Numerical Processing Method for Waves at a Protected Wharf

Abstract

The present invention discloses a method for numerically processing waves at a sheltered wharf, which relates to the technical field of wave forecasting and includes the following steps: obtaining a specific relationship between the predicted values and the measured values of the wave conditions and wind conditions at the model boundary; setting up a wave mathematical model using the swan wave numerical simulation software, and combining the predicted values of the historical wave conditions and wind conditions at the model boundary to simulate and obtain the predicted values of the historical wave conditions and wind conditions in the port; deriving a specific relationship between the predicted values and the measured values of the wave conditions and wind conditions in the port; obtaining the predicted values of the latest wave conditions and wind conditions at the model boundary and making corrections; simulating and obtaining the initial predicted values of the wave conditions and wind conditions in the port and making corrections to obtain the final predicted values of the wave conditions and wind conditions in the port. The present invention can obtain the predicted values of the waves in the sheltered wharf according to the predicted values of the waves outside the port, thereby guiding the operation arrangement of the ships in the port and providing basic data support for the port operation management.

Description

Technical Field

[0001] The present invention relates to the technical field of wave prediction. More specifically, the present invention relates to a method for numerically processing waves at a sheltered wharf. Background Art

[0002] Wave data, as an important basic input condition, affects the safety of port operations. Currently, there are generally two methods for obtaining waves in the port: 1) real-time monitoring through buoys, but this monitoring has the characteristic of delay and cannot conduct refined management of the operations of port ships; 2) purchasing data of existing prediction models, such as Windy prediction data, but these data only have the predicted values of waves outside the port and no predicted values of waves inside the sheltered wharf, so they cannot directly guide the operation arrangements of ships inside the port. The prior art, such as the invention patent application with the publication number CN110728042A, discloses a method for quickly predicting coastal wave elements on a long time scale, which can realize the prediction of nearshore wave elements based on the wind conditions, wave conditions, and tide level data on the open sea for a long time scale. However, in practical applications, the marine environment changes rapidly, resulting in poor real-time performance of the predicted nearshore wave elements. If the data is not updated in a timely manner, it may lead to the disconnection between the prediction results and the actual situation, and there are areas for improvement. Summary of the Invention

[0003] An object of the present invention is to provide a method for numerically processing waves at a sheltered wharf, which realizes the wave prediction inside the port, adapts to the changes in the marine environment, and effectively improves the accuracy of the prediction.

[0004] To achieve these objects and other advantages of the present invention, according to one aspect of the present invention, the present invention provides a method for numerically processing waves at a sheltered wharf, including the following steps:

[0005] Step 1: Obtain the predicted values and measured values of the wave conditions and wind condition parameters at the offshore model boundary in history, and derive a specific relational expression I between the predicted values and measured values of the wave conditions and wind condition parameters at the offshore model boundary;

[0006] Step 2: Use the swan wave numerical simulation software to set up a wave mathematical model inside the port, and combine the predicted values of the wave conditions and wind condition parameters at the offshore model boundary in history to simulate the predicted values of the wave conditions and wind condition parameters inside the port in history;

[0007] Step 3: Obtain the measured values of the wave conditions and wind condition parameters inside the port in history, and combine the predicted values of the wave conditions and wind condition parameters inside the port in history to derive a specific relational expression II between the predicted values and measured values of the wave conditions and wind condition parameters inside the port;

[0008] Step 4: Obtain the predicted values and measured values of the latest wave conditions and wind conditions parameters at the offshore model boundary, and correct the predicted values of the latest wave conditions and wind conditions parameters at the offshore model boundary according to a specific relationship formula 1 between the predicted values and measured values of the wave conditions and wind conditions parameters at the offshore model boundary, to obtain the corrected predicted values of the latest wave conditions and wind conditions parameters at the model boundary;

[0009] Step 5: According to the in-port wave mathematical model, and in combination with the corrected predicted values of the latest wave conditions and wind conditions parameters at the model boundary, simulate and obtain the initial predicted values of the in-port wave conditions and wind conditions parameters;

[0010] Step 6: Obtain the measured values of the latest wave conditions and wind conditions parameters in the port, and correct the initial predicted values of the in-port wave conditions and wind conditions parameters according to a specific relationship formula 2 between the predicted values and measured values of the in-port wave conditions and wind conditions parameters, to obtain the final predicted values of the in-port wave conditions and wind conditions parameters.

[0011] Preferably, the wave conditions and wind conditions parameters include wave height, wave period, wave direction, wind speed, and wind direction.

