A method and system for investigating ocean subsurface eddies and their submesoscale processes

Abstract

This invention discloses a method and system for investigating subsurface eddies and their submesoscale processes in the ocean. The method includes acquiring three-dimensional temperature, salinity, depth, and current data for a designated sea area, and plotting vertical distribution maps of temperature, salinity, density, and flow field; screening isodense surfaces based on vertical density anomalies and the location of maximum flow velocity; identifying subsurface eddies based on the geopotential height contour maps and vertical flow field maps of the identified isodense surfaces; acquiring satellite altimeter data for the designated sea area and plotting satellite orbit distribution maps for different dates; designing and plotting flight routes for the identified subsurface eddies and satellite orbit distribution maps; and plotting station distribution maps based on the flight route distribution maps for hydrological surveys. This invention aims to provide a solution for identifying and locating subsurface eddies, investigating and analyzing submesoscale processes of subsurface eddies, and designing observation flight routes, thereby solving the problems of difficulty in locating and observing subsurface eddies and their submesoscale processes in the ocean.

Description

Technical Field

[0001] The present invention relates to the field of ocean survey technology, and in particular to a method and system for surveying ocean subsurface vortices and sub-mesoscale processes thereof. Background Art

[0002] Mesoscale eddies contain more than 90% of the ocean's kinetic energy and are the main power carrier of the ocean's material energy cycle. They are also key dynamic processes that contribute to sea-air interactions and changes in the marine ecological environment. Unlike surface-intensified mesoscale eddies, subsurface eddies in the ocean are a type of special eddies with lens-shaped, low potential vorticity and a long life cycle. They can carry water bodies with abnormal properties from the source to sea areas thousands of kilometers away. Subsurface eddies often appear in modal water areas or boundary flow areas, and their formation may be related to the subsidence of modal water and the existence of subsurface undercurrents in boundary flow areas. Unlike surface-intensified eddies, subsurface eddies do not have obvious signals on the sea surface, and it is difficult to identify subsurface eddies based solely on traditional satellite remote sensing observations. Because subsurface eddies are difficult to track and observe, their formation mechanisms are mostly not very clear.

[0003] Although some subsurface vortices can also be reflected in the sea surface height, most subsurface vortices can only be found through field observations of temperature and salinity or flow data. Therefore, how to locate and track subsurface vortices in order to carry out observational investigations has become a key issue in the investigation and research of subsurface vortices. Previous researchers mainly used sea surface anomaly fields (SLA), sea surface height or geostrophic velocity data to identify and track subsurface mesoscale vortices, but this method has limitations for a type of subsurface vortices that are difficult to identify on the sea surface. On this basis, this study uses Copernicus three-dimensional data and the potential height of a specific isopycnic surface to identify subsurface vortices. In addition, the distribution of ocean subsurface vortices is accompanied by sub-mesoscale phenomena. Combined with satellite altimeter data, the study of sub-mesoscale phenomena can be realized. Traditional cruise and large-surface station observation and investigation methods are only suitable for pure sub-surface mesoscale vortex observations, and are not suitable for the observation of ocean subsurface vortices and their sub-mesoscale processes. So far, there is no complete observation and investigation plan to address the difficulties in obtaining subsurface intensification structures and real-time identification of subsurface vortices, as well as the comprehensive analysis of subsurface vortices and their sub-mesoscale processes. Summary of the invention

[0004] The technical problem to be solved by the present invention is as follows: In view of the pain points in the prior art that subsurface vortices are difficult to locate, sub-mesoscale information of subsurface vortices is difficult to obtain, and sub-mesoscale investigation routes are difficult to design, a method and system for investigating ocean subsurface vortices and their sub-mesoscale processes are provided. The present invention aims to achieve accurate identification and positioning of ocean subsurface vortices and their sub-mesoscale processes and design observation routes based on the identified ocean subsurface vortices and their sub-mesoscale processes, so as to solve the problems of difficulty in locating and observing ocean subsurface vortices and their sub-mesoscale processes.

[0005] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0006] A method for investigating ocean subsurface eddies and their submesoscale processes comprises the following steps:

[0007] S1, obtain the three-dimensional temperature, salinity, depth and current data of the specified sea area;

[0008] S2, draw the vertical distribution map of temperature, salinity, density and flow field based on the three-dimensional temperature-salinity-depth flow data;

[0009] S3, screening isodense surfaces based on the vertical density anomaly structure and the location of the maximum flow velocity in the vertical distribution diagram of temperature, salinity, density and flow field;

