Real-time analysis method for sea level observation data of ocean station

Abstract

The invention discloses a real-time analysis method for sea level observation data of an ocean station, and belongs to the field of ocean observation. The method comprises the following steps: a, acquiring tide level data in real time; b, carrying out tide level extreme value exceeding test; the current tide level value is extracted at set intervals, and the tide level value is compared with the tide level extreme value of the month in the same historical period; the sea level extreme value comprises a historical same-month maximum value and a historical same-month minimum value; if the current tide level value is higher than the historical maximum value in the same month or lower than the historical minimum value in the same month, an alarm is triggered; c, carrying out tide level change abnormity detection; d, carrying out continuity abnormity test; and e, carrying out blockage and deposition inspection. According to the invention, after data is obtained, physical law analysis and inspection can be carried out on the data, whether the data is abnormal or not and whether an alarm is needed or not are judged, and operators on duty are guided to inspect and maintain observation equipment. The device can give an alarm in time when the tide level is abnormal, and meanwhile, the normal tide level change cannot be misalarmed.

Description

Technical Field

[0001] The present invention relates to the field of ocean observation, and in particular to a real-time analysis method for ocean station tide observation data. Background Art

[0002] Storm surges are the most serious marine hazards facing China. Tide observation data, which records changes in tide levels during storm surges, is essential for storm surge forecasting, loss assessment, and disaster prevention and mitigation. With my country's emphasis on and continued development of ocean observation, a large number of ocean stations have been built along its coasts to conduct tide observations.

[0003] Tide observations at oceanographic stations typically involve constructing tide wells along the coast, channeling seawater into the wells after wave damping, and using instruments to measure the liquid level to obtain tide data. However, due to the corrosive nature of seawater and the impact of wind and waves during severe storm surges on observation facilities, these facilities are prone to malfunction, resulting in missing and anomalies in observation data.

[0004] Because tidal observation data is prone to omissions and anomalies, personnel are required to verify and quality control the data and observation equipment. However, most coastal tide stations are currently unmanned, and even those with staff cannot easily monitor the data continuously 24 hours a day. Furthermore, some tide observation anomalies are more subtle and difficult to detect directly by on-duty personnel alone, requiring detailed data analysis to detect them.

[0005] Currently, there are some methods for abnormal alarm of tide observation data, which are mainly aimed at data integrity, that is, whether the observation equipment is working normally, whether the data transmission line is interrupted, etc. However, there is currently no method to verify the physical properties of the data, that is, whether the data conforms to physical laws and whether it is reasonable. Summary of the Invention

[0006] In response to the above technical problems, the present invention proposes a real-time analysis method for ocean station tide observation data.

[0007] The technical solution adopted by the present invention is: A method for real-time analysis of tide level observation data at an ocean station, comprising the following steps: a. Obtain tide data in real time; b. Conduct tidal extreme value test; At regular intervals, the current tide level is extracted and compared with the historical extreme tide levels for the same period. Extreme tide levels include the historical maximum and minimum values ​​for the same month. If the current tide level is higher than the historical maximum or lower than the historical minimum, an alarm is triggered. c. Conduct inspection for abnormal tidal level changes; c1. Extract the tide level value N minutes past the current moment, Indicates the tide level value of minute data, , Indicates the tide level value in the past N minutes, Indicates the minimum value of the tide level in the past N minutes. Indicates the maximum value of the tide level in the past N minutes, and the difference between the maximum value and the minimum value. ; c2. If If the value is higher than the upper threshold, it indicates that the tide level change is jittering and triggers an alarm; c3. If If the tide level is lower than the lower threshold and is neither within 1 hour of high tide nor within 1 hour of low tide, it indicates that the tide level is becoming fixed and an alarm is triggered. d. Conduct continuous abnormality test; d1. Extract hourly tide data for the current time and the previous 4 hours. , , 0 represents the current time, -4~-1 represents the previous 4 hours, Indicates the observed tide level value; d2. Using the tide level observation values ​​of the previous -4, -3, -1, and 0 hours, calculate the fitting value of the tide level data at -2 hours. The calculation formula of the fitting value is , represents the fitted value at -2 hours, and calculates the absolute difference between the fitted value at -2 hours and the tide level observation value. ; d3. If If it is higher than the set threshold, it indicates that there is a discontinuity problem in the tide level data of the current time and the previous 4 hours, triggering an alarm; e. Carry out blockage and siltation inspection; e1. Extract the storm surge data for the previous 72 hours. Represents the time series of water increase data in the past 72 hours; e2. Yes The time series is decomposed by Fourier to obtain the amplitude value of the series at different periods, that is, ,in represents the Fourier transform function, represents the amplitude sequence after Fourier transformation, Indicates the period is The amplitude of the sinusoid in hours; e3. Extract the amplitude value and compare it with the threshold. If it is higher than the threshold, an alarm is triggered.

