Method and system for constructing long-period wave height time series process at in-port berth

Abstract

The application discloses a construction method and system for long-period sea wave height time sequence process at a berth in a port, and the method comprises the following steps: constructing a wave propagation model; obtaining a wave spectrum process curve of a typical group of a boundary of the model based on measured or reanalyzed long-time sequence wind wave data, so as to drive the wave propagation model; obtaining wave parameters at the berth based on the driven wave propagation model, and calculating a nonlinear fitting relationship between the wave parameters at the boundary and the sea wave height at the berth; and obtaining long-time sequence wave parameters at the boundary, and obtaining the gravity wave short wave and low-frequency long wave process of the long-time sequence sea wave at the berth based on the nonlinear fitting relationship and the long-time sequence wave parameters at the boundary. The application can quickly realize the long-time sequence process of low-frequency long waves and gravity short waves at any berth in a port, provide dynamic load conditions of the berth affecting ship movement, and provide basic wave conditions for evaluating ship operation loss days.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of sea wave simulation, and particularly relates to a method and system for constructing a long-period sea wave height time sequence process at a berth in a harbor. BACKGROUND

[0002] Wave load is a main dynamic factor affecting the berthing stability of a ship in a harbor. Long-time sequence sea waves in a harbor area are necessary conditions for correctly evaluating a ship operation window and a berthing / de-berthing window. Especially in a sea area affected by long-period sea waves, gravity waves and low-frequency waves have different influences on the movement of a ship. Low-frequency waves have stronger penetrating power, and when encountering a breakwater, part of the wave energy can penetrate the breakwater to generate transmitted waves, thereby affecting the berthing stability in the harbor and causing the movement of the ship to increase significantly. Therefore, quickly obtaining the wave time sequence process at the berth is helpful to evaluate the safety and feasibility of ship mooring under different wave conditions.

[0003] Currently, when evaluating the safety of ship operation, short-term wave data observed in an engineering area or reanalyzed sea wave data are usually used to obtain the time sequence sea wave data process at the berth by using the significant wave height relationship provided in a propagation model. The prior art cannot comprehensively consider the different influences of gravity short waves and low-frequency long waves on ship operation. SUMMARY

[0004] The application provides a method and system for constructing a long-period sea wave height time sequence process at a berth in a harbor to solve the technical problems in the prior art.

[0005] To achieve the above-mentioned purpose, the application provides a method for constructing a long-period sea wave height time sequence process at a berth in a harbor, comprising the following steps:

[0006] constructing a wave propagation model;

[0007] obtaining a wave spectrum process curve of a typical group at a boundary based on the wave propagation model, and obtaining wave parameters at the boundary based on the wave spectrum process curve;

[0008] obtaining wave parameters at the berth based on the wave propagation model, wherein the wave parameters at the berth include gravity short waves at the berth and low-frequency long waves at the berth; and calculating a nonlinear fitting relationship between the wave parameters at the boundary and the wave parameters at the berth, wherein the nonlinear fitting relationship includes a first nonlinear fitting relationship between the wave parameters at the boundary and the gravity short waves at the berth and a second nonlinear fitting relationship between the wave parameters at the boundary and the low-frequency long waves at the berth;

[0009] obtaining long-period wave parameters at the boundary, and obtaining gravity short waves and low-frequency long waves of long-period sea waves at the berth based on the long-time sequence wave parameters at the boundary through the nonlinear fitting relationship.

[0010] Preferably, the wave propagation model is a time-domain wave propagation model of wave refraction and harbor wall reflection.

[0011] Preferably, the method further comprises, before obtaining the wave spectrum process curve of the typical group at the boundary, the following steps:

[0012] Based on the wave propagation model, obtaining a typical group characterized by wave height-period-direction;

[0013] Based on the typical group, obtaining the wave spectrum process curve of the typical group at the boundary.

[0014] Preferably, the wave spectrum process curve comprises a low-frequency wave spectrum distribution curve and a gravity wave spectrum distribution curve.

[0015] Preferably, the wave parameters at the boundary comprise wave height, period and direction.

[0016] Preferably, the method further comprises obtaining wave parameters at a detection point, and based on the wave parameters at the detection point and the wave parameters at the boundary, obtaining a third nonlinear fitting relationship;

[0017] Based on the wave parameters at the boundary and the third nonlinear fitting relationship, verifying an observation value at the detection point, wherein the observation value at the detection point comprises a low-frequency wave height observation value and a gravity wave height observation value.

