We present a method to unify the calculation of Green's functions for an electromagnetic(EM) transmitting source embedded in a homogeneous stratified medium.A virtual interface parallel to layer interfaces is intro...We present a method to unify the calculation of Green's functions for an electromagnetic(EM) transmitting source embedded in a homogeneous stratified medium.A virtual interface parallel to layer interfaces is introduced through the source location.The potentials for Green's function are derived by decomposing the partial wave solutions to Helmholtz's equations into upward and downward within boundaries.The amplitudes of the potentials in each stratum are obtained recursively from the initial amplitudes at the source level.The initial amplitudes are derived by coupling with the transmitting sources and following the discontinuity of the tangential electric and magnetic fields at the source interface.Only the initial terms are related to the transmitting sources and thus need to be modified for different transmitters,whereas the kernel connected with the stratified media stays unchanged.Hence,the present method can be easily applied to EM transmitting sources with little modification.The application of the proposed method to the marine controlled-source electromagnetic method(MCSEM) demonstrates its simplicity and flexibility.展开更多
Since the ocean bottom is a sedimentary environment wherein stratification is well developed, the use of an anisotropic model is best for studying its geology. Beginning with Maxwell's equations for an anisotropic mo...Since the ocean bottom is a sedimentary environment wherein stratification is well developed, the use of an anisotropic model is best for studying its geology. Beginning with Maxwell's equations for an anisotropic model, we introduce scalar potentials based on the divergence-free characteristic of the electric and magnetic (EM) fields. We then continue the EM fields down into the deep earth and upward into the seawater and couple them at the ocean bottom to the transmitting source. By studying both the DC apparent resistivity curves and their polar plots, we can resolve the anisotropy of the ocean bottom. Forward modeling of a high-resistivity thin layer in an anisotropic half-space demonstrates that the marine DC resistivity method in shallow water is very sensitive to the resistive reservoir but is not influenced by airwaves. As such, it is very suitable for oil and gas exploration in shallowwater areas but, to date, most modeling algorithms for studying marine DC resistivity are based on isotropic models. In this paper, we investigate one-dimensional anisotropic forward modeling for marine DC resistivity method, prove the algorithm to have high accuracy, and thus provide a theoretical basis for 2D and 3D forward modeling.展开更多
In planning and executing marine controlled-source electromagnetic methods, seafloor electromagnetic receivers must overcome the problems of noise, clock drift, and power consumption. To design a receiver that perform...In planning and executing marine controlled-source electromagnetic methods, seafloor electromagnetic receivers must overcome the problems of noise, clock drift, and power consumption. To design a receiver that performs well and overcomes the abovementioned problems, we performed forward modeling of the E-field abnormal response and established the receiver's characteristics. We describe the design optimization and the properties of each component, that is, low-noise induction coil sensor, low-noise Ag/AgCI electrode, low-noise chopper amplifier, digital temperature-compensated crystal oscillator module, acoustic telemetry modem, and burn wire system. Finally, we discuss the results of onshore and offshore field tests to show the effectiveness of the developed seafloor electromagnetic receiver and its performance: typical E-field noise of 0.12 nV/m/rt(Hz) at 0.5 Hz, dynamic range higher than 120 dB, clock drift lower than 1 ms/day, and continuous operation of at least 21 days.展开更多
In order to suppress the airwave noise in marine controlled-source electromagnetic (CSEM) data, we propose a 3D deconvolution (3DD) interferometry method with a synthetic aperture source and obtain the relative an...In order to suppress the airwave noise in marine controlled-source electromagnetic (CSEM) data, we propose a 3D deconvolution (3DD) interferometry method with a synthetic aperture source and obtain the relative anomaly coefficient (RAC) of the EM field reflection responses to show the degree for suppressing the airwave. We analyze the potential of the proposed method for suppressing the airwave, and compare the proposed method with traditional methods in their effectiveness. A method to select synthetic source length is derived and the effect of the water depth on RAC is examined via numerical simulations. The results suggest that 3DD interferometry method with a synthetic source can effectively suppress the airwave and enhance the potential of marine CSEM to hydrocarbon exploration.展开更多
