2011 Vol. 33, No. 6
Display Method:
2011, 33(6): 1-8.
Abstract:
Based on the Acoustic Doppler Current Profilers obtained from a shallow mooring deployed in the Central Channel of the Chukchi Sea(71°40.024'N,167°58.910'W) during 5 August to 7 September in the third Chinese Arctic Research Expedition 2008, the distribution of sea currents is studied, focusing on the trend of the vertical structure of currents, profile characteristics and baroclinicity. Main results incudes:(1) 6 significant tidal constituents predominate in this area, which are the semidiurnal tidal M1, S2 and N2, and the recent tidal O1, astronomical tidal MM and MSF, while the M2 semidiurnal tidal represents the most significant, the trend of all the half-day tidal ellipses shows counterclockwise Rotation; (2) The average measured current profile throughout the flow is north-northeast flow with the average residual current magnitude of 6.6 cm/s; (3) There is a significant vertically synchronous cyclical changes for the residual current in all layers; (4) In depth range of 8~11 m, the average baroclinic kinetic energy is stronger, while it is relatively weak below 18 m, in depth of 11~18 m the average kinetic energy of baroclinic decrease gradually from up to down, with the average baroclinic flow change to be smaller gradually.
Based on the Acoustic Doppler Current Profilers obtained from a shallow mooring deployed in the Central Channel of the Chukchi Sea(71°40.024'N,167°58.910'W) during 5 August to 7 September in the third Chinese Arctic Research Expedition 2008, the distribution of sea currents is studied, focusing on the trend of the vertical structure of currents, profile characteristics and baroclinicity. Main results incudes:(1) 6 significant tidal constituents predominate in this area, which are the semidiurnal tidal M1, S2 and N2, and the recent tidal O1, astronomical tidal MM and MSF, while the M2 semidiurnal tidal represents the most significant, the trend of all the half-day tidal ellipses shows counterclockwise Rotation; (2) The average measured current profile throughout the flow is north-northeast flow with the average residual current magnitude of 6.6 cm/s; (3) There is a significant vertically synchronous cyclical changes for the residual current in all layers; (4) In depth range of 8~11 m, the average baroclinic kinetic energy is stronger, while it is relatively weak below 18 m, in depth of 11~18 m the average kinetic energy of baroclinic decrease gradually from up to down, with the average baroclinic flow change to be smaller gradually.
2011, 33(6): 9-18.
Abstract:
The sea surface temperature (SST) data from AVHRR during 1985-2005 were applied to analyze the variability in East China Sea (ECS) and the warming trend is found in general. The Empirical Orthogonal Function (EOF) and Spectrum analysis were used to analyze the variability of SST anormality (SSTA). The first model (EOF1) explains 34.8% of the total variation and its main period is 3~5 a. It shows that there is a warming trend in most area and the largest variation appear in the inshore area.The period of EOF2 (10.7%) is 2 a and it denotes the change of SSTA in south-east area is opposite to that of north-west.The variation range of SSTA in Taiwan Strait and the south in ECS are similar, while that of the north is much stronger.They all contain the period of 5~7 a, same as that of ENSO.The SSTA in 3 area are affected strongly by ENSO and the 2a delay is obvious.There are 8~9 and 16~18 month delay between the south of ECS and ENSO. It mainly due to the anomalous Kuroshio transport. The SSTA of the north shows a close correlation with the variation of air temperature there and the correlation up to 0.92.
The sea surface temperature (SST) data from AVHRR during 1985-2005 were applied to analyze the variability in East China Sea (ECS) and the warming trend is found in general. The Empirical Orthogonal Function (EOF) and Spectrum analysis were used to analyze the variability of SST anormality (SSTA). The first model (EOF1) explains 34.8% of the total variation and its main period is 3~5 a. It shows that there is a warming trend in most area and the largest variation appear in the inshore area.The period of EOF2 (10.7%) is 2 a and it denotes the change of SSTA in south-east area is opposite to that of north-west.The variation range of SSTA in Taiwan Strait and the south in ECS are similar, while that of the north is much stronger.They all contain the period of 5~7 a, same as that of ENSO.The SSTA in 3 area are affected strongly by ENSO and the 2a delay is obvious.There are 8~9 and 16~18 month delay between the south of ECS and ENSO. It mainly due to the anomalous Kuroshio transport. The SSTA of the north shows a close correlation with the variation of air temperature there and the correlation up to 0.92.
2011, 33(6): 19-28.
Abstract:
Using reanalysis ocean subsurface data and 130 a(1870-1999) results of CCSM3 model of NCAR,this study examines the 3-D spatial structures and the temporal evolution of Pacific Decadal Oscillation(PDO). The results indicate the model simulates well many features of the observed North Pacific variability. Both the reanalysis data and the models results show that the pattern of PDO is not prescribed in the ocean surface, but exists in the whole top North Pacific Ocean from surface to subsurface.There is a passage of PDO signal propagation in subsurface of the North Pacific Ocean which exhibits a clockwise rotation in an association with the subtropical gyre: form the eastern North Pacific propagates west-southward to the tropical western Pacific, and then northward to the Kuroshio/Oyashio extension(KOE) region, then eastward reaching the middle of North Pacific at last, which complete a phase-changing. However, the propagation of PDO signal is not in the same depth, but is deepening gradually, and the depth is deepest when the signal reaches the middle of North Pacific at last.