[0018] In order to achieve the above technical purposes, the present application further provides a system for constructing a long-period sea wave height time sequence process at a berth in a harbor, for implementing any one of the methods for constructing a long-period sea wave height time sequence process at a berth in a harbor, and the system comprises:

[0019] A model construction module for constructing a wave propagation model;

[0020] A parameter acquisition module for, based on the wave propagation model, obtaining a wave spectrum process curve of a typical group at a boundary, and based on the wave spectrum process curve, obtaining wave parameters at the boundary;

[0021] A fitting calculation module for, based on the wave propagation model, acquiring wave parameters at a berth, wherein the wave parameters at the berth comprise gravity short waves at the berth and low-frequency long waves at the berth; and calculating a nonlinear fitting relationship between the wave parameters at the boundary and the wave parameters at the berth, wherein the nonlinear fitting relationship comprises a first nonlinear fitting relationship between the wave parameters at the boundary and the gravity short waves at the berth and a second nonlinear fitting relationship between the wave parameters at the boundary and the low-frequency long waves at the berth;

[0022] A parameter fitting module is configured to obtain long-period wave parameters at the boundary, and obtain the gravity short wave and the low-frequency long wave of the long-period sea wave at the berth based on the long-period wave parameters at the boundary and the nonlinear fitting relationship.

[0023] Compared with the prior art, the present application has the following advantages and technical effects:

[0024] The present application provides a method for constructing a long-period sea wave height time series process at a berth in a harbor. Firstly, a wave propagation model is constructed. Secondly, based on the wave propagation model, a wave spectrum process curve of a typical group at the boundary is obtained, and wave parameters at the boundary are obtained based on the wave spectrum process curve. Thirdly, wave parameters at the berth are obtained, wherein the wave parameters at the berth include a gravity short wave at the berth and a low-frequency long wave at the berth. Fourthly, a nonlinear fitting relationship between the wave parameters at the boundary and the wave parameters at the berth is calculated, wherein the nonlinear fitting relationship includes a first nonlinear fitting relationship between the wave parameters at the boundary and the gravity short wave at the berth and a second nonlinear fitting relationship between the wave parameters at the boundary and the low-frequency long wave at the berth. Finally, long-period wave parameters at the boundary are obtained, and the gravity short wave and the low-frequency long wave of the long-period sea wave at the berth are obtained based on the long-period wave parameters at the boundary and the nonlinear fitting relationship.

[0025] The present application can quickly realize the long-period time series process of the low-frequency long wave and the gravity short wave at any berth in the harbor area, provide the dynamic load conditions affecting the ship motion at the berth, and be beneficial to correctly evaluating the ship operation window and the berthing and unberthing window, thereby providing important support for harbor design and operation. BRIEF DESCRIPTION OF DRAWINGS

[0026] The accompanying drawings, which form a part of this application, are included to provide a further understanding of the application and are incorporated in and constitute a part of this application. The embodiments of the present application illustrated in the drawings and their descriptions are used to explain the present application and are not intended to limit the present application. In the drawings:

[0027] Figure 1 A wave propagation model from outside the harbor to the harbor area according to an embodiment of the present application;

[0028] Figure 2 A wave height-period-wave direction scatter plot and group setting diagram according to an embodiment of the present application, wherein (a) is an effective wave height-effective period scatter plot according to an embodiment of the present application, wherein the black circles represent a typical group distribution diagram; (b) is an effective wave height-wave direction scatter plot according to an embodiment of the present application, wherein the black circles represent a typical group distribution diagram; and (c) is an effective period-wave direction scatter plot according to an embodiment of the present application, wherein the black circles represent a typical group distribution diagram.

[0029] Figure 3The wave height-period-wave direction point distribution and group number setting schematic diagram of the embodiment of the present application, wherein (a) is the embodiment of constructing a typical group number overall spectrum curve, and (b) is the embodiment of constructing a typical group number low-frequency wave spectrum curve;

[0030] Figure 4 The position schematic diagram of the inspection point and the berth of the embodiment of the present application;

[0031] Figure 5 The wave height parameters obtained at the inspection point and the berth under different typical group numbers of the embodiment of the present application, wherein (a) is the gravity wave height (unit: cm) obtained at the inspection point under different typical group numbers, (b) is the low-frequency wave height (unit: cm) obtained at the inspection point under different typical group numbers, (c) is the gravity wave height (unit: cm) obtained at the berth under different typical group numbers, and (d) is the low-frequency wave height (unit: cm) obtained at the berth under different typical group numbers;

