A sea surface height verification device deployment method based on interferometric altimeter

Abstract

The application discloses a sea surface height inspection equipment layout method based on an interferometric imaging altimeter, belongs to the technical field of altimeter inspection, and is used for sea surface height inspection equipment layout, and comprises the following steps: obtaining position data of a Glider buoy and temperature-salinity-depth data of a profile observed by the Glider buoy; before a satellite passes, the Glider buoy and a GNSS buoy are simultaneously and regionally launched, and synchronous observation of the GNSS and the Glider buoy is realized; the Glider buoy is positioned when descending and ascending to the outcrop, is matched with a grid position in a swath range observed by the satellite, and sea surface height is inverted by using the temperature-salinity-depth data of the profile observed by the Glider buoy. The application is suitable for data characteristics of different resolutions of the interferometric imaging altimeter, realizes synchronous observation of sea surface height under satellite passing by using satellite data of different spatial resolutions, and accurately completes calibration inspection of the altimeter satellite.

Description

Technical Field

[0001] This invention discloses a method for deploying sea surface height inspection equipment based on an interferometric imaging altimeter, belonging to the field of altimeter inspection technology. Background Technology

[0002] Current calibration and verification technologies for altimeters primarily target traditional altimeters. However, traditional altimeters only provide nadir observations, and their nadir footprint is limited to a relatively large area of ​​3 km. Calibration for traditional altimeters mainly involves time-space tradeoffs or distance derivation. However, for interferometric imaging altimeters, research should be conducted on the deployment methods and systems for sea surface height verification equipment, taking into account their swath range and data resolution. Currently, feasibility studies have been conducted on interferometric imaging altimeter verification methods based on existing altimeter verification methods, along with theoretical analyses based on specific volume height and the basic conditions under different meteorological conditions. However, how to utilize these factors to complete the field deployment of interferometric imaging altimeter sea surface height verification equipment remains unresolved. Summary of the Invention

[0003] The purpose of this invention is to provide a method for deploying sea surface height inspection equipment based on interferometric imaging altimeter, so as to solve the problem in the prior art that the deployment of sea surface height inspection equipment based on interferometric imaging altimeter does not take into account its swath range and data resolution.

[0004] A method for deploying sea surface height measurement equipment based on an interferometric imaging altimeter includes:

[0005] S1. Based on the wind and vortex prediction in the observation area, select a period of time with small winds and waves during the time the vortex passes through to carry out sea surface height calibration verification.

[0006] S2. Use GNSS buoys to observe and obtain the instantaneous sea surface height to the height and spatial location information of the reference ellipsoid at the observation point, and obtain the position data of the Glider buoy and the temperature, salinity and depth data of the profile obtained by the Glider buoy observation;

[0007] S3. Before the satellite passes overhead, Glider buoys and GNSS buoys will be deployed simultaneously in the same area to achieve synchronous observation between GNSS buoys and Glider buoys;

[0008] S4. Conduct three-dimensional positional relationship observations and generate an observation dataset during the satellite's transit time;

[0009] The S5 and Glider buoys are positioned when they descend and rise, and their positions are matched with the grid positions within the swath area observed by satellite. The sea surface height is then retrieved using the temperature, salinity, and depth data of the profile obtained from the Glider buoy observations.

[0010] S6. For data in a 250m grid, a time-for-space approach is used to verify the data using the altitude and spatial location information from GNSS buoy observations.

[0011] For the 2km grid data, the sea surface height was retrieved by inverting the temperature, salinity, and depth profile data observed by the Glider buoy and verified using the spatial averaging method.

[0012] S1 includes S1.1, which analyzes the root mean square error, error and correlation coefficient inside and outside the vortex using historical data or reanalysis model data for the observation area to be tested, and determines the location to carry out the calibration test by combining the calibration test accuracy under different vortex conditions in the observation area.