Using reanalysis ocean subsurface data and 130 a(1870-1999) results of CCSM3 model of NCAR,this study examines the 3-D spatial structures and the temporal evolution of Pacific Decadal Oscillation(PDO). The results indicate the model simulates well many features of the observed North Pacific variability. Both the reanalysis data and the models results show that the pattern of PDO is not prescribed in the ocean surface, but exists in the whole top North Pacific Ocean from surface to subsurface.There is a passage of PDO signal propagation in subsurface of the North Pacific Ocean which exhibits a clockwise rotation in an association with the subtropical gyre: form the eastern North Pacific propagates west-southward to the tropical western Pacific, and then northward to the Kuroshio/Oyashio extension(KOE) region, then eastward reaching the middle of North Pacific at last, which complete a phase-changing. However, the propagation of PDO signal is not in the same depth, but is deepening gradually, and the depth is deepest when the signal reaches the middle of North Pacific at last.
2011, 33(6): 29-38.
Abstract:
The variability of one warming event which occurred on the equatorial Pacific Ocean in the summer 2009/2010 was analyzed using the temperature and wind data from tropical atmosphere ocean (TAO) project dataset. The variation and propagation of anomalous subsurface ocean temperature in equatorial Pacific were discussed in the process of El Niño event. The results indicated that there were two different mechanisms in eastern equatorial Pacific warming process in the summer 2009/2010. One was the propagation of the anomalous subsurface ocean temperature along the thermocline from west to east Pacific and the local warming in eastern Pacific. The other was the increase of west wind in the western Pacific warm pool (WPWP) made the wind convergence. This convergence conduced to the warm water downwelling from surface to subsurface. Then the subsurface water was warm again and eastward propagated. These results indicated that the anomalous temperature from the subsurface signal cycle in the tropical Pacific, the local warming in the eastern equatorial Pacific due to the decrease of wind and the atmosphere forcing in WPWP were the main reasons which induced the warmer event in 2009/2010.
The variability of one warming event which occurred on the equatorial Pacific Ocean in the summer 2009/2010 was analyzed using the temperature and wind data from tropical atmosphere ocean (TAO) project dataset. The variation and propagation of anomalous subsurface ocean temperature in equatorial Pacific were discussed in the process of El Niño event. The results indicated that there were two different mechanisms in eastern equatorial Pacific warming process in the summer 2009/2010. One was the propagation of the anomalous subsurface ocean temperature along the thermocline from west to east Pacific and the local warming in eastern Pacific. The other was the increase of west wind in the western Pacific warm pool (WPWP) made the wind convergence. This convergence conduced to the warm water downwelling from surface to subsurface. Then the subsurface water was warm again and eastward propagated. These results indicated that the anomalous temperature from the subsurface signal cycle in the tropical Pacific, the local warming in the eastern equatorial Pacific due to the decrease of wind and the atmosphere forcing in WPWP were the main reasons which induced the warmer event in 2009/2010.
2011, 33(6): 39-54.
Abstract:
Sea surface temperature (SST) is an important environmental thermodynamic factor affecting tropical cyclone (TC)activity, the fidelity of SST over tropical regions(30°S-30°N)in the coupled general circulation models (CGCM) participating in the Forth Assessment Report(AR4) of Intergovernmental Panel on Climate Change (IPCC)is accessed by virtue of comparing simulated climate field, spatial patterns in linear trends, multidecadal and interannual changes of SST during 1948-1999. It is found that although 24 IPCC-AR4 models show a good performance in mean state, most of SST in models shows a cold bias in comparison with ERSST. Regional mean annual SST gives a warming trend in all models, but there is much discrepancy between the amplitude of trends in models and ERSST. According to the performance of simulation in spatial structure of linear trends and multidecadal changes, six (INM CM3_0, MRI_CGCM2,3.2a, INGV_ECHAM4, UKMO_HADCM3,NCAR_PCM1, MPI_ECHAM5) of 24 IPCC AR4 models should not be ensemble to study a global warming scenario of tropical cyclone activity because of much difference of spatial patterns between these models and ERSST.The first five models, their spatial patterns of linear trends and multidecadal variations represent well with that of ERSST, are CGCM3.1_T47, GISS ER, MIROC_HIRES, GFDL CM2.1, GFDL CM2.0, successively. It also showed that both linear trend and multidecadal change of SST from June to October, a major TC active season, are simulated better over North Atlantic basin than over north western Pacific and South China Sea after evaluating the performance of SST over above three TC active regions. 18 of 24 models have significant relationship in multidecadal series between simulated SST and ERSST over North Atlantic. The performance of UKMO_HADGEM1 and MPI_ECHAM5 in interannual change of SST over north western Pacific is good enough to use them but it is UKMO_HADCM3 in South China Sea.
