nature. To examine the rifting evolution of the South China Sea, we have reprocessed with modern algorithms multichannel seismic profiles acquired during Sonne49 and BGR84 cruises across the three major subbasins: NW, SW and East subbasins. State-of-the-art of processing techniques have been used to increase the signal to noise ratio, including Tau-P and Wiener predictive deconvolution, multiple attenuation by both radon filtering and wave-equation-based surface-related multiple elimination (SRME) and time migration. To complement seismic interpretation, available vintage multichannel seismic data have been reprocessed with a post-stack flow, including Wiener deconvolution, FK-filtering, space and time variant band-pass filter and time migration. The improving quality of the seismic images shows a range of features including post-rift and syn-rift sediments, the structure of

  11. Carbamate derivatives and sesquiterpenoids from the South China Sea gorgonian Melitodes squamata.

    PubMed

    Huang, Li-Si; He, Fei; Huang, Hui; Zhang, Xiao-Yong; Qi, Shu-Hua

    2012-01-01

    Five carbamate derivatives, obtucarbamates C and D (1, 2), dimethyl ((carbonylbis(azanediyl))bis(2-methyl-5,1-phenylene))dicarbamate (3), obtucarbamates A and B (4, 5), and four aromadendrane-type sesquiterpenoids, (+)-4β-N-methenetauryl-10β-methoxy-1β,5α,6β,7β-aromadendrane (6), (-)-4β-N-methenetauryl-10β-methoxy-1β,5β,6α,7α-aromadendrane (7), (-)-4α,10β-aromadendranediol (8), (+)-4β,10β-aromadendranediol (9) were obtained from the South China Sea gorgonian coral Melitodes squamata Nutting. Compounds 1, 2, 6, and 7 were new, and their structures were established by spectroscopic analyses. Compounds 6 and 7 contained a taurine group that was rarely found in marine natural compounds, and 7 showed moderate antibacterial activity. The possible biosynthesis routes of 1-5 were conjectured. PMID:22423284

  12. Basin modeling of the Parang (Socotra) Basin, northern East China Sea shelf: Implications for hydrocarbon potential

    NASA Astrophysics Data System (ADS)

    Kim, H.; Moon, S.; Lee, G.; Yoon, Y.; Kim, H.

    2013-12-01

    The hydrocarbon potential of the Parang (Socotra) Basin in the northern East China Sea shelf has remained poorly understood. We performed one-dimensional basin modeling for a dummy well located in the depocenter of the northern part of the Parang Basin to investigate the timings of hydrocarbon generation and expulsion. First, a depth-converted seismic profile crossing the dummy well was restored by backstripping and decompaction for eight regional and subregional unconformities, including the top of the acoustic basement, to reconstruct the subsidence history and to determine the timing of trap formation. The basin modeling, assuming rifting heat-flow model and source rocks with type III kerogen, suggests that the main phase of hydrocarbon (mostly gas) expulsion peaked in the Late Eocene, predating the inversion that created traps in the early Middle to latest Middle Eocene. Thus, the potential for large hydrocarbon accumulations in the northern Parang Basin is probably limited.

  13. Increased zooplankton PAH concentrations across hydrographic fronts in the East China Sea.

    PubMed

    Hung, Chin-Chang; Ko, Fung-Chi; Gong, Gwo-Ching; Chen, Kuo-Shu; Wu, Jian-Ming; Chiang, Hsin-Lun; Peng, Sen-Chueh; Santschi, Peter H

    2014-06-15

    The Changjiang has transported large quantities of polycyclic aromatic hydrocarbons (PAHs) to the East China Sea (ECS), but information of these pollutants in zooplankton is limited. To understand PAHs pollution in zooplankton in the ECS, total concentrations of PAHs in zooplankton from surface waters were measured. Values of PAHs ranged from 2 to 3500 ng m(-3) in the ECS, with highest PAHs levels located at the salinity front between the Changjiang Diluted Water (CDW) and the mid-shelf waters. In contrast, concentrations of zooplankton PAHs in the mid-shelf and outer-shelf waters were significantly lower (2-23 ng m(-3)) than those in the CDW. These results demonstrate that PAHs are conspicuously accumulated in zooplankton at the salinity front between the CDW and the mid-shelf waters. These higher levels of PAHs in zooplankton at the salinity front may be further biomagnified in marine organisms of higher trophic levels through their feeding activities. PMID:24775063

  14. Responses of benthic foraminifera to the 2011 oil spill in the Bohai Sea, PR China.

    PubMed

    Lei, Yan Li; Li, Tie Gang; Bi, Hongsheng; Cui, Wen Lin; Song, Wen Peng; Li, Ji Ye; Li, Cheng Chun

    2015-07-15

    The 2011 oil spill in the Bohai Sea was the largest spill event in China. Nine sediment cores were taken near the spill site and environmental factors including Polycyclic Aromatic Hydrocarbon (PAHs), oils, sulfides, organic carbon were measured 6 months later. Benthic foraminifera were separated into >150 μm (large) and 63-150 μm (small) size fractions for 2-cm depth interval of each sediment core. Statistical analyses suggested that the species composition of living foraminifera was impacted by oils, PAHs and sulfides. Large foraminifera were more sensitive to the oils than the small. Abnormal specimens were positively correlated with oils or PAHs. Small forms, however, tended to have high reproduction and mortality. Pollution-resistant and opportunistic taxa were identified to calculate a Foraminiferal Index of Environmental Impacts (FIEI). The FIEI increased from low to high oil-polluted station and from deep layer to surface sediment reflects the impact of oil pollution in this area. PMID:26002093

  15. Seismic, satellite, and site observations of internal solitary waves in the NE South China Sea

    PubMed Central

    Tang, Qunshu; Wang, Caixia; Wang, Dongxiao; Pawlowicz, Rich

    2014-01-01

    Internal solitary waves (ISWs) in the NE South China Sea (SCS) are tidally generated at the Luzon Strait. Their propagation, evolution, and dissipation processes involve numerous issues still poorly understood. Here, a novel method of seismic oceanography capable of capturing oceanic finescale structures is used to study ISWs in the slope region of the NE SCS. Near-simultaneous observations of two ISWs were acquired using seismic and satellite imaging, and water column measurements. The vertical and horizontal length scales of the seismic observed ISWs are around 50 m and 1–2 km, respectively. Wave phase speeds calculated from seismic observations, satellite images, and water column data are consistent with each other. Observed waveforms and vertical velocities also correspond well with those estimated using KdV theory. These results suggest that the seismic method, a new option to oceanographers, can be further applied to resolve other important issues related to ISWs. PMID:24948180

  16. Two new species of Hexactinellida (Porifera) from the South China Sea.

    PubMed

    Gong, Lin; Li, Xinzheng; Qiu, Jian-Wen

    2015-01-01

    In this paper, two new sponge species, Semperella jiaolongae sp. nov. (Amphidiscosida, Pheronematidae) and Saccocalyx microhexactin sp. nov. (Lyssacinosida, Euplectellidae) are described based on materials from the South China Sea. Semperella jiaolongae sp. nov. is diagnosed mainly by the dermal areas present on both sides of the body, occurring together with atrial areas randomly distributed on one side, and the distinctive shape of micropentactins. Saccocalyx microhexactin sp. nov. is characterized by possession of two types of drepanocomes and one of microhexactins. An analysis based on partial sequence of the 16S rRNA gene was undertaken to show the congruence between morphological identification and phylogenetic classification of the two new species. PMID:26624437

  17. Distortion and broadening of internal solitary wavefront in the northeastern South China Sea deep basin

    NASA Astrophysics Data System (ADS)

    Xie, Jieshuo; He, Yinghui; Lü, Haibin; Chen, Zhiwu; Xu, Jiexin; Cai, Shuqun

    2016-07-01

    Internal solitary waves (ISWs) with peculiar fronts are frequently observed in the world ocean by satellite images, though with quite few explanations. In this study a distorted and broadening ISW front across the northeastern South China Sea deep basin is presented by using synthetic aperture radar (SAR) image. To illustrate this peculiar front, a nonlinear refraction model is developed to simulate and evaluate the effects of realistic bottom topography, current, and stratification on its transformation. Simulated results in realistic oceanic environments show good agreements with this SAR-observed front. Based on separate and comparative results in different background environments, we demonstrate that the distortion is actually caused by the strong mesoscale currents at periphery of an anticyclonic eddy. Moreover, the broadening is due to the difference in change of wave half width at different rays, which is associated with the different transformation of ISWs across variable bottom topography in the deep basin.