[0010] S4, identifying the subsurface vortex based on the potential height contour map and vertical flow field map of the determined isodense surface, including: S4.1, finding the maximum and minimum values ​​in the potential height contour map and vertical flow field map of the determined isodense surface through a moving window of a specified size and using them to determine the vortex center; S4.2, for each determined vortex center, drawing closed contour lines from the vortex center outward by increasing or decreasing the specified potential height value, and the difference in potential height value between the outermost closed contour line and the vortex center is greater than the set value; S4.3, for each determined vortex center, the closed contour line The area surrounded by the contour lines is regarded as the vortex distribution area, and concentric circles are drawn, and the radius of the concentric circles is used as the vortex radius of the vortex; for each determined vortex center, the type of vortex is determined according to the type of water body rotation: in the northern hemisphere, if the water body rotates in a cyclonic manner, the type of vortex is determined to be a cold vortex, and if the water body rotates in an anticyclonic manner, the type of vortex is determined to be a warm vortex; in the southern hemisphere, if the water body rotates in an anticyclonic manner, the type of vortex is determined to be a cold vortex, and if the water body rotates in a cyclonic manner, the type of vortex is determined to be a warm vortex; S4.4, the type of vortex and the vortex radius are screened to obtain the screened subsurface vortex;

[0011] S5, obtaining satellite altimeter data of a designated sea area and drawing satellite orbit distribution maps on different dates;

[0012] S6, route design and route drawing based on the identified subsurface vortex and satellite orbit distribution map;

[0013] S7, draw a site distribution map based on the route distribution map for hydrological survey.

[0014] Optionally, step S3 includes: superimposing abnormal data of temperature, salinity, density of the annual climate state for a specified period of time on the vertical distribution diagram of temperature, salinity, density and flow field, drawing isodense surface diagram and flow field diagram for the vertical density structure and the location where the maximum flow velocity occurs, and screening the isodense surface according to the vertical density structure and the location where the maximum flow velocity occurs.

[0015] Optionally, when screening the type and radius of the vortex to obtain the screened subsurface vortex in step S4.4, it includes retaining the cold vortex and warm vortex of the subsurface mesoscale vortex or the subsurface sub-mesoscale vortex as the screened subsurface vortex, the vortex radius of the mesoscale vortex is 10-1000 km, and the vortex radius of the subsurface sub-mesoscale vortex is 1-10 km.

[0016] Optionally, when obtaining the satellite altimeter data of the specified sea area and drawing the satellite orbit distribution maps of different dates in step S5, it includes sampling the satellite orbit data of the sea surface height according to the specified data sampling frequency, selecting the orbit that passes through the survey area and whose orbit date coincides with the cruise observation time, extracting the orbit information and drawing the satellite orbit distribution maps of different dates.

[0017] Optionally, in step S6, when designing and drawing a route for the identified subsurface vortex and the satellite orbit distribution map, it includes the design of a lateral survey line, a longitudinal survey line and a return route. The design of the lateral survey line includes: first, according to the basic characteristics of the subsurface vortex distribution, a lateral survey line is designed to pass through the center of the vortex, and the length of the survey line exceeds the longest horizontal distance of the vortex, which serves as the lateral survey line of the subsurface vortex; the design of the longitudinal survey line includes: first, based on the satellite orbit distribution map, checking the orbit date of the survey area and the satellite re-entry period, combining the subsurface vortex characteristics, selecting the orbit that is measured in the survey area and passes through the center of the vortex, and using this orbital path as a reference to design a longitudinal survey line to observe sub-mesoscale information; and after completing the design of the lateral survey line and the design of the longitudinal survey line, the return route is supplemented to finally complete the route design and draw the route.

[0018] Optionally, step S7 includes: according to the designed route, as well as the temperature-salinity-depth background field information and flow field information, using the survey ship for on-site operations, setting up multiple stations at specified intervals along the horizontal survey line, setting up multiple stations at specified intervals along the longitudinal survey line, dropping a throwable temperature-salinity-depth profiler XCTD at every other station along the route to obtain on-site temperature-salinity data at a vertical depth of more than 800m, and obtaining the vertical velocity distribution of the sections of the two survey lines by detecting the ship-borne acoustic Doppler current profiler ADCP on the survey ship.

[0019] In addition, the present invention also provides a system for investigating ocean subsurface vortices and sub-mesoscale processes thereof, comprising a microprocessor and a memory connected to each other, wherein the microprocessor is programmed or configured to execute the method for investigating ocean subsurface vortices and sub-mesoscale processes thereof.

[0020] In addition, the present invention also provides a computer-readable storage medium, which stores a computer program or instruction, and the computer program or instruction is programmed or configured to execute the method for investigating the ocean subsurface vortex and its sub-mesoscale process through a processor.

[0021] In addition, the present invention also provides a computer program product, including a computer program or instructions, which are programmed or configured to execute the method for investigating ocean subsurface vortices and sub-mesoscale processes through a processor.

[0022] Compared with the prior art, the present invention has the following advantages: the survey method of the ocean subsurface vortex and its submesoscale process of the present invention provides an identification mechanism for the horizontal structure of the subsurface vortex, and realizes three-dimensional observation of the subsurface vortex by designing the route, which helps to solve the problem of difficulty in obtaining the subsurface reinforcement structure; through real-time cruise observation, the real-time identification of the subsurface vortex is realized; combined with the satellite altimeter data, the submesoscale elements of the subsurface vortex are analyzed, and a comprehensive analysis of the subsurface vortex and its submesoscale phenomena is realized. The survey method of the ocean subsurface vortex and its submesoscale process of the present invention can realize the accurate identification of the ocean subsurface vortex and its submesoscale and design the observation route based on the identified ocean subsurface vortex and its submesoscale, effectively solving the problem of difficulty in positioning and observing the ocean subsurface vortex and its submesoscale process. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 Schematic diagram of the basic flow of the method of the embodiment of the present invention.