[0012] Preferably, the predicted values of the wave conditions and wind conditions parameters at the historical offshore model boundary, and the predicted values of the latest wave conditions and wind conditions parameters at the offshore model boundary both adopt Windy forecast data, and the measured values of the wave conditions and wind conditions parameters at the historical offshore model boundary, and the measured values of the historical in-port wave conditions and wind conditions parameters are both obtained by arranging buoy measuring stations for measurement.

[0013] Preferably, both the specific relationship formula 1 between the predicted values and measured values of the wave conditions and wind conditions parameters at the offshore model boundary, and the specific relationship formula 2 between the predicted values and measured values of the in-port wave conditions and wind conditions parameters are derived by plotting scatter plots and using polynomial fitting.

[0014] Preferably, in Step 2, setting the in-port wave mathematical model using the swan wave numerical simulation software includes setting model parameters and setting the model terrain file. The model parameter settings include bottom friction parameters and breaking parameters, both of which adopt the recommended values of the model; the model terrain file is generated using the SMS terrain production software.

[0015] Preferably, it further includes an update mechanism, that is, the processes of Step 1 and Step 3 are repeated irregularly to update the specific relationship formula 1 between the predicted values and measured values of the wave conditions and wind conditions parameters at the offshore model boundary, and the specific relationship formula 2 between the predicted values and measured values of the in-port wave conditions and wind conditions parameters. Specifically:

[0016] Perform cluster analysis on the changes in the marine environment, and classify the changes in the marine environment into a calm period, a general change period, and a drastic change period:

[0017] During the calm period, continuously accumulate the predicted values and measured values of the wave conditions and wind conditions parameters at the boundary of the historical model outside the port, as well as the predicted values and measured values of the wave conditions and wind conditions parameters inside the historical port. Repeat the processes of Step 1 and Step 3 every 1 to 3 months;

[0018] During the general change period, monitor the change amplitude of each parameter in real time. If the cumulative change amplitude of each parameter exceeds a certain threshold, immediately start repeating the processes of Step 1 and Step 3;

[0019] During the drastic change period, start repeating the processes of Step 1 and Step 3 every 15 to 30 minutes.

[0020] Preferably, during the general change period, the thresholds for the change amplitude of each parameter are: the wave height changes by 0.5 to 1.2 m, and the wind speed changes by 3 to 6 m / s.

[0021] Preferably, the determination methods for the calm period, general change period, and drastic change period are as follows:

[0022] When the wave height is lower than 0.3 m, the wind speed is less than 3 m / s, the sea current speed is weak, and the water temperature and salinity remain relatively constant, the sea area where it is located is determined to be in the calm period;

[0023] When the wave height is between 0.3 and 0.6 m, the wind speed is between 3 and 6 m / s, the sea current speed is less than 0.5 knots, the water temperature is between 15 and 18 °C, and the salinity is between 34‰ - 35‰, the sea area where it is located is determined to enter the general change period;

[0024] When the wave height is greater than 1.5 m, the wind speed is greater than 10 m / s, the sea current speed is greater than 1 knot, the water temperature suddenly changes by more than 2 °C, and the salinity fluctuates by more than 1‰, the sea area where it is located is determined to enter the drastic change period.

[0025] The present invention has at least the following beneficial effects: By obtaining the predicted values, measured values of the wave conditions and wind conditions parameters at the boundary of the historical model outside the port, as well as the predicted values, measured values of the wave conditions and wind conditions parameters inside the historical port, respectively derive the specific relationships between them, and use these relationships to correct the predicted values. This way of establishing relationships and making corrections based on actual data effectively improves the accuracy of wave prediction inside the port; By performing cluster analysis on the changes in the marine environment, dividing the calm period, general change period, and drastic change period, and updating the specific relationships at different frequencies in different periods, the prediction method can better adapt to the complex and changeable marine environment, ensuring the timeliness and accuracy of the prediction results.

[0026] Other advantages, objectives, and features of the present invention will be partially reflected by the following description, and partially will also be understood by those skilled in the art through the research and practice of the present invention. Description of the Drawings

[0027] Figure 1 This is the flowchart of the wave numerical processing method for the sheltered wharf in a technical solution of the present invention.

[0028] Figure 2 This is the scatter plot of the measured and predicted wave heights at the south boundary of the offshore historical model in Embodiment 1 of the present invention.

[0029] Figure 3 This is the schematic diagram of the terrain file of the wave mathematical model in the port in Embodiment 1 of the present invention.