[0013] S1.2. Using historical data or reanalysis model data, conduct calibration verification to analyze the relationship between sea surface height and specific volume height under different wind speed conditions at different locations, and determine the wind speed section for calibration verification.

[0014] S1.3 Analyze the differences in sea surface height and specific volume height in the observation area during different seasons to determine the time for calibration testing.

[0015] S2 includes the specific volume height calculated from the temperature, salinity, and depth data obtained from Glider buoy observations. :

[0016] ;

[0017] ;

[0018] In the formula, It is the gravitational constant. It's atmospheric pressure. It is the pressure at the bottom of the sea. It has a salinity of 35, a temperature of 0 degrees Celsius, and a pressure of [missing information]. The volume below, It is a high specific volume anomaly. It is the depth of the sea. It is a reference density. It's a density anomaly. It's about depth.

[0019] S3 includes S3.1, which combines the position and time of satellite overpass and deploys two devices simultaneously in the ocean before the time window arrives. The GNSS buoy is anchored in the center of the observation area, while the Glider buoy drifts to the bottom. After deployment, the staff immediately move away from the deployment area.

[0020] S3.2 Conduct a GNSS buoy observation and Glider buoy profile observation in the same area, and locate the difference between sea surface height and specific volume height in the observation area based on the results of the profile observation inversion.

[0021] S3.3 Before the satellite passes overhead, control the Glider buoy to rise to the sea surface and send a signal for positioning, and synchronize with the positioning position of the GNSS buoy. Use the Glider buoy's own power to deploy the two devices in the area within the swath range around the GNSS.

[0022] The location of the difference between sea level and specific volume height in the observation area includes:

[0023] ;

[0024] In the formula, It is the initial absolute value of sea surface height measured by GNSS buoys. It is the initial value of the specific volume height.

[0025] S4 includes S4.1, ensuring that the GNSS buoy anchoring position is within the swath space observed by the satellite;

[0026] S4.2 At the moment of satellite transit, the GNSS buoy transmits a signal to obtain its three-dimensional spatial information. The horizontal position of the GNSS buoy is obtained through the latitude and longitude information of the three-dimensional spatial information. The horizontal position of the GNSS buoy is matched with the altimeter observation grid to obtain the matched horizontal position of the GNSS buoy. The elevation information is compared with the satellite observation data of the matched grid to obtain the average difference after multiple comparisons. The systematic error of the altimeter error is determined, and the altimeter verification is completed. The elevation information is the vertical position of the GNSS buoy to the reference ellipsoid.

[0027] S5 includes Glider buoys that drift on the ocean floor after being deployed and before satellites pass overhead;

[0028] As the satellite approaches, the Glider buoy surfaces to determine its location in space and uses its own energy and power to propel itself to the area of ​​the swath space observed by the satellite.

[0029] As the satellite passes overhead, the Glider buoy completes its descent and ascent, conducts two temperature, salinity, and depth (TDM) profile observations, obtains TDM data at different depths, calculates its specific volume height, and locates its position after ascent, thus obtaining spatial information about the Glider buoy's descent and ascent processes.

[0030] S6 includes assimilating the temperature, salinity, and depth profile data observed by the Glider buoy into the same profile, analyzing the spatial position information of the two contacts with the water surface during the dive and ascent, and if the two contacts are in the same grid, then the grid used for altimeter data calibration and verification by the Glider buoy is used as the grid for altimeter data verification; if the two contacts belong to different grids, then the grid where the center of the two spatial positions is located is used as the grid for altimeter data verification.

[0031] The specific volume height was calculated from the data observed by the Glider buoy, and the initial value of the specific volume height was obtained. This value was then converted into the absolute sea level height required for the test, thus completing the test.