Because of the special physico-chemical properties and toxicity of oil in ocean, it causes the acute and chronic toxicity in marine life, through food chain comes into human body, has a serious harm on human's health...Because of the special physico-chemical properties and toxicity of oil in ocean, it causes the acute and chronic toxicity in marine life, through food chain comes into human body, has a serious harm on human's health. This test analysis influence of oil pollution in ocean, provides theoretical guidance of governing.展开更多
Based on more than 4000 km 2D seismic data and seismic stratigraphic analysis, we discussed the extent and formation mechanism of the Qiongdongnan deep sea channel. The Qiongdongnan deep sea channel is a large incised...Based on more than 4000 km 2D seismic data and seismic stratigraphic analysis, we discussed the extent and formation mechanism of the Qiongdongnan deep sea channel. The Qiongdongnan deep sea channel is a large incised channel which extends from the east boundary of the Yinggehai Basin, through the whole Qiongdongnan and the Xisha trough, and terminates in the western part of the northwest subbasin of South China Sea. It is more than 570 km long and 4–8 km wide. The chaotic (or continuous) middle (or high) amplitude, middle (or high) continuity seismic facies of the channel reflect the different lithological distribution of the channel. The channel formed as a complex result of global sea level drop during early Pliocene, large scale of sediment supply to the Yinggehai Basin, inversion event of the Red River strike-slip fault, and tilted direction of the Qiongdongnan Basin. The large scale of sediment supply from Red River caused the shelf break of the Yinggehai Basin to move torwards the S and SE direction and developed large scale of prograding wedge from the Miocene, and the inversion of the Red River strike-slip fault induced the sediment slump which formed the Qiongdongnan deep sea channel.展开更多
A quasi-global high-resolution HYbrid Coordinate Ocean Model (HYCOM) is used to investigate seasonal variations of water transports through the four main straits in the South China Sea. The results show that the annua...A quasi-global high-resolution HYbrid Coordinate Ocean Model (HYCOM) is used to investigate seasonal variations of water transports through the four main straits in the South China Sea. The results show that the annual transports through the four straits Luzon Strait, Taiwan Strait, Sunda Shelf and Mindoro Strait are -4.5, 2.3, 0.5 and 1.7 Sv (1 Sv=106 m3s-1), respectively. The Mindoro Strait has an important outflow that accounts for over one third of the total inflow through the Luzon Strait. Furthermore, it indicates that there are strong seasonal variations of water transport in the four straits. The water transport through the Luzon Strait (Taiwan Strait, Sunda Shelf, Mindoro Strait) has a maximum value of -7.6 Sv in December (3.1 Sv in July, 2.1S v in January, 4.5Sv in November), a minimum value of -2.1 Sv in June (1.5 Sv in October, -1.0 Sv in June, -0.2 Sv in May), respectively.展开更多
Gametophytes of Laminaria japonica were cryopreserved in liquid nitrogen using encapsulation-dehydration with two-step cooling method. Gametophytes cultured at 10℃ and under continuous irradiance of 30 μmol m^-2 s^-...Gametophytes of Laminaria japonica were cryopreserved in liquid nitrogen using encapsulation-dehydration with two-step cooling method. Gametophytes cultured at 10℃ and under continuous irradiance of 30 μmol m^-2 s^-1 for 3 weeks were encapsulated in calcium alginate beads. The beads were dehydrated in 0.4 molLl sucrose prepared with seawater for 6 h, desiccated in an incubator set at 10℃ and 70% relative humidity for 4 h, pre-frozen at either -40℃ or -60℃ for 30 min, and stored in liquid nitrogen for 〉24 h. As high as 43% of survival rate was observed when gametophytes were thawed by placing the beads in 40℃ seawater and re-hydrated in 0.05 molL^-1 citrate sodium prepared using 30‰ NaCl 7 d later. More cells of male gametophytes survived the whole procedure in comparison with female gametophytes. The cells of gametophytes surviving the preservation were able to grow asexually and produce morphologically normal sporophytes.展开更多
Natural gas hydrates are considered as strategic resources with commercial potential in the 21st century. Obvious BSR characteristics will be shown on seismic profiles, if there exist natural gas hydrates. The AVO met...Natural gas hydrates are considered as strategic resources with commercial potential in the 21st century. Obvious BSR characteristics will be shown on seismic profiles, if there exist natural gas hydrates. The AVO method is one of the methods which can be used to identify and forecast lithologic characteristics and fluid properties by using the relationship between Amplitude and Offset. AVO anomaly is one of the significant signs to check out whether or not there is free gas below the BSR, so it can be used to detect natural gas hydrates from the seismic profile. Considering the geological and geophysical characteristics of the Okinawa Trough and making use of the techniques mentioned above, we can conclude that the conditions there are favorable for the formation and concentration of natural gas hydrates. By analyzing the data collected from the study area, one can discover many different anomalous phenomena on the seismic profile which are related to the existence of natural gas hydrates. Preliminary estimation of the natural gas hydrates in the Okinawa Trough shows that the trough is rich in natural gas hydrates and may become a potential important resources exploration area.展开更多