[0032] Figure 6 The inspection result schematic diagram of the simulated wave height and the fitted wave height at the inspection point of the embodiment of the present application, wherein (a) is the inspection result of the low-frequency wave at the inspection point under different typical group numbers, and (b) is the inspection result of the gravity wave at the inspection point under different typical group numbers;

[0033] Figure 7 The comparison and verification process schematic diagram of the fitted wave height and the observed wave height at the inspection point of the embodiment of the present application, wherein (a) is the low-frequency wave sequence verification process at the inspection point, and (b) is the gravity wave sequence verification process at the inspection point;

[0034] Figure 8 The fitted wave height time sequence process schematic diagram at the berth of the embodiment of the present application; wherein (a) is the gravity wave sequence process at the berth, and (b) is the low-frequency wave sequence process at the berth;

[0035] Figure 9 The construction method flowchart of the embodiment of the present application. DETAILED DESCRIPTION

[0036] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0037] It should be noted that the steps shown in the flowchart of the accompanying drawings can be executed in a computer system such as a group of computer executable instructions, and although the logical order is shown in the flowchart, in some cases, the steps shown or described can be executed in an order different from that herein.

[0038] Embodiment One

[0039] As Figure 9As shown, the embodiment provides a method for constructing a long-period wave height time series process at a berth in a harbor, comprising:

[0040] Constructing a wave propagation model;

[0041] Specifically, a wave numerical model is established for wave propagation from outside the harbor to inside the harbor. From the model, the corresponding wave conditions of the harbor under different incident wave conditions can be obtained. The model needs to consider the diffraction, refraction, and reflection of waves by buildings and walls in the harbor. A time-domain wave propagation model is used, and open-source software such as FUNWAVE, SWASH, or MIKE-BW software is used without specific requirements.

[0042] When establishing the wave propagation model from outside the harbor to the harbor, a refined coastline file, a water depth file, and an input wave spectrum file are prepared. Specifically, the simulated harbor layout coastline file, water depth file, and input parameter conditions are obtained in advance. The harbor coastline file needs to correctly describe the characteristics of the harbor layout, the contour of the surrounding coastline, and a grid generator and a file generator are used to generate the wave calculation grid and the required format of the input wave spectrum file. Then, these files are input into the harbor propagation wave mathematical model to calculate the output wave parameters and the water surface line process, where the wave parameter data at least includes the wave height and the wave period. Figure 1 As shown is an example of the simulation range of the wave propagation model of a certain project in Peru.

[0043] Based on the wave propagation model, the wave spectrum process curve of the typical group at the boundary is obtained, and based on the wave spectrum process curve, the wave parameters at the boundary are obtained;

[0044] Before obtaining the wave spectrum process curve of the typical group at the boundary, it further includes:

[0045] Based on the wave propagation model, the typical group with wave height-period-direction as characteristic values is obtained;

[0046] Based on the typical group, the wave spectrum process curve of the typical group at the boundary is obtained.

[0047] Specifically, a scatter density analysis of the wave-period-direction three parameters at the boundary of the model is carried out. It includes three subgraphs: wave height-period scatter distribution, wave height-direction scatter distribution, and direction-period scatter distribution. From the scatter distribution graph, a typical group is selected, which needs to meet the principle of full coverage of wave height-period-direction, the period and direction corresponding to the maximum wave height, the period and direction corresponding to the minimum wave height; the wave height and direction corresponding to the maximum period, the wave height and direction corresponding to the minimum period; all directions in the boundary wave sequence; wave height-period scatter density concentration area, wave height-direction scatter density concentration area, and wave period-direction scatter concentration area.

[0048] Figure 2The main characteristic values of the effective wave height in the shown example are between 1.00m and 3.50m, the main characteristic values of the short wave effective period are between 8s and 20s, and the main characteristic values of the wave direction are between 210° and 250°. In combination with the layout characteristics of the engineering plane scheme, the selected short wave height characteristic values are 0.6m, 1m, 1.2m, 1.4m, 1.5m, 2m, 2.25m, 2.5m, 2.75m, 3m, 3.25m and 3.5m; the short wave period characteristic values are 6s, 9s, 10s, 12s, 14s, 15s, 16s, 18s and 20s; and the direction characteristic values are 210°, 230°, 250° and 270°, which form a total of 432 combinations, from which 116 groups are selected as typical group times for wave propagation model calculation from the outside of the port to the inside of the port.