[0024] Figure 2 This is a cross-sectional diagram at 23°N drawn in an embodiment of the present invention, wherein (a) is a cross-sectional diagram of temperature, (b) is a cross-sectional diagram of salinity, and (c) is a cross-sectional diagram of density.

[0025] Figure 3 The data of temperature anomaly, salinity anomaly and density anomaly plotted in the embodiment of the present invention, wherein (a) is temperature anomaly, (b) is salinity anomaly, and (c) is density anomaly.

[0026] Figure 4 This is a 23°N deep velocity section drawn in an embodiment of the present invention.

[0027] Figure 5 24.5 is drawn in the embodiment of the present invention Potential height distribution diagram of isopycnic surface.

[0028] Figure 6 24.5 is drawn in the embodiment of the present invention The subsurface vortex characteristic map is extracted by using the potential height contour lines of the isodense surface. The contour lines are the potential height distribution, superimposed with the corresponding 150m depth flow field.

[0029] Figure 7 This is a HY-2A satellite orbit diagram drawn in an embodiment of the present invention.

[0030] Figure 8 This is a route distribution map drawn in an embodiment of the present invention.

[0031] Fig. 9 This is a route station distribution map drawn in an embodiment of the present invention.

[0032] Fig.10 The 24.5 Potential height distribution diagram of isopycnic surface.

[0033] Fig.11 This is a sea surface SLA distribution map drawn in an embodiment of the present invention. DETAILED DESCRIPTION

[0034] like Figure 1 As shown, the investigation method of ocean subsurface vortex and its submesoscale process in this embodiment includes the following steps:

[0035] S1, obtain the three-dimensional temperature, salinity, depth and current data of the specified sea area;

[0036] S2, draws the vertical distribution map of temperature, salinity, density and flow field based on the three-dimensional temperature-salinity-depth flow data;

[0037] S3, screening isodense surfaces based on temperature, salinity, density, vertical density anomaly structure in the vertical distribution map of the flow field and the location of the maximum flow velocity;

[0038] S4, identifying the subsurface vortex based on the potential height contour map and vertical flow field map of the determined isodense surface;

[0039] S5, obtaining satellite altimeter data of a designated sea area and drawing satellite orbit distribution maps on different dates;

[0040] S6, route design and route drawing based on the identified subsurface vortex and satellite orbit distribution map;

[0041] S7, draw a site distribution map based on the route distribution map for hydrological survey.

[0042] refer to Figure 1 It can be seen that the identification of ocean subsurface vortices and their submesoscale processes in the investigation method of ocean subsurface vortices and their submesoscale processes in this embodiment is mainly divided into two parts: subsurface vortex identification and satellite altimeter screening, which are processed using different observation data of the Copernicus Marine Environment Monitoring Service (CMEMS). When the three-dimensional temperature-salinity-depth data of the specified sea area are obtained in step S1 of this embodiment to draw the vertical distribution map of the temperature-salinity-density current, the three-dimensional temperature, salinity, height, geostrophic flow and mixed layer depth data of the global ocean published by CMEMS are used for multiple observations, and the horizontal resolution is 0.25° × 0.25°.

[0043] In step S2 of this embodiment, according to the global ocean physics reanalysis and global ocean physics analysis and prediction data released by the Copernicus Marine Environment Monitoring Service (CMEMS) from October 1, 2014 to October 7, 2014, the horizontal resolution is 0.083° × 0.083°, the time resolution is daily, and the elements used include seawater temperature, seawater salinity, seawater depth, flow rate and other data; you can also choose to observe the global ocean three-dimensional temperature, salinity, height, geostrophic flow and mixed layer depth data released by CMEMS for multiple times, the horizontal resolution is 0.25° × 0.25°, the time resolution is weekly / monthly, and the elements used include seawater temperature, seawater salinity, seawater depth, flow rate, potential height and other data. Wherein, when drawing the potential density cross-section diagram according to the three-dimensional temperature-salinity-depth data, the seawater potential density is calculated using the GSW Oceanographic Toolbox of TEOS-10 (The Gibbs SeaWater Oceanographic Toolbox of TEOS-10). Finally, in this embodiment, a cross-section of temperature, salinity, and density at 23°N is drawn as follows: Figure 2As shown, (a) is the temperature cross-section, (b) is the salinity cross-section, and (c) is the density cross-section. The horizontal axis in each cross-section is longitude (°E is east longitude), and the vertical axis is depth (unit: m). In the density cross-section, the black bold line is 24.5 The distribution position of isopycnic surface, where represents the unit of potential density, and θ represents the potential temperature of sea water.