Sea surface temperature (SST) is an important environmental thermodynamic factor affecting tropical cyclone (TC)activity, the fidelity of SST over tropical regions(30°S-30°N)in the coupled general circulation models (CGCM) participating in the Forth Assessment Report(AR4) of Intergovernmental Panel on Climate Change (IPCC)is accessed by virtue of comparing simulated climate field, spatial patterns in linear trends, multidecadal and interannual changes of SST during 1948-1999. It is found that although 24 IPCC-AR4 models show a good performance in mean state, most of SST in models shows a cold bias in comparison with ERSST. Regional mean annual SST gives a warming trend in all models, but there is much discrepancy between the amplitude of trends in models and ERSST. According to the performance of simulation in spatial structure of linear trends and multidecadal changes, six (INM CM3_0, MRI_CGCM2,3.2a, INGV_ECHAM4, UKMO_HADCM3,NCAR_PCM1, MPI_ECHAM5) of 24 IPCC AR4 models should not be ensemble to study a global warming scenario of tropical cyclone activity because of much difference of spatial patterns between these models and ERSST.The first five models, their spatial patterns of linear trends and multidecadal variations represent well with that of ERSST, are CGCM3.1_T47, GISS ER, MIROC_HIRES, GFDL CM2.1, GFDL CM2.0, successively. It also showed that both linear trend and multidecadal change of SST from June to October, a major TC active season, are simulated better over North Atlantic basin than over north western Pacific and South China Sea after evaluating the performance of SST over above three TC active regions. 18 of 24 models have significant relationship in multidecadal series between simulated SST and ERSST over North Atlantic. The performance of UKMO_HADGEM1 and MPI_ECHAM5 in interannual change of SST over north western Pacific is good enough to use them but it is UKMO_HADCM3 in South China Sea.
2011, 33(6): 55-63.
Abstract:
Using wavelet transform, Lanczos filter, correlation analysis, Multi-scale characteristics of onset date of South China Sea summer monsoon (SCSSM) and its relationship with sea surface temperature (SST) on interannual and decadal time scale are explored. The optimal subset regression prediction method with the view of multiple time scales is developed as the new method of short-term climate prediction for onset date of SCSSM. The results show that the mean onset date of SCSSM is about 18 May and the mean square deviation is about 10 days during 1958-2008. The SCSSM seems to break out little early trend. It exhibits decadal variation with 15.4 years period and interannual variation with 5.3 years period. On interannual time scale, there are four regions with significant correlation between SSCSM onset dates and SST during previous winter, which occur in tropical southern Indian Ocean, tropical northwestern Pacific east of Philippine, equatorial central and eastern Pacific, and tropical eastern Pacific. On decadal time scale, besides tropical western Pacific, which is consistent with the result on interannual time scale, there are additional five regions with significant correlation between onset dates of SSCSM and SST during previous year (from last March to February), which occur in southwestern Indian Ocean, southeastern Indian Ocean, north Pacific, tropical southeastern Pacific and southeastern Pacific. The test of independent samples from 1999 to 2008 shows that the maximal prediction error of multi-scale optimal subset regression prediction is 8.5 days. The probability of difference less than 5 days between prediction and actual value is accounted for 50 percent. The anomalous early and late onset date of SSCSM can be better predicted. The multi-scale optimal subset regression prediction is significantly better than optimal subset regression prediction and single/multiple variable linear regression prediction. So, the prediction from multi-scale optimal subset regression prediction can offer important reference to operational prediction of short tern climate prediction for onset date of SSCSM.
Using wavelet transform, Lanczos filter, correlation analysis, Multi-scale characteristics of onset date of South China Sea summer monsoon (SCSSM) and its relationship with sea surface temperature (SST) on interannual and decadal time scale are explored. The optimal subset regression prediction method with the view of multiple time scales is developed as the new method of short-term climate prediction for onset date of SCSSM. The results show that the mean onset date of SCSSM is about 18 May and the mean square deviation is about 10 days during 1958-2008. The SCSSM seems to break out little early trend. It exhibits decadal variation with 15.4 years period and interannual variation with 5.3 years period. On interannual time scale, there are four regions with significant correlation between SSCSM onset dates and SST during previous winter, which occur in tropical southern Indian Ocean, tropical northwestern Pacific east of Philippine, equatorial central and eastern Pacific, and tropical eastern Pacific. On decadal time scale, besides tropical western Pacific, which is consistent with the result on interannual time scale, there are additional five regions with significant correlation between onset dates of SSCSM and SST during previous year (from last March to February), which occur in southwestern Indian Ocean, southeastern Indian Ocean, north Pacific, tropical southeastern Pacific and southeastern Pacific. The test of independent samples from 1999 to 2008 shows that the maximal prediction error of multi-scale optimal subset regression prediction is 8.5 days. The probability of difference less than 5 days between prediction and actual value is accounted for 50 percent. The anomalous early and late onset date of SSCSM can be better predicted. The multi-scale optimal subset regression prediction is significantly better than optimal subset regression prediction and single/multiple variable linear regression prediction. So, the prediction from multi-scale optimal subset regression prediction can offer important reference to operational prediction of short tern climate prediction for onset date of SSCSM.
2011, 33(6): 64-72.
Abstract:
With the development of remote sensing technology, satellite observation data have been used to study the numerical model assimilation technology. The 3-D northwest Pacific sea temperature, salinity and current forecast system developed by the National Marine Environment Forecasting Center is applied here to assimilating the sea surface height abnormal (SSHA) of the Collecte Localisation Satellites altimeter data with OVALS(ocean variational analysis system) which is based on 3-D-VAR scheme. The sea temperature and salinity profile data transformed from altimeter data are assimilated in the horizontal layer to find out the effect of the altimeter data on the numerical prediction. The results show that the forecasting accuracy by adding altimeter data assimilation is better than without assimilation, which verifies that the altimeter data assimilation for the improvement of the short-term numerical prediction is valid.