[0032] Compared with the prior art, the present invention has the following advantages: The present invention adapts to the data characteristics of different resolutions of interferometric imaging altimeters, realizes synchronous observation of sea surface altitude under satellite transit for satellite data with different spatial resolutions, and accurately completes the calibration and verification of altimeter satellites. Attached Figure Description

[0033] Figure 1 This describes the differences in sea level and specific volume height under different wind speeds in the test area;

[0034] Figure 2 This describes the difference between sea surface height and specific volume height under U-direction wind speed in the test area;

[0035] Figure 3 This describes the difference between sea surface height and specific volume height under wind speeds in the V direction in the test area;

[0036] Figure 4 It represents the root mean square error of the sea surface height and specific volume height inside and outside the eddy in the test area in different months;

[0037] Figure 5 The difference in the sea surface height and specific volume height inside and outside the eddy in the test area in different months;

[0038] Figure 6 It is the difference in the correlation coefficients between the sea surface height and specific volume height inside and outside the eddy in different months in the test area;

[0039] Figure 7 This describes the differences in the correlation coefficients between sea surface height and specific volume height under different wind speeds in the test area.

[0040] Figure 8This describes the differences in the correlation coefficients between sea surface height and specific volume height under U-direction wind speeds in the test area;

[0041] Figure 9 This describes the differences in the correlation coefficients between sea surface height and specific volume height under wind speeds in the V direction in the test area.

[0042] Figure 10 It relates to the relationship between sea level and specific volume height;

[0043] Figure 11 It is a deployment scheme for GNSS buoys and Gliders when satellites pass overhead. Detailed Implementation

[0044] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention are described clearly and completely below. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0045] A method for deploying sea surface height measurement equipment based on an interferometric imaging altimeter includes:

[0046] S1. Based on the wind and vortex prediction in the observation area, select a period of time with small winds and waves during the time the vortex passes through to carry out sea surface height calibration verification.

[0047] S2. Use GNSS buoys to observe and obtain the instantaneous sea surface height to the height and spatial location information of the reference ellipsoid at the observation point, and obtain the position data of the Glider buoy and the temperature, salinity and depth data of the profile obtained by the Glider buoy observation;

[0048] S3. Before the satellite passes overhead, Glider buoys and GNSS buoys will be deployed simultaneously in the same area to achieve synchronous observation between GNSS buoys and Glider buoys;

[0049] S4. Conduct three-dimensional positional relationship observations and generate an observation dataset during the satellite's transit time;

[0050] The S5 and Glider buoys are positioned when they descend and rise, and their positions are matched with the grid positions within the swath area observed by satellite. The sea surface height is then retrieved using the temperature, salinity, and depth data of the profile obtained from the Glider buoy observations.

[0051] S6. For data in a 250m grid, a time-for-space approach is used to verify the data using the altitude and spatial location information from GNSS buoy observations.

[0052] For the 2km grid data, the sea surface height was retrieved by inverting the temperature, salinity, and depth profile data observed by the Glider buoy and verified using the spatial averaging method.

[0053] S1 includes S1.1, which analyzes the root mean square error, error and correlation coefficient inside and outside the vortex using historical data or reanalysis model data for the observation area to be tested, and determines the location to carry out the calibration test by combining the calibration test accuracy under different vortex conditions in the observation area.

[0054] S1.2. Using historical data or reanalysis model data, conduct calibration verification to analyze the relationship between sea surface height and specific volume height under different wind speed conditions at different locations, and determine the wind speed section for calibration verification.

[0055] S1.3 Analyze the differences in sea surface height and specific volume height in the observation area during different seasons to determine the time for calibration testing.

[0056] S2 includes the specific volume height calculated from the temperature, salinity, and depth data obtained from Glider buoy observations. :

[0057] ;

[0058] ;

[0059] In the formula, It is the gravitational constant. It's atmospheric pressure. It is the pressure at the bottom of the sea. It has a salinity of 35, a temperature of 0 degrees Celsius, and a pressure of [missing information]. The volume below, It is a high specific volume anomaly. It is the depth of the sea. It is a reference density. It's a density anomaly. It's about depth.