[0008] The beneficial technical effects of the present invention are as follows: After acquiring the data, the present invention can analyze and verify the data for physical laws, determine whether the data is abnormal and whether an alarm is needed, and guide the on-duty personnel to inspect and repair the observation equipment. The present invention can not only issue an alarm in a timely manner when the tide level is abnormal, but also avoid false alarms for normal tide level changes.

[0009] Specifically, this method has the following advantages: 1) Different from conventional methods that only verify data integrity, this invention analyzes the characteristics of tide data based on physical laws, can detect outliers and automatically trigger an alarm mechanism.

[0010] 2) The present invention designs a method for judging abnormal changes in tide level, and determines whether the test is abnormal by calculating the difference between the maximum and minimum tide levels within 10 minutes.

[0011] 3) The present invention designs a method for judging the abnormality of tide continuity, and determines whether the test is abnormal by calculating the difference between the fitted value and the observed value.

[0012] 4) The present invention designs a method for determining whether a tide well is blocked or silted. The amplitude of the 12-hour and 24-hour cycles is calculated through Fourier transform to determine whether the test is abnormal.

[0013] 5) The method of the present invention has the advantages of high accuracy, simple and convenient operation, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 Schematic diagram of the flow of the real-time analysis method of ocean station tide observation data of the present invention; Figure 2 This is an example curve of abnormal tidal level jitter in a specific application example of the present invention; Figure 3 This is an example curve of a constant tide level in a specific application example of the present invention; Figure 4 This is an example curve of abnormal tidal continuity observation data in a specific application example of the present invention; Figure 5 The tidal curves and amplitude curves after Fourier transformation at a certain ocean station from August 30 to September 2; the black line in (a) is the observed tidal curve, the blue line is the astronomical tide curve, and the red line is the storm surge curve; the light blue line in (b) is the amplitude curve; Figure 6 The tidal level curve and Fourier transformed amplitude curve of a certain ocean station from November 4 to November 7; the black line in (a) is the observed tide level curve, the blue line is the astronomical tide curve, and the red line is the storm surge curve; the light blue line in (b) is the amplitude curve. DETAILED DESCRIPTION

[0015] Tide data includes: (1) Tidal level exceeding extreme values: The tidal level is higher than the maximum value in the same period in history, or lower than the minimum value in the same period in history. The possibility of the tidal level exceeding the extreme value is small, and when it occurs, the instrument should be checked to confirm whether it is true.

[0016] (2) Abnormal tidal level changes: One is that the tide level shows abnormal high-frequency up and down jitters, which may be caused by wave jitters due to insufficient wave absorption in the tide well; the other is that the tide level is fixed at a value and does not change, which may be that the instrument for measuring the liquid level is stuck and fails to change with the tide level.

[0017] (3) Abnormal tide level continuity: The tide level curve is not smooth and continuous, and there is a systematic deviation, which may be due to problems with the instrument base.

[0018] (4) Tide wells are blocked and silted up: Tide wells are blocked and silted up, which results in poor inflow and outflow of tide water, which is manifested as delayed changes in tide level, inability to reach low tide and high tide.

[0019] Previous tide-level monitoring methods at ocean stations focused solely on data integrity, focusing on whether tide-level observation equipment was functioning and data transmission was uninterrupted. These methods failed to verify whether the observation equipment was operating normally or whether the observed data was reasonable. At unmanned ocean stations, if problems with tide-level data go undetected, accurate observation data can be lost. Furthermore, some observation equipment anomalies cannot be directly identified based solely on on-duty personnel's observations; they require analysis combined with historical data.

