摘要
根据海水温度和盐度平流扩散方程给出一种数值计算方案并采用混合长度理论给出垂直涡动粘性系数的计算方法。对于温度和盐度方程，其平流过程采用了Lax－Wendroff格式，水平扩散采用显格式，垂直扩散采用隐格式。时间步长主要受平流过程的Courant-Friedrichs-Lewy条件限制。垂直涡动粘性系数计算依据Prandtl混合长度理论，并考虑了海水层化的抑制作用，因而其数值与流场及密度场结构有关。温度、盐度及垂直涡动粘性系数的计算与动力方程中内模态的计算同步进行。应用本模式模拟渤、黄、东海由潮流、密度流和风海流迭加而成的综合海流，得出了良好的结果。
A numrical scheme for solving warer temperature and salinity equations and a method for computing vertical eddy viscosity are presented. The advection processes of temperature and salinity are calculated prognostically with the Lax-Wendroff scheme and the vertical and lateral diffusions are calculated with implicit and explicit schemes respectively. The time step is mainly restricted by the Courant-Friedrichs-Lewy condition for advection processes. The coefficient of the vertical eddy viscosity is calculated based on Prandti's mixing length theory with suppressive effect from sea water stratification considered, and thus varies with variation of the structures of flow and density fields. The temperature, salinity and vertical eddy viscosity are calculated at the same steps as the calculations of the internal modes of velocities.As a preliminary application, a numrical model of the Bohai, Yellow and East China Seas was estabished. The model grid resolution is 15' × 15' with 15 levels in the vertical. The monthly resulwt cunnts driven by tide, wind and density are computed diagnostically. The water levels along the open boundaries are specified a priori. Their oscillating part is predicted from the tidal harmonic constants. The mean water level part is adjusted so as to produce appropriare mean inflow / outflow volume transports. The monthly water density fields are created by objectively analyzing the recorded temperature and salinity data. The optimal interpolation technique is used in the objective analysis. The Hellerman-Rosenstein's (1983) monthly wind stress fields are imposed on the sea suxface. The present paper shows a part of the computed current fields. It can be observed that the currents on the shelf are governed by tides and those in the southeastem East China Sea are controlled by the Kurshio. Counter currents appear to the southast of the Kurshio.
出处
《海洋与湖沼》
CAS
CSCD
北大核心
1998年第4期381-388,共8页
Oceanologia Et Limnologia Sinica
基金
国家自然科学基金!49136142
49576280
国家科委资助!85-903-08-02
关键词
海洋
动力学
数值模式
盐度
涡动粘性系数
温度
Temperature and salinity equations
Lax-Wendroff scheme
Vertical eddy viscosity
Mixing length theory
