A general spatial interpolation method for tidal properties has been developed by solving a partial differential equation with a combination of different orders of harmonic operators using a mixed finite element metho...A general spatial interpolation method for tidal properties has been developed by solving a partial differential equation with a combination of different orders of harmonic operators using a mixed finite element method. Numerically, the equation is solved implicitly without iteration on an unstructured triangular mesh grid. The paper demonstrates the performance of the method for tidal property fields with different characteristics, boundary complexity, number of input data points, and data point distribution. The method has been successfully applied under several different tidal environments, including an idealized distribution in a square basin, coamplitude and cophase lines in the Taylor semi-infiite rotating channel, and tide coamplitude and cophase lines in the Bohai Sea and Chesapeake Bay. Compared to Laplace’s equation that NOAA/NOS currently uses for interpolation in hydrographic and oceanographic applications, the multiple-order harmonic equation method eliminates the problem of singularities at data points, and produces interpolation results with better accuracy and precision.展开更多
19-year tidal data of the 3 stations, Huludao, Qinhuangdao and Kanmen, have totally been analysed, and the amplitudes and phases of 472 tidal constituents have been calculated with a resolution of Δ≥ 0.002 2 /h. Bas...19-year tidal data of the 3 stations, Huludao, Qinhuangdao and Kanmen, have totally been analysed, and the amplitudes and phases of 472 tidal constituents have been calculated with a resolution of Δ≥ 0.002 2 /h. Based on the draconitic tide, the anomalistic tide and pole tide obtained, the ultra-long-period variations of the mean sea level have been predicted. The annual tidal analysis of 19-year data at the above-mentioned stations and at Tanggu, Longkou has been carried out. The stability of the annual tidal analysis has been investigated with regard to the astronomical factors, the nonlinear effects and the variations of sea-bottom topography.展开更多
Since 2008 a network of five sea-level monitoring stations was progressively installed in French Polynesia.The stations are autonomous and data,collected at a sampling rate of 1 or 2 min,are not only recorded locally,...Since 2008 a network of five sea-level monitoring stations was progressively installed in French Polynesia.The stations are autonomous and data,collected at a sampling rate of 1 or 2 min,are not only recorded locally,but also transferred in real time by a radio-link to the NOAA through the GOES satellite.The new ET34-ANA-V80 version of ETERNA,initially developed for Earth Tides analysis,is now able to analyze ocean tides records.Through a two-step validation scheme,we took advantage of the flexibility of this new version,operated in conjunction with the preprocessing facilities of the Tsoft software,to recover co rrected data series able to model sea-level variations after elimination of the ocean tides signal.We performed the tidal analysis of the tide gauge data with the highest possible selectivity(optimal wave grouping)and a maximum of additional terms(shallow water constituents).Our goal was to provide corrected data series and modelled ocean tides signal to compute tide-free sea-level variations as well as tidal prediction models with centimeter precision.We also present in this study the characteristics of the ocean tides in French Polynesia and preliminary results concerning the non-tidal variations of the sea level concerning the tide gauge setting.展开更多
The synthetic tidal parameters with high spatial resolution for gravity over China and its neighbor area are constructed with Earth＇s tidal model and ocean tide loading calculated using TPXO7 global ocean tide model ...The synthetic tidal parameters with high spatial resolution for gravity over China and its neighbor area are constructed with Earth＇s tidal model and ocean tide loading calculated using TPXO7 global ocean tide model as well as tidal data over China seas. The comparison between synthetic parameters and ones observed by spring gravimeters at some seismic network stations and Hong Kong station and one observed by super-conducting gravimeter at Wuhan station shows that the average differences in amplitude factors and phases are smaller than 0.005 and 0.5° respectively; and that the discrepancies between observational and synthetic parameters are dependent on gravimetric technique in that the synthetic parameters are in well agreement with the superconducting gravimetric observations. This also indicates that the synthetic result is a good estimation for tidal gravity, and the numerical results in the present paper not only can provide ground and space gravimetry such as absolute gravimetry with correction model of tidal gravity, but also provide effective tidal parameters over areas where no observation is carried out.展开更多
The tidal current duration （TCD） and velocity （TCV） and suspended sediment concentration （SSC） were measured in the dry season in December, 2011 and in the flood season in June, 2012 at the upper part of the Nor...The tidal current duration （TCD） and velocity （TCV） and suspended sediment concentration （SSC） were measured in the dry season in December, 2011 and in the flood season in June, 2012 at the upper part of the North Channel of Changjiang Estuary. They were assimilated with the measured data in 2003, 2004, 2006 and 2007, using the tidal range＇s proportion conversion. Variations in TCD and TCV, preferential flow and SSC have been calculated. Influences of typical engineering projects such as Qingcaosha fresh water reservoir, Yangtze River Bridge, and land reclamation on the ebb and flood TCD, TCV and SSC in the North Channel for the last 10 years are discussed. The results show that： （1） currently, in the upper part of North Channel, the ebb tide dominates; after the construction of the typical projects, ebb TCD and TCV tends to be larger and the vertical average ebb and flood SSC decrease during the flood season while SSC increases during the dry season; （2） changes in the vertical average TCV are mainly contributed by seasonal runoff variation during the flood season, which is larger in the flood season than that in the dry season; the controlling parameters of increasing ebb TCD and TCV are those large-scale engineering projects in the North Channel; variation in SSC may result mainly from the reduction of basin annual sediment loads, large-scale nearshore projects and so on.展开更多