  18. Identification of Surface Water Quality along the Coast of Sanya, South China Sea

    PubMed Central

    Wu, Zhen-Zhen; Che, Zhi-Wei; Wang, You-Shao; Dong, Jun-De; Wu, Mei-Lin

    2015-01-01

    Principal component analysis (PCA) and cluster analysis (CA) are utilized to identify the effects caused by human activities on water quality along the coast of Sanya, South China Sea. PCA and CA identify the seasonality of water quality (dry and wet seasons) and polluted status (polluted area). The seasonality of water quality is related to climate change and Southeast monsoons. Spatial pattern is mainly related to anthropogenic activities (especially land input of pollutions). PCA reveals the characteristics underlying the generation of coastal water quality. The temporal and spatial variation of the trophic status along the coast of Sanya is governed by hydrodynamics and human activities. The results provide a novel typological understanding of seasonal trophic status in a shallow, tropical, open marine bay. PMID:25894980

  19. Pseudolella major sp. nov. (Axonolaimidae, Nematoda) from the intertidal zone of the East China Sea

    NASA Astrophysics Data System (ADS)

    Wang, Chunming; Huang, Yong

    2016-03-01

    A new species of free-living nematode, Pseudolella major sp. nov. is described from the intertidal mudflats of Ximen Island in the East China Sea. Pseudolella major sp. nov. is characterized as follows: body length ~1 300 μm; short cephalic setae, 2-3 μm long; amphidial fovea loop-shaped with elongated ventral branch; ventral branch 50-60 μm long and extending past the base of buccal cavity; buccal cavity cylindrical with arching or spherical base; three heavy outwardly-curving odontia with blunt tips located at anterior of buccal cavity; pharynx short with posterior bulb; ventral gland cell elongate oval-shaped, located posterior to pharyngo-intestinal junction; excretory pore situated at the level of the middle of buccal cavity; tail conical to cylindrical; spicules arched, with double-cephalate proximal end; gubernaculum with a strong dorsal caudal apophysis.

  20. Free polyamine content during algal bloom succession in the East China Sea in spring 2010

    NASA Astrophysics Data System (ADS)

    Liu, Yan; Zhao, Weihong; Li, Caiyan; Miao, Hui

    2016-03-01

    We measured the concentrations and distribution of major polyamines (spermine, putrescine and spermidine) in seawater during successive spring algal blooms in an area of frequent harmful blooms in the East China Sea. Spermine, putrescine, and spermidine concentrations were analyzed by high performance liquid chromatography and ranged from 1-64, 7-81, and 0-19 nmol/L. Spermine was present at the highest concentrations, followed by putrescine and spermidine. In late April, when a diatom bloom dominated by Skeletonema costatum dispersed, polyamine concentrations increased, presumably as a result of diatom decomposition. In early May, when a dinoflagellate bloom dominated by Prorocentrum donghaiense occurred, the polyamine concentration decreased from the level seen in late April. The abundant polyamines that decomposed and were released during the diatom bloom in late April may have promoted the growth of P. donghaiense, resulting in its dominance.

  1. A new bioactive steroidal ketone from the South China Sea sponge Xestospongia testudinaria.

    PubMed

    He, Wen-Fei; Xue, Duo-Qing; Yao, Li-Gong; Li, Jia; Liu, Hai-Li; Guo, Yue-Wei

    2016-01-01

    A new steroidal ketone (1), with an ergosta-22,25-diene side chain, was obtained from the South China Sea marine sponge Xestospongia testudinaria. The structure of 1 was determined on the basis of detailed spectroscopic analysis and by comparison with literature. Compound 1 exhibited significant inhibitory activity against protein tyrosine phosphatase 1B (PTP1B), a key target for the treatment of type II diabetes and obesity, with an IC50 value of 4.27 ± 0.55 μM, which is comparable with the positive control oleanolic acid (IC50 = 2.63 ± 0.22 μM). PMID:26289715

  2. Bioactive pregnane steroids from a South China Sea gorgonian Carijoa sp.

    PubMed

    Zhao, Hong-Ying; Shao, Chang-Lun; Li, Zhi-Yong; Han, Lei; Cao, Fei; Wang, Chang-Yun

    2013-01-01

    A new pregnane steroid, 1, and three known analogues 2-4, have been isolated from a gorgonian Carijoa sp. collected from the South China Sea. The planar structure and relative configuration of 1 were elucidated from comprehensive spectroscopic data. Its absolute configuration was determined by application of the modified Mosher method. Compounds 1, 3 and 4 exhibited cytotoxicity against the human hepatoma cell line Bel-7402, with IC50 values of 9.33, 11.02 and 18.68 µM, respectively. Additionally, compound 1 exhibited promising antibacterial activity against Pseudomona puido, with a MIC value of 31 nM, which is approximately 5-fold more potent than ciprofloxacin (MIC = 156 nM). PMID:23503119

  3. Well log and seismic character of tertiary terumbu carbonate, South China Sea, Indonesia

    SciTech Connect

    May, J.A.

    1985-09-01

    The Esso Exploration and Production Inc. Natuna DAlpha block lies approximately 125 mi (200 km) northeast of Natuna Island in the Indonesian portion of the South China Sea. The block contains a large Miocene platform carbonate complex called the L-structure. The Terumbu Formation L-structure, situated in front of and isolated from a much larger carbonate shelf, is similar to the carbonate atolls developed in front of the barrier-reef complex offshore of Belize. The lower platform and upper platform have a similar log character. The detrital facies is composed of fore-reef talus, pelagic, and hemipelagic carbonates. By mapping the Terumbu carbonate facies, the growth history of the L-structure is revealed.

  4. Coherent and incoherent internal tides in the southern South China Sea

    NASA Astrophysics Data System (ADS)

    Liu, Qian; Xie, Xiaohui; Shang, Xiaodong; Chen, Guiying

    2016-03-01

    Coherent and incoherent internal tides (CITs and ICITs) in the southern South China Sea were investigated from two sets of 18-month mooring current records. The CITs were mainly composed of diurnal Q 1, O 1, P 1 and K 1 and semidiurnal M 2. The observed diurnal internal tides (ITs) were more coherent than the semidiurnal constituents. Coherent diurnal variance accounted for approximately 58% of the diurnal motion, whereas semidiurnal tides contained a much smaller fraction (35%) of coherent motion. The ICITs mainly consisted of motion at non-tidal harmonic frequencies around the tidal frequency, and showed clear intermittency. The modal decomposition of CITs and ICITs showed that CITs were dominated by mode- 1, whereas mode-1 and higher modes in ICITs signals showed comparable amplitudes. CITs and ICITs accounted for approximately 64% and 36% of the total kinetic energy of internal tides, respectively.

  5. Using mutiproxy approach to reconstruct 1991 coral mortality episode in the South China Sea

    NASA Astrophysics Data System (ADS)

    WU, C. C.; Shen, C. C.; Chang, C. C.; Chou, Y. M.; Pallister, J. S.; Lam, D. D.; Yu, K. F.; Yi, L.; Wang, C. C.; Chung, S. L.

    2015-12-01

    A mysterious coral mortality occurred in low-latitude of western Pacific and eastern Indian Ocean, during late summer and fall 1991, cannot be simply attributed to El Niño/Southern Oscillation (ENSO) episode. Here we present a significant multiproxy records of two modern Porites corals, collected from Son Tra Island (16° 13' N, 108° 12' E) and the Meiji Reefs (9° 55' N, 115° 32' E), in the western and southern South China Sea (SCS), to probe this coral mortality episode. Both abrupt tephra-inferred REE anomalies reveal that a large amount of fallout by Mt. Pinatubo eruption (15° 14' N, 120° 35' E) was sufficient to wreck coral reef ecosystems, leading to the coral mortality in late 1991. Our findings highlight an abrupt event like a giant volcano eruption, may escalate the threat to marine ecosystems under IPCC AR5 global warming scenarios.

  6. Seismic, satellite, and site observations of internal solitary waves in the NE South China Sea.

    PubMed

    Tang, Qunshu; Wang, Caixia; Wang, Dongxiao; Pawlowicz, Rich

    2014-01-01

    Internal solitary waves (ISWs) in the NE South China Sea (SCS) are tidally generated at the Luzon Strait. Their propagation, evolution, and dissipation processes involve numerous issues still poorly understood. Here, a novel method of seismic oceanography capable of capturing oceanic finescale structures is used to study ISWs in the slope region of the NE SCS. Near-simultaneous observations of two ISWs were acquired using seismic and satellite imaging, and water column measurements. The vertical and horizontal length scales of the seismic observed ISWs are around 50 m and 1-2 km, respectively. Wave phase speeds calculated from seismic observations, satellite images, and water column data are consistent with each other. Observed waveforms and vertical velocities also correspond well with those estimated using KdV theory. These results suggest that the seismic method, a new option to oceanographers, can be further applied to resolve other important issues related to ISWs. PMID:24948180

  7. Near-surface circulation in the South China Sea during the winter monsoon

    NASA Astrophysics Data System (ADS)

    Centurioni, L. R.; Niiler, P. N.; Lee, D.-K.

