EXPERIMENTS OF SEA ICE SIMULATION

As a substitute for the original displaced pole grids, a simple rotated spherical coordinate system was intro duced into the Community Sea Ice Model version 4（CSIM4）, which is a component of the Community Climate System Model（CCSM） of the American National Center of Atmospheric Researeh（NCAR）, to deal with the ＂pole problems＂. In the new coordinates, both the geographical North Pole and South Pole lie in the model equator and grid sizes near the polar region are more uniform. With reanalysis dataset of American National Centers for Environment Prediction （NCEP） and Levitus dataset without considering sub-mixed layer heat flux, the model was integrated for 100 years with thermodynamics proce.ss involved only in the former 49 years and both dynamic and thermodynamic processes involved in the left time. Inner consistency of model results was checked with no contradiction found. The results of last 10 years＇ model output were analyzed and it is shown that the simulated sea ice seasonal variation is rational whereas sea ice extent in the Barcnts Sea in winter is larger than that of observation, Numerical experiment on influence of sub-mixed layer heat flux was also carried out and it is shown that the sub-mixed layer heat flux can modulate seasonal variation of sea ice greatly. As a model component, the sea ice model with rotated spherical coordinates was coupled with other models （the oceanic general cir culation model is the LASG/IAP Climate System Ocean Model （LICOM） with reduced grid, other models are components of NCAR CCSM2） forming a climate system model and its preliminary results were also given briefly.     

NUMERICAL SIMULATIONS OF SEA ICE WITH DIFFERENT ADVEC- TION SCHEMES

Numerical simulations are carried out for sea ice with four different advection schemes to study their effects on the simulation results.The sea ice model employed here is the Sea Ice Simulator(SIS) of the Geophysical Fluid Dynamics Laboratory(GFDL) Modular Ocean Model version 4b(MOM4b) and the four advection schemes are,the upwind scheme originally used in the SIS,the Multi-Dimensional Positive Advection(MDPA) scheme,the Incremental Remapping Scheme(IRS) and the Two Step Shape Preserving(TSSP) scheme.The latter three schemes are newly introduced.To consider the interactions between sea ice and ocean,a mixed layer ocean model is introduced and coupled to the SIS.The coupled model uses a tri-polar coordinate with 120×65 grids,covering the whole earth globe,in the horizontal plane.Simulation results in the northern high latitudes are analyzed.In all simulations,the model reproduces the seasonal variation of sea ice in the northern high latitudes well.Compared with the results from the observation,the sea ice model produces some extra sea ice coverage in the Greenland Sea and Barents Sea in winter due to the exclusion of ocean current effects and the smaller simulated sea ice thickness in the Arctic basin.There are similar features among the results obtained with the introduced three advection schemes.The simulated sea ice thickness with the three newly introduced schemes are all smaller than that of the upwind scheme and the simulated sea ice velocities of movement are all smaller than that of the upwind scheme.There are more similarities shared in the results obtained with the MPDA and TSSP schemes.     

MODEL OF SEA ICE BREAKUP ON SHALLOW BEACH DUE TO TIDAL FLUCTUATION

1.　 INTRODUCTIONThe breakup ofice isthe basis to analyze the mechanism of ice ride-up and pile-up,andto further study the formation of rafted ice and ice ridge.Up till now,researcheshave focused on the effectof wind and currenton shore fasticebreakup.Christensen F.T.[1 ] analyzed the possible size ofthe ice pieces when the ice floe in-teracts with the slope underthe action of wind and currentdriving forces.S rensen C.[3] in-vestigated the failure of a floating ice floe when itcollided w…     

A PARADOX OF TRANSIENT EKMAN DRIFT MODEL AND ITS EXPLAINATION

1 .　ＩＮＴＲＯＤＵＣＴＩＯＮＡｃｃｏｒｄｉｎｇｔｏｔｈｅｌｉｎｅａｒｆｌｕｉｄｄｙｎａｍｉｃｅｑｕａｔｉｏｎｉｎｒｏｔａｔｉｎｇｆｒａｍｅａｎｄｉｔｓＦｒｅｄｈｏｌｍ’ｓｓｏｌｕｔｉｏｎ ,Ｅｋ ｍａｎ[1 ] ( 1 90 5 )ｓｕｃｃｅｓｓｆｕｌｌｙｅｘｐｌａｉｎｅｄｔｈｅｐｈｅｎｏｍｅｎａｔｈａｔｔｈｅｄｒｉｆｔｉｎｇｄｉｒｅｃｔｉｏｎｏｆｉｃｅｂｅｒｇｓｄｅｖｉａｔｅｆｒｏｍｔｈｅｗｉｎｄｄｉｒｅｃｔｉｏｎｉｎｔｈｅｒｅｇｉｏｎｏｆａｒｃｔｉｃｎｅａｒＮｏｒ ｗｅｇｉａｎｓｅａ .Ｃｏｎｓｉｄｅｒｉｎｇｔ…     