[0049] The spectrum shape of the incident wave spectrum under the typical group time is obtained. The input spectrum includes the frequency spectrum distribution of low-frequency waves and gravity waves, wherein the gravity waves use the JONSWAP wave making method, and the low-frequency wave part uses a uniformly distributed white noise spectrum when the wave frequency is less than 0.03Hz. According to the spectrum characteristics of the sea area where the project is located, an appropriate spectrum spectrum shape and a corresponding spectrum peak factor of 3.3 are used.

[0050] Figure 3 The incident wave spectrum curve under the shown typical group time (input Hs=1.5m, Tm=12s) is obtained by using the JONSWAP theoretical spectrum calculation method when the frequency is in the range of 0.03-1Hz, the wave energy distribution, the spectrum peak factor is selected as 3.3, and the wave energy distribution when the frequency is less than 0.03Hz is obtained by using the white noise spectrum method, as shown in (b) of FIG. 8. Figure 3 If the wave frequency is greater than 0.03Hz and the wave energy is lower than the low-frequency wave energy, the low-frequency wave energy value is used, as shown in (a) of FIG. 8. Figure 3

[0051] The construction method further includes obtaining wave parameters at the detection points, obtaining a third nonlinear fitting relationship based on the wave parameters at the detection points and the wave parameters at the boundary, and verifying the observation values at the detection points based on the wave parameters at the boundary and the third nonlinear fitting relationship, wherein the observation values at the detection points include low-frequency wave height observation values and gravity wave height observation values.

[0052] ​Specifically, wave propagation process calculations are performed within the harbor to obtain wave parameters at checkpoints and berths under different calculation conditions. The checkpoints and berths are located as follows: wave observations should be conducted at the checkpoints to verify and compare wave height parameters; the berths should be located within sheltered berth areas within the harbor, and multiple berths can be selected for analysis. This example only uses one point for illustration, where the checkpoint coordinates are (11.58°S, 77.30°E) with a water depth of -30m, and the berth coordinates are (11.59°S, 77.28°E) with a water depth of -15m. Figure 4 As shown.

[0053] Wave height parameter values ​​at test points and berths were obtained under different calculation conditions for selected typical wave propagation processes within the harbor. These wave height parameter values ​​include gravity wave height values ​​and low-frequency wave height values.

[0054] Figure 5 In the demonstration example, the typical incident wave height range is 0.6m to 3.5m, the incident period range is 6s to 20s, the gravity wave height range at the test point is 0.2 to 3.5m, the low-frequency wave height range at the test point is 0 to 0.6m, and they show a positive correlation with wave height and period; the gravity wave height range at the berth point is 0 to 0.9m, the low-frequency wave height range at the test point is 0 to 0.5m, and they show a nonlinear correlation with wave height and period.

[0055] Establish a fitting relationship between the input wave parameters and the low-frequency wave height and gravity wave height at the test point. First, using the wave height H, period T, and incident wave direction D at the boundary of the typical calculation group as dependent variables, and the low-frequency wave height (H) at the test point calculated by the model as the model... S_IG ), gravity wave height (H S_SW Using time-series data as independent variables, a nonlinear regression equation is employed to establish a third nonlinear fitting relationship. This includes establishing H... S_IG With H, T, D, H 2 T 2 The multi-parameter low-frequency nonlinear regression equation of HT is used to establish H S_SW With H, T, D, H 2 T 2 The multi-parameter gravity wave nonlinear regression equation for HT is given in equations (1) and (2) below. The goodness of fit is 0.99, the p-test values ​​for each parameter are close to 0, and the average standard error of the three parameters is 0.11. Wave height H S_IG Compared with the test results of predicted low-frequency wave height, wave height H S_SW See the test results for the predicted gravity wave values. Figure 6 (a)~ Figure 6 (b)

[0056] H S_SW= -12.14H + 19.49T + 3.34D - 1.33H 2 -0.49T 2 + 2.85HT - 490.7 (1)

[0057] H S_IG = 0.28H - 1.18T + 0.26D + 0.37H 2 - 0.02T 2 + 0.92HT - 26.8 (2)

[0058] The wave height time sequence process at the test point is verified. The wave height time sequence process parameters input by the boundary are input into the third nonlinear fitting relationship model to calculate the low-frequency wave height and gravity wave height process, which are compared with the observed low-frequency wave height and gravity wave height for verification. Figure 7 The observation wave height time at the test point is shown in 2018 / 07 / 07-2018 / 10 / 10, the wave parameter sequence value in this period at the boundary is obtained, the wave height period is taken as an input parameter to input into the third nonlinear fitting relationship model, the low-frequency wave height value and gravity wave height value at the test point in this period are obtained, wherein the correlation coefficient in the low-frequency wave height verification is 0.93, and the relative error is 8.1%; the correlation coefficient in the gravity wave height verification is 0.92, and the relative error is 10.6%. The verification index meets the verification requirement.