    2009-03-01

    Original velocity measurements at 15 m depth from Surface Velocity Program drifters are used to calculate the circulation in the South China Sea during the Winter Monsoon. The Ekman currents are computed with a new method and subtracted from drifter's velocity to calculate the residual circulation, which is approximately in geostrophic balance. The Ekman flow is nearly zonal and comparable to the zonal geostrophic flow in the northern basin. The geostrophic flow is cyclonic and extends into the southern Luzon Strait. Strong jets occur south of Hainan, off Vietnam and, to the south, off peninsular Malaysia. The Vietnam jet is concentrated inshore of the 200 m isobath, with mean speeds in excess of 1 m s-1. The onshore Ekman transport and pumping velocity computed from the wind stress curl offer a qualitative explanation of the existence and behavior of such jets.

  8. Assessment of metal contamination in surface sediments from Zhelin Bay, the South China Sea.

    PubMed

    Wang, Zhao-Hui; Feng, Jie; Jiang, Tao; Gu, Yang-Guang

    2013-11-15

    Metals and biogenic elements were analyzed from surface sediments collected from Zhelin Bay in the South China Sea in December 2008. The high concentrations of TOC, TN and BSi indicate the high nutrient level and diatom productivity in Zhelin Bay. The concentrations of metals were generally far lower than the effects-range-low (ERL) values that define pollutant levels. Enrichment factors (EF) and geoaccumulation indices (Igeo) suggest there are pollution levels of Cd, Cu and Zn at some stations. As, Cu, and Pb are potentially biotoxic in some stations. Correlation and principal component analyses indicate that most of the metals primarily originate from natural sources, and from maricultural activities as well. Mariculture contributes considerable Cd and Cu contamination. As and Pb comes primarily from combustion of gasoline and diesel fuel by ships. PMID:23998852

  9. Spatial variability of dissolved phosphorous concentrations and alkaline phosphatase activity in the East China Sea

    NASA Astrophysics Data System (ADS)

    Liu, H.; Chang, J.; Ho, T.; Gong, G.

    2010-12-01

    The concentrations of dissolved inorganic phosphorus (DIP) and alkaline phosphatase activity (APA) have been determined at about 25 sampling stations in the East China Sea since 2003. The stations are mainly distributed from the Changjiang river mouth to northern Taiwan and east to the shelf break. In addition to the Changjiang discharge, we have found a specific nutrient source around a coastal site (122° 2’30’’ E, 28° 40’ N). Elevated DIP and nitrate concentrations have been constantly observed around the sampling station for 8 years, where the surface DIP concentrations are generally around 0.3 µM. The nutrient source may either originate from ground water discharge or coastal upwelling, where lower temperature has been observed in the water column around the station. In general, APA has been negatively correlated with DIP concentrations in the studies sites, with lowest APA around the high DIP station and the Changjiang river mouth.

  10. Lead in the western South China Sea: Evidence of atmospheric deposition and upwelling

    NASA Astrophysics Data System (ADS)

    Chen, Mengli; Goodkin, Nathalie F.; Boyle, Edward A.; Switzer, Adam D.; Bolton, Annette

    2016-05-01

    In recent decades, rapid industrial developments have increased lead (Pb) inputs to the South China Sea. To quantify the increasing variability, we investigated 170 years of skeletal Pb and Pb isotopes from an offshore, central Vietnamese coral. The Pb/Ca in the coral was 10-16 nmol/mol before the mid-1950s and increased to more than 30 nmol/mol by 2000. While the regional phaseout of leaded petrol commenced in 2000, coral Pb/Ca continued increasing until 2004, possibly due to regional upwelling and the transport of previously emitted Pb from tropical Pacific waters. The 206Pb/207Pb ratio in the coral was 1.191-1.195 before mid-1950s, suggesting natural sources. Since then, the ratio decreased, reaching ~1.165 in 2004. Lead isotopes show high linearity between natural and Chinese emitted Pb, with the latter contributing ~40%~60% of the skeletal Pb after 2000.

  11. Assessment on vulnerability of coastal wetlands to sea level rise in the Yangtze Estuary, China

    NASA Astrophysics Data System (ADS)

    Cui, L.; Ge, Z.; Zhang, L.

    2013-12-01

    The Yangtze Delta in China is vital economic hubs in terms of settlement, industry, agriculture, trade and tourism as well as of great environmental significance. In recent decades, the prospect of climate change, in particular sea level rise and its effects on low lying coastal areas have generated worldwide attention to coastal ecosystems. Coastal wetlands, as important parts of coastal ecosystem, are particularly sensitive to sea level rise. To study the responses of coastal wetlands to climate change, assess the impacts of climate change on coastal wetlands and formulate feasible and practical mitigation strategies are the important prerequisites for securing the coastal zone ecosystems. In this study, taking the coastal wetlands in the Yangtze Estuary as a case study, the potential impacts of sea-level rise to coastal wetlands habitat were analyzed by the Source-Pathway-Receptor-Consequence (SPRC) model. The key indicators, such as the sea-level rise rate, subsidence rate, elevation, daily inundation duration of habitat and sedimentation rate, were selected to build a vulnerability assessment system according to the IPCC definition of vulnerability, i.e. the aspects of exposure, sensitivity and adaptation. A quantitatively spatial assessment method on the GIS platform was established by quantifying each indicator, calculating the vulnerability index and grading the vulnerability. The vulnerability assessment on the coastal wetlands in the Yangtze Estuary under the sea level rise rate of the present trend and IPCC A1F1 scenario were performed for three sets of projections of short-term (2030s), mid-term (2050s) and long-term (2100s). The results showed that at the present trend of sea level rise rate of 0.26 cm/a, 92.3 % of the coastal wetlands in the Yangtze Estuary was in the EVI score of 0 in 2030s, i.e. the impact of sea level rise on habitats/species of coastal wetlands was negligible. While 7.4 % and 0.3 % of the coastal wetlands were in the EVI score of

  12. China's Yangtze delta: Geochemical fingerprints reflecting river connection to the sea

    NASA Astrophysics Data System (ADS)

    Gu, Jiawei; Chen, Jing; Sun, Qianli; Wang, Zhanghua; Wei, Zixin; Chen, Zhongyuan

    2014-12-01

    This study investigates sediment source to sink relating the connection of the Yangtze River to the sea. A sediment borehole (PD) on the river coast, penetrating thick Quaternary sediments and thin sediments of late Pliocene age down to the bedrock, recorded a change in sediment provenance through time. Geochemical elements and magneto-stratigraphy help identify five zones. Zone I (the late Pliocene-the Early Pleistocene), characterized by Pb, Th, U, Ba, La, Ce, Nd, Hf, Y, Zr, Nb and Mn, indicates a local sediment provenance. This means that the study area was a localized sub-basin. Zone II (the Early Pleistocene-the mid-stage of the Early Pleistocene), with remarkable high Fe, K, As and Rb implies a new sediment provenance joining the sub-basin from the middle Yangtze reach after the opening of the Zhenjiang Gorge. Zone III (the mid-stage of Early Pleistocene-the Middle Pleistocene), featured by Ti, V, Cr, Sr, Sc, Cu, Co, Ni, Mg, Ca, Na and P suggests a further extension of sediment provenance to the upper Yangtze basin, where a large block of the E'mei basalt and carbonate occurs. This suggests that the Three Gorges valley linking the upper and middle Yangtze reaches had developed by that time. Zones IV and V (the Middle Pleistocene-the Holocene) have shown their geochemical similarity to Zone III. Discrimination ratio f(Cr, Th), f(La) and f(K, La), a new approach developed for tracing sediment provenance, confirms a basin-wide sediment source through Zones III-V. These together witness a progressive extension of the sediment provenance towards the upper Yangtze basin, corresponding to the long-term tilting effect of the Cenozoic Topographic Reversal of the eastern China continent. The timing of the Yangtze River running through into the East China Sea appears at ca. 1.0-1.2 Ma (bottom of Zone III).