[0060] S3 includes S3.1, which combines the position and time of satellite overpass and deploys two devices simultaneously in the ocean before the time window arrives. The GNSS buoy is anchored in the center of the observation area, while the Glider buoy drifts to the bottom. After deployment, the staff immediately move away from the deployment area.

[0061] S3.2 Conduct a GNSS buoy observation and Glider buoy profile observation in the same area, and locate the difference between sea surface height and specific volume height in the observation area based on the results of the profile observation inversion.

[0062] S3.3 Before the satellite passes overhead, control the Glider buoy to rise to the sea surface and send a signal for positioning, and synchronize with the positioning position of the GNSS buoy. Use the Glider buoy's own power to deploy the two devices in the area within the swath range around the GNSS.

[0063] The location of the difference between sea level and specific volume height in the observation area includes:

[0064] ;

[0065] In the formula, It is the initial absolute value of sea surface height measured by GNSS buoys. It is the initial value of the specific volume height.

[0066] S4 includes S4.1, ensuring that the GNSS buoy anchoring position is within the swath space observed by the satellite;

[0067] S4.2 At the moment of satellite transit, the GNSS buoy transmits a signal to obtain its three-dimensional spatial information. The horizontal position of the GNSS buoy is obtained through the latitude and longitude information of the three-dimensional spatial information. The horizontal position of the GNSS buoy is matched with the altimeter observation grid to obtain the matched horizontal position of the GNSS buoy. The elevation information is compared with the satellite observation data of the matched grid to obtain the average difference after multiple comparisons. The systematic error of the altimeter error is determined, and the altimeter verification is completed. The elevation information is the vertical position of the GNSS buoy to the reference ellipsoid.

[0068] S5 includes Glider buoys that drift on the ocean floor after being deployed and before satellites pass overhead;

[0069] As the satellite approaches, the Glider buoy surfaces to determine its location in space and uses its own energy and power to propel itself to the area of ​​the swath space observed by the satellite.

[0070] As the satellite passes overhead, the Glider buoy completes its descent and ascent, conducts two temperature, salinity, and depth (TDM) profile observations, obtains TDM data at different depths, calculates its specific volume height, and locates its position after ascent, thus obtaining spatial information about the Glider buoy's descent and ascent processes.

[0071] S6 includes assimilating the temperature, salinity, and depth profile data observed by the Glider buoy into the same profile, analyzing the spatial position information of the two contacts with the water surface during the dive and ascent, and if the two contacts are in the same grid, then the grid used for altimeter data calibration and verification by the Glider buoy is used as the grid for altimeter data verification; if the two contacts belong to different grids, then the grid where the center of the two spatial positions is located is used as the grid for altimeter data verification.

[0072] The specific volume height was calculated from the data observed by the Glider buoy, and the initial value of the specific volume height was obtained. This value was then converted into the absolute sea level height required for the test, thus completing the test.

[0073] In this embodiment of the invention, the relationship between sea surface height and specific volume height in the regions inside and outside the vortex was analyzed, as shown in Table 1.

[0074] Table 1. Relationship between sea level height and specific volume height in the inner and outer regions of the vortex.

[0075] ;

[0076] Comparing the results in the inner and outer regions of the vortex in Table 1, a significant improvement can be observed in the results within the vortex. In this case, the interferometric imaging altimeter test is better conducted within the vortex region. However, since the spatial location of the vortex is not fixed, a station can be set up at a fixed location to wait for the vortex and satellite to pass over each other before conducting the test.

[0077] By utilizing historical data or reanalysis model data, this study examines the relationship between sea level height and specific volume height under different wind speed conditions in the experimental area. It identifies the most suitable wind speed zones for conducting the study and obtains the differences in sea level height and specific volume height under different wind speeds in the experimental area. Figure 1 As shown, the differences between sea surface height and specific volume height under U-direction wind speed in the test area are as follows: Figure 2 As shown, the differences between sea surface height and specific volume height under wind speeds in the V direction in the test area are as follows: Figure 3 As shown, the frequency distribution of differences in sea surface height and specific volume height under different wind speeds and wind speeds in the U and V directions is analyzed within the test area. Some anomalous data appear when the wind speed in the V direction is around 9 m / s, at which point the wind speed in the U direction is around 10 m / s. In most cases within this test area, the wind speed in the U direction is concentrated around -2 m / s, and the wind speed in the V direction is concentrated around 0 m / s.