Sea surface temperature(SST)data obtained from coastal stations in Jiangsu,China during 20102014 are quality controlled before analysis of their characteristic semidiurnal and seasonal cycles,including the correlation...Sea surface temperature(SST)data obtained from coastal stations in Jiangsu,China during 20102014 are quality controlled before analysis of their characteristic semidiurnal and seasonal cycles,including the correlation with the variation of the tide.Quality control of data includes the validation of extreme values and checking of hourly values based on temporally adjacent data points,with 0.15℃/h considered a suitable threshold for detecting abnormal values.The diurnal variation amplitude of the SST data is greater in spring and summer than in autumn and winter.The diurnal variation of SST has bimodal structure on most days,i.e.,SST has a significant semidiurnal cycle.Moreover,the semidiurnal cycle of SST is negatively correlated with the tidal data from March to August,but positively correlated with the tidal data from October to January.Little correlation is detected in the remaining months because of the weak coastal offshore SST gradients.The quality control and understanding of coastal SST data are particularly relevant with regard to the validation of indirect measurements such as satellite-derived data.展开更多
The textural and mineralogical characteristics of subsurface sediments along with Ground Penetrating Radar (GPR) data collected along the Western margin of India were used to understand the depositional environments a...The textural and mineralogical characteristics of subsurface sediments along with Ground Penetrating Radar (GPR) data collected along the Western margin of India were used to understand the depositional environments and the provenance of sediments. Textural attributes such as mean, standard deviation, skewness and Kurtosis show fluctuations due to fluvio-marine interaction and it is well understood that the bottom sediments are enriched with muddy sand, which may be deposited by mean of tidal invasion. The abundance of very coarse silt to very fine sand indicates the prevalence of low energy environment. The Linear Discriminate Function analysis indicates the fluvio marine deposition of sediments under low energy condition. GPR data upto a depth of 5 m shows the stratigraphic sequences of very fine sands and coarse silt. Optically Stimulated Luminescence (OSL) dating of sediments implies that the tidal sediments had deposited between ~30 ± 1 and ~90 ± 4 years before Present. XRD studies results the dominance of K-feldspar and deficiency of clay minerals, indicating that most of the sediments are derived from hinterland. Studies indicate that the Provenance of sediments in the Mandvi area is not related to Indus delta even though a considerable part of Gulf sediments are deposited by the Indus River.展开更多
文摘A general spatial interpolation method for tidal properties has been developed by solving a partial differential equation with a combination of different orders of harmonic operators using a mixed finite element method. Numerically, the equation is solved implicitly without iteration on an unstructured triangular mesh grid. The paper demonstrates the performance of the method for tidal property fields with different characteristics, boundary complexity, number of input data points, and data point distribution. The method has been successfully applied under several different tidal environments, including an idealized distribution in a square basin, coamplitude and cophase lines in the Taylor semi-infiite rotating channel, and tide coamplitude and cophase lines in the Bohai Sea and Chesapeake Bay. Compared to Laplace’s equation that NOAA/NOS currently uses for interpolation in hydrographic and oceanographic applications, the multiple-order harmonic equation method eliminates the problem of singularities at data points, and produces interpolation results with better accuracy and precision.
文摘19-year tidal data of the 3 stations, Huludao, Qinhuangdao and Kanmen, have totally been analysed, and the amplitudes and phases of 472 tidal constituents have been calculated with a resolution of Δ≥ 0.002 2 /h. Based on the draconitic tide, the anomalistic tide and pole tide obtained, the ultra-long-period variations of the mean sea level have been predicted. The annual tidal analysis of 19-year data at the above-mentioned stations and at Tanggu, Longkou has been carried out. The stability of the annual tidal analysis has been investigated with regard to the astronomical factors, the nonlinear effects and the variations of sea-bottom topography.
基金funding from the“Talent Introduction Scientific Research Start-Up Fund”of Shandong University of Science and Technology(Grant number 0104060510217)the“Open Fund of State Key Laboratory of Geodesy and Earth’s Dynamics”(Grant number SKLGED2021-3-5)。
文摘Since 2008 a network of five sea-level monitoring stations was progressively installed in French Polynesia.The stations are autonomous and data,collected at a sampling rate of 1 or 2 min,are not only recorded locally,but also transferred in real time by a radio-link to the NOAA through the GOES satellite.The new ET34-ANA-V80 version of ETERNA,initially developed for Earth Tides analysis,is now able to analyze ocean tides records.Through a two-step validation scheme,we took advantage of the flexibility of this new version,operated in conjunction with the preprocessing facilities of the Tsoft software,to recover co rrected data series able to model sea-level variations after elimination of the ocean tides signal.We performed the tidal analysis of the tide gauge data with the highest possible selectivity(optimal wave grouping)and a maximum of additional terms(shallow water constituents).Our goal was to provide corrected data series and modelled ocean tides signal to compute tide-free sea-level variations as well as tidal prediction models with centimeter precision.We also present in this study the characteristics of the ocean tides in French Polynesia and preliminary results concerning the non-tidal variations of the sea level concerning the tide gauge setting.