[0020] Based on this, the present invention proposes a real-time analysis method for tide observation data of ocean stations. The method performs real-time analysis on tide observation data, and through data verification every minute, hour, and day, makes real-time judgments on problems such as extreme tide levels, abnormal tide changes, abnormal tide continuity, and blockage and siltation of tide gauge wells. The method can further design recognition algorithms to automatically detect data anomalies, and then promptly remind the on-duty personnel of the ocean station to inspect and repair the equipment and resume normal data observation as soon as possible.

[0021] The present invention will be further described below with reference to the accompanying drawings and specific embodiments: like Figure 1 As shown, a real-time analysis method for tide level observation data of an ocean station includes the following steps: a. Obtain tide data in real time; The tidal data includes tidal values, astronomical tidal values, and storm surge data. The tidal values ​​come from tide well instruments, the astronomical tides are calculated based on the harmonic analysis of historical data, and the storm surge data is the difference between the tidal values ​​and the astronomical tidal values.

[0022] b. Conduct tidal extreme value test; Every minute, the current tide level is extracted and compared with the historical extreme tide level for the same month. Extreme tide levels include the historical maximum and minimum values ​​for the same month. If the current tide level is higher than the historical maximum or lower than the historical minimum for the same month, an alarm is triggered, notifying the on-duty personnel and notifying them that the tide level is higher than the historical maximum or lower than the historical minimum for the same month.

[0023] c. Conduct inspection for abnormal tidal level changes; This is done once every minute. There are two types of abnormal tide changes: one is that the tide level fluctuates rapidly in a short period of time, and the other is that the tide level remains unchanged for a period of time. The specific steps are as follows: c1. Extract the tide level value 10 minutes past the current moment, Indicates the tide level value of minute data, , Indicates the tide level value in the past 10 minutes. Indicates the minimum value of the tide level in the past 10 minutes. Indicates the maximum value of the tide level in the past 10 minutes, and the difference between the maximum value and the minimum value. .

[0024] c2. If If it is higher than the upper threshold, it means that the tide level change is jittering, triggering an alarm; notifying the on-duty personnel and prompting: the tide level is jittering abnormally.

[0025] c3. If If the tide level is lower than the lower threshold and is neither within 1 hour of high tide nor within 1 hour of low tide, it indicates that the tide level change is fixed and an alarm is triggered; the on-duty personnel are notified and prompted: the tide level value is fixed.

[0026] Specifically, when determining whether the tide level is constant or abnormal, a judgment condition should be established to distinguish it from normal conditions. This means that even at the peak of normal high and low tides, and during slack tides, the tide level remains constant, which is a normal phenomenon. The key to distinguishing between these two conditions is to consider the time outside of high and low tides.

[0027] Therefore, if ∆Tmin is lower than the lower limit threshold, it indicates that there may be a problem of fixed tide level at this time. However, it should also be distinguished from normal high and low tide periods. Therefore, there should be a judgment condition. That is, if this time is neither within 1 hour of high tide nor within 1 hour of low tide, it means that the tide level change is fixed and the alarm is triggered.

[0028] The upper and lower thresholds are determined based on historical tide data statistics; the historical tide data is calculated every minute. , make a cumulative probability curve, and select the 0.5% and 99.5% quantiles as the upper and lower thresholds, respectively.

[0029] d. Conduct continuous abnormality test; This test is conducted every hour. It mainly checks the hourly tide level data to see if there are any rapid changes or discontinuities. The specific steps are as follows: d1. Extract hourly tide data for the current time and the previous 4 hours , , 0 represents the current time, -4~-1 represents the previous 4 hours, Indicates the observed tide level value.

[0030] d2. Using the tide level observations at -4, -3, -1, and 0 hours, calculate the fitted value of the tide level data at -2 hours. The calculation formula for the fitted value is: , represents the fitted value at -2 hours, and calculates the absolute difference between the fitted value at -2 hours and the tide level observation value. .

[0031] d3. If If it is higher than the set threshold, it indicates that there is a discontinuity problem in the tide level data of the current time and the previous 4 hours, triggering an alarm; notifying the on-duty personnel and prompting: the hourly tide level value is discontinuous.