PHYSICAL PROPERTIES AND ELASTIC MODULUS OF DUT-1 MODEL ICE

1 .　INTRODUCTIONTherearemany problemsassociatedwithiceinriversandseasinChina .Withthedevelopmentoftheeconomyandtechnology ,theBohaiSea ,anareawhichexperiencesfreezing ,israpidlybeingexploredanddeveloped .Also ,thestudiesoficeproblemsininlandrivers ,suchastheYellowRiverandtheSonghuaRiver ,aremainlyfocusedonthespringiceseason .Inaddition ,someprojectsthatareeither plannedorinoperation ,suchastheSouth NorthWaterTransferProject ,theexplo rationanduseoftheTumenRiver ,andtheopenwatercanal…     

NUMERICAL SIMULATION OF ICE CONTROL EFFECT OF SOLAR ENERGY ON TIBETAN CHANNELS

With the Tanghe Diversion Channel in Tibet as an example, the theoretical study on the ice control effect of the solar sacks was conducted based on the previous study. The numerical simulation method was adopted and a one-dimensional numerical model for ice crystal in diversion channels in high-altitude cold regions was developed in this article. The heat transfer through the air-water interface and the mass transfer between ice and water were considered in the model. The model was validated by the field observation data on the diversion channel of the Tanghe Hydropower Station. The results show that the ice control effect of the solar sacks is obvious in the channel with large mass flow rate in the high-altitude cold regions.     

FLOATING RATE OF FRAZIL ICE PARTICLES IN FLOWING WATER IN BEND CHANNELS——A THREE-DIMENSIONAL NUMERICAL ANALYSIS

In this article,based on the theory of two-phase flow and laboratory data,a three-dimensionally model is developed to simulate the floating rates of frazil ice particles in water under covered condition.The Lagrangian trajectory method is used in the three dimensional simulation for floating rates of frazil ice particles along a 180o bend channel.The velocity profiles in longitudinal and transverse directions,the turbulence intensity,and the residual pressure are simulated.Under the condition of gravitation...     

利用卤化银提取海洋遥感微弱信息

该文着重从光化学角度论述了利用卤化银感光材料的感色特性提出海洋遥感影像中的微弱信息的原理,并以香港及大鹏湾海域的悬浮泥沙微弱信息提以过程为例,详细介绍了提取的工艺.     

OBLIQUE TOWING TEST AND MANEUVER SIMULATION AT LOW SPEED AND LARGE DRIFT ANGLE FOR DEEP SEA OPEN-FRAMED REMOTELY OPERATED VEHICLE

This article presents the newly designed oblique towing test in the horizontal plane for the scaled model of 4 500 m deep sea open-framed Remotely Operated Vehicle (ROV),which is being researched and developed by Shanghai Jiao Tong University.Accurate hydrodynamics coefficients measurement is significant for the maneuverability and control system design.The scaled model of ROV was constructed by 1:1.6.Hydrodynamics tests of large drift angle were conducted through Large Amplitude Horizontal Planar Motion Mechanism (LAHPMM) under low speed.Multiple regression method is adopted to process the test data and obtain the related hydrodynamic coefficients.Simulations were designed for the horizontal plane motion of large drift angle to verify the coefficients calculated.And the results show that the data can satisfy with the design requirements of the ROV developed.     

STUDY OF NON-BOUSSINESQ EFFCET ON SEA SURFACE HEIGHT

A set of equations was derived for a nonBoussinesq ocean model in this paper. A new time-splitting scheme was introduced which incorporates the 4th-order Runge-Kutta explicit scheme of low-frequency mode and an implicit scheme of high-frequency mode. With this model, potential temperature, salinity fields and sea surface height were calculated simultaneously such that the numerical error of extrapolation of density field from the current time level to the next one could be reduced while using the equation of mass conservation to determine sea surface height. The non-Boussinesq effect on the density field and sea surface height was estimated by numerical experiments in the final part of this paper.     

A COMPARATIVE STUDY OF SPECTRAL METHODS WITH SEA WAVE DATA

Two spectral methods are used to study sea wave data.Firstly, the estimated results calculated by the sequency spectrum method and frequency spectrum method are compared, and then the differences between the two methods are discussed.Furthermore, compared with frequency spectral analysis, sequency spectral analysis has many advantages: faster calculating speed, convenient use and high distinguishability.     

SEASONAL REVERSE OF SEA SURFACE SLOPE IN THE NORTHERN YELLOW SEA AND ITS DYNAMIC RELATION WITH MONSOON EFFECTS

Based on the monthly average sea level data from the tide gauge measurement (1999-2001), the seasonal variability of the sea level in the Northern and Middle Yellow Sea is studied to reveal that the sea surface height at all the tide gauges becomes higher in summer than that in winter. In addition, the sea surface height of the Northern Yellow Sea is higher than the one of the Middle Yellow Sea with a slope downward from the north to the south in summer, while it is lower with a reversed slope in winter. The seasonal reverse of the sea surface slope can be attributed to the monsoon effects i.e. the annual reverse of the monsoon direction and the annual variation of the monsoon rainfall. A set of equations are established in light of the dynamic principles to expound how the monsoon forcing and the sea surface slope generate a summer outflow and a winter inflow in the Yellow Sea.     