[0044] In this embodiment, step S3 includes: superimposing the abnormal data of temperature, salinity, density of the annual climate state for a specified time period on the vertical distribution diagram of temperature, salinity, density and flow field, drawing isodense surface diagrams and flow field diagrams for the vertical density structure and the location where the maximum flow velocity occurs, and screening isodense surfaces according to the vertical density structure and the location where the maximum flow velocity occurs. After drawing the vertical distribution diagram of temperature, salinity, density and flow field in this embodiment, the temperature anomaly, salinity anomaly and density anomaly data of the 10-year climate state are superimposed. Specifically, taking October 1, 2014 to October 7, 2014 as an example, the temperature anomaly (unit: ℃), salinity anomaly (unit: psu), and density anomaly (unit: kg / m³) profiles of 100m, 300m, 500m, 700m and 1000m drawn in this embodiment are superimposed with geostrophic flow vectors such as Figure 3 As shown, (a) is temperature anomaly, (b) is salinity anomaly, (c) is density anomaly, X coordinate is longitude (°E is east longitude), Y coordinate is latitude (°N is north latitude), and Z coordinate is depth (unit: m).

[0045] On this basis, isopycnic surface maps and flow field maps are drawn for the vertical density structure and the location where the maximum flow velocity occurs, and isopycnic surfaces are selected according to the vertical density structure and the location where the maximum flow velocity occurs. Taking the super-large subsurface anticyclonic vortex existing in the subtropical circulation in the northwest Pacific from October 1 to October 7, 2014 as an example, isopycnic surface maps and flow field maps are drawn for the vertical density structure and the location where the maximum flow velocity occurs, and isopycnic surfaces are selected according to the vertical density structure and the location where the maximum flow velocity occurs. The subsurface vortex presents a unique lens-shaped structure in the vertical direction. The vertical structure of the vortex is checked for the cross-section map of the study area. In the vertical structure of the subsurface anticyclonic vortex, the seasonal thermocline is convex upward, the main thermocline is concave downward, and the density presents a positive-negative anomaly dual-core structure in the vertical direction; in the vertical structure of the subsurface cyclonic vortex, the seasonal thermocline is concave downward, the main thermocline is convex upward, and the density presents a negative-positive anomaly dual-core structure in the vertical direction. At the same time as the lens-shaped structure, the vortex velocity shows a cyclonic / anticyclonic subsurface enhancement structure, which is used to determine the vortex type. In this embodiment, in identifying the vertical density structure, Figure 2It can be seen that there is a standard lens-shaped vertical structure in this sea area. At the vortex center of 124°E-128°E, the seasonal thermocline is concave downward and the main thermocline is convex upward, which is the subsurface anticyclone vortex. The diameter of this subsurface anticyclone vortex is about 460 km and the depth can reach 700 m. The subsurface anticyclone vortex is sliced ​​and the corresponding depth flow field is superimposed ( Figure 3 ), further checking its vertical structure, it was found that the center of the maximum negative temperature anomaly (about -1.3℃) in the vertical direction was located at a depth of about 100m, and the center of the maximum positive temperature anomaly (about 3.5℃) was located at a depth of about 500m. In this embodiment, in identifying the location where the maximum flow velocity occurs, based on the distribution area of ​​the lens-shaped structure, a cross-sectional diagram of the deep flow velocity at 23°N is drawn, and the horizontal distribution and depth distribution of the subsurface vortex are identified based on the velocity contours and the maximum flow velocity position. Taking October 1, 2014 to October 7, 2014 as an example, Figure 4 The 23°N longitudinal velocity section drawn in this example, the horizontal axis is longitude (°E is east longitude), the vertical axis is depth (unit: m), the red line and the pink-purple line are the 0.1 m / s longitudinal velocity distribution contour lines, from Figure 4 It can be seen that the maximum flow velocity position of the lens-shaped vertical structure in this sea area is distributed at about 100 m-200 m. Based on the vertical density structure in this embodiment, the appropriate position density contour line is selected, which is usually the location where the maximum flow velocity occurs. The 24.5 at a depth of 100m-200m is selected. Potential density, draw the potential height contour map of the isodense surface, and superimpose the corresponding 150m flow field, Figure 5 24.5 is drawn in the embodiment of the present invention The potential height distribution map of the isopycnic surface. The black contour lines are the potential height distribution in meters, which can identify the horizontal structure of the subsurface vortex.

