Ocean vortex sea surface temperature and salinity anomaly extraction method

Abstract

The invention provides an ocean vortex sea surface temperature and salinity anomaly extraction method. The method comprises the following steps: step 1, data acquisition and preprocessing; step 2, identifying vortex characteristics; step 3, constructing a vortex sea surface temperature background field and a salinity background field; and 4, extracting a vortex sea surface temperature abnormal field and a salinity abnormal field. According to the method, observation sea surface temperature and salinity data are extracted in a vortex environment area, regression analysis is carried out in combination with climate state sea surface temperature and salinity data, and a more reasonable background temperature and salinity field is constructed. The method can adapt to temperature and salinity changes in different seasons and different areas, the adaptability of a background temperature and salinity field is improved, and errors caused by purely using average climate state data for many years are avoided.

Description

Technical Field

[0001] The invention relates to the field of physical oceanography and data analysis technology, and in particular to a method for extracting anomalies of sea surface temperature and salinity of an ocean vortex. Background Art

[0002] Ocean eddies are an important part of ocean circulation, which has a significant impact on material transport, energy exchange and marine ecosystems. Sea surface temperature and salinity anomalies are important indicators reflecting the dynamic characteristics of mesoscale eddies, and can characterize the dynamic thermodynamic structure of eddies. However, traditional eddy sea surface temperature and salinity anomaly calculations often simply use observational data minus climatological data, or perform time and space filtering on observational data. These methods often find it difficult to completely eliminate large-scale signals such as seasonal changes and ENSO, or are subjective and difficult to accurately capture the detailed characteristics of eddy sea surface temperature and salinity anomalies. Accurately extracting eddy sea surface temperature and salinity anomalies still faces huge challenges.

[0003] The existing methods for extracting ocean eddy sea surface temperature and salinity anomalies have the following main problems: (1) The background temperature and salinity field is estimated inaccurately; Traditional methods usually use large-scale climatological sea surface temperature and salinity as the background temperature and salinity field, without fully considering the local temperature and salinity changes, resulting in large errors in the calculated sea surface temperature anomalies and sea surface salinity anomalies. Directly using the long-term average temperature and salinity field (such as the multi-year climatological mean) as the background temperature and salinity field may ignore the influence of seasonal changes and local temperature and salinity gradients, affecting the physical accuracy of the anomalies.

[0004] (2) It is impossible to effectively distinguish the temperature and salinity anomalies caused by eddies from large-scale background changes; The observed sea surface temperature and sea surface salinity not only include signals generated by eddy dynamic processes, but may also be affected by other large-scale signals (such as El Niño events, seasonal warming, etc.). Existing methods are relatively rough in separating eddies from background fields, and it is difficult to eliminate changes in sea surface temperature and sea surface salinity caused by non-eddy factors. Summary of the invention

[0005] Purpose of the invention: The technical problem to be solved by the present invention is to provide a method for extracting anomalies of sea surface temperature and salinity of ocean vortices in view of the deficiencies of the prior art, comprising the following steps: Step 1, data collection and preprocessing; Step 2, identifying vortex characteristics; Step 3, constructing the vortex sea surface temperature background field and salinity background field; Step 4: Extract the vortex sea surface temperature anomaly field and salinity anomaly field.

[0006] Step 1 includes: Step 1.1, collect climate data, including sea surface temperature, salinity, and sea surface height; Step 1.2, collect sea surface observation data, including sea surface temperature, salinity, and sea surface height data; Step 1.3: Standardize the climatological data and sea surface observation data and interpolate them to grid points with uniform spatial resolution.

[0007] Step 2 includes: Step 2.1, identify the vortex center: The spatial resolution of AVISO ocean satellite remote sensing data is The sea surface height data Y1 is subtracted from the climatological sea surface height data Y2 to obtain the sea surface height anomaly data Y3 = Y1-Y2. The sea surface height anomaly data is scanned with a 5×5 grid point window to find the extreme point. The maximum point is the anticyclonic vortex center, and the minimum point is the cyclonic vortex center. Step 2.2, identify the vortex boundary: take the sea surface height anomaly at the vortex center as the starting value, and gradually increase or decrease the value of the sea surface height anomaly outward until the outermost contour line only contains the unique vortex center. At this time, the contour line is the vortex boundary; Step 2.3, define the radius corresponding to a circle with the same area as the vortex boundary as the vortex radius; Step 2.4, select the annular area between 1 times the radius and 1.5 times the radius of the vortex as the environmental area of ​​the vortex.

