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

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Journal of Hydrodynamics 2001年第3期13卷 10-16页

作者： zhang qing-{2., Li Jian ke,{3., state oceanic administration, qingdao 266061, china Key Laboratory of Marine science and numerical modeling, state oceanic administration, qingdao 266061, china first Inst. of oceanography State Oceanic Administration Qingdao 266061 China

The scale analysis of the layered flow problem of the shallow sea shows that the parameter of E V represented the relative thickness of the friction layer is the little value larger than Rossby number. This illustrates that they are not ignorable and the important control factors of the layered flow although friction effect is only limited within interface Ekman layer and bottom Ekman layer. Using larger little parameter E V as the little perturbation parameter is more reasonable than using the classical Rossby number ε. By using the perturbation expansion and doing the researches of the structure of the Ekman layer on the sea surface, sea bottom and interface, a group of new layered flow vorticity equation is derived. It combines the vorticity of the flow of every layer, the inclination of the interface, the inclination of the sea bottom and the wind stress vorticity on the sea surface. Different from the conventional vorticity equation, which derived by using Rossby number as little parameter and is applied to large scale motion, it allows relatively large interfaces fluctuation, even it is applied to the problem that interface touch the bottom or touch the sea surface.

关键词： interface Ekman layer interface fluctuation touch the bottom touch the sea surface

KUROSHIO INTRUSION INTO THE SOUTH china SEA

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Journal of Hydrodynamics 2006年第6期18卷 702-713页

作者： zhang qing-{2. FAN Hai-mei {3. yuan-yuan institute of Physical oceanography Ocean University of China Qingdao 266003 China Key Laboratory of Marine science and numerical {2. State Oceanic Administration Qingdao 266061China

In this article, the circulation of the South china Sea （SCS）, which is idealized as the rectangular basin with constant depth, is studied under Kuroshio boundary forces. Starting from the linearly quasi-geostrophic vorticity equation, the solution of the SCS circulation is given in the form of corrected Fourier series under proper boundary conditions. The results show that the intruded current flows westward and separates into the northward branch and the southward branch before arriving at the western boundary. The southward branch flows out of the SCS through the southwestern passage, at the same time, the induced cyclonic （anti-clockwise） ring almost occupies the middle and southern parts, and concomitant anti-cyclonic （clockwise） vortex appears between the cyclone and the western boundary. While the northward branch outflows through the northeastern passage, the anti-cyclonic （clockwise） ring is triggered at the northern part of the SCS. The above two vortexes are both intensified if the south-entering and the north-leaving current loop intrusion are superposed. The outer flow of the northern vortex flows westward, then northward, and then eastward, and it is very similar to the configuration of the SCS Warm Current （SCSWC） at the northern part of the SCS, thus, a kind of generating mechanism of the SCSWC is presented.

关键词： Kuroshio boundary forces South china Sea (SCS) SCS Warm Current (SCSWC)

ANALYTIC METHOD FOR INVERSING THE OPEN BOUNDARY CONDITIONS IN A SEMI-CLOSED SEA AREA—CASE I FOR INVERSING THE TIDAL LEVELS AT OPEN BOUNDARY

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Journal of Hydrodynamics 2004年第5期16卷 590-595页

作者： zhangqing-{2. YIN{3.n-qiang MAJian quyuan-yuan KeyLaboratoryofMarinescienceandnumerical{2. TheFirstInstituteofOceanographyStateOceanicAdministrationQingdao266061China KeyLaboratoryofMarinescienceandnumerical{2. TheFirstInstituteofOceanographyStateOceanicAdministrationQingdao266061China

In this paper, a computational case was employed to describe thecomputational procedure for inversing the tidal level open boundary conditions using an analyticmethod. The area for finding the solution is a circular area with a circular arc with the openingangle 60°-being the open boundary and the other circular arc being the solid wall *** from the reestablished elliptic partial differential equation satisfied by the tidallevel function, the extended spectrum method was used to derive the general solution of the equationfor the sea of constant depth, and the impermeable solid wall condition (the second class boundarycondition) and the adequately specified open boundary conditions were then applied to determine theundetermined coefficients of the general solution, thus obtaining the tidal level distributionfunction. In this way, both the {3. and second class boundary values at the solid wall boundarywere obtained. With the above boundary values as the boundary conditions, the tidal level values atthe open boundary were then inversed by means of the general solution of tidal wave equation. Thevalidity of inversion method could be verified by comparing the inversed tidal level distributionswith the originally specified open boundary values.

