1. A dynamic simulation method for calculating real-time wave breaking-induced mixing is characterized by comprising the following steps:

step 1, calculating a wave field in a certain time period through an offshore wave mode, and outputting wave parameters required for calculating wave breaking parameters;

step 2, establishing a wave breaking parameter calculation model, taking the wave parameters obtained in the step 1 as the input of the wave breaking parameter calculation model, and calculating through the wave breaking parameter calculation model to obtain a wave breaking parameter field;

step 3, improving the Princeton ocean model to enable the improved Princeton ocean model to comprise an unsteady wave breaking parameterization calculation method;

and 4, taking the wave breaking parameter field obtained in the step 2 as the input of the improved Princeton ocean model, simulating an ocean dynamic process containing unsteady wave breaking in real time through the improved Princeton ocean model, outputting ocean hydrological element data serving as important parameters for analyzing an ocean physical process and an ocean biochemical process, analyzing an ocean dynamic process, and predicting and forecasting the ocean environment disaster.

2. The dynamic simulation method for calculating real-time wave-breaking-induced mixing according to claim 1, wherein in step 1, the wave parameters required for calculating the wave-breaking parameters include wavelength, wave spectrum peak period and sea surface effective wave height.

3. The method of claim 1, wherein in step 2, the wave breaking parameter field comprises wave energy factor, Charnock number and water side friction speed; the wave breaking parameter calculation model comprises:

calculating the phase velocity C of the wave at the dominant frequency according to the formula (1)_p(x,y)：

Wherein, L (x, y) is wavelength, T (x, y) is wave spectrum peak period, and L (x, y) and T (x, y) are obtained by the near-shore wave mode output in the step 1;

calculation of wave energy factor alpha from equation (2)_CB(x,y)：

In the formula u_*a(x, y) is the air side friction velocity, related to wind speed and roughness, u_*a(x, y) is calculated according to equation (3):

wherein k is von Karman constant, and the value of k is 0.41; u shape₁₀(x, y) is the wind speed ten meters above the sea surface; z is a radical of₀(x, y) is the sea surface air side roughness, calculated according to equation (4):

in the formula, H_s(x, y) is sea surface effective wave height, and is obtained by the offshore wave mode output in the step 1;

the charnoock number β (x, y) is calculated according to equation (5):

calculating the water side friction velocity u according to equation (6)_*w(x,y)：

u_*a(x,y)＝(ρ_w/ρ_a)u_*w(x,y) (6)

In the formula, ρ_wIs the sea water density, ρ_aFor air density, take

Further, the sea surface friction z is calculated from equation (7)_w(x, y) for subsequent step 3 calculation:

wherein g is the acceleration of gravity.

4. The method of claim 1, wherein in step 3, the improved Princeton ocean model comprises:

the modified turbulence energy equation is shown in equation (8):

the boundary conditions of the modified turbulence energy equation are:

in the formula, q²(ii)/2 is the kinetic energy of turbulence; z is a vertical coordinate; t is time; s²Is the average speed of the shear to be measured,u is the flow velocity in the x direction and V is the flow in the y directionSpeed; n is a radical of²Is a potential density gradient of the liquid crystal,ρ₀is a reference to the density of the ink,is the average density; b is₁16.6 is the model constant;

K_Mis a mixing coefficient of momentum, K_HIs the mixing coefficient of temperature, K_qIs the mixing coefficient of turbulence, K_M,K_H,K_qThe calculation formula (2) is shown as (10):

(K_M,K_H,K_q)＝lq(S_M,S_H,S_q) (10)

in the formula, S_MIs K_MOf a stabilization function of S_HIs K_HOf a stabilization function of S_qIs K_qOf a stabilization function of S_MAnd S_HIs (lN/q)²Function of (1), generally S_q＝0.41S_H(ii) a At the near surface (S)_M，S_H，S_q)＝(0.30,0.49,0.20)；

l is the turbulent mixing length near the sea surface, calculated from equation (11):

l＝max(kz_w(x,y),l_z) (11)

in the formula I_zIs the value of the turbulent mixing length calculated by the Mellor-Yamada2.5 order turbulence closed model in the Princeton ocean model.

5. The dynamic simulation method for calculating real-time wave-breaking-induced mixing of claim 1, wherein in step 4, the marine hydrological element data includes marine temperature, salinity and flow velocity field.

