1991 Vol. 10, No. 2
Display Method:
1991, (2): 167-181.
Abstract:
Using a two-dimensional semi-geostrophic model.the stability of fronts near shelf break (shelfbreak font,western boundary current front) and its mechanism are studied.We find that the stability of the front is related to the frontal structure.In general,the increase of the lower layer depth lowers the unstable growth rate (α1).(1) The shelfbreak front is baroclinically unstable and α1 increases with the increase of the bottom slope,different from the conclusion of Flagg and Beardsley (1978).(2) A western boundary current front with uniform vorticity in the upper layer is barotropically unstable,due to the strong horizontal shear of the mean current.The unstable growth rate of this front for a realistic topography is only one seventh of that of the flat bottom case.(3) For a western boundary current front with hyperbolic tangent structure,we find its wave propagation speed to be about 0.5 m/s,in agreement with the observed values.The front is baroclinically unstable.(4)The unstable growth rate of a domed structure front and its wave speed do not to be related to its wavelength.The front is batoclinically unstable.
Using a two-dimensional semi-geostrophic model.the stability of fronts near shelf break (shelfbreak font,western boundary current front) and its mechanism are studied.We find that the stability of the front is related to the frontal structure.In general,the increase of the lower layer depth lowers the unstable growth rate (α1).(1) The shelfbreak front is baroclinically unstable and α1 increases with the increase of the bottom slope,different from the conclusion of Flagg and Beardsley (1978).(2) A western boundary current front with uniform vorticity in the upper layer is barotropically unstable,due to the strong horizontal shear of the mean current.The unstable growth rate of this front for a realistic topography is only one seventh of that of the flat bottom case.(3) For a western boundary current front with hyperbolic tangent structure,we find its wave propagation speed to be about 0.5 m/s,in agreement with the observed values.The front is baroclinically unstable.(4)The unstable growth rate of a domed structure front and its wave speed do not to be related to its wavelength.The front is batoclinically unstable.
1991, (2): 183-198.
Abstract:
low-frequency sea level fluctuations in the Hangzhou Bay in winter and summer,1973-1974 are analyzed in this paper.The established multi-spectrum response models effectively identify the different dynamical factors and their contributions to the low-frequency sea level fluctuations inside the bay.The results show that the Ekman transport due to longshore winds is the major mechanism to induce the sea level fluctuations,more important than the frictional effect of local winds.There also exists obviously the influental effect of the free fluctuations of the continental shelf.In addition,a simple estimation suggests that the remarkable sea level fluctuation of 0.4 d-1 in the bay is related to the resonance of the Huanghai Sea and the Bohai Sea (taken as a single bay).
low-frequency sea level fluctuations in the Hangzhou Bay in winter and summer,1973-1974 are analyzed in this paper.The established multi-spectrum response models effectively identify the different dynamical factors and their contributions to the low-frequency sea level fluctuations inside the bay.The results show that the Ekman transport due to longshore winds is the major mechanism to induce the sea level fluctuations,more important than the frictional effect of local winds.There also exists obviously the influental effect of the free fluctuations of the continental shelf.In addition,a simple estimation suggests that the remarkable sea level fluctuation of 0.4 d-1 in the bay is related to the resonance of the Huanghai Sea and the Bohai Sea (taken as a single bay).
1991, (2): 199-216.
Abstract:
In this paper further mathematical analysis on "correlation transfer technique" by Polge el al.is carried out,the tenable conditions and the extent of suitability for the said method are proved as well.In consideration of the influence of skewness of the sea surface elevation on spectral shape,a "quasi-correlation transfer techique" is developed by the modification of the simulated target spectrum.Meanwhile,the numerical simulation of the non-Gaussian process of wind waves is carried out in view of the two conditions of the surface elevation probability distribution and the spectrum.By using its simulated results,the influence of skewness of the sea surface elevation on two parameters in the distribution of wave heights (which had been fitted by using the Weibull distribution) is analysed.The "quasi-correlation tranfer technique" is verified and compared with the selection wave data observed in the Jiaozhou Bay in the period of 1980 to 1981.Results make clear that,as far as the statistical distribution of the wave heights and the distribution of the maximum (minimum) values of the sea surface elevation are concerned,the said method is obviously superior to the conventional mothed of the linear wave superposition,and that the simulated results are closet to the observation data.