  13. Spatial variations in the Kuroshio nutrient transport from the East China Sea to south of Japan

    NASA Astrophysics Data System (ADS)

    Guo, X. Y.; Zhu, X.-H.; Long, Y.; Huang, D. J.

    2013-04-01

    Based on absolute geostrophic velocity calculated from repeated hydrographic data of 39 cruises from 2000 to 2009 and nitrate concentrations measured at the same sections from 1964 to 2011, we obtained temporally averaged nitrate flux (the product of velocity and nitrate concentration) and nitrate transport (integration of flux over a section) through 4 sections along the Kuroshio path from the East China Sea (sections PN and TK) to south of Japan (sections ASUKA and 137E). In addition, we examined section OK east of the Ryukyu Islands in order to understand the contribution of Ryukyu Current to the Kuroshio nutrient transport south of Japan. The mean nitrate flux shows a subsurface maximum core with a value of 10, 10, 11, 11, and 6 mol m-2 s-1 at sections PN, TK, ASUKA, 137E, and OK, respectively. The depth of subsurface maximum core changes among five sections and is approximately 400, 500, 500, 400, and 800 m at sections PN, TK, ASUKA, 137E, and OK respectively. The mean downstream nitrate transport is 199.3, 176.3, 909.2, 1385.5, and 341.2 kmol m-1 at sections PN, TK, ASUKA, 137E, and OK respectively. The nutrient transports at these sections suggest the presence of Kuroshio nutrient stream from its upstream region to downstream. The deep current structure of Ryukyu Current (section OK) makes it contribute more nitrate transport than the Kuroshio in the East China Sea (section TK) to the Kuroshio south of Japan. In addition, the positive difference between the downstream nitrate transport through section ASUKA and the sum of nitrate transports through sections TK and OK, as well as the positive difference of downstream nitrate transport between sections 137E and ASUKA, suggest that the Kuroshio recirculation significantly intensifies the downstream (eastward) nitrate transport by the Kuroshio.

  14. Rifted Structure of the Vietnam Continental Margin Near the South China Sea Spreading Center

    NASA Astrophysics Data System (ADS)

    Reid, I. D.; Fyhn, M. B.; Boldreel, L. O.; Nielsen, L. H.; Duc, N. A.; Huyen, N. T.; Thang, L. D.

    2007-12-01

    The extinct spreading center of the South China Sea intersects the continental margin off Vietnam, providing an excellent opportunity to study the interaction of these two features. As part of a collaborative project between the Geological Survey of Denmark and Greenland, the University of Copenhagen and the Vietnam Petroleum Institute, the crustal structure of this area has been investigated by the use of seismic reflection profiles, to provide control on the sedimentary and basement structure, combined with modelling of gravity data from global satellite altimetry, to constrain the crustal thickness. A complex pattern of rifting is seen, which may be ascribed to the complex stress fields of the propagating rift axis, together with an apparent progression in structure. In the more oceanic area, the rifting is relatively sharp, with fairly rapid crustal thnning of about 10 km. Towards the continent, in the region of the tip of the rift axis, the crustal thinning is less, around 5-7 km, and takes place over a greater distance. In the absence of data on the deep crustal structure it is not possible to determine the absolute crustal thickness with certainty, but the gravity modelling suggests that the pre-existing crust was no more than 20 km thick, having been thinned in earlier stages of formation of the South China Sea. A preliminary analysis of the isostatic balance along the various transects was inconclusive but suggests that the sedimentary sequences are largely isostatically compensated, rather than being supported by lithospheric rigidity. Detailed modelling of the rifting and subsidence may provide further insight into the processes that occur when an oceanic spreading center intersects and propagates into a continental margin.

  15. Observed wintertime tidal and subtidal currents over the continental shelf in the northern South China Sea

    NASA Astrophysics Data System (ADS)

    Li, Ruixiang; Chen, Changsheng; Xia, Huayong; Beardsley, Robert C.; Shi, Maochong; Lai, Zhigang; Lin, Huichan; Feng, Yanqing; Liu, Changjian; Xu, Qichun; Ding, Yang; Zhang, Yu

    2014-08-01

    Synthesis analyses were performed to examine characteristics of tidal and subtidal currents at eight mooring sites deployed over the northern South China Sea (NSCS) continental shelf in the 2006-2007 and 2009-2010 winters. Rotary spectra and harmonic analysis results showed that observed tidal currents in the NSCS were dominated by baroclinic diurnal tides with phases varying both vertically and horizontally. This feature was supported by the CC-FVCOM results, which demonstrated that the diurnal tidal flow over this shelf was characterized by baroclinic Kelvin waves with vertical phase differences varying in different flow zones. The northeasterly wind-induced southwestward flow prevailed over the NSCS shelf during winter, with episodic appearances of mesoscale eddies and a bottom-intensified buoyancy-driven slope water intrusion. The moored current records captured a warm-core anticyclonic eddy, which originated from the southwestern coast of Taiwan and propagated southwestward along the slope consistent with a combination of β-plane and topographic Rossby waves. The eddy was surface-intensified with a swirl speed of >50 cm/s and a vertical scale of ˜400 m. In absence of eddies and onshore deep slope water intrusion, the observed southwestward flow was highly coherent with the northeasterly wind stress. Observations did not support the existence of the permanent wintertime South China Sea Warm Current (SCSWC). The definition of SCSWC, which was based mainly on thermal wind calculations with assumed level of no motion at the bottom, needs to be interpreted with caution since the observed circulation over the NSCS shelf in winter included both barotropic and baroclinic components.

  16. Seismic Stratigraphy of the Central South China Sea Basin and Implications for Neotectonics

    NASA Astrophysics Data System (ADS)

    Li, C. F.; Ding, W.; Franke, D.; Yao, Y.; Pang, X.; Shi, H.; Li, J.; Cao, Y.

    2014-12-01

    International Ocean Discovery Program (IODP) Expedition 349 drilled five sites in the central South China Sea Basin. Three sites (U1431 in the East Subbasin, and U1433 and U1434 in the Southwest Subbasin) reached basalt interpreted to be igneous basement of the oceanic crust. Site U1435 on the northern continent-ocean boundary recovered pre-Oligocene sedimentary rocks deposited prior to the opening of the South China Sea. Furthermore, a full suite of geophysical logging was also carried out at Sites U1431 and U1433. These coring and logging data and physical property measurements are integrated with, and correlated to, regional reflection seismic data to map regional sequence stratigraphic boundaries and seismic facies of the central basin and the continent-ocean transition zone. With our carefully selected seismic profiles, stratigraphic correlation is possible even between the continent-ocean transition zone and the central basin, circumventing preexisting basement highs near the continent-ocean boundary that often prevent direct correlation. We interpret four sequence boundaries, which are Oligocene/Miocene, middle Miocene/late Miocene, Miocene/Pliocene, and Pliocene/Pleistocene boundaries. Seismic facies between sequence boundaries are often characteristic and distinctive, allowing relatively straightforward regional correlation. For example, massive Miocene carbonate deposits, if well consolidated, are readily distinguishable by strong seismic reflectivities, caused by their relatively higher density and velocity in contrast to those of interbedded turbidite clastic sediments. However, we found abrupt seismic facies changes both temporally and spatially. In particular, the fossil spreading ridge and the Zhongnan ridge between the East and Southwest Subbasins acted as major sedimentary barriers, across which seismic facies changes sharply and cannot be easily correlated. The well-constrained seismic sequence boundaries also allow us to estimate the timing of

  17. Reservoir delineation using high resolution seismic data in the South China Sea

    SciTech Connect

    Tsay, D.L.J.

    1996-12-31

    Conventional seismic data with the frequency bandwidth of 10-80 hz has been playing an invaluable role in mapping favorable subsurface structure for initial exploratory drilling. However, in order to characterize the reservoir properties over the discovered field for reservoir delineation, the seismic data must have the frequency components higher than 80 hz. This is particularly true when the desirable reservoir properties to be delineated are the thickness and porosity of several thin layers within the Miocene carbonate reservoir in the South China Sea. In this paper, two methods of enhancing seismic resolution will be discussed and illustrated with the examples of real data taken from the South China Sea. The first method of enhancing seismic resolution is to apply the technique of spectral whitening to the original seismic data. The resulted data shows that the frequency bandwidth is almost doubled from the original 10-80 hz to 10-140 hz. As a result, the thickness of each thin layer within Miocene carbonate reservoir can be resolved at 7m instead of 12m from the original data. The second method is to designed a new field parameter by using a shallower towed depth of seismic energy source at 4m instead of 6m used previously. Because of shallower towed depth, the first notch of source ghost becomes higher and leads to higher resolution of acquired field data with the frequency range of 10-140 hz. Consequently, a thin bed of 7m within carbonate reservoir can be resolved. The success of enhancing seismic resolution has led to better reservoir delineation, drilling operation design and development plan.