[0008] Step 3 includes: Step 3.1, constructing the vortex sea surface temperature background field, specifically includes the following steps: Step 3.1.1: Extract the sea surface temperature data of the vortex environment area from the observed sea surface temperature data .

[0009] Step 3.1.2, establish the climatological temperature field of the eddy sea surface environment: Read the month of the vortex , extract the monthly mean climatological moon, moon, Monthly vortex sea surface environment regional temperature data , , ,in The month is the month before the vortex month. It is the month after the month in which the vortex occurs; Step 3.1.3, sea surface temperature data for the eddy's surrounding area Monthly mean climatological moon, moon, Monthly vortex sea surface environment regional temperature data , , Do linear regression analysis: (1), in is the error term, and the regression coefficient is ; Step 3.1.4: Extract the monthly mean climatological state of the vortex region moon, moon, Monthly Sea Surface Temperature Data , , , using the regression coefficient Get the eddy sea surface temperature background field : (2); Step 3.2, constructing the vortex sea surface salinity background field, includes the following steps: Step 3.2.1: Extract the sea surface salinity data of the vortex environment area from the observed sea surface salinity data ; Step 3.2.2, establish the regional climatological salinity field of the eddy sea surface environment: Read the month of the vortex , extract the monthly mean climatological moon, moon, Monthly eddy sea surface environment regional salinity data , , ; Step 3.2.3, sea surface salinity data Monthly mean climatological moon, moon, Monthly eddy sea surface environment regional salinity data , , Do linear regression analysis: (3), in is the error term, and the regression coefficient is ; Step 3.2.4, establish the eddy sea surface salinity background field: extract the monthly average climatological state of the eddy region moon, moon, Monthly sea surface salinity data , , , using the regression coefficient Get the eddy sea surface salinity background field .

[0010] In step 3.2.4, the vortex sea surface salinity background field is obtained using the following formula: : (4).

[0011] Step 4 includes: Step 4.1, extract the vortex sea surface temperature anomaly: calculate the difference between the observed sea surface temperature field inside the vortex and the background temperature field to obtain the vortex sea surface temperature anomaly field ; Step 4.2, extract the vortex sea surface salinity anomaly: calculate the difference between the observed sea surface salinity field inside the vortex and the background salinity field to obtain the vortex sea surface salinity anomaly field.

[0012] In step 4.1, the vortex sea surface temperature anomaly field is obtained using the following formula: : (5), in, is the observed sea surface temperature field in the vortex area (the observed sea surface temperature field within 1 times the radius of the vortex), This is the background field of sea surface temperature in the constructed eddy area.

[0013] In step 4.2, the vortex sea surface salinity anomaly field is obtained using the following formula: : (6), in, The observed sea surface salinity field in the vortex area (the observed sea surface salinity field within 1 times the radius of the vortex), This is the sea surface salinity background field in the constructed eddy area.

[0014] The present invention also provides an electronic device, comprising a processor and a memory, wherein the memory stores program code, and when the program code is executed by the processor, the processor executes the steps of the described method.

[0015] The present invention also provides a storage medium storing a computer program or instruction. When the computer program or instruction is run on a computer, the steps of the method described are executed.

[0016] The present invention improves calculation accuracy and applicability by the following technical means: (1) Use sea surface height anomalies to accurately extract the vortex range, avoid the uncertainty of artificially setting the vortex boundary, and improve the physical rationality of the calculation.

[0017] (2) Construct the background temperature and salinity field based on the vortex environment area (annular area between 1 times the radius and 1.5 times the radius). Perform regression analysis using climatological data and observational data to ensure the accuracy and adaptability of the background temperature and salinity field.

[0018] (3) Removing large-scale background effects. By constructing the background field, the influence of large-scale signal anomalies such as seasonal changes and El Niño on sea surface temperature anomalies and sea surface salinity anomalies is eliminated, making the extracted sea surface temperature anomalies and sea surface salinity anomalies more accurate.