The development of robust damage detection methods for offshore structures is crucial to prevent catastrophes caused by structural failures. In this research, we developed an Improved Modal Strain Energy (IMSE) meth...The development of robust damage detection methods for offshore structures is crucial to prevent catastrophes caused by structural failures. In this research, we developed an Improved Modal Strain Energy (IMSE) method for detecting damage in offshore platform structures based on a traditional modal strain energy method (the Stubbs index method). The most significant difference from the Stubbs index method was the application of modal frequencies. The goal was to improve the robustness of the traditional method. To demonstrate the effectiveness and practicality of the proposed IMSE method, both numerical and experimental studies were conducted for different damage scenarios using a jacket platform structure. The results demonstrated the effectiveness of the IMSE method in damage location when only limited, spatially incomplete, and noise-polluted modal data is available. Comparative studies showed that the IMSE index outperformed the Stubbs index and exhibited stronger robustness, confirming the superiority of the proposed approach.展开更多
The global climate is intimately connected to changes in the polar oceans. The variability of sea ice coverage affects deep-water formations and large-scale thermohaline circulation patterns. The polar radiative budge...The global climate is intimately connected to changes in the polar oceans. The variability of sea ice coverage affects deep-water formations and large-scale thermohaline circulation patterns. The polar radiative budget is sensitive to sea-ice loss and consequent surface albedo changes. Aerosols and polar cloud microphysics are crucial players in the radioactive energy balance of the Arctic Ocean. The main biogenic source of sulfate aerosols to the atmosphere above remote seas is dimethylsulfide (DMS). Recent research suggests the flux of DMS to the Arctic atmosphere may change markedly under global warming. This paper describes climate data and DMS production (based on the five years from 1998 to 2002) in the region of the Barents Sea (30–35°E and 70–80°N). A DMS model is introduced together with an updated calibration method. A genetic algorithm is used to calibrate the chlorophyll-a (CHL) measurements (based on satellite SeaWiFS data) and DMS content (determined from cruise data collected in the Arctic). Significant interannual variation of the CHL amount leads to significant interannual variability in the observed and modeled production of DMS in the study region. Strong DMS production in 1998 could have been caused by a large amount of ice algae being released in the southern region. Forcings from a general circulation model (CSIRO Mk3) were applied to the calibrated DMS model to predict the zonal mean sea-to-air flux of DMS for contemporary and enhanced greenhouse conditions at 70–80°N. It was found that significantly decreasing ice coverage, increasing sea surface temperature and decreasing mixed-layer depth could lead to annual DMS flux increases of more than 100% by the time of equivalent CO2 tripling (the year 2080). This significant perturbation in the aerosol climate could have a large impact on the regional Arctic heat budget and consequences for global warming.展开更多
A dataset of surface current vectors with error estimate from 1999 to 2007 is derived from the trajectories of the Array for Real-time Geostrophic Oceanography (Argo) drifting on surface over the global ocean. The err...A dataset of surface current vectors with error estimate from 1999 to 2007 is derived from the trajectories of the Array for Real-time Geostrophic Oceanography (Argo) drifting on surface over the global ocean. The error of the estimated surface currents is about 4.7 cm s-1 which is equivalent to the accuracy of the currents determined from the surface drifters. Geographically, the Argo-derived surface currents can fill many gaps left by the Global Drifter Program due to the greater number of floats, and can provide a complementary in situ observational system for monitoring global ocean surface currents. The surface currents from the Argo floats are compared with the surface drifter-derived currents and the Tropical Atmosphere Ocean program (TAO) measurements. The comparisons show good agreement for both the current amplitude and the direction of surface currents. Results indicate the feasibility of obtaining ocean surface currents from the Argo array and of combining the surface currents from Argo and the ocean surface drifters for in situ mapping of the global surface currents. The authors also make the dataset available to users of interest for many types of applications.展开更多
