CN109557333B - Method for inverting surface ocean current based on navigation buoy data - Google Patents

Abstract

The invention discloses a method for inverting surface ocean current based on navigation buoy data, which comprises the following steps: step one, arranging a navigation buoy in an observation sea area, and carrying a sea current data measuring system; collecting buoy position data according to an ocean current data measuring system, and correcting to obtain motion parameters of the buoy; thirdly, collecting buoy position data according to the ocean current data measurement system to establish a buoy stress model; analyzing the parameters of the ocean current resistance of the buoy in the buoy stress model through an ocean current inversion algorithm; calculating the movement parameters of the buoy in the step two and the ocean current resistance parameters of the buoy in the step three to obtain initial values of the flow velocity and the direction of the ocean current in the observation sea area; and step six, correcting the initial values of the flow velocity and the direction of the ocean current obtained in the step five to obtain a final ocean current flow velocity value. The invention realizes accurate measurement of the ocean current in a specific sea area through the navigation buoy, and overcomes the defects of the traditional measurement method.

Description

A method for inversion of surface currents based on navigation buoy data

technical field

The invention relates to the technical field of ocean current observation, in particular to a method for inverting surface ocean current based on navigation buoy data.

Background technique

Ocean currents have important influences and constraints on various physical, chemical, biological and geological processes in the ocean and the processes of transporting salinity, chlorophyll and ocean heat, as well as the formation and changes of climate and weather over the ocean. In terms of activities, ocean currents are of great social and economic significance to ocean development, navigation, military, port construction, marine fishing and defense against marine meteorological disasters. The traditional method of current flow measurement is mainly through the measurement of fixed current meters in the sea or the use of altitude satellite data for inversion. Compared with traditional measurement methods, the use of navigation buoys to invert currents can not only reduce the cost of purchasing instruments, but also avoid marine life. The error caused by the surface attachment of the instrument, and can achieve fixed-point measurement of ocean currents.

SUMMARY OF THE INVENTION

The purpose of the present invention is to overcome the deficiencies in the prior art, and propose a method for inverting surface currents based on navigation buoy data, the specific technical scheme is as follows:

A method for retrieving surface ocean currents based on navigation buoy data, comprising the following steps:

Step 1. Set up navigation buoys in the observation sea area and carry an ocean current data measurement system;

Step 2: Collecting the position value and wind speed value of the buoy according to the ocean current data measurement system and correcting to obtain its motion parameters; at the same time, collecting the actual parameters of the buoy's mass, water entry depth and anchor chain length according to the ocean current data measurement system;

Step 3: Establish a buoy force model according to the buoy motion parameters and actual parameters;

Step 4: Analyze the resistance parameters of the buoy received by the current in the force model of the buoy through the current inversion algorithm;

Step 5: Calculating the motion parameters of the buoy in Step 2 and the resistance parameters of the buoy by the ocean current in Step 3 to obtain the initial value of the magnitude and direction of the current flow velocity in the observed sea area;

Step 6: Correct the initial values of the magnitude and direction of the current flow velocity obtained in the fifth step to obtain the final value of the current flow velocity.

The ocean current data measurement system includes a navigation buoy, a GPS locator, an anemometer, a data transmission unit and an anchor chain; an anemometer is connected to the upper part of the buoy, and a GPS locator and a data transmission unit are respectively set at the position of the inner center of gravity of the buoy, An anchor chain is connected to the lower part of the buoy.

The ocean current inversion algorithm described in step 4 includes the following steps:

3.1. Calculate the motion acceleration of the buoy according to the buoy position value in the buoy force model;

3.2. According to the buoy wind speed value in the buoy force model, calculate the wind stress of the buoy according to formula (1);

R2=kqA _d (1)

3.3. According to the length of the buoy anchor chain in the buoy force model, calculate the anchor chain tension of the buoy according to formula (2);

3.4. Calculate the gravity of the buoy according to the mass of the buoy in the buoy force model;

3.5. Calculate the buoyancy of the buoy according to the buoy's immersion depth value in the buoy force model;

3.6. According to the known parameters of the buoy generated in steps 3.1 to 3.5, obtain the current resistance parameter R1 of the buoy through the N-S control equation of the buoy motion established by Newton's second law of motion;

3.7. According to the known current resistance parameter R1, obtain the current velocity V according to the formula (3).

R1=C(ρV^2)Ω/2 (3)

beneficial effect

Compared with the prior art, the beneficial effects brought by the technical solution of the present invention are:

1. Compared with the current traditional inversion method of current flow rate obtained by the current traditional current meter and satellite data inversion method, the method of inversion of ocean current obtained by installing a GPS locator in the navigation buoy combined with the force model of the buoy, it is obvious that this method It can greatly reduce the cost of obtaining the current flow velocity, and compared with the satellite inversion method, the simple algorithm needs to use a small amount of data.