[0019] (4) Providing standardized and automated calculation processes to ensure that the methods are applicable to different ocean areas around the world and to improve data processing efficiency and the repeatability of results.

[0020] The present invention can be widely used in the fields of marine scientific research, climate change monitoring, fishery resource management and marine forecasting, and has important scientific value and application prospects.

[0021] The present invention effectively solves the deficiencies of traditional methods in background temperature and salinity field estimation, differentiation of eddy field and large-scale background field changes, temperature and salinity anomaly calculation accuracy and automation by accurately extracting eddy sea surface temperature and salinity anomalies. The specific beneficial effects include the following: (1) Improving the accuracy of the background temperature and salinity field: by extracting the observed sea surface temperature and salinity data in the eddy environment area and combining it with the climatological sea surface temperature and salinity data for regression analysis, a more reasonable background temperature and salinity field is constructed. The method can adapt to the temperature and salinity changes in different seasons and regions, improve the adaptability of the background temperature and salinity field, and avoid the errors caused by simply using multi-year average climatological data.

[0022] (2) Effectively distinguish vortex temperature and salinity anomalies from large-scale background changes: By establishing a background temperature and salinity field through regression analysis, the interference of large-scale phenomena such as seasonal changes and El Niño on the calculation of sea surface temperature anomalies and sea surface salinity anomalies is eliminated, so that the calculated temperature and salinity anomalies more accurately reflect the dynamic thermodynamic characteristics of the vortex itself. This method can more accurately distinguish the local sea surface temperature and sea surface salinity anomalies caused by vortices from external background changes, and improve the physical rationality of sea surface temperature anomalies and sea surface salinity anomalies.

[0023] (3) Improve the rationality of the comparison between the temperature and salinity inside and outside the vortex: Traditional methods usually use the mean temperature and salinity of a fixed range outside the vortex as the background temperature and salinity, and fail to fully consider the local temperature and salinity gradient. This method optimizes the background temperature and salinity field through regression analysis, which can more accurately reflect the temperature and salinity distribution characteristics around the vortex. The method of dynamically constructing the background temperature and salinity field makes the calculation of sea surface temperature anomalies and sea surface salinity anomalies more stable, reducing the errors caused by improper selection of background temperature and salinity.

[0024] (4) Improve the standardization and automation of calculations: This method automatically extracts the vortex center and radius through sea surface height anomalies, and combines regression analysis to construct the background temperature and salinity field, forming a standardized calculation process, reducing human subjective intervention, and improving the consistency and repeatability of the results. This method can be widely used in the analysis of vortex sea surface temperature anomalies and sea surface salinity anomalies in different regions and time scales, and can be integrated into the ocean data analysis system to improve data processing efficiency.

[0025] The present invention solves the key technical problem of vortex sea surface temperature and salinity anomaly extraction, and provides new tools and methods for research and application in related fields. The invention method is not only applicable to the extraction of vortex sea surface temperature and salinity anomalies, but also applicable to the extraction of anomalies of other vortex variables such as chlorophyll. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 is a flow chart of the method according to the present invention.

[0027] Figure 2 It is a schematic diagram of the sea surface height anomaly in the research sea area on January 1, 2010, and the identified vortex center (five-pointed star), boundary (black solid line), 1 times radius and 1.5 times radius (black dotted line) provided according to an embodiment of the present invention.

[0028] Figure 3 It is a schematic diagram of vortex sea surface observation temperature provided according to an embodiment of the present invention.

[0029] Figure 4 is a schematic diagram of the vortex sea surface temperature background field provided according to an embodiment of the present invention.

[0030] Figure 5 It is a schematic diagram of the vortex sea surface temperature anomaly field provided according to an embodiment of the present invention.

[0031] Figure 6 is a schematic diagram of vortex sea surface observation salinity provided according to an embodiment of the present invention.

[0032] Figure 7 It is a schematic diagram of the vortex sea surface salinity background field provided according to an embodiment of the present invention.

[0033] Figure 8 It is a schematic diagram of the vortex sea surface salinity anomaly field provided according to an embodiment of the present invention. DETAILED DESCRIPTION

[0034] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments, and the above and / or other advantages of the present invention will become more clear.