In this paper further mathematical analysis on "correlation transfer technique" by Polge el al.is carried out,the tenable conditions and the extent of suitability for the said method are proved as well.In consideration of the influence of skewness of the sea surface elevation on spectral shape,a "quasi-correlation transfer techique" is developed by the modification of the simulated target spectrum.Meanwhile,the numerical simulation of the non-Gaussian process of wind waves is carried out in view of the two conditions of the surface elevation probability distribution and the spectrum.By using its simulated results,the influence of skewness of the sea surface elevation on two parameters in the distribution of wave heights (which had been fitted by using the Weibull distribution) is analysed.The "quasi-correlation tranfer technique" is verified and compared with the selection wave data observed in the Jiaozhou Bay in the period of 1980 to 1981.Results make clear that,as far as the statistical distribution of the wave heights and the distribution of the maximum (minimum) values of the sea surface elevation are concerned,the said method is obviously superior to the conventional mothed of the linear wave superposition,and that the simulated results are closet to the observation data.
1991, (2): 217-288.
Abstract:
In this paper the stochastic Green function method is used to solve random wave equation of the electromagnetic field.The volume scattering coefficient formula of the sea surface containing bubbles is given.It is also point out that when the incident angle of the electromagnetic wave is less than 30°,the surface scattering model is not sufficient.The joint problem of the volume scattering and the surface scattering coefficient in the neighbourhood of incident angle 30° is discussed.
In this paper the stochastic Green function method is used to solve random wave equation of the electromagnetic field.The volume scattering coefficient formula of the sea surface containing bubbles is given.It is also point out that when the incident angle of the electromagnetic wave is less than 30°,the surface scattering model is not sufficient.The joint problem of the volume scattering and the surface scattering coefficient in the neighbourhood of incident angle 30° is discussed.
1991, (2): 229-236.
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In this paper,the discussion is made on the problem of the oceanic response caused by air-sea interaction under storm.First,the perturbation differential equations for the problem are given,and the interaction functions are supposed to be the solving conditions.Next,the nonlinear diffusion equations of the problem are solved by using the method of the given variable transforms and the specific variable power series.Finally,the response disturbances to the circular intense storm is calculated so as to discribe quantitatively the evolution processes of the oceanic response.
In this paper,the discussion is made on the problem of the oceanic response caused by air-sea interaction under storm.First,the perturbation differential equations for the problem are given,and the interaction functions are supposed to be the solving conditions.Next,the nonlinear diffusion equations of the problem are solved by using the method of the given variable transforms and the specific variable power series.Finally,the response disturbances to the circular intense storm is calculated so as to discribe quantitatively the evolution processes of the oceanic response.
1991, (2): 237-248.
Abstract:
The reclamation rate formula for concentrating tritium by the addition of "regular and quantitative aqueous sample" is advanced.
Effects of different adding modes on reclamation rate and the reclamation rate reappearance are studied; and the analytic program of tritium in seawater is also proposed.By using Fe-Ni electrodes and the electrolysis temperature of 2±0.5℃,β value reaches 20.Reclamation rates reach 83% and 76% when 250 cm3 and 500 cm3 seawater is concentrated to 8 cm3.
The relatively appropriate toluene/Trition ratio for counting aqueous sample under the normal temperature is proposed.
The computer program of different addition electrolytic concentrations for measuring tritium is coded,and the tritium data base is established.
The reclamation rate formula for concentrating tritium by the addition of "regular and quantitative aqueous sample" is advanced.
Effects of different adding modes on reclamation rate and the reclamation rate reappearance are studied; and the analytic program of tritium in seawater is also proposed.By using Fe-Ni electrodes and the electrolysis temperature of 2±0.5℃,β value reaches 20.Reclamation rates reach 83% and 76% when 250 cm3 and 500 cm3 seawater is concentrated to 8 cm3.
The relatively appropriate toluene/Trition ratio for counting aqueous sample under the normal temperature is proposed.
The computer program of different addition electrolytic concentrations for measuring tritium is coded,and the tritium data base is established.
1991, (2): 249-262.