2. The present invention can effectively solve the measurement error due to biological adhesion and other problems. In addition, the anchor point of the buoy can be changed at any time according to the measurement needs, so that the current size and direction of a specific sea area can be measured anytime, anywhere.

Description of drawings

Figure 1 is a schematic diagram of the installation of the instrument of the navigation buoy measurement system;

Fig. 2 is the solution flow chart of the current inversion algorithm.

Reference number:

1-buoy 2-GPS locator 3-data transmission equipment 4-anemometer 5-anchor chain

Detailed ways

The technical solution of the present patent will be described in further detail below in conjunction with specific embodiments.

The present invention introduces a method for retrieving surface ocean currents based on navigation buoy data, which refers to a method for acquiring data by carrying a high-precision GPS locator on an ocean buoy and analyzing the magnitude and direction of the current flow rate through the data. The specific process is as follows:

Step 1. Lay the navigation buoy 1 in the observation sea area and fix it at the anchor point with the anchor chain 5. The buoy is equipped with a high-precision GPS locator 2 , an anemometer 4 and a data transmission device 3 . All instruments are rigidly connected to buoy 1, and the installation method and location are shown in Figure 1. The GPS locator 2 is used to collect the position parameters of the buoy, including information such as longitude, latitude and elevation of the buoy; the anemometer 4 is used to measure the wind force received by the buoy at sea; the data transmission device 3 is used to transmit the data to the shore base.

Step 2: Collect buoy position data. Obtain the longitude and latitude information of the buoy through the GPS locator 2 and correct the attitude of the buoy to obtain the buoy motion trajectory, thereby obtaining the motion parameters of the buoy, such as acceleration, etc.; and then establish a buoy force model, and its establishment method is as follows:

The buoy in the water is mainly affected by the current resistance, wind load and other factors, in addition to the pulling force of the mooring cable.

At present, there are many formulas for calculating the frictional resistance of the ocean current. The commonly used resistance calculation formula in my country is based on the plate test and theoretical analysis. Its expression is:

R1=C(ρV^2)Ω/2 (3)

where V is the seawater velocity.

The wind pressure acting on the buoy body can be determined by the calculation formula given in the "Code for Calculation of Port Engineering":

R2=kqA _d (1)

According to the balance analysis of H.0. Beto and Satoshi Iwai on the force of the buoy, the cable is in the shape of a catenary curve, and its length and force can be determined by the following formulas:

Through the force analysis of the buoy, it can be seen that the water flow force on the buoy has a certain correlation with the current flow rate. The water flow force can be obtained through the buoy motion equation according to other known forces, and then the magnitude of the ocean current flow rate can be obtained by referring to the empirical formula and used The experimental data are corrected. The direction of the flow velocity can also be determined by the direction of the movement trajectory of the buoy. The core idea of the method is to invert the velocity of the ocean current through the motion trajectory of the anchored buoy.

Step 4: Combining the motion parameters of the winning bid in Step 2 and the algorithm of the current resistance parameter of the buoy in Step 3 to estimate the ocean current, the initial value of the current flow velocity and direction in the sea area is obtained; as shown in the flowchart in Figure 2, the data collected by the buoy first After correcting the attitude of the buoy and the buoy, the movement trajectory of the buoy is obtained, which is the embodiment of all the forces on the buoy; and then combined with the force analysis, the known forces obtained include the buoyancy, wind, and anchor chain binding force, gravity, For buoyancy, the current resistance to the buoy can be calculated according to Newton's law of motion and the N-S control equation of motion. Finally, the current flow rate can be obtained according to the empirical formula R1=C(ρV^2)/2Ω of the current resistance and the size of the current. The specific method is as follows:

a. Use the GPS locator to obtain the position value of the buoy, and use the anemometer to obtain the wind speed value of the buoy. According to the actual measurement, the quality of the buoy, the depth of water entry, and the length of the anchor chain are obtained.