关键词： semi-closed sea open boundary condition extended spectrum method generalsolution of equation in-version

UNIFICATION AND APPLICATIONS OF MODERN oceanic/ATMOSPHERIC DATA ASSIMILATION ALGORITHMS

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Journal of Hydrodynamics 2004年第5期16卷 501-517页

作者： QIAOFang-li zhangShao-{2. {3.Ye-li instituteofoceanography ChineseAcademyofSciencesQingdao266071China GeophysicalFluidDynamicsLaboratory PrincetonUniversityPrincetonNJ08542USA KeyLaboratoryofMarinescienceandnumerical{2. TheFirstInstituteofOceanographyStateOceanicAdministrationQingdao266061China

The key mathematics and applications of various modern atmospheric/oceanicdata assimilation methods including Optimal Interpolation (OI), 4-dimensional variational approach(4D-Var) and filters were systematically reviewed and classified. Based on the data assimilationphilosophy, i. e. , using model dynamics to extract the observational information, the commoncharacter of the problem, such as the probabilistic nature of the evolution of theatmospheric/oceanic system, noisy and irregularly spaced observations, and the advantages anddisadvantages of these data assimilation algorithms, were discussed. In the filtering framework, allmodern data assimilation algorithms were unified: OI/3.-Var is a stationary filter, 4D-Var is alinear (Kalman) filter and an ensemble of Kalman filters is able to construct a nonlinear *** nonlinear filter such as the Ensemble Kalman Filter (EN-KF), Ensemble Adjustment Kalman Filter(EAKF) and Ensemble Transformation Kalman Filter (ETKF) can, to some extent, account for thenon-Gaussian information of the prior distribution from the model. The flow-dependent covarianceestimated by an ensemble filter may be introduced to OI and 4D-Var to improve these traditionalalgorithms. In practice, the performance of algorithms may depend on the specific {2. modeland the choice of algorithm may depend on the specific problem. However, the unification ofalgorithms allows us to establish a unified test system to evaluate these algorithms, which providesmore insights into data assimilation philosophies and helps improve data assimilation techni{3.es.

关键词： data assimilation oceanic/atmospheric system filtering optimalinterpolation (OI) 4-dimensional variational(4D-Var) approach

AN ACCURATE SOLUTION OF THE LINEAR THEORY OF THE WIND-DRIVEN OCEAN CIRCULATION-I. THE GENERALIZED SOLUTION

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Journal of Hydrodynamics 2003年第6期15卷 96-105页

作者： zhang qing-{2., {3. yuan-yuan, Xia Chang-shuiKey Laboratory of Marine science and numerical modeling, state oceanic administration, first institute of {12.,{13., china, e-mail: {3.-helen @ *** Key Laboratory of Marine science and numerical {2. State Oceanic Administration First Institute of Oceanography Qingdao 266061 China

To model the wind-driven ocean circulation of the isobath rectangular basin,the linear vorticity equation with the meridional friction terra was used compared to the Munk'stheory on the ocean circulation. The generalized solution of the vorlicity equation was thus workedout in the sense of Fourier averaging by using the corrected Fourier expansion. The method to obtainthe undetermined coefficients was presented using the viscous boundary conditions.

关键词： wind-driven ocean circulation meridional friction corrected fourierexpansion

ASSIMILATION OF ALTIMETER WIND DATA IN MESOSCALE numerical MODEL (MM5)

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Journal of Hydrodynamics 2001年第3期13卷 49-56页

作者： Ma, Yan zhang, qing-{2. {3., yuan-yuan first Inst. of oceanography State Oceanic Administration Qingdao 266061 China

Making use of altimeter wind data and standard sounding data in a mesoscale numerical model of PSU/NCAR (MM5), we test four-dimensional data assimilation scheme based on nudging. The purpose of this paper is to determine what meteorological fields and what assimilation method have positive effect on typhoon sea surface wind by simulating two typhoon cases in MM5. We perform seven experiments for 9608 Typhoon (Case 1): one control experiment, three analysis nudging experiments, two observation nudging experiments and one analysis and observation nudging experiment; we perform one control experiment and one analysis nudging experiment for 9711 Typhoon (Case 2.. The results show assimilating wind-thermal fields can effectively improve simulation accuracy of the model; the experiment combining standard sounding data and surface observations can improve greatly the simulation accuracy of the model; the altimeter data contain lots of sea surface information and also have positive impact on typhoon sea surface wind.

关键词： Data processing numerical analysis Statistical methods Wind