  18. The sensitivity of the general circulation to Arctic Sea ice boundaries - A numerical experiment

    NASA Technical Reports Server (NTRS)

    Herman, G. F.; Johnson, W. T.

    1978-01-01

    Results are presented for a set of numerical experiments conducted with the Goddard (formerly GISS) general circulation model. The experiments were designed to test the model atmospheric response to a single fixed and specified parameter, the total ice cover in the Davis Strait, Barents Sea, East Greenland Sea, Sea of Okhotsk and Bering Sea. Margin variations are considered that are substantially smaller than those involved in ice age or ice-free Arctic simulations. Anomaly is defined as the mean of two runs corresponding to climatological maximum sea ice conditions. Model results indicate that the ice margin anomalies are capable of altering local climates in certain regions of high and middle latitudes. Possible interactions between high latitudes and subtropical regions are suggested.

  19. Rapid East Asian Monsoon change during the Last Interglacial in the Bohai Sea Coastal Zone, China

    NASA Astrophysics Data System (ADS)

    Du, S.; Li, B.; Chen, M.; Zhang, D.; Xiang, R.; Niu, D.

    2013-12-01

    The Bohai Sea coastal zone of China faces the Pacific Ocean to the east and the Eurasian continent to the west, hence, this region is influenced by both the ocean and continental landmasses. The Bohai Sea coastal zone has significant monsoon climate characteristics and a strong sensitivity to climate change. The Miaodao stratigraphical section (MDS) contains historical information about climate features in the region, especially the high-frequency variations during the last interglacial, sea level changes, and the evolution of the East Asian monsoon. By analyzing the ages of different sedimentary facies in combination with proxy paleoclimatic indices (i.e., grain <63 μm fraction, average grain size (Mz), clay + silt/sand content (SC/D), magnetic susceptibility, and the ratios of Na2O/Al2O3 and (Al2O3+TOFe)/SiO2, in the fifth segments of the MDS from the last-interglacial (MDS5), we conclude that subsections 5a, 5c, and 5e were controlled by summer monsoons, whereas subsections 5b and 5d were formed when winter monsoons prevailed. These results were similar to oxygen isotope analyses from previous studies including the Spectral Mapping Project (SPECMAP) and the North Greenland Ice Core Project (NorthGRIP). Five and a half comparable oscillations in proxy indices that were dated to ca. 116.1, 118.3, 121.2, 122.7, 125.9, and 128.7 ka occurred within the MDS 5e subsection when winter monsoon winds strengthened. This millennial-scale climate variability during the Eemian period may have reached up to ten and a half oscillations with a quasi-periodicity of approximately a 1,470 year cycle during the late glacial period. This rapid period of climate change has been recorded in northern and central Europe, central Asia, as well as in East Asia. The climate forming mechanism was probably initiated by changes in solar activity, and driven by the East Asian monsoon and sea level oscillations. Comparison of Miaodao section records with other paleoclimatic records during the

  20. Orbital Variation in South China Sea Nitrogen Fixation over the Past 420,000 yrs

    NASA Astrophysics Data System (ADS)

    Ren, H. A.; Sigman, D. M.; Anderson, R. F.; Martinez-Garcia, A.; Chen, M.; Straub, M.; Haug, G. H.

    2012-12-01

    Previous records of planktonic foraminifera shell-bound nitrogen isotopes (FB-δ15N) in the Caribbean Sea and the South China Sea (SCS) both indicate lower nitrogen fixation during the last glacial maximum than the current interglacial and have been explained as a N fixation response to the supply of excess phosphorus ultimately arising from denitrification. In this study, we extended the FB-δ15N record in the SCS (MD97-2142) back to 420 ka. The extended SCS record confirms previous findings that the N fixation rate was higher during interglacials. The full glacial/interglacial amplitude of the SCS N fixation change is similar to that observed in the Caribbean. At all 5 glacial terminations, an increase in N fixation in the SCS coincides with the G. ruber δ18Oc decrease, sea level rise, and the deglacial increase in water column denitrification in the eastern tropical North Pacific, although the SCS FB-δ15N decrease appears to be slower than the δ18O decrease in the two most recent terminations. More broadly, SCS FB-δ15N and δ18Oc are similar in large scale structure and together imply a strong connection of SCS N fixation to sea level. This is arguably to be expected, as the extensive continental shelf area adjacent to the southern SCS appears to be a global hotspot for benthic denitrification during interglacials, while this shelf area would have been nearly completely lost during peak ice ages. For the interglacials in which there is a clear precession cycle in SCS FB-δ15N, δ15N minima lag δ18Oc minima by about 5-7 kyrs at the precession band. This suggests that the N fixation maxima are roughly anti-phased with water column denitrification, which peaks during northern hemisphere warm phases. On the precession time scale, maxima in N fixation rate (minima in FB-δ15N) coincide with stronger upwelling and shallower thermocline depth as indicated by changes in planktonic foraminifera species abundance at the same site. We infer that periods of lower

  1. Mesoscale Dongsha Cyclonic Eddy in the northern South China Sea by drifter and satellite observations

    NASA Astrophysics Data System (ADS)

    Chow, Chun-Hoe; Hu, Jian-Hwa; Centurioni, Luca R.; Niiler, Pearn P.

    2008-04-01

    Near the center of the northern South China Sea (NSCS), the Dongsha atoll is situated on the continental slope that runs from Taiwan to Hainan. A mesoscale cyclonic eddy, south or southwest of Dongsha, seems to appear annually and has been identified as the Dongsha Cyclonic Eddy (DCE). Historical drifter (1988-2005) and satellite altimeter (2000-2005) data were adopted to study the variations to, and characteristics of, the DCE. Some typical features were derived such as mean tangential speed of ˜20 cm/s, moving speed of ˜8 km/d (i.e., 9 cm/s), eddy size of ˜22 × 103 km2, center sea surface lowering (height difference, DIF) of ˜6 cm, and angular velocity of ˜9°/d. Mean tangential speeds of 12-16 cm/s in late spring and summer are slower than those of 16-31 cm/s in winter and early spring. Moving speeds are of the order of the Rossby wave at NSCS latitudes. Variations in the time series of eddy size and DIF are generally similar and show a positive linear relation between them. The DCE starts near Dongsha and moves southwestward along the continental slope at a depth of 1000-2000 m. The eddy peaks with maximum eddy size and DIF when reaching 114°E, and then diminishes south of Hainan because of trapping of the underwater bay formed by the continental slope. The DCE typically exists 1-2 times per year and lasts 1-3 months. Roughly 90% of observed DCEs formed in winter or spring. A unique DCE was identified in the summer of 2000 and lasted for over 4 months. Its birth was associated with typhoon Kai-Tak. The positive linear relationship between eddy size and DIF in this case was unique before reaching 114°E and then returned to the typical relationship of other DCEs. The DIF of this unique DCE attained the highest of 24 cm right at the climax longitude. According to AVHHR and SeaWIFs images, such a DCE is associated with a core of which sea surface temperature is ˜2°C lower and chlorophyll-a concentration is ˜0.1 mg/m3 higher than those of surrounding seas

  2. Particulate organic matter in the northwest East China Sea: Implications from amino acids enantiomers

    NASA Astrophysics Data System (ADS)

    Zhu, Z. Y.; Zhang, J.; Wu, Y.; Shao, L.

    2012-04-01

    The north west East China Sea along the main land coast of China is an important region under the strong influence of the Changjiang (Yangtze) River. It is a main pathway for the particulate matter of the Changjiang travelling to the open ocean. An investigation was carried out in this interesting region north in May, 2007. Besides common parameters such as pH, nutrients, organic carbon and particulate nitrogen (PN), particulate amino acids enantiomers (PAA) were analyzed for all the surface samples and two typical sections. As influenced by strong terrestrial input, nutrients (e.g. dissolved inorganic nitrogen) in the surface increased much when closing the river mouth. Total suspended matter (TSM) concentrated in region close to the river mouth and around Zhoushan Archipelago, which then quickly decreased seawards. PN and PAA ranged from 0.6-7.8 μmol/L and 0.46-5.53 μmol/L, respectively. Elevated PAA concentration can be found along TSM front area. Asx, Glx and Gly were the main amino acids contributors. D-enantiomers accounts for 2%-7.6% of total PAA, indicating the activities of microbial activities. Relatively higher Degradation index (DI) suggests that particulate matter in this region is fresh, relative to other regions in the world.