[0046] In step S4 of this embodiment, based on the potential height contour lines and flow field diagram of the specific isodense surface, the subsurface vortex is identified using the closed contour method. The basic principle of the closed contour method for identifying subsurface vortices is that the convergence / divergence associated with the anticyclone / cyclone vortex leads to an abnormal increase / decrease in the potential height, resulting in the appearance of a local high / low value center. Specifically, step S4 in this embodiment includes:

[0047] S4.1, the potential height contour map and vertical flow field map of the determined isopycnic surface ( Figure 5 ) uses a moving window of a specified size (such as 4°×4°, etc.) to find the maximum and minimum values ​​and use them to determine the vortex center;

[0048] S4.2, for each determined vortex center, draw closed contour lines from the vortex center outward by increasing or decreasing the specified potential height value, and the difference in potential height value between the outermost closed contour line and the vortex center is greater than a set value (such as 0.1m);

[0049] S4.3, for each determined vortex center, regard the area surrounded by the closed contour lines as the vortex distribution area, draw concentric circles, and use the obtained concentric circle radius as the vortex radius of the vortex; for each determined vortex center, determine the type of the vortex according to the type of water body rotation: in the northern hemisphere, if the water body rotates in a cyclonic manner, the type of the vortex is determined to be a cold vortex, and if the water body rotates in an anticyclonic manner, the type of the vortex is determined to be a warm vortex; in the southern hemisphere, if the water body rotates in an anticyclonic manner, the type of the vortex is determined to be a cold vortex, and if the water body rotates in a cyclonic manner, the type of the vortex is determined to be a warm vortex;

[0050] S4.4, screening is performed according to the type and radius of the vortex to obtain the screened subsurface vortex. Figure 6 24.5 drawn in this example The subsurface vortex feature map is extracted using the potential height contour line of the isodense surface. The contour line is the potential height distribution, superimposed with the corresponding 150m depth flow field. Among them, the green dot represents the center of the vortex, and the green circle is the outermost concentric circle of the contour line. The radius of the concentric circle (vortex radius) is 172.17km. Figure 6 It can be seen that there is a subsurface anticyclonic vortex with a vortex radius r of 172.17 km in the study area, and its vortex center is located at 126.125°E, 22.635°N.

[0051] In this embodiment, when the type and vortex radius of the vortex are screened in step S4.4 to obtain the screened subsurface vortex, the cold vortex and warm vortex of the subsurface mesoscale vortex or the subsurface sub-mesoscale vortex are retained as the screened subsurface vortex, the vortex radius of the mesoscale vortex is 10-1000 km, and the vortex radius of the subsurface sub-mesoscale vortex is 1-10km. The vortex usually rotates clockwise and counterclockwise in the northern hemisphere, which are respectively called anticyclonic vortex and cyclonic vortex. The identification of the above-mentioned ocean subsurface vortex is to provide temperature-salinity-depth background field information and flow field information for route design, obtain the approximate position of the subsurface vortex, determine the vortex center position and vortex radius, so as to assist in the design of the lateral survey line.

[0052] The altimeter data can select the HY-2A satellite altimeter in the near-real-time (NRT) global altimeter satellite along-track sea surface height anomaly data released by CMEMS. The data sampling frequency is 1Hz, the spatial resolution is 7km×1km, the time resolution is instantaneous, and the elements used include sea surface height anomalies, etc. According to the HY-2A satellite altimeter data, the orbit distribution map of different dates is drawn, and the orbit that passes through the survey area and the orbit date coincides with the cruise observation time is selected to extract the orbit information. In step S5 of this embodiment, when obtaining the satellite altimeter data of the specified sea area and drawing the satellite orbit distribution map of different dates, it includes sampling the satellite orbit data of the sea surface height according to the specified data sampling frequency, selecting the orbit that passes through the survey area and the orbit date coincides with the cruise observation time, extracting the orbit information and drawing the satellite orbit distribution map of different dates. Taking the subsurface vortex distribution from October 1 to October 7, 2014 as an example, Figure 7 The HY-2A satellite orbit diagram drawn in this embodiment. Taking October 1, 2014 to October 7, 2014 as an example, the potential height contour lines are superimposed, the horizontal axis is longitude (°E is east longitude), and the vertical axis is latitude (°N is north latitude). Based on Figure 7 The HY-2A satellite orbit map shown in the figure screens the HY-2A satellite orbit distribution in the survey area, and it can be seen that the orbit passing through the subsurface vortex area is on October 1, 2014. The purpose of the above HY-2A satellite orbit positioning is to design longitudinal routes, assist cruise observations, and provide data support for further analysis of the sub-mesoscale process of the subsurface vortex.

[0053] In this embodiment, in step S6, when designing and drawing a route for the identified subsurface vortex and the satellite orbit distribution map, it includes the design of a lateral survey line, a longitudinal survey line and a return route. The design of the lateral survey line: first, according to the basic characteristics of the subsurface vortex distribution, a lateral survey line is designed to pass through the center of the vortex, and the length of the survey line exceeds the longest horizontal distance of the vortex (usually the length of the survey line can be taken to exceed 2 times the radius of the vortex), as the lateral survey line of the subsurface vortex, for example, the length is 394.94 km in this embodiment; the design of the longitudinal survey line includes: first, based on the satellite orbit distribution map, checking the orbit date of the survey area and the satellite re-entry period, combining the characteristics of the subsurface vortex, selecting the orbit that is measured in the survey area and passes through the center of the vortex, and taking this orbital path as a reference, designing it as a longitudinal survey line (for example, the length is 318.88 km in this embodiment), so as to realize a comprehensive analysis of sub-mesoscale information in combination with satellite altimeter data; and after completing the design of the lateral survey line and the design of the longitudinal survey line, the return route is supplemented to finally complete the route design and draw the route. Figure 8It is a route (navigation survey route) distribution map drawn in an embodiment of the present invention. The route distribution map takes October 1, 2014 to October 7, 2014 as an example, and has horizontal survey lines and vertical survey lines, superimposed vortex center positions and potential height contour lines, the horizontal coordinate is longitude (°E is east longitude), and the vertical coordinate is latitude (°N is north latitude).