Abstract A real-time photo-realistic rendering algorithm of ocean color is introduced in the paper, which considers the impact of ocean bio-optical model. The ocean bio-optical model mainly involves the phytoplankton,...Abstract A real-time photo-realistic rendering algorithm of ocean color is introduced in the paper, which considers the impact of ocean bio-optical model. The ocean bio-optical model mainly involves the phytoplankton, colored dissolved organic material (CDOM), inorganic suspended particle, etc., which have different contributionsto absorption and scattering of light. We decompose the emergent light of the ocean surface into the reflected light from the sun and the sky, and the subsurface scattering light. We estab- lish an ocean surface transmission model based on ocean bidirectional reflectance distribution function (BRDF) and the Fresnel law, and this model's outputs would be the incident light parameters of subsurface scattering. Using ocean subsurface scattering algorithm combined with bio-optical model, we compute the scattering light emergent radiation in different directions. Then, we blend the re- flection of sunlight and sky light to implement the real-time ocean color rendering in graphics processing unit (GPU). Finally, we use two kinds of radiance reflectance calculated by Hydrolight radiative transfer model and our algorithm to validate the physical reality of our method, and the results show that our algorithm can achieve real-time highly realistic ocean color scenes.展开更多
The pigments in Laminaria japonica was extracted with six organic solvents and analyzed in spectroscopy analysis. The extractions conditions were screened by an orthogonal test and the quantity of extracted pigments w...The pigments in Laminaria japonica was extracted with six organic solvents and analyzed in spectroscopy analysis. The extractions conditions were screened by an orthogonal test and the quantity of extracted pigments was determined spectroscopically. The results show that: (1) among the six organic solvents, acetone was the most effective one for the extraction; (2) the optimum extraction conditions were as follows: the ratio of S/M (solvent volume/material weight) was 30 ml/g; fresh seaweed was extracted 2 times in 2h; (3) the average total content of pigments was 1.85 mg/g (calculated with dry L. japonica).展开更多
Based on the ArcGIS geographic information system and the ORACLE database management system,this paper reports our studies on the technology of Marine Engineering Geological Exploration Information System(MEGEIS). By ...Based on the ArcGIS geographic information system and the ORACLE database management system,this paper reports our studies on the technology of Marine Engineering Geological Exploration Information System(MEGEIS). By analyzing system structure,designing function modules and discussing data management,this paper systematically proposes a framework of technol-ogy to integrate,manage,and analyze the seabed information comprehensively. Then,the technology is applied to the design and development of the Bohai Sea Oilfield Paradigm Area Information System. The system can not only meet the practical demands of marine resources exploration and exploitation in the Bohai Sea oilfield,but also serve as a preparatory work in theory and technology for the realization of the 'Digital Seabed'.展开更多
Sponges are the most primitive of multicellular animals, and are major pharmaceutical sources of marine secondary metabolites. A wide variety of new compounds have been isolated from sponges. In order to produce suffi...Sponges are the most primitive of multicellular animals, and are major pharmaceutical sources of marine secondary metabolites. A wide variety of new compounds have been isolated from sponges. In order to produce sufficient amounts of the compounds of the needed, it is necessary to obtain large amount of sponges. The production of sponge biomass has become a focus of marine biotechnology.展开更多
Seven compounds (1–7) were identified from the cultivation of the endophytic fungus Exophiala oligosperma (EN-21) that was isolated from the inner tissue of the marine red alga Laurencia similis. Their structures wer...Seven compounds (1–7) were identified from the cultivation of the endophytic fungus Exophiala oligosperma (EN-21) that was isolated from the inner tissue of the marine red alga Laurencia similis. Their structures were identified with spectroscopic and chemical methods as 2-phenoxynaphthalene (1), (2S, 3R, 4E, 8E)-1-O-β-D-glucopyranosyl-3-hydroxy-2-[(R)-2′-hydroxyoctadecanoyl] amino-9-methyl-4, 8-octadeca-diene (2), (22E,24R)-ergosta-7,22-dien-3β,5α,6β-triol (3), (22E, 24R)-3β, 5α, 9α-trihydroxy- ergosta-7, 22-dien-6-one (4), (22E, 24R)-5α, 6α-epoxy-ergosta-8, 22-dien-3β, 7α-diol (5), (22E, 24R)- ergosta-4, 6, 8(14), 22-tetraen-3-one (6), and euphorbol (7). This paper reports for the first time the chemical constituents of fungus Exophiala oligosperma and the discovery of compound 1 as a natural product from the fungus.展开更多