  3. Holocene paleomagnetic secular variation from East China Sea and a PSV stack of East Asia

    NASA Astrophysics Data System (ADS)

    Zheng, Yan; Zheng, Hongbo; Deng, Chenglong; Liu, Qingsong

    2014-11-01

    Paleomagnetic secular variation (PSV) provides information on the mechanisms of the geodynamo and can also be used for stratigraphic correlation on a regional scale. In this study, we constructed PSV curves of relative rapidly deposited Holocene marine sequence from East China Sea. Results show that the dominant magnetic carriers are pseudo-single domain (PSD) to multidomain (MD) magnetites. Paleomagnetic directions are preserved by coarse-grained magnetite, even affected by post-depositional diagenetic alteration. The PSV record of core MD06-3040 exhibits six major inclination peaks and five declination swings during the Holocene. The periodicities for inclination are about 2000 and 550 years, and for declination are about 1400 and 500 years. The PSV of MD06-3040 is comparable to archeomagnetic and historic results for the last 2500 years and to PSV results from lake sediments in southern China and Japan during the Holocene. A PSV stack of East Asia is constructed by sedimentary and archeological PSV results, which can be used as an important reference curve for a large region, and the PSV correlation between sites can be applied for relative dating of East Asia.

  4. Performances of seven datasets in presenting the upper ocean heat content in the South China Sea

    NASA Astrophysics Data System (ADS)

    Chen, Xiao; Yan, Youfang; Cheng, Xuhua; Qi, Yiquan

    2013-09-01

    In this study, the upper ocean heat content (OHC) variations in the South China Sea (SCS) during 1993-2006 were investigated by examining ocean temperatures in seven datasets, including World Ocean Atlas 2009 (WOA09) (climatology), Ishii datasets, Ocean General Circulation Model for the Earth Simulator (OFES), Simple Ocean Data Assimilation system (SODA), Global Ocean Data Assimilation System (GODAS), China Oceanic ReAnalysis system (CORA), and an ocean reanalysis dataset for the joining area of Asia and Indian-Pacific Ocean (AIPO1.0). Among these datasets, two were independent of any numerical model, four relied on data assimilation, and one was generated without any data assimilation. The annual cycles revealed by the seven datasets were similar, but the interannual variations were different. Vertical structures of temperatures along the 18°N, 12.75°N, and 120°E sections were compared with data collected during open cruises in 1998 and 2005-08. The results indicated that Ishii, OFES, CORA, and AIPO1.0 were more consistent with the observations. Through systematic comparisons, we found that each dataset had its own shortcomings and advantages in presenting the upper OHC in the SCS.

  5. Geophysics Characteristic on Gas Hydrates Zone in Northern South China Sea

    NASA Astrophysics Data System (ADS)

    Sha, Zhibin

    2015-04-01

    Gas hydrates are very important because of their vast resources potential, their roles as submarine geohazard, and their effects on global climate in the word. In China, the research of gas hydrates was initiated further later ,but the South China Sea has found a number of geophysical anomalies of gas hydrate by researching of almost 10 years. In order to determine the nature and distribution of marine gas hydrate, a series of geophysical techniques are used. By using the traditional seismic data processing, purpose seismic data processing, wave impedance inversion techniques and geophysical well logging data processing based on Self-organizing feature map neural network, a great deal of useful information are abstracted to determine the gas hydrate zone beneath the seabed. The results show (1) Conventional multi-channel seismic reflection processing data from the SCS reveal various seismic indicators of gas hydrate and associated gas, such as the BSR, enhanced reflections below the BSR, Weak reflection or blanking zone above the BSRs.;(2) special processing techniques, such as attribute extraction and wave impedance inversion, is necessary so as to mine more effective data, they could compensate the shortage of conventional seismic data processing techniques used for distinguishing gas-bearing reservoirs;(3) as a kind of intelligent information processing technology, SOFM neural network is feasible for lithologic identification by logging data and has a high rate of identification of gas hydrate. In the end, the author hopes it may provide some useful clues to the exploration of gas hydrate.

  6. Gas hydrate saturation from acoustic impedance and resistivity logs in the shenhu area, south china sea

    USGS Publications Warehouse

    Wang, X.; Wu, S.; Lee, M.; Guo, Y.; Yang, S.; Liang, J.

    2011-01-01

    During the China's first gas hydrate drilling expedition -1 (GMGS-1), gas hydrate was discovered in layers ranging from 10 to 25 m above the base of gas hydrate stability zone in the Shenhu area, South China Sea. Water chemistry, electrical resistivity logs, and acoustic impedance were used to estimate gas hydrate saturations. Gas hydrate saturations estimated from the chloride concentrations range from 0 to 43% of the pore space. The higher gas hydrate saturations were present in the depth from 152 to 177 m at site SH7 and from 190 to 225 m at site SH2, respectively. Gas hydrate saturations estimated from the resistivity using Archie equation have similar trends to those from chloride concentrations. To examine the variability of gas hydrate saturations away from the wells, acoustic impedances calculated from the 3 D seismic data using constrained sparse inversion method were used. Well logs acquired at site SH7 were incorporated into the inversion by establishing a relation between the water-filled porosity, calculated using gas hydrate saturations estimated from the resistivity logs, and the acoustic impedance, calculated from density and velocity logs. Gas hydrate saturations estimated from acoustic impedance of seismic data are ???10-23% of the pore space and are comparable to those estimated from the well logs. The uncertainties in estimated gas hydrate saturations from seismic acoustic impedances were mainly from uncertainties associated with inverted acoustic impedance, the empirical relation between the water-filled porosities and acoustic impedances, and assumed background resistivity. ?? 2011 Elsevier Ltd.

  7. In-situ burning - one method of effective oil spill response in the South China Sea

    SciTech Connect

    Boben, M.E.; Yanting, Yue

    1996-12-31

    Phillips Petroleum International Corporation Asia (PPICA) is the operator of the twin Xijiang Oilfields in the South China Sea. The very special characteristics of the Xijiang crude demanded that innovative means of cleanup be employed in the event of a major oil spill. The Xijiang crude has a very high wax content and high pour point. The crude must be heated to flow. In the event of a major oil spill, clean up would require non-traditional means of response. During the laboratory analysis it was discovered that if a specific thickness of crude could be contained on the surface of the water that it could be ignited and burned. The potential effectiveness of the burn was ascertained to be 95-98%. A decision was made in 1992 during the design engineering phase to utilize in-situ burning as the primary means of response in the event of a major oil spill. During April 1995 the first ever demonstration of in-situ burning was conducted in Shekou, Sheizhen, People`s Republic of China by Phillips Petroleum International Corporation Asia. This exercise clearly demonstrated the effectiveness of in-situ burning on the Xijiang crude.

  8. First record of Pantropical spotted dolphins Stenella attenuata in the Yellow Sea, China

    NASA Astrophysics Data System (ADS)

    Wu, Fuxing; Wang, Xianyan; Zhang, Qiuxia; Miao, Xing; Zhang, Ting; Zhu, Qian

    2015-07-01

    On October 1, 2009, sixteen dolphins were obtained from fishermen by incidental catching in the Yellow Sea, China. As the dolphins' skin color was ambiguous, morphological parameters were measured, and mitochondrial DNA cytochrome b (Cyt b) gene sequence was studied to identify the species. Morphological characteristics were consistent with Pantropical spotted dolphins, Stenella attenuata. Furthermore, a partial mitochondrial DNA cytochrome b (Cyt b) gene sequence as long as 328-bp was studied by extracting genomic DNA from the skins, and six haplotypes were detected in the sixteen dolphins. By comparing homologous sequences available in GenBank (www.ncbi.nlm.nih.gov), all the six haplotypes had maximal genetic similarity with Pantropical spotted dolphin. Eight species of cetacean (whales and dolphins) are now recognised in the Yellow Sea. To the best of our knowledge, this is the first record of Pantropical spotted dolphins from this region. Despite this species being listed as a Grade II National Key Protected Animal since 1988, little is known of its biology in Chinese waters. We recommend remedial research be undertaken to ensure appropriate management.