[0054] Based on the designed route distribution map, the three-dimensional structure of the subsurface vortex and the sub-mesoscale phenomenon can be observed while cruising, and a hydrological survey can be conducted on the three-dimensional structure distribution of the survey area. In step S7 of this embodiment, a high-frequency sampling cruise observation is carried out along the designed route of the survey area. The discardable temperature-salinity-depth profiler XCTD on the survey ship can be used to continuously obtain the profile data of the subsurface vortex, such as seawater temperature, salinity, flow velocity, etc.; at the same time, the ship-borne acoustic Doppler current profiler ADCP on the survey ship is used to obtain the flow velocity and flow direction data of the subsurface vortex under investigation. Through the on-site operation of the survey ship, the position of the subsurface vortex is tracked, and the dynamic three-dimensional structure of the subsurface vortex in the survey area is obtained, providing data support for the analysis of the subsurface vortex phenomenon. Among them, the eXpendable-Conductivity-Temperature-Depth (XCTD) is a temperature and salinity profiler that is placed in the seawater while the ship is sailing. When the probe reaches its maximum working depth, the cable is disconnected to complete a temperature and salinity profile measurement. The Acoustic Doppler Current Profilers (ADCP) is a current measurement instrument that uses the acoustic Doppler principle to measure the frequency shift information of the scattered signal of the stratified water medium, and uses the vector synthesis method to obtain the vertical profile distribution of the ocean current. In this embodiment, step S7 includes: according to the designed route, temperature-salinity-depth background field information and flow field information, using the survey ship for on-site operations, setting multiple stations at intervals of specified sizes along the transverse survey line, setting multiple stations at intervals of specified sizes along the longitudinal survey line, dropping a disposable temperature-salinity-depth profiler XCTD at every other station along the route to obtain the temperature-salinity data at a depth of more than 800m vertically on site, and using the ship-borne acoustic Doppler current profiler ADCP on the survey ship to detect and obtain the vertical velocity distribution of the sections of the two survey lines. Specifically, the hydrological survey in this embodiment includes: according to the designed route, temperature-salinity-depth background field information and flow field information, using the survey ship for on-site operations, setting 38 stations at intervals of 0.1° along the transverse survey line, setting 28 stations at intervals of 0.1° along the longitudinal survey line, dropping an XCTD at every other station along the route to obtain the temperature-salinity data at a depth of more than 800m vertically on site. The vertical velocity distribution of the two survey lines was obtained by ADCP. The data sampling rate was set to 3s / ping, the bin length was set to 16m, and the ship speed during the survey was about 13 knots ( Fig. 9 ). Fig. 9 This is a route site distribution map drawn in an embodiment of the present invention. The distribution map takes October 1, 2014 to October 7, 2014 as an example. The solid points represent XCTD sites, superimposed 150m flow field distribution, superimposed vortex center position and potential height contour lines, the horizontal axis is longitude (°E is east longitude), and the vertical axis is latitude (°N is north latitude).

[0055] In this embodiment, the potential density and vertical velocity structure of the measurement area are mapped through CMEMS reanalysis and prediction data to determine the distribution of subsurface vortices, and the potential height of a specific isodense surface is mapped through the vertical density anomaly structure and maximum velocity of the vortex to determine the horizontal distribution structure of the subsurface vortex, thereby locating the subsurface vortex. Since the convex amplitude of the subsurface vortex isodense lines in this embodiment is smaller than the concave amplitude, there is still a rotation speed on the sea surface, so the signal can also be seen from the sea surface height (positive anomaly of sea surface height). By comparing the distribution of the sea surface SLA (sea surface anomaly field) with the subsurface vortex structure extracted in this embodiment, it is found that the fit is high, and the route can more completely measure the horizontal structure of the subsurface vortex ( Fig.10 ), which further confirms the reliability of the method for extracting subsurface vortices in this study. Fig.10 The 24.5 Iso-dense surface distribution map, Fig.11 The above distribution map is based on the sea surface SLA (sea surface anomaly field) distribution map drawn in the embodiment of the present invention. The above distribution map is extracted from October 1, 2014 to October 7, 2014 as an example. The pink-purple dots in the figure represent the vortex center extracted based on the isodense surface in this embodiment, the turquoise dots represent the vortex center extracted based on the sea surface SLA, and the blue line segment is the designed route. The horizontal coordinate is longitude (°E is east longitude), and the vertical coordinate is latitude (°N is north latitude). This method also provides a way of locating a type of subsurface vortex with unclear sea surface signals, and can effectively solve the problem of the difficulty in obtaining subsurface reinforcement structures. In addition, in this embodiment, the route is designed based on the high-resolution satellite altimeter orbit, which can realize the comprehensive analysis of aerial survey data and satellite altimeter data, thereby enhancing the research on sub-mesoscale processes. Based on this, it can be seen from this example that the investigation method of ocean subsurface eddies and their sub-mesoscale processes can effectively solve the problems of difficulty in obtaining subsurface enhanced structures and difficulty in real-time identification of subsurface eddies, and achieve the purpose of observing ocean subsurface eddies and their sub-mesoscale processes by using ocean survey ships in combination with multi-source heterogeneous platforms.