[0035] The embodiment of the present invention provides a method for extracting anomalies of sea surface temperature and salinity of an ocean vortex, comprising the following steps: Step 1, data collection and preprocessing, specifically includes the following steps: Step 1.1, climatological data: The required climatological data include sea surface temperature, salinity, and sea surface height. The climatological monthly average sea surface temperature and salinity data are extracted from the World Ocean Atlas (WOA) database, and the climatological monthly average sea surface height is obtained by calculating the monthly average of the ocean satellite remote sensing data AVISO from January 1, 2010 to December 31, 2019.

[0036] Step 1.2, Sea surface observation data: Sea surface observation data include sea surface temperature, salinity, and sea surface height data. The sea surface temperature is observed using the Optimal Interpolated Sea Surface Temperature (OISST) v2.1 version of the National Oceanic and Atmospheric Administration of the United States, with a temporal resolution of 1 day and a spatial resolution of The observed sea surface salinity uses the multivariate optimal interpolation sea surface salinity developed by the Italian National Research Council (CNR), with a temporal resolution of 1 day and a spatial resolution of The sea surface height observations are from AVISO, with a temporal resolution of 1 day and a spatial resolution of The sea surface height anomaly caused by the vortex is the observed sea surface height minus the climatological monthly mean sea surface height.

[0037] Step 1.3: Interpolate the climatological monthly mean sea surface temperature, salinity, sea surface height, and observed sea surface temperature, salinity, and sea surface height data to a uniform spatial resolution of Grid points.

[0038] Step 2, vortex feature identification, specifically includes the following steps: Step 2.1, vortex center identification; For AVISO, the spatial resolution is The sea surface height anomaly data is scanned with a 5×5 grid point window to find the extreme points. The maximum point is the potential center of the anticyclonic vortex, and the minimum point is the potential center of the cyclonic vortex.

[0039] Step 2.2, vortex boundary identification; Taking the sea surface height anomaly at the vortex center as the starting value, gradually increase (cyclonic vortex) or decrease (anticyclonic vortex) the value of the sea surface height anomaly outward (the step size can be 0.001 meters) until the outermost contour line only contains the only vortex center. At this time, the contour line is the vortex boundary.

[0040] Step 2.3, vortex radius; The radius of a circle with the same area as the vortex boundary is defined as the vortex radius.

[0041] Step 2.4, vortex environment area; The annular area between 1 times and 1.5 times the radius of the vortex is defined as the environmental area of ​​the vortex.

[0042] like Figure 2 As shown, it is a schematic diagram of the sea surface height anomaly in the study area on January 1, 2010. The five-pointed star is the identified vortex center, the black solid line is the vortex identification boundary, the black dotted line is the circle of 1 times and 1.5 times the radius of the vortex, and the annular area between the two black dotted lines is the environmental area of ​​the vortex.

[0043] Step 3, constructing the vortex sea surface temperature field and salinity background field, specifically includes the following steps: Step 3.1, constructing the vortex sea surface temperature background field, specifically includes the following steps: Step 3.1.1, temperature field of vortex sea surface environment area; For the observed sea surface temperature data, extract the sea surface temperature data of the vortex environment area (the area between 1 times the radius and 1.5 times the radius) ,Right now Figure 3 Temperature data at the black dot in the middle (the five-pointed star represents the center of the vortex, the black dotted line represents the 1 times radius and 1.5 times radius of the vortex, and the black dot represents the location of the sea surface temperature grid point observed in the vortex environment area).

[0044] Step 3.1.2, climatological temperature field of eddy sea surface environment area; Read the month of the vortex , extract the monthly mean of climatological state moon, moon, Monthly vortex sea surface environment regional temperature data , , ,in The month is the month before the vortex month. It is the month after the month in which the vortex occurs.

[0045] Step 3.1.3, sea surface temperature data for the eddy's surrounding area Monthly mean climatological moon, moon, Monthly vortex sea surface environment regional temperature data , , Do linear regression analysis: (1), in is the error term, and the regression coefficient is ; Step 3.1.4: Extract the monthly mean climatological state of the vortex region moon, moon, Monthly Sea Surface Temperature Data , , , using the regression coefficient Get the eddy sea surface temperature background field : (2); The eddy sea surface temperature background field constructed in this example is as follows Figure 4 As shown (the five-pointed star represents the vortex center, the black dotted line represents the 1 times radius and 1.5 times radius of the vortex, and the black dots represent the grid point positions of the sea surface temperature background field in the vortex environment area).