With the development of remote sensing technology, satellite observation data have been used to study the numerical model assimilation technology. The 3-D northwest Pacific sea temperature, salinity and current forecast system developed by the National Marine Environment Forecasting Center is applied here to assimilating the sea surface height abnormal (SSHA) of the Collecte Localisation Satellites altimeter data with OVALS(ocean variational analysis system) which is based on 3-D-VAR scheme. The sea temperature and salinity profile data transformed from altimeter data are assimilated in the horizontal layer to find out the effect of the altimeter data on the numerical prediction. The results show that the forecasting accuracy by adding altimeter data assimilation is better than without assimilation, which verifies that the altimeter data assimilation for the improvement of the short-term numerical prediction is valid.
2011, 33(6): 73-78.
Abstract:
The spatiotemporal variation in SO2 over the Bohai Sea during 2005 was analyzed from the planetary boundary layer (PBL) SO2 column densities retrieved from aura ozone monitoring instrument (OMI) data. Using the HYSPLIT model and FNL reanalysis data, the backward trajectories arriving in the Bohai Sea were calculated in order to identify the lead contributors. The obtained results indicate that the SO2 concentration over the Bohai Sea varies greatly with seasons, the mean concentration of SO2 shows the high values in autumn and winter, low values in spring and summer. the highest value which exceeds 6.187×1016 cm-2 in winter, the lowest concentration is 3.766×1016 cm-2 in summer; moreover the SO2 concentration varies greatly in the spatial distribution in different seasons. The results of the backward trajectory analysis show that SO2 emission from the region around the Bohai Sea has great influence on the Bohai Sea, the influence is the greatest in winter and the weakest in summer.
The spatiotemporal variation in SO2 over the Bohai Sea during 2005 was analyzed from the planetary boundary layer (PBL) SO2 column densities retrieved from aura ozone monitoring instrument (OMI) data. Using the HYSPLIT model and FNL reanalysis data, the backward trajectories arriving in the Bohai Sea were calculated in order to identify the lead contributors. The obtained results indicate that the SO2 concentration over the Bohai Sea varies greatly with seasons, the mean concentration of SO2 shows the high values in autumn and winter, low values in spring and summer. the highest value which exceeds 6.187×1016 cm-2 in winter, the lowest concentration is 3.766×1016 cm-2 in summer; moreover the SO2 concentration varies greatly in the spatial distribution in different seasons. The results of the backward trajectory analysis show that SO2 emission from the region around the Bohai Sea has great influence on the Bohai Sea, the influence is the greatest in winter and the weakest in summer.
2011, 33(6): 79-84.
Abstract:
Optical scattering methods have been widely used in the studies of marine microorganisms. It has been known that one can measure the size and abundance of the micron sized microorganisms from the spatial distributions of the scattered light. However, resent studies show that polarization dependent measurements of the scattered light are sensitive only to the submicron structure within the microorganisms. In this article, we approximate the microorganisms as a mixture of microspheres whose sizes are either much bigger (Mie scatterers) or much smaller (Rayleigh scatterers) than the wavelength of the scattered light. Using polarization sensitive Monte Carlo simulations, we prove: the intensity spatial distribution and polarization properties of the scattered light are determined by the scatterings of Mie and Rayleigh particles respectively. Therefore, the scatterings of unpolarized light provide information on "bigger particles" such as the microorganisms themselves and their nuclei, but polarization features of the scattered photons reveal information on the "small scatterers" such as organelles within the cells.
Optical scattering methods have been widely used in the studies of marine microorganisms. It has been known that one can measure the size and abundance of the micron sized microorganisms from the spatial distributions of the scattered light. However, resent studies show that polarization dependent measurements of the scattered light are sensitive only to the submicron structure within the microorganisms. In this article, we approximate the microorganisms as a mixture of microspheres whose sizes are either much bigger (Mie scatterers) or much smaller (Rayleigh scatterers) than the wavelength of the scattered light. Using polarization sensitive Monte Carlo simulations, we prove: the intensity spatial distribution and polarization properties of the scattered light are determined by the scatterings of Mie and Rayleigh particles respectively. Therefore, the scatterings of unpolarized light provide information on "bigger particles" such as the microorganisms themselves and their nuclei, but polarization features of the scattered photons reveal information on the "small scatterers" such as organelles within the cells.
2011, 33(6): 85-92.
Abstract:
Underway measurements of surface seawater and atmospheric partial pressure of CO2(pCO2)along BR Section in the Bering Sea were conducted during the 3rd Chinese national arctic research expedition (CHINARE-2008) in July 2008. CO2 system parameters were detected from discrete water column sampling stations as well. The latitudinal distributions of pCO2in the Bering Sea and its relationships with physical and chemical parameters were discussed. According to the CO2 uptake capacity, the Bering Sea was divided into 4 regions, Bering shelf region (BS), Bering slope current region (BSC), northern Bering Basin Region (NBB) and southern Bering basin region (SBB). The air-sea CO2 fluxes of the BSC is up to -18.72 mmol/(m2·d), which is two times as much as that of northern basin and one order of magnitude higher than that of southern basin. pCO2 in the northern basin and slope increases with temperature, showing a positive correlation. However, the relationship between pCO2 in the slope and southern basin and temperature was indistinct, suggesting that temperature was not the dominant controlling factor there.pCO2 in the northern basin and shelf exhibited a positive correlation with salinity, indicating that pCO2 was mainly affected by mixing of water masses, whereas indistinct relationship existed in the southern basin and slope. The main reason of higher pCO2 in the southern basin is well-mixed water masses with higher temperature; more saline, higher total dissolved inorganic carbon (DIC) and total alkalinity(TA).On the contrary, the water masses in the slope were significantly different from those of other regions in the Bering Sea, with obvious lower temperature, fresher, lower DIC and TA, leading to lower pCO2 in the surface seawater.