[0059] Based on the wave propagation model, the wave parameters at the berth are obtained, wherein the wave parameters at the berth include: gravity short wave at the berth and low-frequency long wave at the berth; the nonlinear fitting relationship between the wave parameters at the boundary and the wave parameters at the berth is calculated, wherein the nonlinear fitting relationship includes: the first nonlinear fitting relationship between the wave parameters at the boundary and the gravity short wave at the berth and the second nonlinear fitting relationship between the wave parameters at the boundary and the low-frequency long wave at the berth;

[0060] Specifically, the boundary wave height H, period T in the above typical calculation group are taken as dependent variables, the model calculated low-frequency wave height (H S_IG ) and gravity wave height (H S_SW ) time sequence data at the berth are taken as independent variables, and a nonlinear regression equation is used to establish a nonlinear fitting relationship. The second nonlinear regression equation of the low-frequency wave H S_IG and H, T, D, H 2 , HT and HD is established, the first nonlinear regression equation of the gravity wave H S_SW and H, T, D, H 2 , HT and HD is established, wherein the goodness of fit is 0.99, the P value of each parameter fitting is close to 0 value, and the average value of the standard error of three parameters is 0.11. The wave height H S_IGThe predicted low-frequency wave height test result, wave height H S_SW The predicted gravity wave value test result.

[0061] H S_SW = -63.17H - 11.95T - 6.42D - 0.88H 2 + 0.95HT + 0.28HD + 805.3 (3)

[0062] H S_IG = -8.58H - 2.37T - 0.88D + 0.19H 2 + 0.64HT + 0.02HD + 116.2 (4)

[0063] Obtaining the long-period wave parameter at the boundary, and obtaining the gravity short wave and the low-frequency long wave of the long-period sea wave at the berth based on the long-time series wave parameter at the boundary through the nonlinear fitting relationship.

[0064] Specifically, the wave height time series process parameter input by the boundary is input into the first nonlinear fitting relationship and the second nonlinear fitting relationship, and the low-frequency wave height and the gravity wave height process at the berth are calculated and obtained. Figure 8 The observation wave height time at the berth is from January 1, 1979 to December 21, 2019, the wave parameter sequence value at the boundary in this period is obtained, and the wave height period is input into the first nonlinear fitting relationship and the second nonlinear fitting relationship as an input parameter, thereby obtaining the low-frequency wave height value and the gravity wave height value at the berth in this period.

[0065] Compared with the prior art, the embodiment has the following advantages and technical effects:

[0066] The embodiment can quickly realize the long-time series process of the low-frequency long wave and the gravity short wave at any berth in the port area, provide the dynamic load conditions affecting the ship movement at the berth, and provide the basic wave conditions for evaluating the ship operation loss days.

[0067] Embodiment two

[0068] The embodiment provides a construction system of a long-period sea wave height time series process at a berth in a port, which is used for executing the construction method of the long-period sea wave height time series process at the berth in the port in the embodiment one, and the system comprises:

[0069] A model construction module is configured to construct a wave propagation model.

[0070] A parameter acquisition module is configured to obtain a wave spectrum process curve of a typical group at the boundary based on the wave propagation model, and obtain a wave parameter at the boundary based on the wave spectrum process curve.

[0071] a fitting calculation module, configured to obtain a wave parameter at a berth based on the wave propagation model, wherein the wave parameter at the berth comprises a gravity short wave at the berth and a low-frequency long wave at the berth; and calculate a nonlinear fitting relationship between the wave parameter at the boundary and the wave parameter at the berth, wherein the nonlinear fitting relationship comprises a first nonlinear fitting relationship between the wave parameter at the boundary and the gravity short wave at the berth and a second nonlinear fitting relationship between the wave parameter at the boundary and the low-frequency long wave at the berth;

[0072] a parameter fitting module, configured to obtain a long-period wave parameter at a boundary, and obtain a gravity short wave and a low-frequency long wave of a long-period sea wave at a berth based on the long-period wave parameter at the boundary and the nonlinear fitting relationship.