Background

Wave breaking at the surface of the ocean generates a downward input turbulent kinetic energy flux, with the momentum of the wind being transferred first to the waves and then to the flow field, primarily by way of wave breaking. During this process, the turbulence energy near the surface of the sea increases significantly, creating a sub-layer of significantly increased turbulence generation near the surface of the sea. The enhanced turbulent kinetic energy can transfer momentum to the lower ocean layer, thereby influencing the vertical distribution of near-surface circulation and simultaneously influencing the vertical distribution of the upper ocean layer temperature field. The wave breaking phenomenon happens in the sea at any moment, plays a key dynamic role in controlling the power process of the surface of the sea, can greatly influence the mixing of ocean circulation, sea surface temperature and turbulence in the whole depth, provides an energy source of the surface of the sea for the mixing in the sea, is a main physical process of exchanging substances, heat, momentum and energy in the sea, is an important factor influencing the physical and biochemical processes of the sea, and has important influence on the maintenance and change of a global climate system.

In the current wave breaking parameterization scheme, an empirical constant is generally adopted for the value estimation of the wave breaking parameters, and a fixed value is adopted as the wave breaking parameters which are not consistent with the complex wave breaking phenomenon actually occurring in the sea, so that the calculation of the turbulence energy balance of a mixing layer on the sea by wave breaking can be influenced, and the dynamic change brought by the wave breaking effect cannot be reflected. Compared with the empirical constant, the influence of wave-induced turbulence on the sea mixing process and the power process of the Bohai sea area can be more accurately expressed by utilizing the wave-ocean current coupling model to carry out coupling calculation on the wave-induced mixing caused by wave breaking.

Disclosure of Invention

The invention aims to overcome the defects in the prior art and provide a method for calculating real-time wave breaking-induced mixing in the ocean so as to realize dynamic simulation of a physical ocean model and improve the defect that wave breaking parameters are set to be constant values in the original physical ocean model.

The technical scheme adopted by the invention is as follows: a dynamic simulation method for calculating real-time wave breaking-caused mixing comprises the following steps:

step 1, calculating a wave field in a certain time period through an offshore wave mode, and outputting wave parameters required for calculating wave breaking parameters;

step 2, establishing a wave breaking parameter calculation model, taking the wave parameters obtained in the step 1 as the input of the wave breaking parameter calculation model, and calculating through the wave breaking parameter calculation model to obtain a wave breaking parameter field;

step 3, improving the Princeton ocean model to enable the improved Princeton ocean model to comprise an unsteady wave breaking parameterization calculation method;

and 4, taking the wave breaking parameter field obtained in the step 2 as the input of the improved Princeton ocean model, simulating an ocean dynamic process containing unsteady wave breaking in real time through the improved Princeton ocean model, outputting ocean hydrological element data serving as important parameters for analyzing an ocean physical process and an ocean biochemical process, analyzing an ocean dynamic process, and predicting and forecasting the ocean environment disaster.

Further, in step 1, the wave parameters required for calculating the wave breaking parameters include wavelength, wave spectrum peak period and sea surface effective wave height.

Further, in step 2, the wave breaking parameter field comprises a wave energy factor, a Charnock number and a water side friction speed; the wave breaking parameter calculation model comprises:

calculating the phase velocity C of the wave at the dominant frequency according to the formula (1)_p(x，y)：

Wherein, L (x, y) is wavelength, T (x, y) is wave spectrum peak period, and L (x, y) and T (x, y) are obtained by the near-shore wave mode output in the step 1;

calculation of wave energy factor alpha from equation (2)_CB(x，y)：

In the formula u_*a(x, y) is the air side friction velocity, related to wind speed and roughness, u_*a(x, y) is calculated according to equation (3):

wherein k is von Karman constant, and the value of k is 0.41; u shape₁₀(x, y) is the wind speed ten meters above the sea surface; z is a radical of₀(x, y) is the sea surface air side roughness, calculated according to equation (4):

in the formula, H_s(x, y) is sea surface effective wave height, and is obtained by the offshore wave mode output in the step 1;

the charnoock number β (x, y) is calculated according to equation (5):

calculating the water side friction velocity u according to equation (6)_*w(x，y)：

u_*a(x，y)＝(p_w/ρ_a)u_*w(x，y) (6)

In the formula, ρ_wIs the sea water density, ρ_aFor air density, take

Further, the sea surface friction degree zw (x, y) is calculated according to equation (7) for calculation in the subsequent step 3:

wherein g is the acceleration of gravity.