Underway measurements of surface seawater and atmospheric partial pressure of CO2(pCO2)along BR Section in the Bering Sea were conducted during the 3rd Chinese national arctic research expedition (CHINARE-2008) in July 2008. CO2 system parameters were detected from discrete water column sampling stations as well. The latitudinal distributions of pCO2in the Bering Sea and its relationships with physical and chemical parameters were discussed. According to the CO2 uptake capacity, the Bering Sea was divided into 4 regions, Bering shelf region (BS), Bering slope current region (BSC), northern Bering Basin Region (NBB) and southern Bering basin region (SBB). The air-sea CO2 fluxes of the BSC is up to -18.72 mmol/(m2·d), which is two times as much as that of northern basin and one order of magnitude higher than that of southern basin. pCO2 in the northern basin and slope increases with temperature, showing a positive correlation. However, the relationship between pCO2 in the slope and southern basin and temperature was indistinct, suggesting that temperature was not the dominant controlling factor there.pCO2 in the northern basin and shelf exhibited a positive correlation with salinity, indicating that pCO2 was mainly affected by mixing of water masses, whereas indistinct relationship existed in the southern basin and slope. The main reason of higher pCO2 in the southern basin is well-mixed water masses with higher temperature; more saline, higher total dissolved inorganic carbon (DIC) and total alkalinity(TA).On the contrary, the water masses in the slope were significantly different from those of other regions in the Bering Sea, with obvious lower temperature, fresher, lower DIC and TA, leading to lower pCO2 in the surface seawater.
2011, 33(6): 93-99.
Abstract:
A chemiluminescence method measuring the concentration of NO in seawater was established in this paper on the base of a reaction between the mixed solution of luminol-H2O2, the chemiluminescence probe, and NO, in which the chemiluminescence signal was emitted. The optimal results in the determination of NO concentration were under the conditions of a pH 9.2 buffer system with 1×10-2 mol/dm3 carbonate, 8.4×10-5 mol/dm3 luminol, 1×10-2 mol/dm3 H2O2, and under 20 ℃ and 1×10-3 mol/dm3 EDTA as a optimal masking agent. Under these optimal conditions, there was a significant linear relationship between the NO concentration and the peak area of chemiluminescence signal in the range of NO concentration from 1.4×10-12 to 9.8×10-10 mol/ dm3 (R=0.997, P <0.000 1). The detection limit for NO was 1.4×10-12 mol/dm3 (S/N). In 7 times of parallel determination to 1.2×10-11 mol/dm3NO aqueous solution, the relative standard deviation (RSD) was 13.6%. The NO concentration in the surface seawater of Jiaozhou Bay, China was successfully determined using this method and the results indicated that the concentrations of NO ranged from undetected to 7.1×10-11 mol/ dm3 with an average of (1.6±1.8)×10-11 mol/dm3.
A chemiluminescence method measuring the concentration of NO in seawater was established in this paper on the base of a reaction between the mixed solution of luminol-H2O2, the chemiluminescence probe, and NO, in which the chemiluminescence signal was emitted. The optimal results in the determination of NO concentration were under the conditions of a pH 9.2 buffer system with 1×10-2 mol/dm3 carbonate, 8.4×10-5 mol/dm3 luminol, 1×10-2 mol/dm3 H2O2, and under 20 ℃ and 1×10-3 mol/dm3 EDTA as a optimal masking agent. Under these optimal conditions, there was a significant linear relationship between the NO concentration and the peak area of chemiluminescence signal in the range of NO concentration from 1.4×10-12 to 9.8×10-10 mol/ dm3 (R=0.997, P <0.000 1). The detection limit for NO was 1.4×10-12 mol/dm3 (S/N). In 7 times of parallel determination to 1.2×10-11 mol/dm3NO aqueous solution, the relative standard deviation (RSD) was 13.6%. The NO concentration in the surface seawater of Jiaozhou Bay, China was successfully determined using this method and the results indicated that the concentrations of NO ranged from undetected to 7.1×10-11 mol/ dm3 with an average of (1.6±1.8)×10-11 mol/dm3.
2011, 33(6): 100-109.
Abstract:
The research and analysis on the dynamic characteristics of the hypoxic zone adjacent to the Changjiang Estuary are of greatly scientific and practical significance to the sustainable development of the Changjiang River Delta.Through the analysis on the historical data in typical months of the hypoxic zone and the marine ecological environment evolution off the Changjiang Estuary,the trends that the hypoxic zone moved northward,dissolved oxygen minimum value volatility decreased and the hypoxic area was growing were fully revealed from the time scale,meanwhile,the relationships between the evolution of the hypoxic zone and the eutrophication and the hydrodynamic environment were expounded,besides,the changing process of the hypoxic zone location in different months in summer half year(June-October)of 2006 was also discussed.The results show that the trend that the hypoxic zone moved northward(that is, the hypoxic zone extended to the southwestern area of the southern Huanghai Sea)was dominated by the eutrophication and the hydrological power variation,the enhanced northward expansion trend was a result of the long-term evolution of the ecological environment adjacent to the Changjiang Estuary,the enhancement of the Taiwan Warm Current and the northward moving of the upwelling area associated to it play a crucial role in the decadal variability of the core location of the hypoxic zone;the monthly variation of the currents and the changing of the phytoplankton biomass intensive areas adjacent to the Changjiang estuary affected the hypoxic zone location in summer half year to some extent.