[0078] This study analyzes the seasonal differences in sea level and specific volume height in the region to determine the appropriate time for calibration testing. The root mean square errors of sea level and specific volume height inside and outside the eddy in the test area for different months are obtained, as shown below. Figure 4As shown, the differences in errors of sea surface height and specific volume height inside and outside the eddy in different months in the test area are as follows: Figure 5 As shown, the correlation coefficients of sea surface height and specific volume height inside and outside the eddy in the test area differ in different months. Figure 6 As shown, the changing patterns of different indicators over time are basically consistent across the inner vortex region, outer vortex region, and the overall vortex region. For conducting tests, the selection of different regions is more important; however, March is not suitable for conducting tests, while August to November yields better results. The differences in the correlation coefficients between sea surface height and specific volume height under different wind speeds in the test area are shown below. Figure 7 As shown, the differences in the correlation coefficients between sea surface height and specific volume height under U-direction wind speed in the test area are as follows: Figure 8 As shown, the differences in the correlation coefficients between sea surface height and specific volume height under wind speeds in the V direction in the test area are as follows: Figure 9 As shown in the figure, the solid line represents the correlation and the dashed line represents the wind speed. It can be clearly seen that there is a negative correlation between the two, and it can be found that the correlation worsens as the wind speed increases, but this is only the overall trend.

[0079] The relationship between sea level and specific volume height is as follows: Figure 10 As shown, the deployment scheme of GNSS buoys and Gliders during satellite transit is as follows: Figure 11 As shown, the sea surface height in satellite data is obtained by subtracting the satellite positioning height from the satellite observation height; it is the distance from the instantaneous sea surface height at the moment of satellite observation to the satellite positioning reference surface—the reference ellipsoid. Specific volume height, on the other hand, is the height change caused by density variations between the instantaneous sea surface and the observation reference surface; therefore, it is not an absolute height, but rather a variation in height. The verification of the sea surface height reconstructed based on specific volume height is conducted by examining the differences between the sea surface height and specific volume height within different pixels of the interferometric altimeter.

[0080] The smallest observation unit of this invention is one GNSS and one Glider, but it can be expanded into a network observation unit using any device. Each type of observation device can be further expanded, as long as the safe operating distance between devices is ensured, and the absolute height difference positioning of the Glider observation data is achieved using GNSS.

[0081] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for deploying sea surface height measurement equipment based on an interferometric imaging altimeter, characterized in that, include: S1. Based on the wind and vortex prediction in the observation area, select a period of time with small winds and waves during the time the vortex passes through to carry out sea surface height calibration verification. S2. Use GNSS buoys to observe and obtain the instantaneous sea surface height to the height and spatial location information of the reference ellipsoid at the observation point, and obtain the position data of the Glider buoy and the temperature, salinity and depth data of the profile obtained by the Glider buoy observation; S3. Before the satellite passes overhead, Glider buoys and GNSS buoys will be deployed simultaneously in the same area to achieve synchronous observation between GNSS buoys and Glider buoys; S4. Conduct three-dimensional positional relationship observations and generate an observation dataset during the satellite's transit time; The S5 and Glider buoys are positioned when they descend and rise, and their positions are matched with the grid positions within the swath area observed by satellite. The sea surface height is then retrieved using the temperature, salinity, and depth data of the profile obtained from the Glider buoy observations. S6. For data in a 250m grid, a time-for-space approach is used to verify the data using the altitude and spatial location information from GNSS buoy observations. For the 2km grid data, the sea surface height was retrieved by inverting the spatial averaging method using temperature, salinity, and depth profile data observed by the Glider buoy for verification. S1 includes S1.1, which analyzes the root mean square error, error and correlation coefficient inside and outside the vortex using historical data or reanalysis model data for the observation area to be tested, and determines the location to carry out the calibration test by combining the calibration test accuracy under different vortex conditions in the observation area. S1.