[0046] Step 3.2, constructing the eddy sea surface salinity background field, specifically includes the following steps: Step 3.2.1, eddy sea surface environment regional salinity field; For the observed sea surface salinity data, extract the sea surface salinity data of the eddy environment area (the area between 1 times the radius and 1.5 times the radius) ,Right now Figure 6 Temperature data at the black dot in the middle (the five-pointed star represents the center of the vortex, the black dotted line represents the 1 times radius and 1.5 times radius of the vortex, and the black dot represents the location of the sea surface salinity grid point observed in the vortex environment area).

[0047] Step 3.2.2, regional climatological salinity field of eddy sea surface environment; Read the month of the vortex , extract the monthly mean of climatological state moon, moon, Monthly eddy sea surface environment regional salinity data , , ;in The month is the month before the vortex month. It is the month after the month in which the vortex occurs.

[0048] Step 3.2.3, analysis of regional salinity field and climatological salinity field of eddy sea surface environment; Observational data of sea surface salinity in the eddy sea surface environment area Climatological sea surface salinity data , , Do linear regression analysis: (3), Get the regression coefficient .

[0049] Step 3.2.4, eddy sea surface salinity background field; Extract the monthly average climate state of the eddy region moon, moon, Monthly sea surface salinity data , , , using the regression coefficient Get the eddy sea surface salinity background field : (4), The eddy sea surface salinity background field constructed in this example is as follows Figure 7 As shown (the five-pointed star represents the vortex center, the black dotted line represents the 1 times radius and 1.5 times radius of the vortex, and the black dots represent the grid point positions of the sea surface salinity background field in the vortex environment area).

[0050] Step 4, extracting the vortex sea surface temperature field and salinity anomaly field, specifically includes the following steps: Step 4.1, extracting the eddy sea surface temperature anomaly field; The difference between the observed sea surface temperature field inside the vortex and the background temperature field is calculated to obtain the vortex sea surface temperature anomaly field SSTA: (5), in, Observe the sea surface temperature field in the vortex area. is the constructed vortex sea surface temperature background field. The vortex sea surface temperature anomaly field extracted in this example is as follows Figure 5 As shown (the five-pointed star represents the vortex center, the black solid line represents the vortex boundary, the black dotted line represents the 1 times radius and 1.5 times radius of the vortex, and the black dots represent the grid point locations of the sea surface temperature anomaly field in the vortex environment area).

[0051] Step 4.2, extracting the eddy sea surface salinity anomaly field; The difference between the observed sea surface salinity field inside the vortex and the background salinity field is calculated to obtain the vortex sea surface salinity anomaly field SSSA: (6), in, Observe the sea surface salinity field in the eddy region. is the background field of sea surface salinity in the constructed eddy region. The eddy sea surface salinity anomaly field extracted in this example is as follows: Figure 8 As shown (the five-pointed star represents the vortex center, the black solid line represents the vortex boundary, the black dotted line represents the 1 times radius and 1.5 times radius of the vortex, and the black dots represent the grid point positions of the sea surface salinity anomaly field in the vortex environment area).

[0052] The present invention provides a method for extracting anomalies of sea surface temperature and salinity of an ocean vortex. There are many methods and ways to implement the technical solution. The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the protection scope of the present invention. All components not specified in this embodiment can be implemented by existing technologies.