计算浮标所受锚链拉力，用浮标的质量计算浮标所受的重力，用入水深度计算浮标所受浮力；b. Use the position value to obtain the motion acceleration of the buoy, use the wind speed value to obtain the wind stress on the buoy according to the wind pressure formula R2=kqAd, and use the anchor chain length of the buoy according to the anchor given by H.0. Beto and Iwai Satoshi chain tension formula

Calculate the anchor chain tension of the buoy, calculate the gravity of the buoy with the mass of the buoy, and calculate the buoyancy of the buoy with the depth of water entry;

c. Establish the N-S control equation of buoy motion according to Newton's second law of motion, and obtain the current pulling force R1 on the buoy by solving the N-S control equation according to the known acceleration, wind stress, anchor chain tension, gravity, and buoyancy.

d. According to the obtained water current pulling force R1, use the current resistance calculation formula R1=C(ρV^2)Ω/2 based on the flat plate test and theoretical analysis to solve the current flow velocity V. From this, the initial value of the magnitude and direction of the current velocity is obtained.

Step 5: Correct the initial values of the magnitude and direction of the current flow velocity obtained in the fourth step to obtain the final result. Since the results obtained in step 4 are obtained by empirical formulas, it is necessary to repeat the experiment to correct the relevant parameters to obtain more accurate results.

The above are only the preferred embodiments of the present invention. It should be pointed out that for those skilled in the art, several improvements and changes can be made without departing from the principles of the present invention. These improvements and changes also It should be regarded as the scope of protection of the invention.

Claims (2)

1. A method for inverting surface ocean currents based on navigation buoy data comprises the following steps:

step one, arranging a navigation buoy in an observation sea area, and carrying a sea current data measuring system;

step two, collecting a buoy position value and a wind speed value according to the ocean current data measurement system, and correcting to obtain a motion parameter of the buoy; meanwhile, collecting actual parameters of the quality, the underwater depth and the anchor chain length of the buoy according to an ocean current data measuring system;

step three, establishing a buoy stress model according to the buoy motion parameters and the actual parameters;

analyzing the parameters of the ocean current resistance borne by the buoy in the buoy stress model through an ocean current inversion algorithm;

the ocean current inversion algorithm in the fourth step comprises the following steps:

3.1, calculating to obtain the movement acceleration of the buoy according to the buoy position value in the buoy stress model;

3.2, calculating according to the buoy wind speed value in the buoy stress model and the formula (1) to obtain the buoy wind stress;

R2＝kqA_d (1)

3.3, calculating the anchor chain tension borne by the buoy according to the length of the anchor chain of the buoy in the buoy stress model and a formula (2);

3.4, calculating the gravity borne by the buoy according to the mass of the buoy in the buoy stress model;

3.5, calculating buoyancy borne by the buoy according to the water entry depth of the buoy in the buoy stress model;

3.6, obtaining an ocean current resistance parameter R1 borne by the buoy according to the known parameters of the buoy generated in the step 3.1 to 3.5 through a buoy motion N-S control equation established by a Newton second motion law;

3.7 obtaining the current flow velocity V according to the formula (3) according to the known current resistance parameter R1:

R1＝C(ρV^2)Ω/2 (3)

step five, calculating the movement parameters of the buoy in the step two and the ocean current resistance parameters borne by the buoy in the step four to obtain initial values of the flow velocity and the direction of the ocean current in the observation sea area;

and step six, correcting the initial values of the flow velocity and the direction of the ocean current obtained in the step five to obtain a final ocean current flow velocity value.

2. The method for inverting surface ocean currents based on navigation buoy data according to claim 1, wherein the ocean current data measuring system comprises a navigation buoy, a GPS locator, an anemometer, a data transmission unit and an anchor chain; the upper portion of the buoy is connected with an anemoscope, the gravity center position inside the buoy is provided with a GPS locator and a data transmission unit respectively, and the lower portion of the buoy is connected with an anchor chain.

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