基金supported by CNSF(Granted No.40874050)Chinese High Technology Project(Granted No.2011YQ05006010)
文摘We present a method to unify the calculation of Green's functions for an electromagnetic(EM) transmitting source embedded in a homogeneous stratified medium.A virtual interface parallel to layer interfaces is introduced through the source location.The potentials for Green's function are derived by decomposing the partial wave solutions to Helmholtz's equations into upward and downward within boundaries.The amplitudes of the potentials in each stratum are obtained recursively from the initial amplitudes at the source level.The initial amplitudes are derived by coupling with the transmitting sources and following the discontinuity of the tangential electric and magnetic fields at the source interface.Only the initial terms are related to the transmitting sources and thus need to be modified for different transmitters,whereas the kernel connected with the stratified media stays unchanged.Hence,the present method can be easily applied to EM transmitting sources with little modification.The application of the proposed method to the marine controlled-source electromagnetic method(MCSEM) demonstrates its simplicity and flexibility.
基金financially supported by the National Hi-tech Research and Development Program of China(863 Program)(No.2012AA09A20103)
文摘Since the ocean bottom is a sedimentary environment wherein stratification is well developed, the use of an anisotropic model is best for studying its geology. Beginning with Maxwell's equations for an anisotropic model, we introduce scalar potentials based on the divergence-free characteristic of the electric and magnetic (EM) fields. We then continue the EM fields down into the deep earth and upward into the seawater and couple them at the ocean bottom to the transmitting source. By studying both the DC apparent resistivity curves and their polar plots, we can resolve the anisotropy of the ocean bottom. Forward modeling of a high-resistivity thin layer in an anisotropic half-space demonstrates that the marine DC resistivity method in shallow water is very sensitive to the resistive reservoir but is not influenced by airwaves. As such, it is very suitable for oil and gas exploration in shallowwater areas but, to date, most modeling algorithms for studying marine DC resistivity are based on isotropic models. In this paper, we investigate one-dimensional anisotropic forward modeling for marine DC resistivity method, prove the algorithm to have high accuracy, and thus provide a theoretical basis for 2D and 3D forward modeling.
基金sponsored by the 863 Program(No.2009AA09A2012012AA09A201)+1 种基金China Geological Survey Project(No.201100307)the Fundamental Research Funds of the Ministry of Education for the Central Universities(No.2652011249)
文摘In planning and executing marine controlled-source electromagnetic methods, seafloor electromagnetic receivers must overcome the problems of noise, clock drift, and power consumption. To design a receiver that performs well and overcomes the abovementioned problems, we performed forward modeling of the E-field abnormal response and established the receiver's characteristics. We describe the design optimization and the properties of each component, that is, low-noise induction coil sensor, low-noise Ag/AgCI electrode, low-noise chopper amplifier, digital temperature-compensated crystal oscillator module, acoustic telemetry modem, and burn wire system. Finally, we discuss the results of onshore and offshore field tests to show the effectiveness of the developed seafloor electromagnetic receiver and its performance: typical E-field noise of 0.12 nV/m/rt(Hz) at 0.5 Hz, dynamic range higher than 120 dB, clock drift lower than 1 ms/day, and continuous operation of at least 21 days.
基金supported by the national project"Deep Exploration Technology and Experimentation"(SinoProbe-09-02)
文摘In order to suppress the airwave noise in marine controlled-source electromagnetic (CSEM) data, we propose a 3D deconvolution (3DD) interferometry method with a synthetic aperture source and obtain the relative anomaly coefficient (RAC) of the EM field reflection responses to show the degree for suppressing the airwave. We analyze the potential of the proposed method for suppressing the airwave, and compare the proposed method with traditional methods in their effectiveness. A method to select synthetic source length is derived and the effect of the water depth on RAC is examined via numerical simulations. The results suggest that 3DD interferometry method with a synthetic source can effectively suppress the airwave and enhance the potential of marine CSEM to hydrocarbon exploration.