Claims

1. A method for extracting anomalies of sea surface temperature and salinity of ocean vortices, characterized in that: The following steps are involved: Step 1, data collection and preprocessing; Step 2, identifying vortex characteristics; Step 3, constructing the vortex sea surface temperature background field and salinity background field; Step 4, extracting the vortex sea surface temperature anomaly field and salinity anomaly field; Step 1 includes: Step 1.1, collect climate data, including sea surface temperature, salinity, and sea surface height; Step 1.2, collect sea surface observation data, including sea surface temperature, salinity, and sea surface height data; Step 1.3: Standardize the climatological data and sea surface observation data and interpolate them to grid points with uniform spatial resolution; Step 2 includes: Step 2.1, identify the vortex center: For the sea surface height data Y1 with a spatial resolution of 1 / 4º×1 / 4º of the ocean satellite remote sensing data AVISO, subtract the climatological sea surface height data Y2 to obtain the sea surface height anomaly data Y3= Y1-Y2. Scan the sea surface height anomaly data with a 5×5 grid point window to find the extreme point. The maximum point is the center of the anticyclonic vortex, and the minimum point is the center of the cyclonic vortex. Step 2.2, identify the vortex boundary: take the sea surface height anomaly at the vortex center as the starting value, and gradually increase or decrease the value of the sea surface height anomaly outward until the outermost contour line only contains the unique vortex center. At this time, the contour line is the vortex boundary; Step 2.3, define the radius corresponding to a circle with the same area as the vortex boundary as the vortex radius; Step 2.4, select the annular area between 1 times the radius and 1.5 times the radius of the vortex as the environmental area of ​​the vortex.

2. The method according to claim 1, characterized in that Step 3 includes: Step 3.1, constructing the vortex sea surface temperature background field, specifically includes the following steps: Step 3.1.1: Extract the sea surface temperature data of the vortex environment area from the observed sea surface temperature data ; Step 3.1.2, establish the climatological temperature field of the eddy sea surface environment: Read the month of the vortex , extract the monthly mean climatological moon, moon, Monthly vortex sea surface environment regional temperature data , , ,in The month is the month before the vortex month. It is the month after the month in which the vortex occurs; Step 3.1.3, sea surface temperature data for the eddy's surrounding area Monthly mean climatological moon, moon, Monthly vortex sea surface environment regional temperature data , , Do linear regression analysis: （1）， in is the error term, and the regression coefficient is ; Step 3.1.4: Extract the monthly mean climatological state of the vortex region moon, moon, Monthly Sea Surface Temperature Data , , , using the regression coefficient Get the eddy sea surface temperature background field : （2）； Step 3.2, constructing the vortex sea surface salinity background field, includes the following steps: Step 3.2.1: Extract the sea surface salinity data of the vortex environment area from the observed sea surface salinity data ; Step 3.2.2, establish the regional climatological salinity field of the eddy sea surface environment: Read the month of the vortex , extract the monthly mean climatological moon, moon, Monthly vortex sea surface environment regional salinity data , , ; Step 3.2.3, sea surface salinity data Monthly mean climatological moon, moon, Monthly vortex sea surface environment regional salinity data , , Do linear regression analysis: （3）， in is the error term, and the regression coefficient is ; Step 3.2.4, establish the eddy sea surface salinity background field: extract the monthly average climatological state of the eddy region moon, moon, Monthly sea surface salinity data , , , using the regression coefficient Get the eddy sea surface salinity background field .

3. The method according to claim 2, characterized in that In step 3.2.4, the vortex sea surface salinity background field is obtained using the following formula: : （4）。 4. The method according to claim 3, characterized in that Step 4 includes: Step 4.1, extract the vortex sea surface temperature anomaly: calculate the difference between the observed sea surface temperature field inside the vortex and the background temperature field to obtain the vortex sea surface temperature anomaly field ; Step 4.2, extract the vortex sea surface salinity anomaly: calculate the difference between the observed sea surface salinity field inside the vortex and the background salinity field to obtain the vortex sea surface salinity anomaly field.

5. The method according to claim 4, characterized in that In step 4.1, the vortex sea surface temperature anomaly field is obtained using the following formula: : （5）， in, Observe the sea surface temperature field in the vortex area. This is the background field of sea surface temperature in the constructed eddy area.

6. The method according to claim 5, characterized in that In step 4.2, the vortex sea surface salinity anomaly field is obtained using the following formula: : （6）， in, Observe the sea surface salinity field in the eddy region. This is the sea surface salinity background field in the constructed eddy area.

7. An electronic device, characterized in that: The method comprises a processor and a memory, wherein the memory stores program codes, and when the program codes are executed by the processor, the processor executes the steps of the method according to any one of claims 1 to 6.

8. A storage medium, characterized in that: A computer program or instruction is stored, and when the computer program or instruction is run on a computer, the steps of the method according to any one of claims 1 to 6 are executed.

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