INCIPIENT MOTION OF NON-COHESIVE SEDIMENT UNDER ICE COVER - AN EXPERIMENTAL STUDY

Based on a series of experiments under both ice-covered and free surface conditions, the present article discusses the role of flow velocity and critical shear Reynolds number for incipient motion of bed material. The influence of the resistance coefficients of both the underside of the ice cover and the channel bed on the location of the maximum velocity has been discussed. In addition, the impacts of ice and composite resistance coefficients on flow velocity for incipient motion of bed material have been assessed. The diagram describing the critical shear Reynolds number and the dimensionless shear stress for the incipient motion of sediment under ice covered conditions with different under cover resistance coefficient has been established. The effects of grain size on densimetric Froude number for incipient motion of bed material have been investigated. A relationship between the densimetric Froude number for incipient motion of bed material and the median grain size of bed material as well as the roughness coefficient of channel bed and roughness coefficient of ice cover has been established.     

THE RE-DERIVATION OF THE VORTICITY EQUATION OF THE LAYERED FLOW OF THE SHALLOW SEA

1 .　ＩＮＴＲＯＤＵＣＴＩＯＮＦｏｒｔｈｅｌａｒｇｅ ｓｃａｌｅｏｃｅａｎｉｃｆｌｏｗ ,ｐｅｏｐｌｅｕｓｕａｌｌｙｓｅｅｋｔｈｅｓｏｌｕｔｉｏｎｓｆｒｏｍｔｈｅｑｕａｓｉ ｇｅｏｓｔｒｏｐｈｉｃｖｏｒｔｉｃｉ ｔｙｅｑｕａｔｉｏｎｄｅｒｉｖｅｄｆｒｏｍｔｈｅｐｅｒｔｕｒｂａｔｉｏｎｂｙｕｓｉｎｇＲｏｓｓｂｙｎｕｍｂｅｒεａｓａｌｉｔｔｌｅｐａｒａｍｅｔｅｒ.Ａｎｉｍｐｏｒｔａｎｔａｐｐｒｏｘｉｍａｔｉｏｎｗｈｅｎｄｅｄｕｃｔｉｎｇｖｏｒｔｉｃｉｔｙｅｑｕａｔｉｏｎｉｎｔｈｅｌａｙｅｒｅｄｓｅａｗａｔ…     

A NUMERICAL STUDY FOR MICROWAVE BACKSCATTERING CROSS-SECTION OF SEA SURFACE

Based on Tian et al. ＇s theoretical model of microwave scattering, by using the wind wave spectrum suggested by Fung et al. , numerical results of polarized back-scattering were calculated. The quantitative relationships between the calculated backscattering cross section and the environmental parameters, such as wind speeds, azimuthal angles and incidence angles, were studied. Compared with the traditional two-scale scattering model, the results are much more coincident with the observations under the condition of moderate incidence angles, which is very useful to make up for the two-scale model. To make the new calculation model to be used conveniently in the practice, its simplified form was proposed.     

MATHEMATICAL MODELING OF OIL SPILL ON THE SEA AND APPLICATION OF THE MODELING IN DAYA BAY

Through the study of the theory of oil spill model, a mathematical modeling of oil spill on the sea is developed which with the consideration of spread, diffusion, drifting and attenuation of oil slick is influenced by evaporation and emulsification factors. A model that under the effect of ocean dynamic condition of tide, wind and wave, using Monte Carlo method to simulate the movement of oil slick is established. The modeling is applied to calculate and predict pollution range of oil spill at oil quay and oil ship in Daya Bay. The prediction results have basically shown the pollution situation by emergency of oil spill on the sea.     

THE EFFECTS OF RADIATION STRESS ON WAVE HEIGHTS AND SEA LEVEL IN THE INTERACTION OF COUPLED WAVE-TIDE-SURGE IN THE COASTAL AREA

1 .　ＩＮＴＲＯＤＵＣＴＩＯＮＷｉｎｄｇｅｎｅｒａｔｅｓｂｏｔｈｗａｖｅｓａｎｄｓｔｏｒｍｓｕｒｇｅｓ,ｓｏｔｈｅｉｒ ｇｅｎｅｒａｔｉｏｎｉｓｃｌｏｓｅｌｙｒｅｌａｔｅｄ .Ｆｕｒｔｈｅｒ ｍｏｒｅ ,ｓｔｒｏｎｇｌｙｎｏｎｌｉｎｅａｒｉｎｔｅｒａｃｔｉｏｎｓｂｅｔｗｅｅｎｔｉｄｅｓａｎｄｓｔｏｒｍｓｕｒｇｅｓｅｘｉｓｔｉｎｓｈａｌｌｏｗｗａｔｅｒ .Ｔｈｅｉｎｔｅｒａｃｔｉｏｎｓｂｅｔｗｅｅｎｗａｖｅａｎｄｔｉｄｅ ｓｕｒｇｅｍｏｔｉｏｎ ,ｂｅｔｗｅｅｎｗａｖｅａｎｄｔｈｅｍｅａｎｆｌｏｗｏｒｗａｔｅ…