The research and analysis on the dynamic characteristics of the hypoxic zone adjacent to the Changjiang Estuary are of greatly scientific and practical significance to the sustainable development of the Changjiang River Delta.Through the analysis on the historical data in typical months of the hypoxic zone and the marine ecological environment evolution off the Changjiang Estuary,the trends that the hypoxic zone moved northward,dissolved oxygen minimum value volatility decreased and the hypoxic area was growing were fully revealed from the time scale,meanwhile,the relationships between the evolution of the hypoxic zone and the eutrophication and the hydrodynamic environment were expounded,besides,the changing process of the hypoxic zone location in different months in summer half year(June-October)of 2006 was also discussed.The results show that the trend that the hypoxic zone moved northward(that is, the hypoxic zone extended to the southwestern area of the southern Huanghai Sea)was dominated by the eutrophication and the hydrological power variation,the enhanced northward expansion trend was a result of the long-term evolution of the ecological environment adjacent to the Changjiang Estuary,the enhancement of the Taiwan Warm Current and the northward moving of the upwelling area associated to it play a crucial role in the decadal variability of the core location of the hypoxic zone;the monthly variation of the currents and the changing of the phytoplankton biomass intensive areas adjacent to the Changjiang estuary affected the hypoxic zone location in summer half year to some extent.
2011, 33(6): 110-116.
Abstract:
Based on the data of hydrology and water quality of the Xiaoling River (1992-1995, 2004-2007), the Daling River, the Liaohe River and the Daliao River (1995-2007), pollutant fluxes of the four major rivers discharged into the sea on the north shore of the Liaodong Gulf, were preliminarily analyzed.The results indicate that besides the Xiaoling River, the pollutants flux trend of the other three rivers into the sea basically increases.The change of pollutants flux into the sea is mainly affected by the river runoff, and the specific situation of economic development and industrial structure in the watershed of each river.
Based on the data of hydrology and water quality of the Xiaoling River (1992-1995, 2004-2007), the Daling River, the Liaohe River and the Daliao River (1995-2007), pollutant fluxes of the four major rivers discharged into the sea on the north shore of the Liaodong Gulf, were preliminarily analyzed.The results indicate that besides the Xiaoling River, the pollutants flux trend of the other three rivers into the sea basically increases.The change of pollutants flux into the sea is mainly affected by the river runoff, and the specific situation of economic development and industrial structure in the watershed of each river.
2011, 33(6): 117-124.
Abstract:
Based on the 1-D tectonic subsidence analysis of Dongsha rise and adjacent area, combined with the previous researches on basement, faults, subsidence, it is proposed that the tectonic evolution history of Dongsha rise can be divided into five stages:compression setting in Cretaceous; initial extension in Paleocene to early Oligocene; denudation at the end of early Oligocene; quick thermal subsidence in later Oligocene to Miocene; fault block adjustment from later Miocene. The high velocity layer in the lower crust is the main cause of the Dongsha rise uplifting and erosion in the early Oligocene,but it has no appavent relationship with magnetic quiet zone and high magnetic zone.
Based on the 1-D tectonic subsidence analysis of Dongsha rise and adjacent area, combined with the previous researches on basement, faults, subsidence, it is proposed that the tectonic evolution history of Dongsha rise can be divided into five stages:compression setting in Cretaceous; initial extension in Paleocene to early Oligocene; denudation at the end of early Oligocene; quick thermal subsidence in later Oligocene to Miocene; fault block adjustment from later Miocene. The high velocity layer in the lower crust is the main cause of the Dongsha rise uplifting and erosion in the early Oligocene,but it has no appavent relationship with magnetic quiet zone and high magnetic zone.
2011, 33(6): 125-133.
Abstract:
A total of 17 box-cores, collected from the Bohai and Huanghai Seas (BHS), were studied to investigate the sedimentation rate (SR) using the 210Pb geochronology.The results show that the SRs at the offshore of Huanghe Delta show the highest values(＞2 cm/a), whereas the SRs are always lower than 0.5 cm/a in the Bohai Gulf, the central Huanghai.Combined with the previous studies, the distribution pattern of the 210Pb SR in the BHS is obtained, which is mainly controlled by the riverine sediment supply and the marine dynamics conditions.The high SRs are found in the mouths of rivers surrounding the BHS, whereas the offshore areas are characterized by the low SRs. In the northern Shandong Peninsula, the isoline of SRs extended northeastward and decreased stepwise, with the lowest SR areas located at the east Chengshantou. The SRs displayed a concave-like type in the southern Huanghai Sea (SHS), with higher SR on both sides and lower in the central area.In the southwest SH, a ligule-like isoline of SRs extended toward the central SHS. Based on the distribution pattern of the 210Pb SR in the southern Bohai and Huanghai Seas, the dispersal pattern of the Huanghe sediments can be illustrated. Most of the Huanghe sediments were deposited within the coastal area. However, small parts of the Huanghe sediments were transported along the northern Shandong Peninsula and through the Bohai Straits into the northern Huanghai Sea. Furthermore, in the SHS, the distribution of the Huanghe sediments may be limited in the west of 123 E areas, whereas the Korean riverine sediments in the east of 125°E, which may be related to the ocean fronts in the southern Huanghai Sea.