[0056] In summary, the investigation method of the ocean subsurface vortex and its sub-mesoscale process in the present embodiment includes obtaining three-dimensional temperature-salinity-depth current data of a specified sea area, drawing isothermal-salinity cross-section diagrams and vertical flow field diagrams, screening isodense surfaces according to the vertical density anomaly structure and the location of the maximum flow velocity, and identifying the subsurface vortex based on the potential height contour map and flow field map of the specific isodense surface; obtaining satellite altimeter data of the specified sea area, drawing satellite orbit distribution maps of different dates, and screening the date orbits of the sea area; designing horizontal survey lines in combination with the location of the subsurface vortex, designing vertical survey lines in combination with the satellite orbit, and drawing route distribution maps; conducting cruise observations based on the designed routes, and conducting hydrological surveys on the subsurface vortex and its sub-mesoscale process. The investigation method of the ocean subsurface vortex and its submesoscale process in this embodiment has the following advantages: (1) New data: Reanalysis and prediction data are used to identify and locate subsurface vortices; (2) New vortex extraction method: The vertical density anomaly structure of the subsurface vortex and the location of the maximum flow velocity are used to screen isopycnals, and the subsurface vortices are identified based on the potential height contour map and vertical flow field map of the specific isopycnals; (3) Combination with submesoscale: The satellite altimeter orbit is used to design the route to achieve comprehensive analysis of aerial survey data and satellite altimeter data.

[0057] In addition, this embodiment also provides a system for investigating ocean subsurface vortices and sub-mesoscale processes thereof, comprising a microprocessor and a memory connected to each other, wherein the microprocessor is programmed or configured to execute the method for investigating ocean subsurface vortices and sub-mesoscale processes thereof.

[0058] In addition, this embodiment also provides a computer-readable storage medium, which stores a computer program or instruction, and the computer program or instruction is programmed or configured to execute the investigation method of the ocean subsurface vortex and its sub-mesoscale process through a processor.

[0059] In addition, this embodiment also provides a computer program product, including a computer program or instructions, which are programmed or configured to execute the method for investigating ocean subsurface vortices and sub-mesoscale processes through a processor.

[0060] Those skilled in the art should understand that the technical solutions provided by the embodiments of the present application may be in the form of methods, systems, or computer program products. Therefore, the present application may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present application may take the form of a computer program product implemented on one or more computer-readable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program codes. The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the process Figure 1 A process or multiple processes and / or boxes Figure 1 These computer program instructions can also be stored in a computer-readable memory that can guide a computer or other programmable data processing device to work in a specific way, so that the instructions stored in the computer-readable memory produce a product including an instruction device, which implements the functions specified in the process. Figure 1 A process or multiple processes and / or boxes Figure 1 These computer program instructions can also be loaded onto a computer or other programmable data processing device, so that a series of operation steps are executed on the computer or other programmable device to produce a computer-implemented process, so that the instructions executed on the computer or other programmable device provide for implementing the process in the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0061] The above is only a preferred embodiment of the present invention, and the protection scope of the present invention is not limited to the above embodiments. All technical solutions under the concept of the present invention belong to the protection scope of the present invention. It should be pointed out that for ordinary technicians in this technical field, some improvements and modifications without departing from the principle of the present invention should also be regarded as the protection scope of the present invention.