[0030] Figure 4 This is the wave prediction result at a certain moment in Embodiment 1 of the present invention. Detailed implementation manners

[0031] The following further elaborates on the present invention in conjunction with the accompanying drawings and specific implementation manners, so that those skilled in the art can implement it with reference to the description in the specification.

[0032] It should be understood that terms such as "having", "including", and "comprising" as used herein do not exclude the presence or addition of one or more other elements or their combinations.

[0033] Embodiment 1

[0034] Wave prediction for a fishing port in a certain place

[0035] Step 1: Deduce the relationship at the south boundary of the model

[0036] Obtain the predicted values (Windy prediction data) and measured values (obtained through buoy measurement stations) of wave conditions (wave height, wave period, wave direction) and wind conditions (wind speed, wind direction) parameters at the south boundary of the offshore historical model.

[0037] Taking the wave height as an example, draw a scatter plot of the measured and predicted values (see Figure 2), and obtain the relational expression by polynomial fitting, such as , with the correlation coefficient R = 0.92. Similar methods are used for other parameters.

[0038] Step 2: Set up the wave mathematical model in the port and simulate the historical parameters in the port

[0039] Use the SMS terrain production software to generate the model terrain file (see Figure 3), and set the parameters of the wave mathematical model in the port based on the dynamic spectrum balance equation formula (the bottom friction parameter and the breaking parameter adopt the recommended values).

[0040] Obtain the predicted values of wave conditions and wind conditions parameters at the boundary of the offshore historical model, and use the swan wave numerical simulation software to simulate and obtain the predicted values of historical wave conditions and wind conditions parameters in the port in combination with the model settings.

[0041] Step 3: Deduce the relationship of wave condition parameters in the port

[0042] Obtain the measured values of historical wave conditions and wind conditions parameters in the port through observation equipment such as in-port buoys.

[0043] Using a method similar to that in Step 1, obtain the relationship between the measured values and the predicted values of the wave conditions and wind conditions parameters in the port.

[0044] Step 4: Obtain and correct the latest predicted values of the southern boundary outside the port

[0045] Use Windy to obtain the latest predicted values of wave conditions and wind conditions parameters at the southern boundary of the offshore model.

[0046] According to the relationship obtained in Step 1, correct the latest predicted data to obtain the corrected latest predicted values of wave conditions and wind conditions parameters.

[0047] The correction process is as follows: After obtaining the latest predicted wave height value at the southern boundary of the offshore model, substitute it into the above relationship to calculate the corresponding theoretical measured value. Then, compare the theoretical measured value with the actually obtained latest measured sample value. If there is a deviation from the expectation, it can be adjusted according to the deviation situation. For example, if the theoretical measured value is significantly greater than the measured sample, the predicted value can be appropriately reduced; otherwise, it can be appropriately increased. The adjustment amplitude is determined according to the linear adjustment strategy.

[0048] For other wave conditions parameters (wave period, wave direction) and wind conditions parameters (wind speed, wind direction), the latest predicted values are corrected in the same way as above to ensure the accuracy of the boundary parameters, thus providing a more reliable basis for the subsequent simulation and correction of wave conditions parameters in the port.

[0049] Step 5: Simulate the initial predicted values in the port

[0050] Based on the in-port wave mathematical model set in Step 2, combined with the corrected latest predicted values of wave conditions and wind conditions parameters at the southern boundary, use the swan wave numerical simulation software to obtain the initial predicted values of wave conditions and wind conditions parameters in the port.

[0051] Step 6: Calculate the final predicted values in the port

[0052] Combined with the relationship between the measured values and the predicted values of wave conditions and wind conditions parameters in the port obtained in Step 3, correct the initial predicted values to obtain the final predicted values of wave conditions and wind conditions parameters in the port (see Figure 4). The correction process is the same as above.

[0053] Real-time monitoring and update judgment

[0054] During the calm period, repeat Step 1 and Step 3 every two months to accumulate more data to update the relationship and ensure the prediction accuracy.

[0055] During the general change period, a professional marine environment monitoring system is used to conduct 24-hour real-time monitoring of key parameters such as wave height and wind speed. For example, high-precision wave height meters and wind speed sensors are installed at this port, and data is automatically collected every 10 minutes and transmitted to the monitoring center.

[0056] Set the change amplitude threshold. When the cumulative change in wave height reaches 0.8m and the cumulative change in wind speed reaches 4m / s, the system automatically issues an alarm and triggers the update mechanism. Suppose during the monitoring on a certain day, starting at 8 am, the wave height gradually increases from the initial 0.4m and reaches a cumulative increase of 0.8m at 2 pm. At the same time, the wind speed increases from 5m / s to 9m / s, with a cumulative change reaching 4m / s, and the monitoring system immediately initiates the subsequent update process.