A total of 17 box-cores, collected from the Bohai and Huanghai Seas (BHS), were studied to investigate the sedimentation rate (SR) using the 210Pb geochronology.The results show that the SRs at the offshore of Huanghe Delta show the highest values(＞2 cm/a), whereas the SRs are always lower than 0.5 cm/a in the Bohai Gulf, the central Huanghai.Combined with the previous studies, the distribution pattern of the 210Pb SR in the BHS is obtained, which is mainly controlled by the riverine sediment supply and the marine dynamics conditions.The high SRs are found in the mouths of rivers surrounding the BHS, whereas the offshore areas are characterized by the low SRs. In the northern Shandong Peninsula, the isoline of SRs extended northeastward and decreased stepwise, with the lowest SR areas located at the east Chengshantou. The SRs displayed a concave-like type in the southern Huanghai Sea (SHS), with higher SR on both sides and lower in the central area.In the southwest SH, a ligule-like isoline of SRs extended toward the central SHS. Based on the distribution pattern of the 210Pb SR in the southern Bohai and Huanghai Seas, the dispersal pattern of the Huanghe sediments can be illustrated. Most of the Huanghe sediments were deposited within the coastal area. However, small parts of the Huanghe sediments were transported along the northern Shandong Peninsula and through the Bohai Straits into the northern Huanghai Sea. Furthermore, in the SHS, the distribution of the Huanghe sediments may be limited in the west of 123 E areas, whereas the Korean riverine sediments in the east of 125°E, which may be related to the ocean fronts in the southern Huanghai Sea.
2011, 33(6): 134-141.
Abstract:
The population structures of Gammaridae amphipods in Yundang Lagoon were studied from Noverber 2007 to May 2008 when macroalgae existed in the lagoon, and their population productions were estimated by the size-frequency method. The results showed that, the amphipods (i.e., Corophium uenoi, Grandidierella japonica and Ampithoe valida) dwelling in the Ulva lactuca canopy were characterized by short life cycle, female-biased quantity structure and high proportion of ovigerous individuals and juveniles, revealing high population production and semiannual turnover rate in Gammaridae amphipods, being up to(dw) 101.91 g dw/m2/6 month and 12.34/6 month for C. uenoi,9.49 g dw/m2/6 month and 4.93/6 month for G. Japonica and 29.17 g dw/m2/6 month and 8.34/6 month for A. valida, respectively. It was suggested that rich food resources from macroalgal canopies and the life cycle strategy of amphipods should be accounted for such high population production of Gammaridae amphipods in Yundang Lagoon. However, the migration of individuals may cause the overestimation of population production of some amphipods, e.g. A. valida.
The population structures of Gammaridae amphipods in Yundang Lagoon were studied from Noverber 2007 to May 2008 when macroalgae existed in the lagoon, and their population productions were estimated by the size-frequency method. The results showed that, the amphipods (i.e., Corophium uenoi, Grandidierella japonica and Ampithoe valida) dwelling in the Ulva lactuca canopy were characterized by short life cycle, female-biased quantity structure and high proportion of ovigerous individuals and juveniles, revealing high population production and semiannual turnover rate in Gammaridae amphipods, being up to(dw) 101.91 g dw/m2/6 month and 12.34/6 month for C. uenoi,9.49 g dw/m2/6 month and 4.93/6 month for G. Japonica and 29.17 g dw/m2/6 month and 8.34/6 month for A. valida, respectively. It was suggested that rich food resources from macroalgal canopies and the life cycle strategy of amphipods should be accounted for such high population production of Gammaridae amphipods in Yundang Lagoon. However, the migration of individuals may cause the overestimation of population production of some amphipods, e.g. A. valida.
2011, 33(6): 142-150.
Abstract:
The species and numbers of Vibrio bacteria and some environmental factors were investiged from winter of 2006 to autumn of 2007 for the inshore surface water of Xiaohai, Wanning City, Hainan Province. The results of Vibrio species survey showed that, totally 27 Vibrio species were isolated from the inshore surface water of Xiaohai and the main Vibrio species isolated from Xiaohai including V. parahaemolyticus, V. vulnificus, V. alginolyticus, V. Cholerae, V. fluvialis and V. mimicus. V. alginolyticus, V. parahaemolyticus and V. cholerae were the dominant species in summer and autumn; V. fluvialis was the dominant species in spring and summer; V. harveyi and V. mimicus were the dominant species in winter; V. vulnificus could be detected in all seasons and its numbers were constant in differdent season. The total numbers of Vibrio were higher in spring and autumn, lower in summer and winter. Correlation analysis showed that, the correlation between the number of Vibrio distribution and salinity, pH were notable, the correlation between Vibrio distribution and temperature, salinity, dissolved oxygen and pH were different among different Vibrio species, different sampling stations and different seasons. The results of cluster analysis showed that, the composition of Vibrio species had high similarity in summer and autumn and at the stations with shorter distance.
The species and numbers of Vibrio bacteria and some environmental factors were investiged from winter of 2006 to autumn of 2007 for the inshore surface water of Xiaohai, Wanning City, Hainan Province. The results of Vibrio species survey showed that, totally 27 Vibrio species were isolated from the inshore surface water of Xiaohai and the main Vibrio species isolated from Xiaohai including V. parahaemolyticus, V. vulnificus, V. alginolyticus, V. Cholerae, V. fluvialis and V. mimicus. V. alginolyticus, V. parahaemolyticus and V. cholerae were the dominant species in summer and autumn; V. fluvialis was the dominant species in spring and summer; V. harveyi and V. mimicus were the dominant species in winter; V. vulnificus could be detected in all seasons and its numbers were constant in differdent season. The total numbers of Vibrio were higher in spring and autumn, lower in summer and winter. Correlation analysis showed that, the correlation between the number of Vibrio distribution and salinity, pH were notable, the correlation between Vibrio distribution and temperature, salinity, dissolved oxygen and pH were different among different Vibrio species, different sampling stations and different seasons. The results of cluster analysis showed that, the composition of Vibrio species had high similarity in summer and autumn and at the stations with shorter distance.