文摘Because of the special physico-chemical properties and toxicity of oil in ocean, it causes the acute and chronic toxicity in marine life, through food chain comes into human body, has a serious harm on human's health. This test analysis influence of oil pollution in ocean, provides theoretical guidance of governing.
基金Supported by the National High Technology Research and Development Program of China (863 Program, 2006AA09Z349)the National Basic Research Program of China (2007CB411703)
文摘Based on more than 4000 km 2D seismic data and seismic stratigraphic analysis, we discussed the extent and formation mechanism of the Qiongdongnan deep sea channel. The Qiongdongnan deep sea channel is a large incised channel which extends from the east boundary of the Yinggehai Basin, through the whole Qiongdongnan and the Xisha trough, and terminates in the western part of the northwest subbasin of South China Sea. It is more than 570 km long and 4–8 km wide. The chaotic (or continuous) middle (or high) amplitude, middle (or high) continuity seismic facies of the channel reflect the different lithological distribution of the channel. The channel formed as a complex result of global sea level drop during early Pliocene, large scale of sediment supply to the Yinggehai Basin, inversion event of the Red River strike-slip fault, and tilted direction of the Qiongdongnan Basin. The large scale of sediment supply from Red River caused the shelf break of the Yinggehai Basin to move torwards the S and SE direction and developed large scale of prograding wedge from the Miocene, and the inversion of the Red River strike-slip fault induced the sediment slump which formed the Qiongdongnan deep sea channel.
基金Supported by National Natural Science Foundation of China (No. 40806012, 40876013)Open Fund of the Key Laboratory of Ocean Circulation and Waves, Chinese Academy of Sciences (No. KLOCAW0803)Scientific Research Foundation for talent, Guangdong Ocean University (No. E06118)
文摘A quasi-global high-resolution HYbrid Coordinate Ocean Model (HYCOM) is used to investigate seasonal variations of water transports through the four main straits in the South China Sea. The results show that the annual transports through the four straits Luzon Strait, Taiwan Strait, Sunda Shelf and Mindoro Strait are -4.5, 2.3, 0.5 and 1.7 Sv (1 Sv=106 m3s-1), respectively. The Mindoro Strait has an important outflow that accounts for over one third of the total inflow through the Luzon Strait. Furthermore, it indicates that there are strong seasonal variations of water transport in the four straits. The water transport through the Luzon Strait (Taiwan Strait, Sunda Shelf, Mindoro Strait) has a maximum value of -7.6 Sv in December (3.1 Sv in July, 2.1S v in January, 4.5Sv in November), a minimum value of -2.1 Sv in June (1.5 Sv in October, -1.0 Sv in June, -0.2 Sv in May), respectively.
文摘Gametophytes of Laminaria japonica were cryopreserved in liquid nitrogen using encapsulation-dehydration with two-step cooling method. Gametophytes cultured at 10℃ and under continuous irradiance of 30 μmol m^-2 s^-1 for 3 weeks were encapsulated in calcium alginate beads. The beads were dehydrated in 0.4 molLl sucrose prepared with seawater for 6 h, desiccated in an incubator set at 10℃ and 70% relative humidity for 4 h, pre-frozen at either -40℃ or -60℃ for 30 min, and stored in liquid nitrogen for 〉24 h. As high as 43% of survival rate was observed when gametophytes were thawed by placing the beads in 40℃ seawater and re-hydrated in 0.05 molL^-1 citrate sodium prepared using 30‰ NaCl 7 d later. More cells of male gametophytes survived the whole procedure in comparison with female gametophytes. The cells of gametophytes surviving the preservation were able to grow asexually and produce morphologically normal sporophytes.
基金supported by the National High Technology Research and Development (863) Program (Grant No.2006AA09Z339)the Natural Science Foundation of Shandong, China (Grant No. Y2006E09)
文摘Natural gas hydrates are considered as strategic resources with commercial potential in the 21st century. Obvious BSR characteristics will be shown on seismic profiles, if there exist natural gas hydrates. The AVO method is one of the methods which can be used to identify and forecast lithologic characteristics and fluid properties by using the relationship between Amplitude and Offset. AVO anomaly is one of the significant signs to check out whether or not there is free gas below the BSR, so it can be used to detect natural gas hydrates from the seismic profile. Considering the geological and geophysical characteristics of the Okinawa Trough and making use of the techniques mentioned above, we can conclude that the conditions there are favorable for the formation and concentration of natural gas hydrates. By analyzing the data collected from the study area, one can discover many different anomalous phenomena on the seismic profile which are related to the existence of natural gas hydrates. Preliminary estimation of the natural gas hydrates in the Okinawa Trough shows that the trough is rich in natural gas hydrates and may become a potential important resources exploration area.