[0057] During the drastic change period, with the help of an automated data collection and processing system, steps one and three are automatically repeated every 20 minutes.

[0058] The specific update process is as follows: Re-collect the measured and predicted values of the new wave conditions and wind conditions parameters at the south boundary of the offshore model, re-draw the scatter plot and perform polynomial fitting, and update the relationship between the measured and predicted values of the wave conditions and wind conditions parameters at the south boundary of the offshore model. For the wave conditions and wind conditions parameters in the port, similarly re-obtain the latest measured values, combine with the current predicted values, re-draw the scatter plot and fit, and update the relationship between the measured and predicted values of the wave conditions and wind conditions parameters in the port.

[0059] Re-obtain the latest predicted values of the wave conditions and wind conditions parameters at the south boundary of the offshore model from Windy, and correct these latest predicted values according to the updated relationship at the south boundary of the offshore model.

[0060] Based on the pre-set wave mathematical model in the port (the model parameters and terrain files remain unchanged, and can be adjusted according to the actual situation in case of special circumstances), combined with the corrected latest predicted values of the wave conditions and wind conditions parameters at the south boundary, use the swan wave numerical simulation software to calculate the initial predicted values of the wave conditions and wind conditions parameters in the port.

[0061] Finally, combine the updated relationship between the measured and predicted values of the wave conditions and wind conditions parameters in the port to correct the initial predicted values, so as to obtain the final predicted values of the wave conditions and wind conditions parameters in the port. The port operation and management department adjusts the ship's loading and unloading plan, inbound and outbound arrangements, etc. in a timely manner according to these latest predicted data to ensure the safety and efficiency of port operations.

[0062] Table 1 Comparison of Measured and Predicted Values of Wave Conditions Parameters in the Port (Taking Wave Height as an Example)

[0063] Time Measured value of wave height in the port (m) Final predicted value of wave height in the port (m) Error value (m) 2024-10-10 08:00 0.65 0.64 0.01 2024-10-11 12:00 0.91 0.93 -0.02 2024-10-12 16:00 0.75 0.72 0.03 2024-10-13 20:00 1.02 1.03 -0.01

[0064] As can be seen from Table 1, the error value (the difference between the measured value of the in-port wave height and the final predicted value of the in-port wave height) between the predicted value of the in-port wave height measured by the method of the present invention and the measured value of the in-port wave height is very small, which proves that the numerical processing method of waves for sheltered wharves of the present invention can effectively improve the accuracy of the prediction of in-port wave condition parameters.

[0065] Table 2 Comparison of the improvement of prediction accuracy after model update in different periods

[0066] Average error of wave height prediction before update (m) Average error of wave height prediction after update (m) Quiet period 0.25 0.15 General change period 0.20 0.12 Severe change period 0.30 0.18

[0067] As can be seen from Table 2, in different periods of ocean environmental changes, according to the set update mechanism (update every 2 months in the calm period, update when reaching the threshold in the general change period, and update every 20 minutes in the drastic change period), after re-collecting data and updating the relational formula, the average error of wave height prediction has been significantly reduced, which proves that the update mechanism of the present invention can effectively improve the prediction accuracy and provide a more reliable basis for port operation and management.

[0068] Although the embodiments of the present invention have been disclosed as above, it is not limited to the applications listed in the specification and embodiments. It can be fully applied to various fields suitable for the present invention. For those familiar with the field, additional modifications can be easily made. Therefore, without departing from the general concept defined by the claims and the equivalent scope, the present invention is not limited to the specific details and the examples shown and described herein.