[0032] The threshold is set based on the historical tide data statistics; the historical tide data is calculated hourly , create a cumulative probability curve, and select the 99.5% quantile as the threshold.

[0033] e. Carry out blockage and siltation inspection; Select a fixed time every day to conduct the test. When the tide well is blocked and silted up, the storm surge of the tide level will show unreasonable periodic changes. Here we mainly test whether this problem occurs. The specific steps are as follows: e1. Extract the storm surge data for the previous 72 hours. Represents the time series of water increase data in the past 72 hours.

[0034] e2. Yes The time series is decomposed by Fourier to obtain the amplitude value of the series at different periods, that is, ,in represents the Fourier transform function, represents the amplitude sequence after Fourier transformation, Indicates the period is The amplitude of the sinusoid in hours.

[0035] e3. Extract the 12-hour and 24-hour amplitude values, and .Will and Comparing with the threshold, if one of them is higher than the threshold, an alarm is triggered, notifying the on-duty personnel and prompting that there is a blockage and siltation problem in the tide well.

[0036] The threshold here can be determined based on experience, and the threshold is generally selected as 10cm.

[0037] The present invention can analyze and test tide level data in real time, can operate continuously for 24 hours, and can be applied to unmanned ocean stations, greatly reducing the workload of on-duty personnel and improving data quality.

[0038] The present invention will be further described below with reference to specific application examples. Since the method for determining the extreme tide level problem is relatively clear and intuitive, only other problems are exemplified here.

[0039] 1. Inspection of abnormal tidal changes; A marine station calculates the tide level every minute based on historical tide data. , to create a cumulative probability curve, the 0.5% and 99.5% quantiles are 5cm and 20cm respectively.

[0040] (1) If Figure 2 As shown in the figure, the ocean station assumes that the current time is 15:03 and conducts minute-by-minute inspections for abnormal tidal changes. The tide level data obtained in the past ten minutes (14:54~15:03) are 172, 173, 174, 174, 175, 176, 208, 480, 545, and 489, respectively. , ,at this time , notify the on-duty personnel and remind them: the tide level is shaking abnormally.

[0041] (2) If Figure 3 As shown in the figure, the ocean station assumes that the current time is 15:38 and conducts minute-by-minute inspections for abnormal tidal changes. The tide level data obtained in the past ten minutes (15:29~15:38) are 323, 323, 324, 324, 324, 324, 324, 324, 324, 325, so , , .

[0042] According to the astronomical tide, the high and low tides of the day are 00:03, 05:30, 12:13, and 17:13. The current time is 15:38, which is 95 minutes away from the nearest time. If the time is more than 1 hour away from high tide / low tide, the alarm will be triggered, the on-duty personnel will be notified and prompted: the tide level value is fixed and unchanged.

[0043] At the same time, please note that at 05:24, the ocean station However, it is only 6 minutes away from the climax and less than 1 hour, so the alarm will not be triggered.

[0044] 2. Tidal level continuity test; like Figure 4 As shown in the figure, at 17:00 on a certain day, a certain ocean station carried out hourly tide level continuity inspection. The tide levels obtained from 13:00 to 17:00 were , , , , Calculate the fitting value for the third hour as , so , triggering an alarm, notifying the on-duty personnel and prompting: the hourly tide level value is discontinuous.

[0045] 3. Blockage and siltation inspection; like Figure 5 As shown in the figure, a certain ocean station carried out a blockage and siltation inspection at 0:00 on September 2. The time series of water increase values ​​for a total of 72 hours from August 30 to September 1 was obtained. ,right Perform Fourier decomposition , obtain amplitude sequences of different periods , draw the sequence curve. As can be seen from the curve, 10, 10. If the conditions are met, an alarm is triggered, the on-duty personnel are notified and prompted that there is a blockage and siltation problem in the tide well.

[0046] like Figure 6 As shown in the figure, a certain ocean station started the blockage and siltation test at 0:00 on November 7. As can be seen from the amplitude curve, 10, 10. This curve is a normal storm surge process curve and does not trigger an alarm.

[0047] Parts not described in the above methods can be achieved by adopting or drawing on existing technologies.