[0073] The embodiment has all the advantages of the method for constructing a long-period sea wave height time series process at a berth in a harbor as described in Embodiment One.

[0074] The above merely describes a preferred specific implementation of the present application, but the protection scope of the present application is not limited to this. Any person skilled in the art can easily think of changes or replacements within the technical scope disclosed by the present application, which should be covered by the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A method of constructing a long-period sea wave height time series process at a berth in a harbour, characterised by, The method comprises the following steps: constructing a wave propagation model; obtaining a wave spectrum process curve of a typical group at the boundary based on the wave propagation model, and obtaining a wave parameter at the boundary based on the wave spectrum process curve; obtaining a spectrum shape of an incident wave spectrum under a typical group, wherein the spectrum of the incident wave spectrum comprises a spectrum distribution of low-frequency waves and gravity waves, and the wave parameter at the boundary comprises a wave height, a wave period and a wave direction; obtaining a wave parameter at a berth based on the wave propagation model, wherein the wave parameter at the berth comprises a gravity short wave at the berth and a low-frequency long wave at the berth; and calculating a nonlinear fitting relationship between the wave parameter at the boundary and the wave parameter at the berth, wherein the nonlinear fitting relationship comprises a first nonlinear fitting relationship between the wave parameter at the boundary and the gravity short wave at the berth and a second nonlinear fitting relationship between the wave parameter at the boundary and the low-frequency long wave at the berth; obtaining a long-period wave parameter at the boundary, and obtaining a gravity short wave and a low-frequency long wave of a long-period sea wave at the berth based on the long-period wave parameter at the boundary and the nonlinear fitting relationship.

2. The method of constructing long period sea wave height time series at an in-harbor berth according to claim 1, wherein, The wave propagation model is a time-domain wave propagation model of wave refraction and harbor wall reflection.

3. The method of constructing long period sea wave height time series at an in-harbor berth according to claim 1, wherein, Before the wave spectrum process curve of the typical group at the boundary is obtained, the method further comprises the following steps: obtaining a typical group with wave height-period-wave direction as characteristic values based on the wave propagation model; obtaining the wave spectrum process curve of the typical group at the boundary based on the typical group.

4. The method of constructing long period sea wave height time series at an in-harbor berth according to claim 1, wherein, The wave spectrum process curve comprises a low-frequency wave spectrum distribution curve and a gravity wave spectrum distribution curve.

5. The method of constructing long period sea wave height time series processes at an in-harbor berth according to claim 1, wherein, The method further comprises the following steps: obtaining a wave parameter at a detection point, and obtaining a third nonlinear fitting relationship based on the wave parameter at the detection point and the wave parameter at the boundary; 6. A system for constructing long-period sea wave height time series at a berth in a harbor, characterized by verifying an observation value at the detection point based on the wave parameter at the boundary and the third nonlinear fitting relationship, wherein the observation value at the detection point comprises a low-frequency wave height observation value and a gravity wave height observation value. The system for implementing the method for constructing a long-period sea wave height time sequence process at a berth in a harbor according to any one of claims 1-5, the system comprising: a model construction module configured to construct a wave propagation model; a parameter acquisition module configured to obtain a wave spectrum process curve of a typical group at a boundary based on the wave propagation model, and obtain a wave parameter at the boundary based on the wave spectrum process curve; and obtain a spectrum shape of an incident wave spectrum under a typical group, wherein the spectrum of the incident wave spectrum comprises a spectrum distribution of low-frequency waves and gravity waves, and the wave parameter at the boundary comprises a wave height, a wave period and a wave direction; a fitting calculation module configured to obtain a wave parameter at a berth based on the wave propagation model, wherein the wave parameter at the berth comprises a gravity short wave at the berth and a low-frequency long wave at the berth; and calculate a nonlinear fitting relationship between the wave parameter at the boundary and the wave parameter at the berth, wherein the nonlinear fitting relationship comprises a first nonlinear fitting relationship between the wave parameter at the boundary and the gravity short wave at the berth and a second nonlinear fitting relationship between the wave parameter at the boundary and the low-frequency long wave at the berth; and obtain a long-period wave parameter at the boundary, and obtain a gravity short wave and a low-frequency long wave of a long-period sea wave at the berth based on the long-period wave parameter at the boundary and the nonlinear fitting relationship. The parameter fitting module is configured to obtain long-period wave parameters at the boundary, and obtain gravity short waves and low-frequency long waves of long-period sea waves at the berth based on the long-period wave parameters at the boundary and the nonlinear fitting relationship.

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