Further, in step 3, the improved princeton ocean model includes:

the modified turbulence energy equation is shown in equation (8):

the boundary conditions of the modified turbulence energy equation are:

in the formula, q²(ii)/2 is the kinetic energy of turbulence; z is a vertical coordinate; t is time; s²Is the average speed of the shear to be measured,u is the flow velocity in the x direction and V is the flow velocity in the y direction; n is a radical of²Is a potential density gradient of the liquid crystal,ρ₀is a reference to the density of the ink,is the average density; b is₁16.6 is the model constant;

K_Mis a mixing coefficient of momentum, K_HIs the mixing coefficient of temperature, K_qIs the mixing coefficient of turbulence, K_M，K_H，K_qThe calculation formula (2) is shown as (10):

(K_M，K_H，K_q)＝lq(S_M，S_H，S_q) (10)

in the formula, S_MIs K_MOf a stabilization function of S_HIs K_HOf a stabilization function of S_qIs K_qOf a stabilization function of S_MAnd S_HIs (lN/q)²Function of (1), generally S_q＝0.41S_H(ii) a At the near surface (S)_M，S_H，S_q)＝(0.30，0.49，0.20)；

l is the turbulent mixing length near the sea surface, calculated from equation (11):

l＝max(kz_w(x，y)，l_z) (11)

in the formula I_zIs the value of the turbulent mixing length calculated by the Mellor-Yamada2.5 order turbulence closed model in the Princeton ocean model.

Further, in step 4, the marine hydrological element data comprises marine temperature, salinity and flow velocity fields.

The invention has the beneficial effects that: the unidirectional coupling system of the invention replaces the fixed value of the wave breaking parameter with the real-time data, embodies the dynamic influence of the wave breaking effect on the ocean, improves the precision of the physical model in the process of simulating the ocean power, has important significance for more accurately analyzing the substance, heat, momentum and energy exchange in the ocean, numerous physical and biochemical processes and perfecting the ocean disaster forecasting model under extreme weather conditions, also provides powerful technical reference for correctly knowing the ocean circulation and the global climate, and lays a foundation for establishing a globalized ocean-air coupling model.

Drawings

FIG. 1: the invention discloses a flow chart of a dynamic simulation method for calculating real-time wave breaking-caused mixing.

Detailed Description

In order to further understand the contents, features and effects of the present invention, the following embodiments are illustrated and described in detail with reference to the accompanying drawings:

as shown in fig. 1, a dynamic simulation method for calculating real-time wave breaking-induced mixing includes the following steps:

step 1, a near-shore wave mode (SWAN) starts to operate, a wave field in a certain time period is calculated through the near-shore wave mode, a wave parameter data file required by calculating wave breaking parameters is output, and the operation is stopped. The wave parameters required for calculating the wave breaking parameters comprise wavelength, wave spectrum peak period and sea surface effective wave height.

SWAN is a third-generation offshore sea wave numerical mode, adopts a balance equation based on the energy conservation principle, selects a fully-implicit finite difference format, is unconditionally stable, and enables a calculation space grid and a time step length to be unlimited. In each source and sink item of the balance equation, wind input, interaction of three-phase waves and four-phase waves, bottom friction, wave breaking and white wave dissipation are considered, and the method is widely applied to wave simulation under shallow water conditions.

And 2, establishing a wave breaking parameter calculation model, starting operation after the wave breaking parameter calculation model receives the wave parameter data file, calculating to obtain a wave breaking parameter field, and stopping operation after the data file is output. Wherein, the wave breaking parameter field comprises a wave energy factor, a Charnock number and a water side friction speed.

The wave breaking parameter calculation model is a model for calculating real-time wave breaking parameters, wave parameter data such as wave height, wavelength, period and the like are required to be input, and the essence is a constant wave breaking parameterization scheme.