  9. Reversal process of the South China Sea western boundary current in autumn 2011

    NASA Astrophysics Data System (ADS)

    Zhang, Zhixin; Guo, Jingsong; Guo, Binghuo

    2016-05-01

    Using merged sea level anomaly and absolute geostrophic velocity products from satellite altimetry and Argos drifter data, we analyzed the reversal process of the South China Sea (SCS) western boundary current (SCSwbc) from a summer to winter pattern in 2011 and important oceanic phenomena during this process. Results show that the outbreak time of the northeast monsoon over the southern SCS lagged that over the northern SCS by about 1 month. During the SCS monsoon reversal period, the SCSwbc reversed rapidly into the winter pattern at the Guangdong continental slope in late September. Subsequently, the southward Vietnam coastal boundary current strengthened. However, the northward Natuna Current maintained a summer state until mid-October. Thus, the balance between the southward and northward currents was lost when they met, their junction moved gradually southward. However, a loop current formed southeast of Vietnam because the main stream of the Vietnam Offshore Current (VOC) remained near its original latitude. Meanwhile, the VOC and associated dipole circulation system strengthened. After mid-October, the northward Natuna Current began to weaken, the loop current finally shed, becoming a cool ring. The VOC and its associated dipole sub-basin circulation system also weakened gradually until it disappeared.

  10. Microbial biomarkers from the East China Sea and implications for paleoenvironmental reconstructions

    NASA Astrophysics Data System (ADS)

    Zhao, M.; Hu, W. J.; Duan, S. S.; Cao, L. Y.; Wang, Y. Y.; Zhao, S. Z.; Xing, L.

    2015-12-01

    We report the vertical and spatial distributions of isoprenoid glycerol dibiphytanyl glycerol tetraethers (GDGTs), ladderanes and phytoplankton biomarkers in suspended particulates from the East China Sea (ECS) to evaluate the living habitat and environments of the planktonic archaea Thaumarchaeota and anaerobic ammonium oxidation (anammox) bacteria, respectively. Maximum GDGT concentration mostly occurred in bottom waters while maximum phytoplankton biomarker concentration occurred in the surface layers; and these results from the ECS provides further evidence for the use of the TEX86 index as a proxy for bottom water temperature in shallow shelf sea environments. Ladderanes were detected in both surface and subsurface particulates, suggesting that anammox activity was widespread in both the hypoxia zone near the Changjiang Estuary and in the mid-shelf of the ECS. Thus, anaerobic condition is not a requirement for anammox bacteria; however, ladderane-derived anammox activity was higher in lower oxygen environments, confirming ladderanes as useful proxies for reconstructing hypoxia changes. Statistical analysis will be presented to assess the link between archaea (Thaumarchaeota) performing aerobic ammonia oxidation and bacteria (anammox) performing anaerobic ammonium oxidation in the ECS, the implications for both carbon and nitrogen cycles.

  11. Can Asian Dust Trigger Phytoplankton Blooms in the Oligotrophic Northern South China Sea?

    NASA Technical Reports Server (NTRS)

    Wang, Sheng Hsiang; Hsu, Nai-Yung Christina; Tsay, Si-Chee; Lin, Neng-Huei; Sayer, Andrew M.; Huang, Shih-Jen; Lau, William K. M.

    2012-01-01

    Satellite data estimate a high dust deposition flux (approximately 18 g m(exp-2 a(exp-1) into the northern South China Sea (SCS). However, observational evidence concerning any biological response to dust fertilization is sparse. In this study, we combined long-term aerosol and chlorophyll-a (Chl-a) measurements from satellite sensors (MODIS and SeaWiFS) with a 16-year record of dust events from surface PM10 observations to investigate dust transport, flux, and the changes in Chl-a concentration over the northern SCS. Our result revealed that readily identifiable strong dust events over this region, although relatively rare (6 cases since 1994) and accounting for only a small proportion of the total dust deposition (approximately 0.28 g m(exp-2 a(exp-1), do occur and could significantly enhance phytoplankton blooms. Following such events, the Chl-a concentration increased up to 4-fold, and generally doubled the springtime background value (0.15 mg m(exp-3). We suggest these heavy dust events contain readily bioavailable iron and enhance the phytoplankton growth in the oligotrophic northern SCS.

  12. Biodiversity of free-living marine nematodes in the southern Yellow Sea, China

    NASA Astrophysics Data System (ADS)

    Liu, Xiaoshou; Xu, Man; Hua, Er; Zhang, Zhinan

    2016-02-01

    Biodiversity patterns of free-living marine nematodes were studied using specific, taxonomic and phylogenetic diversity measures in the southern Yellow Sea, China. The results showed that the average of Shannon-Wiener diversity index ( H') in the study area was 3.17. The higher values were distributed in the east part of Shandong coastal waters and north part of Jiangsu coastal waters, while the lower values were distributed in the southern Yellow Sea Cold Water Mass (YSCWM). The average of taxonomic diversity ( Δ) was 62.09 in the study region. The higher values were distributed in the transitional areas between the coastal areas and the southern YSCWM, while the lower values were distributed near the north part of Jiangsu coastal waters and the YSCWM. Results of correlation analysis of species diversity and taxonomic diversity showed that some of the two kinds of diversity index were independent, which suggested that combining the two kinds of diversity indices can reflect the ecological characteristics better. A test for 95% probability funnels of average taxonomic distinctness and variation in taxonomic distinctness suggested that Station 8794 (in the YSCWM) was outside of the 95% probability funnels, which may be due to the environmental stress. Results of correlation analysis between marine nematodes biodiversity and environmental variables showed that the sediment characteristics (Mdø and Silt-clay fraction) and phaeophorbide a (Pha- a) were the most important factors to determine the biodiversity patterns of marine nematodes.

  13. The contribution of anthropogenic sources to the aerosols over East China Sea

    NASA Astrophysics Data System (ADS)

    Wang, Fujiang; Chen, Ying; Meng, Xi; Fu, Jiangping; Wang, Bo

    2016-02-01

    Total suspended particulate (TSP) samples were collected at a pristine island (Huaniao) in northern East China Sea (ECS) between Mar. 2011 and Jan. 2013 and analyzed for the concentrations of major ions and trace elements. Aerosol sources and the distribution of source regions are identified using positive matrix factorization (PMF) and potential source contribution function (PSCF) methods. It is found that aerosols over Huaniao Island are contributed by six main factors including primary industrial emissions (11.3%), secondary aerosol (22%), oxalate-associated aerosol (15.7%), sea salt (36.7%), ship emission (6.3%) and mineral dust (8.1%). Anthropogenic source contribution to the resolved aerosol mass reached the highest (76.6%) and lowest (18%) values in January 2013 and August 2012 respectively, strongly influenced by the prevailing winds of East Asian monsoon. The main source regions of secondary aerosol are southeastern Hebei and Shandong, which is consistent with the most intensive distribution of coal-fired power plants and the largest emission of precursors in this area. Oxalate-associated aerosol is produced primarily along the coastal line. Primary industrial emissions mainly originate from southwestern Shandong and Yangtze River Delta.

  14. Signals of the South China Sea summer rainfall variability in the Indian Ocean

    NASA Astrophysics Data System (ADS)

    He, Zhuoqi; Wu, Renguang; Wang, Weiqiang

    2016-05-01

    The present study investigates signals of the South China Sea (SCS) summer rainfall variability in the Indian Ocean. It is found that the SCS summer rainfall has a negative relationship with December-January-February (DJF) western-equatorial Indian Ocean (WIO) sea surface temperature (SST), a positive relationship with an asymmetric mode of precipitation anomalies in the tropical Indian Ocean during March-April-May (MAM), and a positive relationship with June-July-August (JJA) South Indian Ocean (SIO) SST. The WIO SST anomalies induce same-sign southeast Indian Ocean SST anomalies through an anomalous zonal vertical circulation. The southeast Indian Ocean SST anomalies last from late winter to early summer and induce opposite-sign SCS summer rainfall anomalies via an anomalous meridional vertical circulation. The asymmetric mode influences the SCS summer rainfall variation via the North Indian Ocean (NIO) SST anomalies with significant cloud-radiation and wind-evaporation effect. Positive (negative) SIO SST anomalies drive an anomalous direct circulation between the SIO and the NIO, and an anomalous indirect circulation between the NIO and the SCS which facilitates the occurrence of cyclonic (anti-cyclonic) wind anomalies over the SCS-western North Pacific and results in positive (negative) SCS summer rainfall anomalies. Partial correlation analysis indicates that the influence of DJF WIO SST anomalies and JJA SIO SST anomalies on the SCS summer rainfall is partly ENSO-independent, while the MAM asymmetric mode is mostly related to the preceding DJF eastern Pacific SST anomalies.