基金Supported by the National Natural Science Foundation of China (51209189, 51379196), and the Natural Science Foundation of Shandong Province (ZR2013 EEQ006, ZR2011 EL049)
文摘The development of robust damage detection methods for offshore structures is crucial to prevent catastrophes caused by structural failures. In this research, we developed an Improved Modal Strain Energy (IMSE) method for detecting damage in offshore platform structures based on a traditional modal strain energy method (the Stubbs index method). The most significant difference from the Stubbs index method was the application of modal frequencies. The goal was to improve the robustness of the traditional method. To demonstrate the effectiveness and practicality of the proposed IMSE method, both numerical and experimental studies were conducted for different damage scenarios using a jacket platform structure. The results demonstrated the effectiveness of the IMSE method in damage location when only limited, spatially incomplete, and noise-polluted modal data is available. Comparative studies showed that the IMSE index outperformed the Stubbs index and exhibited stronger robustness, confirming the superiority of the proposed approach.
基金Supported by the Nantong University Research Funding (No. 09R02)
文摘The global climate is intimately connected to changes in the polar oceans. The variability of sea ice coverage affects deep-water formations and large-scale thermohaline circulation patterns. The polar radiative budget is sensitive to sea-ice loss and consequent surface albedo changes. Aerosols and polar cloud microphysics are crucial players in the radioactive energy balance of the Arctic Ocean. The main biogenic source of sulfate aerosols to the atmosphere above remote seas is dimethylsulfide (DMS). Recent research suggests the flux of DMS to the Arctic atmosphere may change markedly under global warming. This paper describes climate data and DMS production (based on the five years from 1998 to 2002) in the region of the Barents Sea (30–35°E and 70–80°N). A DMS model is introduced together with an updated calibration method. A genetic algorithm is used to calibrate the chlorophyll-a (CHL) measurements (based on satellite SeaWiFS data) and DMS content (determined from cruise data collected in the Arctic). Significant interannual variation of the CHL amount leads to significant interannual variability in the observed and modeled production of DMS in the study region. Strong DMS production in 1998 could have been caused by a large amount of ice algae being released in the southern region. Forcings from a general circulation model (CSIRO Mk3) were applied to the calibrated DMS model to predict the zonal mean sea-to-air flux of DMS for contemporary and enhanced greenhouse conditions at 70–80°N. It was found that significantly decreasing ice coverage, increasing sea surface temperature and decreasing mixed-layer depth could lead to annual DMS flux increases of more than 100% by the time of equivalent CO2 tripling (the year 2080). This significant perturbation in the aerosol climate could have a large impact on the regional Arctic heat budget and consequences for global warming.
基金supported by Knowledge Innovation Program of Chinese Academy of Sciences (Grant Nos. KZCX2-YW-202 and KZCX1-YW-12-03)National Basic Research Program of China (Grant No. 2006CB403600)National Natural Science Foundation of China (Grant Nos. 40221503 and 40776011)
文摘A dataset of surface current vectors with error estimate from 1999 to 2007 is derived from the trajectories of the Array for Real-time Geostrophic Oceanography (Argo) drifting on surface over the global ocean. The error of the estimated surface currents is about 4.7 cm s-1 which is equivalent to the accuracy of the currents determined from the surface drifters. Geographically, the Argo-derived surface currents can fill many gaps left by the Global Drifter Program due to the greater number of floats, and can provide a complementary in situ observational system for monitoring global ocean surface currents. The surface currents from the Argo floats are compared with the surface drifter-derived currents and the Tropical Atmosphere Ocean program (TAO) measurements. The comparisons show good agreement for both the current amplitude and the direction of surface currents. Results indicate the feasibility of obtaining ocean surface currents from the Argo array and of combining the surface currents from Argo and the ocean surface drifters for in situ mapping of the global surface currents. The authors also make the dataset available to users of interest for many types of applications.