Claims

1. A method for numerically processing waves at a sheltered pier, characterized in that: The following steps are involved: Step 1: obtaining the predicted values ​​and measured values ​​of the boundary wave and wind condition parameters of the historical model outside the port, and deriving a specific relationship formula 1 between the predicted values ​​and measured values ​​of the boundary wave and wind condition parameters of the model outside the port; Step 2: using SWAN wave numerical simulation software to set up a mathematical model of waves in the port, combining the predicted values ​​of the boundary wave conditions and wind condition parameters of the historical model outside the port, and simulating the predicted values ​​of the historical wave conditions and wind condition parameters in the port; Step 3: obtaining the measured values ​​of the historical wave and wind parameters in the port, combining the predicted values ​​of the historical wave and wind parameters in the port, and deriving a second specific relationship between the predicted values ​​and the measured values ​​of the wave and wind parameters in the port; Step 4: obtaining the forecast value and measured value of the latest wave condition and wind condition parameters of the model boundary outside the port, and correcting the forecast value of the latest wave condition and wind condition parameters of the model boundary outside the port according to the specific relationship formula 1 between the forecast value and the measured value of the wave condition and wind condition parameters of the model boundary outside the port, so as to obtain the forecast value of the latest wave condition and wind condition parameters of the model boundary after correction; Step 5: According to the mathematical model of the wave in the harbor, combined with the forecast values ​​of the latest wave and wind condition parameters at the modified model boundary, simulate and obtain the initial forecast values ​​of the wave and wind condition parameters in the harbor; Step six, obtaining the measured values ​​of the latest wave and wind parameters in the port, and correcting the initial forecast values ​​of the wave and wind parameters in the port according to the specific relationship between the forecast values ​​and the measured values ​​of the wave and wind parameters in the port to obtain the final forecast values ​​of the wave and wind parameters in the port.

2. The method for numerically processing waves of a sheltered pier according to claim 1, characterized in that: The wave and wind condition parameters include wave height, wave period, wave direction, wind speed and wind direction.

3. The method for numerically processing waves of a sheltered pier according to claim 1, characterized in that: The forecast values ​​of the wave and wind condition parameters at the historical model boundary outside the port and the forecast values ​​of the latest wave and wind condition parameters at the model boundary outside the port all use Windy forecast data, and the measured values ​​of the wave and wind condition parameters at the historical model boundary outside the port and the measured values ​​of the wave and wind condition parameters in the historical port are all obtained by measuring and arranging buoy measuring stations.

4. The method for numerically processing waves of a sheltered pier according to claim 1, characterized in that: The specific relationship between the predicted value and the measured value of the wave condition and wind condition parameters of the outer port model boundary and the specific relationship between the predicted value and the measured value of the wave condition and wind condition parameters in the port are obtained by drawing scatter plots and deriving them using polynomial fitting.

5. The method for numerically processing waves of a sheltered pier according to claim 1, characterized in that: In the step 2, the mathematical model of the waves in the harbor is set by using the swan wave numerical simulation software, including the model parameter setting and the model terrain file setting. The model parameter setting includes the bottom friction parameter and the breaking parameter, both of which adopt the model recommended values; the model terrain file is generated by using the SMS terrain making software.

6. The method for numerically processing waves of a sheltered pier according to claim 1, characterized in that: The method further includes an updating mechanism, i.e., repeating the process of step 1 and step 3 from time to time, updating the specific relationship between the predicted value and the measured value of the wave condition and wind condition parameters at the boundary of the port model, and the specific relationship between the predicted value and the measured value of the wave condition and wind condition parameters in the port, which is specifically: Cluster analysis of marine environmental changes was performed, and marine environmental changes were divided into calm periods, general change periods, and drastic change periods: During the calm period, continuously accumulating the predicted values ​​and measured values ​​of the wave and wind condition parameters of the historical model boundary outside the port, as well as the predicted values ​​and measured values ​​of the wave and wind condition parameters in the historical port, and repeating the process of step 1 and step 3 every 1 to 3 months; During the general change period, the change range of each parameter is monitored in real time. If the cumulative change range of each parameter exceeds a certain threshold, the process of step 1 and step 3 is immediately repeated; During the period of drastic changes, the process of steps 1 and 3 was repeated every 15 to 30 minutes.

7. The method for numerically processing waves of a sheltered pier according to claim 6, characterized in that: During the general change period, the threshold values ​​of the change amplitudes of various parameters are: wave height changes 0.5~1.2m, and wind speed changes 3~6m / s.

8. The method for numerically processing waves of a sheltered pier according to claim 6, characterized in that: The determination method of the calm period, general change period and drastic change period is as follows: When the wave height is less than 0.3m, the wind speed is less than 3m / s, the current speed is weak, and the water temperature and salinity remain relatively constant, the sea area is judged to be in a calm period; When the wave height is between 0.3 and 0.6 m, the wind speed is between 3 and 6 m / s, the current speed is less than 0.5 knots, the water temperature is between 15 and 18 °C, and the salinity is between 34‰ and 35‰, the sea area is judged to have entered the general change period; When the wave height is greater than 1.5m, the wind speed is greater than 10m / s, the current speed is greater than 1 knot, the water temperature changes suddenly by more than 2°C, and the salinity fluctuates by more than 1‰, the sea area is judged to have entered a period of drastic changes.

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