  15. Mesoscale eddies cases study at Xisha waters in the South China Sea in 2009/2010

    NASA Astrophysics Data System (ADS)

    Wang, Qiang; Zeng, Lili; Zhou, Weidong; Xie, Qiang; Cai, Shuqun; Yao, Jinglong; Wang, Dongxiao

    2015-01-01

    the observed currents at Xisha (110.3899°E, 17.1038°N) during May 2009 to May 2010, it is found that the kinetic energy has significant mesoscale variability, and each peak responds to large positive/negative ocean surface current curl caused by mesoscale eddies. Compared the kinetic energy with the wind stress work and the pressure work, it is also found that the barotropic pressure work which is mainly contributed by the sea surface height (SSH) corresponding to the mesoscale eddies behaves like the kinetic energy. The contribution of the mesoscale eddies to the kinetic energy can be up to 90% sometimes and reach deep level every time. Using the satellite altimeter data, the paths of mesoscale eddies contributing to the kinetic energy variability are traced back. In the winter half of the year, the mesoscale eddies propagating along the northern South China Sea shelf or across the basin from the west of the Philippines toward Xisha arrive at Xisha, influencing the kinetic energy. In the summer half of the year, the mesoscale eddies are mainly from the south, which were shed from the Vietnam coast current. And the cause for eddy shedding may be related to the relaxation of the Ekman transport anomalies.

  16. Effects of the Changjiang (Yangtze) River discharge on planktonic community respiration in the East China Sea

    NASA Astrophysics Data System (ADS)

    Chen, Chung-Chi; Shiah, Fuh-Kwo; Chiang, Kuo-Ping; Gong, Gwo-Ching; Kemp, W. Michael

    2009-03-01

    Planktonic communities tend to flourish on the western margins of the East China Sea (ECS) fueled by substrates delivered largely from the Changjiang River, the fifth largest river in the world. To study the effects of the Changjiang River discharge on planktonic community respiration (CR), physical-chemical variables and key processes were measured in three consecutive summers in the ECS. Results showed that concentrations of nitrate and Chl a, protozoan biomass, bacterial production, as well as CR in the surface water were all negatively correlated with sea surface salinity, reflecting the strong influence of river discharge on the ECS shelf ecosystem. Moreover, mean values of nitrate, Chl a concentrations, and CR rates were proportionally related to the area of Changjiang diluted water (CDW; salinity ≤31.0 practical salinity units (psu)), an index of river discharge rate. Presumably, higher river flow delivers higher nutrient concentrations which stimulate phytoplankton growth, which in turn fuels CR. CR exhibited significant monthly and interannual variability, and rates appear to be dominated by bacteria and phytoplankton. Although the plankton community was relatively productive (mean = 0.8 mg C m-2 d-1) in the CDW, the mean ratio of production to respiration was low (0.42). This suggests that the heterotrophic processes regulating CR were supported by riverine organic carbon input in addition to in situ autotrophic production.

  17. Aerosol deposition favors red tide phytoplankton in the East China Sea

    NASA Astrophysics Data System (ADS)

    Mackey, K. R.; Chien, C.; Chen, Y.; Glover, D. M.; Paytan, A.

    2013-12-01

    Chinese marginal seas support vast fisheries and vital economies, but their productivity is threatened by eutrophication from runoff and atmospheric deposition. The East China Sea is inundated with nitrogen from the Yangtze River and anthropogenic emissions, leading to elevated N:P ratios. We show that aerosol additions approximating one week of moderate deposition to offshore waters favor the growth of red tide phytoplankton, such as Skeletonema costatum, by providing nutrients and trace metals (iron and zinc) needed for growth. In contrast toxin-producing Pseudonitzchia does not benefit from aerosols in this region, possibly due to its preference for lower N:P ratios. A dose-dependent toxic response was observed in Synechococcus at high aerosol loads approximating a week of heavy deposition in the region. In contrast, phytoplankton growth at an onshore station was light limited, and aerosol additions did not have an appreciable effect on phytoplankton growth. Aerosol and chlorophyll observations from the Moderate Resolution Imaging Spectroradiometer (MODIS) satellite have the potential to explore the effect of aerosols on phytoplankton blooms over longer time scales and seasons. This study shows the potential for aerosols to control N:P ratios in offshore waters and to shape the phytoplankton community through fertilization and toxicity, contributing to the occurrence of red tides.

  18. The anticyclonic circulation in the southern South China Sea: Observed structure, seasonal development and interannual variability

    NASA Astrophysics Data System (ADS)

    Xiang, Rong; Fang, Wendong; Zhou, Sheng-Qi

    2016-02-01

    In situ hydrographic and current observations from cruises in 1998 and 1999, together with 20-year (1993-2012) sea level anomaly (SLA) data from satellite altermeter, have been used to study the vertical structure, seasonal development, and interannual variability of the anticyclonic circulation in the southern South China Sea (SCS). The relationship between the anticyclonic circulation and its northern flanking cyclonic eddy are described. Three associated circulation patterns are identified. The anticyclonic circulation is present for an average of 108 ± 30 days per year, while its northern flanking cyclonic eddy is present for an average of 54 ± 25 days per year. The intraseasonal variability of the anticyclonic circulation is intense as a result of advection with the flanking northern cyclone, which accompanies the gyre on average about 60% of the time. The vertical structure of the anticyclonic circulation in 1998 (1999) penetrated much deeper, and its horizontal scope became wider in June (July) than in April. The anticyclonic circulation shows some difference between 1998 and 1999, displaying earlier appearance, more northward position, and non-dipole pattern in 1998, suggesting that the interannual variability of the anticyclonic circulation is related to El Niño Southern Oscillation (ENSO) events. The effect of Sverdrup balance via westward propagating Rossby wave on the seasonal development of the anticyclonic circulation has been discussed.

  19. The positive effects of typhoons on the fish CPUE in the South China Sea

    NASA Astrophysics Data System (ADS)

    Yu, Jie; Tang, Danling; Chen, Guobao; Li, Yongzhen; Huang, Zirong; Wang, Sufen

    2014-08-01

    Due to the logistical difficulties associated with fish data sampling after typhoons, short-term effects of typhoons on fishery in the South China Sea (SCS) have not been well-understood. The present study is to evaluate the impacts on the fish catch per unit effort (CPUE) owing to the three typhoons Chanthu, Vicente, and Kai-tak in the northwestern SCS, using long-term fish catch data and satellite data. The results show that the CPUE of total catch and some sorted catches have been changing because of the typhoons. On total catch, firstly, the CPUE has increased approximately 0.32 kg h-1 kw-1, 0.20 kg h-1 kw-1, and 0.25 kg h-1 kw-1 during the three typhoon periods. Then, the CPUEs decreased to the pre-typhoon level in about three weeks. Thirdly, among the three typhoons, the slow-moving Chanthu has caused a larger increase in CPUE. The typhoons impact was two-pronged, depending on fish species. One is the positive effects on meso-demersal fishes, cephalopoda and pelagic fishes. The other is the increase in CPUE of low trophic level carnivorous fishes after the three typhoons. This research provided the first evidence of CPUE increase after typhoons in the open sea.

  20. Simulation of Nonlinear Internal Wave Generation in the Northeastern South China Sea

    NASA Astrophysics Data System (ADS)

    Zhang, Z.; Fringer, O. B.

    2006-12-01

    Large-amplitude nonlinear internal waves (NLIW) in the South China Sea (SCS) are hypothesized to be generated by the interaction of barotropic ocean tides with irregular topography on the eastern end of the sea, but because of a lack of detailed in-situ measurements, the exact location and mechanism remain unclear. To improve our understanding of NLIW generation, a high-resolution numerical simulation is employed with a three-dimensional nonhydrostatic unstructured grid Navier-Stokes simulator (SUNTANS). Both the Luzon Strait and Dongsha Islands are contained in our simulation domain to investigate the entire life cycle of NLIW, including tide-topography interaction (generation and dissipation), tide conversion and propagation. By imposing currents associated with nine tidal components obtained with the OSU Tidal Inversion Software (OTIS) over a 10-day spring tidal period in June 2005 and initializing the 950 km by 550 km domain with a representative summer stratification, we analyze results of east-west (u component) velocity profiles and temperature contours along several transects that cross the Batan Islands in the Luzon Strait, the Dongsha atoll, and mooring sites of recent field observations. These are analyzed in order to identify locations of NLIW generation, to examine the propagation characteristics of NLIW, and to determine how the properties of NLIW change as they propagate from their generation site at the Luzon Strait to the Dongsha atoll. Time series of model results are compared with and verified by data obtained in a 2005 SCS field campaign.