Abstract:
On the basis of the study of ostracean banks in Tianjin area,the present study recognized that the ostracean banks at Ninghe County in Tianjin area are well developed along the west coast of the Bohai Sea; they consist of thanato-coenose and taphocoenose from Crassistrea gigars and C.revularis.From the 14C datings it can be known that the banks had formed from early Middle-Holocene and continued up to over 2 ka BP (14C age).The top has different reliefs.Although there is an effect of spatial shift of estuary position,the top is only distributed in the range of -0.50~-2.50 m(Huanghai elevation minus National elevation system).The banks cannot explain the sea-level fluctuation.As the string ostracean banks are distributed near E-W direction,it suggests that the direction of tidal currents was then similar to that of the present day.
On the basis of the study of ostracean banks in Tianjin area,the present study recognized that the ostracean banks at Ninghe County in Tianjin area are well developed along the west coast of the Bohai Sea; they consist of thanato-coenose and taphocoenose from Crassistrea gigars and C.revularis.From the 14C datings it can be known that the banks had formed from early Middle-Holocene and continued up to over 2 ka BP (14C age).The top has different reliefs.Although there is an effect of spatial shift of estuary position,the top is only distributed in the range of -0.50~-2.50 m(Huanghai elevation minus National elevation system).The banks cannot explain the sea-level fluctuation.As the string ostracean banks are distributed near E-W direction,it suggests that the direction of tidal currents was then similar to that of the present day.
1991, (2): 263-269.
Abstract:
Study on the effects of microorganism secretive membrane and covering layer of macrofouling organisms-Balanus reticulatus,Ostrea plicatula,Membranipora,Corophium and Algae on the corrosion of carbon steel and low-alloy steel by the determination of natural corrosive potentials,linear polarization and the polarization curver of dynamic potential scanning through an electrochemical equipment.
The results show that the microorganism secretion membrane formed on sample surface has some protective role,during the initial period of exposure (about ten days).Then protective role decreases and corrosive rate increases with the lapse of immersion time.The protective role of some macrofouling organisms is shown in order as follows:Corophium > Balanus reticulatus > Algae > Membranipora > Ostrea plicatula.
Study on the effects of microorganism secretive membrane and covering layer of macrofouling organisms-Balanus reticulatus,Ostrea plicatula,Membranipora,Corophium and Algae on the corrosion of carbon steel and low-alloy steel by the determination of natural corrosive potentials,linear polarization and the polarization curver of dynamic potential scanning through an electrochemical equipment.
The results show that the microorganism secretion membrane formed on sample surface has some protective role,during the initial period of exposure (about ten days).Then protective role decreases and corrosive rate increases with the lapse of immersion time.The protective role of some macrofouling organisms is shown in order as follows:Corophium > Balanus reticulatus > Algae > Membranipora > Ostrea plicatula.
1991, (2): 271-280.
Abstract:
By using the expressions for the maximum absorption per wavelength (αλ),and the relaxation frequency ∫r of the boric acid relaxation derived previously by the author and employing the related oceanographic literatures,the effects of pressure,temperature,pH and salinity on (αλ)r and ∫r of the boric acid relaxation in sea water have been estimated.Results show that (αλ),not only increases with pH but also increases approximately linearly with pressure and temperature,and is nearly proportional to the 1.35 power of salinity.However,pressure,pH and salinity have negligible effect on ∫r; therefore,∫r,can be approximately expressed as a function of temperature only.Comparisons of the predicted with the measured (αλ)r and ∫r in different ocean areas are given.
By using the expressions for the maximum absorption per wavelength (αλ),and the relaxation frequency ∫r of the boric acid relaxation derived previously by the author and employing the related oceanographic literatures,the effects of pressure,temperature,pH and salinity on (αλ)r and ∫r of the boric acid relaxation in sea water have been estimated.Results show that (αλ),not only increases with pH but also increases approximately linearly with pressure and temperature,and is nearly proportional to the 1.35 power of salinity.However,pressure,pH and salinity have negligible effect on ∫r; therefore,∫r,can be approximately expressed as a function of temperature only.Comparisons of the predicted with the measured (αλ)r and ∫r in different ocean areas are given.
1991, (2): 281-285.
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1991, (2): 287-288.
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1991, (2): 289-296.
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1991, (2): 297-302.
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1991, (2): 303-310.
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1991, (2): 311-316.
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1991, (2): 317-323.
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