2. Using historical data or reanalysis model data, conduct calibration verification to analyze the relationship between sea surface height and specific volume height under different wind speed conditions at different locations, and determine the wind speed section for calibration verification. S1.3 Analyze the differences in sea surface height and specific volume height in the observation area during different seasons to determine the time for calibration verification; S3 includes S3.1, which combines the position and time of satellite overpass and deploys two devices simultaneously in the ocean before the time window arrives. The GNSS buoy is anchored in the center of the observation area, while the Glider buoy drifts to the bottom. After deployment, the staff immediately move away from the deployment area. S3.2 Conduct a GNSS buoy observation and Glider buoy profile observation in the same area, and locate the difference between sea surface height and specific volume height in the observation area based on the results of the profile observation inversion. S3.3 Before the satellite passes overhead, control the Glider buoy to rise to the sea surface and send a signal for positioning, and synchronize with the positioning position of the GNSS buoy. Use the Glider buoy's own power to deploy the two devices in the area within the swath range around the GNSS. The location of the difference between sea level and specific volume height in the observation area includes: ； In the formula, It is the specific volume height. It is the initial absolute value of sea surface height measured by GNSS buoys. This is the initial value of the specific volume height; S4 includes S4.1, ensuring that the GNSS buoy anchoring position is within the swath space observed by the satellite; S4.2 At the moment of satellite transit, the GNSS buoy transmits a signal to obtain the three-dimensional spatial information of the GNSS buoy at this time. The horizontal position of the GNSS buoy is obtained through the latitude and longitude information of the three-dimensional spatial information. The horizontal position of the GNSS buoy is matched with the altimeter observation grid to obtain the matched horizontal position of the GNSS buoy. The elevation information is compared with the satellite observation data of the matched grid to obtain the average difference after multiple comparisons. The systematic error of the altimeter error is determined, and the altimeter verification is completed. The elevation information is the vertical position of the GNSS buoy to the reference ellipsoid. S5 includes Glider buoys that drift on the ocean floor after being deployed and before satellites pass overhead; As the satellite approaches, the Glider buoy surfaces to determine its location in space and uses its own energy and power to propel itself to the area of ​​the swath space observed by the satellite. As the satellite passes overhead, the Glider buoy completes its descent and ascent, conducts two temperature, salinity, and depth (TDM) profile observations, obtains TDM data at different depths, calculates its specific volume height, and locates its position after ascent, thus obtaining spatial information about the Glider buoy's descent and ascent processes. S6 includes assimilating the temperature, salinity, and depth profile data observed by the Glider buoy into the same profile, analyzing the spatial position information of the two contacts with the water surface during the dive and ascent, and if the two contacts are in the same grid, then the grid used for altimeter data calibration and verification by the Glider buoy is used as the grid for altimeter data verification; if the two contacts belong to different grids, then the grid where the center of the two spatial positions is located is used as the grid for altimeter data verification. The specific volume height was calculated from the data observed by the Glider buoy, and the initial value of the specific volume height was obtained. This value was then converted into the absolute sea level height required for the test, thus completing the test.

2. The method for deploying a sea surface height measurement device based on an interferometric imaging altimeter according to claim 1, characterized in that, S2 is calculated by combining temperature, salinity, and depth data from profiles obtained through Glider buoy observations. : ； ； In the formula, It is the gravitational constant. It's atmospheric pressure. It is the pressure at the bottom of the sea. It has a salinity of 35, a temperature of 0 degrees Celsius, and a pressure of [missing information]. The volume below, It is a high specific volume anomaly. It is the depth of the sea. It is a reference density. It's a density anomaly. It's about depth.

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