基金The Knowledge Innovation Program of the Chinese Academy of Sciences (KZCX2-YW-133)National Nature Science Foundation of China (40730316, 40574034).
文摘The synthetic tidal parameters with high spatial resolution for gravity over China and its neighbor area are constructed with Earth＇s tidal model and ocean tide loading calculated using TPXO7 global ocean tide model as well as tidal data over China seas. The comparison between synthetic parameters and ones observed by spring gravimeters at some seismic network stations and Hong Kong station and one observed by super-conducting gravimeter at Wuhan station shows that the average differences in amplitude factors and phases are smaller than 0.005 and 0.5° respectively; and that the discrepancies between observational and synthetic parameters are dependent on gravimetric technique in that the synthetic parameters are in well agreement with the superconducting gravimetric observations. This also indicates that the synthetic result is a good estimation for tidal gravity, and the numerical results in the present paper not only can provide ground and space gravimetry such as absolute gravimetry with correction model of tidal gravity, but also provide effective tidal parameters over areas where no observation is carried out.
文摘The tidal current duration （TCD） and velocity （TCV） and suspended sediment concentration （SSC） were measured in the dry season in December, 2011 and in the flood season in June, 2012 at the upper part of the North Channel of Changjiang Estuary. They were assimilated with the measured data in 2003, 2004, 2006 and 2007, using the tidal range＇s proportion conversion. Variations in TCD and TCV, preferential flow and SSC have been calculated. Influences of typical engineering projects such as Qingcaosha fresh water reservoir, Yangtze River Bridge, and land reclamation on the ebb and flood TCD, TCV and SSC in the North Channel for the last 10 years are discussed. The results show that： （1） currently, in the upper part of North Channel, the ebb tide dominates; after the construction of the typical projects, ebb TCD and TCV tends to be larger and the vertical average ebb and flood SSC decrease during the flood season while SSC increases during the dry season; （2） changes in the vertical average TCV are mainly contributed by seasonal runoff variation during the flood season, which is larger in the flood season than that in the dry season; the controlling parameters of increasing ebb TCD and TCV are those large-scale engineering projects in the North Channel; variation in SSC may result mainly from the reduction of basin annual sediment loads, large-scale nearshore projects and so on.
基金The Open Fund of State Key Laboratory of Satellite Ocean Environment Dynamics under contract No.SOED1402the Youth Science and Technology Foundation of East China Sea Branch,SOA under contract No.201624
文摘Sea surface temperature(SST)data obtained from coastal stations in Jiangsu,China during 20102014 are quality controlled before analysis of their characteristic semidiurnal and seasonal cycles,including the correlation with the variation of the tide.Quality control of data includes the validation of extreme values and checking of hourly values based on temporally adjacent data points,with 0.15℃/h considered a suitable threshold for detecting abnormal values.The diurnal variation amplitude of the SST data is greater in spring and summer than in autumn and winter.The diurnal variation of SST has bimodal structure on most days,i.e.,SST has a significant semidiurnal cycle.Moreover,the semidiurnal cycle of SST is negatively correlated with the tidal data from March to August,but positively correlated with the tidal data from October to January.Little correlation is detected in the remaining months because of the weak coastal offshore SST gradients.The quality control and understanding of coastal SST data are particularly relevant with regard to the validation of indirect measurements such as satellite-derived data.
文摘The textural and mineralogical characteristics of subsurface sediments along with Ground Penetrating Radar (GPR) data collected along the Western margin of India were used to understand the depositional environments and the provenance of sediments. Textural attributes such as mean, standard deviation, skewness and Kurtosis show fluctuations due to fluvio-marine interaction and it is well understood that the bottom sediments are enriched with muddy sand, which may be deposited by mean of tidal invasion. The abundance of very coarse silt to very fine sand indicates the prevalence of low energy environment. The Linear Discriminate Function analysis indicates the fluvio marine deposition of sediments under low energy condition. GPR data upto a depth of 5 m shows the stratigraphic sequences of very fine sands and coarse silt. Optically Stimulated Luminescence (OSL) dating of sediments implies that the tidal sediments had deposited between ~30 ± 1 and ~90 ± 4 years before Present. XRD studies results the dominance of K-feldspar and deficiency of clay minerals, indicating that most of the sediments are derived from hinterland. Studies indicate that the Provenance of sediments in the Mandvi area is not related to Indus delta even though a considerable part of Gulf sediments are deposited by the Indus River.