基金jointly supported by the International Cooperation and Exchange Projects of the National Natural Science Foundation of China (No.61361163001)the National Key Scientific Instrument and Equipment Development Projects of National Natural Science Foundation of China (No.41527901)the National High-Tech R&D Program (863 Program) (No.2013AA09A505)
文摘Abstract A real-time photo-realistic rendering algorithm of ocean color is introduced in the paper, which considers the impact of ocean bio-optical model. The ocean bio-optical model mainly involves the phytoplankton, colored dissolved organic material (CDOM), inorganic suspended particle, etc., which have different contributionsto absorption and scattering of light. We decompose the emergent light of the ocean surface into the reflected light from the sun and the sky, and the subsurface scattering light. We estab- lish an ocean surface transmission model based on ocean bidirectional reflectance distribution function (BRDF) and the Fresnel law, and this model's outputs would be the incident light parameters of subsurface scattering. Using ocean subsurface scattering algorithm combined with bio-optical model, we compute the scattering light emergent radiation in different directions. Then, we blend the re- flection of sunlight and sky light to implement the real-time ocean color rendering in graphics processing unit (GPU). Finally, we use two kinds of radiance reflectance calculated by Hydrolight radiative transfer model and our algorithm to validate the physical reality of our method, and the results show that our algorithm can achieve real-time highly realistic ocean color scenes.
基金the Technical Program of Jiangsu Province (BE 2006383)the Talent Program of Chinese Academy of Sciences (Dongbei Zhi Chun)
文摘The pigments in Laminaria japonica was extracted with six organic solvents and analyzed in spectroscopy analysis. The extractions conditions were screened by an orthogonal test and the quantity of extracted pigments was determined spectroscopically. The results show that: (1) among the six organic solvents, acetone was the most effective one for the extraction; (2) the optimum extraction conditions were as follows: the ratio of S/M (solvent volume/material weight) was 30 ml/g; fresh seaweed was extracted 2 times in 2h; (3) the average total content of pigments was 1.85 mg/g (calculated with dry L. japonica).
文摘Based on the ArcGIS geographic information system and the ORACLE database management system,this paper reports our studies on the technology of Marine Engineering Geological Exploration Information System(MEGEIS). By analyzing system structure,designing function modules and discussing data management,this paper systematically proposes a framework of technol-ogy to integrate,manage,and analyze the seabed information comprehensively. Then,the technology is applied to the design and development of the Bohai Sea Oilfield Paradigm Area Information System. The system can not only meet the practical demands of marine resources exploration and exploitation in the Bohai Sea oilfield,but also serve as a preparatory work in theory and technology for the realization of the 'Digital Seabed'.
基金Supported by Hi-Tech Research and Development Program of China (201AA620404).
文摘Sponges are the most primitive of multicellular animals, and are major pharmaceutical sources of marine secondary metabolites. A wide variety of new compounds have been isolated from sponges. In order to produce sufficient amounts of the compounds of the needed, it is necessary to obtain large amount of sponges. The production of sponge biomass has become a focus of marine biotechnology.
基金Supported by the Programs from the Ministry of Science and Technology of China (Nos.2007AA09Z446,2010CB833802)the Knowledge Innovation Program of Chinese Academy of Sciences (KZCX2-YW-211-04)
文摘Seven compounds (1–7) were identified from the cultivation of the endophytic fungus Exophiala oligosperma (EN-21) that was isolated from the inner tissue of the marine red alga Laurencia similis. Their structures were identified with spectroscopic and chemical methods as 2-phenoxynaphthalene (1), (2S, 3R, 4E, 8E)-1-O-β-D-glucopyranosyl-3-hydroxy-2-[(R)-2′-hydroxyoctadecanoyl] amino-9-methyl-4, 8-octadeca-diene (2), (22E,24R)-ergosta-7,22-dien-3β,5α,6β-triol (3), (22E, 24R)-3β, 5α, 9α-trihydroxy- ergosta-7, 22-dien-6-one (4), (22E, 24R)-5α, 6α-epoxy-ergosta-8, 22-dien-3β, 7α-diol (5), (22E, 24R)- ergosta-4, 6, 8(14), 22-tetraen-3-one (6), and euphorbol (7). This paper reports for the first time the chemical constituents of fungus Exophiala oligosperma and the discovery of compound 1 as a natural product from the fungus.