[0048] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A real-time analysis method for tide level observation data of an ocean station, characterized in that The following steps are involved: a. Obtain tide data in real time; b. Conduct tidal extreme value test; At regular intervals, the current tide level is extracted and compared with the historical extreme tide levels for the same period. Extreme tide levels include the historical maximum and minimum values ​​for the same month. If the current tide level is higher than the historical maximum or lower than the historical minimum, an alarm is triggered. c. Conduct inspection for abnormal tidal level changes; c1. Extract the tide level value N minutes past the current moment, Indicates the tide level value of minute data, , Indicates the tide level value in the past N minutes, Indicates the minimum value of the tide level in the past N minutes. Indicates the maximum value of the tide level in the past N minutes, and the difference between the maximum value and the minimum value. ; c2. If If the value is higher than the upper threshold, it indicates that the tide level change is jittering and triggers an alarm; c3. If If the tide level is lower than the lower threshold and is neither within 1 hour of high tide nor within 1 hour of low tide, it indicates that the tide level is becoming fixed and an alarm is triggered. d. Conduct continuous abnormality test; d1. Extract hourly tide data for the current time and the previous 4 hours. , , 0 represents the current time, -4~-1 represents the previous 4 hours, Indicates the observed tide level value; d2. Using the tide level observation values ​​of the previous -4, -3, -1, and 0 hours, calculate the fitting value of the tide level data at -2 hours. The calculation formula of the fitting value is , represents the fitted value at -2 hours, and calculates the absolute difference between the fitted value at -2 hours and the tide level observation value. ; d3. If If it is higher than the set threshold, it indicates that there is a discontinuity problem in the tide level data of the current time and the previous 4 hours, triggering an alarm; e. Carry out blockage and siltation inspection; e1. Extract the storm surge data for the previous 72 hours. Represents the time series of water increase data in the past 72 hours; e2. Yes The time series is decomposed by Fourier to obtain the amplitude value of the series at different periods, that is, ,in represents the Fourier transform function, represents the amplitude sequence after Fourier transformation, Indicates the period is The amplitude of the sinusoid in hours; e3. Extract the amplitude value and compare it with the threshold. If it is higher than the threshold, an alarm is triggered.

2. A method for real-time analysis of tide level observation data of an ocean station according to claim 1, characterized in that: In step a: the tide level data includes tide level value, astronomical tide level value and storm surge data; the storm surge data is the difference between the tide level value and the astronomical tide level value.

3. A method for real-time analysis of ocean station tide observation data according to claim 1, characterized in that: In step b: a tidal level extreme value test is performed every minute; the current tidal level value is extracted every minute and compared with the historical tidal level extreme value for the same period; After the alarm is triggered, the on-duty personnel will be notified and prompted: the tide level is higher than the historical maximum value for the same month or the tide level is lower than the historical minimum value for the same month.

4. A method for real-time analysis of tide level observation data of an ocean station according to claim 1, characterized in that: In step c1: N is set to 10; In step c2: after the alarm is triggered, the on-duty personnel are notified and prompted: the tide level fluctuates abnormally; In step c3: after the alarm is triggered, the on-duty personnel are notified and prompted that the tide level value remains fixed.

5. A method for real-time analysis of ocean station tide observation data according to claim 1, characterized in that: In step c: the upper and lower thresholds are determined based on historical tide data statistics; the historical tide data is calculated per minute. , make a cumulative probability curve, and select the 0.5% and 99.5% quantiles as the upper and lower thresholds, respectively.

6. A method for real-time analysis of ocean station tide observation data according to claim 1, characterized in that: In step d3: the threshold is set based on the historical tide data statistics; the historical tide data is calculated hourly. , create a cumulative probability curve and select the 99.5% quantile as the threshold; After the alarm is triggered, the on-duty personnel will be notified and prompted: the hourly tide level value is discontinuous.

7. A method for real-time analysis of ocean station tide observation data according to claim 1, characterized in that: In step e3: extract the 12-hour and 24-hour amplitude values, and ; Will and Comparing with the threshold, if one of them is higher than the threshold, an alarm is triggered, notifying the on-duty personnel and prompting that there is a blockage and siltation problem in the tide well.

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