Claims

1. A method for investigating ocean subsurface eddies and their submesoscale processes, characterized in that: The steps include: S1, obtain the three-dimensional temperature, salinity, depth and current data of the specified sea area; S2, draw the vertical distribution map of temperature, salinity, density and flow field based on the three-dimensional temperature-salinity-depth flow data; S3, screening isodense surfaces based on the vertical density anomaly structure and the location of the maximum flow velocity in the vertical distribution diagram of temperature, salinity, density and flow field; S4, identifying the subsurface vortex based on the potential height contour map and vertical flow field map of the determined isodense surface, including: S4.1, finding the maximum and minimum values ​​in the potential height contour map and vertical flow field map of the determined isodense surface through a moving window of a specified size and using them to determine the vortex center; S4.2, for each determined vortex center, drawing closed contour lines from the vortex center outward by increasing or decreasing the specified potential height value, and the difference in potential height value between the outermost closed contour line and the vortex center is greater than the set value; S4.3, for each determined vortex center, the closed contour line The area surrounded by the contour lines is regarded as the vortex distribution area, and concentric circles are drawn, and the radius of the concentric circles is used as the vortex radius of the vortex; for each determined vortex center, the type of vortex is determined according to the type of water body rotation: in the northern hemisphere, if the water body rotates in a cyclonic manner, the type of vortex is determined to be a cold vortex, and if the water body rotates in an anticyclonic manner, the type of vortex is determined to be a warm vortex; in the southern hemisphere, if the water body rotates in an anticyclonic manner, the type of vortex is determined to be a cold vortex, and if the water body rotates in a cyclonic manner, the type of vortex is determined to be a warm vortex; S4.4, the type of vortex and the vortex radius are screened to obtain the screened subsurface vortex; S5, obtaining satellite altimeter data of a designated sea area and drawing satellite orbit distribution maps on different dates; S6, route design and route drawing based on the identified subsurface vortex and satellite orbit distribution map; S7, draw a site distribution map based on the route distribution map for hydrological survey.

2. The method for investigating ocean subsurface vortices and submesoscale processes according to claim 1, characterized in that: Step S3 includes: superimposing abnormal data of temperature, salinity, density and annual climate state of a specified time period on the vertical distribution diagram of temperature, salinity, density and flow field, drawing isodense surface diagram and flow field diagram for the vertical density structure and the location where the maximum flow velocity occurs, and screening isodense surface according to the vertical density structure and the location where the maximum flow velocity occurs.

3. The method for investigating ocean subsurface vortices and their submesoscale processes according to claim 1, characterized in that: In step S4.4, when screening the type and radius of the vortex to obtain the screened subsurface vortex, it includes retaining the cold vortex and warm vortex of the subsurface mesoscale vortex or the subsurface sub-mesoscale vortex as the screened subsurface vortex, the vortex radius of the mesoscale vortex is 10-1000 km, and the vortex radius of the subsurface sub-mesoscale vortex is 1-10 km.

4. The method for investigating ocean subsurface vortices and submesoscale processes according to claim 1, characterized in that: When obtaining the satellite altimeter data of the specified sea area and drawing the satellite orbit distribution map of different dates in step S5, it includes sampling the satellite orbit data of the sea surface height according to the specified data sampling frequency, selecting the orbit that passes through the survey area and whose orbit date coincides with the cruise observation time, extracting the orbit information and drawing the satellite orbit distribution map of different dates.

5. The method for investigating ocean subsurface vortices and submesoscale processes according to claim 1, characterized in that: In step S6, the route design is performed for the identified subsurface vortex and the satellite orbit distribution map. When drawing the route, it includes the design of a transverse survey line, the design of a longitudinal survey line and a return route. The design of the transverse survey line: first, according to the basic characteristics of the subsurface vortex distribution, a transverse survey line is designed to pass through the vortex center, and the length of the survey line exceeds the longest horizontal distance of the vortex, as the transverse survey line of the subsurface vortex; The design of the longitudinal survey line includes: first, based on the satellite orbit distribution map, checking the orbit date of the survey area and the satellite re-entry period, combining the sub-surface vortex characteristics, selecting the orbit that passes through the vortex center of the survey area, and using this orbit path as a reference to design a longitudinal survey line to observe sub-mesoscale information; and after completing the design of the transverse survey line and the longitudinal survey line, supplement the design of the return route to finally complete the route design and draw the route.

6. The method for investigating ocean subsurface vortices and submesoscale processes according to claim 1, characterized in that: Step S7 includes: according to the designed route, as well as the temperature-salinity-depth background field information and the flow field information, using the survey ship for on-site operations, setting up multiple stations at intervals of specified sizes along the horizontal survey line, setting up multiple stations at intervals of specified sizes along the longitudinal survey line, dropping a throwable temperature-salinity-depth profiler XCTD at every other station along the route to obtain the temperature-salinity data at a vertical depth of more than 800m on site, and using the ship-borne acoustic Doppler current profiler ADCP on the survey ship to detect the vertical velocity distribution of the sections of the two survey lines.

7. A system for investigating ocean subsurface eddies and their submesoscale processes, comprising a microprocessor and a memory connected to each other, characterized in that: The microprocessor is programmed or configured to execute the method for investigating ocean subsurface eddies and sub-mesoscale processes as described in any one of claims 1 to 6.

8. A computer-readable storage medium having a computer program or instruction stored therein, characterized in that: The computer program or instruction is programmed or configured to execute the method for investigating ocean subsurface vortices and sub-mesoscale processes thereof as claimed in any one of claims 1 to 6 through a processor.

9. A computer program product comprising a computer program or instructions, characterized in that The computer program or instruction is programmed or configured to execute the method for investigating ocean subsurface vortices and sub-mesoscale processes thereof as claimed in any one of claims 1 to 6 through a processor.

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