Seasonal changes of phytoplankton community and its indication of environment in Sishili Bay, Yantai
2011, 33(6): 151-164.
Abstract:
Phytoplankton surveys were conducted at 12 stations in Sishili Bay during August, October, December 2009 and March 2010. Three classes including 45 genera and 73 species were identified from the samples. Among them, 46 species were Bacillariphyta; 24 species were Dinophyta; 3 species were Heterokontophyta. Diatoms dominated the phytoplankton community in species richness and biomass. Results presented significant seasonal variations in terms of species richness and cell abundance: species richness was 57 in summer, 40 in autumn, 36 in spring and 21 in winter, respectively; and the cell abundance gradient was summer (8.14×104 cells/dm3) > spring (2.45×104 cells/dm3) > autum (0.46×104 cells/dm3) > winter (0.28×104 cells/dm3). Species including Chattonella marina, Pseudo-nitzschia delicatissima and Paralia sulcata etc. dominated the Sishili Bay in our study. The phytoplankton community had a low biodiversity index in this research. The cell abundance of Chattonella marina was at the threshold value of harmful algal blooming in summer of 2009. Moreover, the eutrophic indicator species Paralia sulcata had a high cell abundance in most stations during the surveys, which indicated that the bay was in a worsening status of water quality.
Phytoplankton surveys were conducted at 12 stations in Sishili Bay during August, October, December 2009 and March 2010. Three classes including 45 genera and 73 species were identified from the samples. Among them, 46 species were Bacillariphyta; 24 species were Dinophyta; 3 species were Heterokontophyta. Diatoms dominated the phytoplankton community in species richness and biomass. Results presented significant seasonal variations in terms of species richness and cell abundance: species richness was 57 in summer, 40 in autumn, 36 in spring and 21 in winter, respectively; and the cell abundance gradient was summer (8.14×104 cells/dm3) > spring (2.45×104 cells/dm3) > autum (0.46×104 cells/dm3) > winter (0.28×104 cells/dm3). Species including Chattonella marina, Pseudo-nitzschia delicatissima and Paralia sulcata etc. dominated the Sishili Bay in our study. The phytoplankton community had a low biodiversity index in this research. The cell abundance of Chattonella marina was at the threshold value of harmful algal blooming in summer of 2009. Moreover, the eutrophic indicator species Paralia sulcata had a high cell abundance in most stations during the surveys, which indicated that the bay was in a worsening status of water quality.
2011, 33(6): 165-172.
Abstract:
A three-dimensional fully nonlinear numerical wave tank (NWT) based on a time-domain higher-order boundary element method (HOBEM) is used. The numerical model is applied to simulating wave transformation over a submerged bar. The present model is validated by comparison with the experimental results. A two-point method is introduced to decompose higher harmonic waves on the lee side of the submerged bar. And then the evolutions of the wave amplitude of the nth free waves with incident wave characteristics and the water depth are further studied. It shows that the amplitude of fundamental waves varies linearly with the incident wave amplitudes. It also indicates that the amplitude of the second-order and third-order free waves can be represented by a quadratic and cubic function of the amplitude of incident waves, respectively. A conclusion can be obtained in which the amplitude of fundamental waves remains approximately unchanged with the incident wave periods. In contrast, the amplitude of the second-order and third-order free waves obeys a quadratic and cubic law with the incident wave periods, respectively.
A three-dimensional fully nonlinear numerical wave tank (NWT) based on a time-domain higher-order boundary element method (HOBEM) is used. The numerical model is applied to simulating wave transformation over a submerged bar. The present model is validated by comparison with the experimental results. A two-point method is introduced to decompose higher harmonic waves on the lee side of the submerged bar. And then the evolutions of the wave amplitude of the nth free waves with incident wave characteristics and the water depth are further studied. It shows that the amplitude of fundamental waves varies linearly with the incident wave amplitudes. It also indicates that the amplitude of the second-order and third-order free waves can be represented by a quadratic and cubic function of the amplitude of incident waves, respectively. A conclusion can be obtained in which the amplitude of fundamental waves remains approximately unchanged with the incident wave periods. In contrast, the amplitude of the second-order and third-order free waves obeys a quadratic and cubic law with the incident wave periods, respectively.
2011, 33(6): 173-179.
Abstract:
The volume of fluid (VOF) method is used to numerically simulate freak wave under the varying water depth condition, and the wavelet analysis method is applied to the numerical results to investigate the energy distribution on the time-frequency domain. It is concluded that water depth variation can enhance nonlinear wave-wave interactions which makes much more energy to transfer to high harmonics and freak waves with higher asymmetry to generate.
The volume of fluid (VOF) method is used to numerically simulate freak wave under the varying water depth condition, and the wavelet analysis method is applied to the numerical results to investigate the energy distribution on the time-frequency domain. It is concluded that water depth variation can enhance nonlinear wave-wave interactions which makes much more energy to transfer to high harmonics and freak waves with higher asymmetry to generate.
2011, 33(6): 180-188.
Abstract:
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