An unsteady wave breaking parameterization scheme:

calculating the phase velocity C of the wave at the dominant frequency according to the formula (1)_p(x，y)：

Wherein, L (x, y) is wavelength, T (x, y) is wave spectrum peak period, and L (x, y) and T (x, y) are obtained by the near-shore wave mode output in the step 1;

calculation of wave energy factor alpha from equation (2)_CB(x，y)：

In the formula u_*a(x, y) is the air side friction velocity, related to wind speed and roughness, u_*a(x, y) is calculated according to equation (3):

wherein k is von Karman constant, and the value of k is 0.41; u shape₁₀(x, y) is the wind speed ten meters above the sea surface; z is a radical of₀(x, y) is sea surface air side roughness,calculated according to equation (4):

in the formula, H_s(x, y) is sea surface effective wave height, and is obtained by the offshore wave mode output in the step 1;

calculating the charock number β (x, y) according to equation (5):

water side friction speed u_*w(x, y) and air side frictional velocity u_*a(x, y) is converted by equation (6):

u_*a(x，y)＝(ρ_w/ρ_a)u_*w(x，y) (6)

in the formula, ρ_wIs the sea water density, ρ_aFor air density, take

Further, the sea surface friction z is calculated from equation (7)_w(x, y) for subsequent step 3 calculation:

wherein g is the acceleration of gravity.

And 3, improving the Princeton ocean model to enable the improved Princeton ocean model to comprise an unsteady wave breaking parameterization calculation method.

The Princeton Ocean Model (POM) is a three-dimensional oblique pressure original equation numerical value ocean mode, adopts a frog leaping finite difference format and a split operator technology, and is widely applied to the simulation of tidal current, wind-generated current, mixed layers and jump layers, hot salt circulation, ocean circulation and transportation by scholars at home and abroad. The original Princeton ocean mode is improved, and a wave breaking effect is added into a Mellor-Yamada2.5 order turbulence closed model of the Princeton ocean mode, so that the Princeton ocean mode comprises an unusual wave breaking parameterization calculation method, and the improved Mellor-Yamada2.5 order turbulence closed model is obtained.

The improved Mellor-Yamada2.5 order turbulence closed model is as follows:

on the basis of the Mellor-Yamada2.5 order turbulence closure scheme, the wave breaking effect is added by modifying the turbulence kinetic energy equation and introducing the turbulence kinetic energy input source term generated by wave breaking at the upper boundary condition of the turbulence kinetic energy equation and sea surface roughness at the upper boundary condition of the turbulence mixing length equation to determine the depth of influence of wave breaking.

The modified turbulence energy equation is shown in equation (8):

the boundary conditions of the modified turbulence energy equation are:

in the formula, q²(ii)/2 is the kinetic energy of turbulence; z is a vertical coordinate; t is time; s²Is the average speed of the shear to be measured,u is the flow velocity in the x direction and V is the flow velocity in the y direction; n is a radical of²Is a potential density gradient of the liquid crystal,ρ₀is a reference to the density of the ink,is the average density; b is₁16.6 is the model constant;

K_Mis a mixing coefficient of momentum, K_HIs the mixing coefficient of temperature, K_qIs the mixing coefficient of turbulence, K_M，K_H，K_qThe calculation formula (2) is shown as (10):

(K_M，K_H，K_q)＝lq(S_M，S_H，S_q) (10)

in the formula, S_MIs K_MOf a stabilization function of S_HIs K_HOf a stabilization function of S_qIs K_qOf a stabilization function of S_MAnd S_HIs (lN/q)²Function of (1), generally S_q＝0.41S_H(ii) a At the near surface (S)_M，S_H，S_q)＝(0.30，0.49，0.20)；

l is the turbulent mixing length near the sea surface, calculated from equation (11):

l＝max(kz_w(x，y)，l_z) (11)

in the formula I_zIs the value of the turbulent mixing length calculated by the Mellor-Yamada2.5 order turbulence closed model in the Princeton ocean model.

And 4, after receiving the wave breaking parameter file, the improved Princeton ocean model starts to operate, simulates the ocean dynamic process including unsteady wave breaking in real time, outputs the ocean hydrological element data (including ocean temperature, salinity, flow velocity field and the like) file, and then stops operating.

When the improved Princeton ocean model is operated, the influence of the wave breaking effect on the ocean circulation process is reflected by the output ocean hydrological element data. Compared with the method without considering the wave breaking process or only considering the steady wave breaking process, the method provided by the invention is more suitable for the physical process occurring in the actual ocean, embodies the dynamic influence of wave breaking on the ocean, and can perfect the physical mechanism of an ocean numerical mode, thereby greatly improving the simulation and forecast precision of the model, and having important significance for researching and analyzing substances, heat, momentum, energy exchange and numerous physical and biochemical processes in the ocean.

Although the preferred embodiments of the present invention have been described above with reference to the accompanying drawings, the present invention is not limited to the above-described embodiments, which are merely illustrative and not restrictive, and those skilled in the art can make many modifications without departing from the spirit and scope of the present invention as defined in the appended claims.