A method for observational assessment of ocean upwelling intensity

Abstract

The present invention relates to the field of next-generation marine information technology and discloses a method for observing and evaluating the intensity of ocean upwelling, comprising: obtaining ocean profile observation data from multiple stations on a straight observation section in a target area; processing the data to obtain the profile distribution of geopotential temperature and geopotential density at each station; performing a multi-point sliding average on the data at each station in the vertical direction to filter out noise and high-frequency signals; plotting the distribution of salinity, geopotential temperature, and geopotential density at the section with respect to depth; marking contour lines of each parameter; selecting areas with consistent contour line distributions, calculating the angle between the contour lines and the horizontal line; and performing dimensionless processing on the angle to obtain an evaluation index. The present invention can quantitatively evaluate the strength of seawater upwelling during a single observation using field observation data of seawater temperature and salinity sections without a network connection. If multiple observations are repeated, the evaluation index can also provide temporal characteristics of the upwelling intensity, providing guidance for ship navigation decisions.

Description

Technical Field

[0001] The present invention relates to the field of new generation ocean information technology, specifically to measuring distance, level or direction, and more particularly to an observation and evaluation method for ocean upwelling intensity. Background Art

[0002] Upwelling, also known as upwelling, is the phenomenon in which the horizontal divergence of the surface seawater causes the seawater below the surface to rise. In particular, if the surface seawater converges horizontally, causing the seawater to flow vertically downward from the sea surface, it is called downwelling. Upwelling and downwelling are collectively called upwelling and downwelling, and are an important part of ocean circulation. Upwelling usually occurs in coastal areas. Due to the wind, the surface seawater is pushed away from the coast, causing the sea level to drop. In order to achieve water pressure balance, the deep seawater compensates and rises, forming an upwelling. Upwelling causes the isopycnal surface to tilt from the horizontal distribution to the rising side. Upwelling actually corresponds to the vertical flow velocity of the fluid. If the vertical flow direction is upward, it is upwelling, and if the vertical flow direction is downward, it is downwelling.

[0003] Because the vertical flow velocity of seawater is too low, the velocity is usually less than 10 -3 m / s, usually about 10 -4 m / s. This velocity magnitude cannot be directly measured in actual oceanographic observations. Therefore, to describe the strength of upwelling, researchers have developed several upwelling indices, such as the wind stress index and the wind stress curl index. Upwelling intensity can even be defined by anomalies in upwelling sea surface temperature. Specifically, these indices use coastal wind stress, wind stress curl, and sea surface temperature anomalies to indicate upwelling strength. These methods are indirect measures of upwelling strength.

[0004] The above indices have certain limitations in practical use. The data required must be collected over a certain period of time and downloaded from the internet. Using wind stress data as the basis for assessing upwelling intensity is crucial. In practice, ships often operate without internet access, making it impossible to download surface wind and temperature data. This hinders ship operators from sensing the intensity of the sea's upwelling, hindering decision-making and operations.

[0005] Currently, there is no method to measure the strength of ocean upwelling using only a single cross-sectional observation. Therefore, a method for assessing ocean upwelling intensity is needed. Without an internet connection, a ship can use temperature and salinity profiles from several stations along a straight line across the ocean surface to quickly assess the strength of upwelling in the area and assist in decision-making. Summary of the Invention

[0006] The purpose of the present invention is to provide an observation and evaluation method for the intensity of ocean upwelling, which uses numerical values ​​to quantitatively evaluate the strength of the upwelling. By performing multiple observations on the section, a time series of upwelling index can be formed to quantitatively evaluate the changes in the strength of the upwelling over time, which can solve the technical problem that the upwelling movement of seawater is difficult to quantitatively calculate and evaluate.

[0007] In order to achieve the above purpose, the technical solutions adopted are as follows:

[0008] A method for observing and evaluating ocean upwelling intensity, comprising:

[0009] Acquire ocean observation data from multiple stations along a straight line section in the target area; wherein the ocean observation data includes seawater temperature and salinity profile data;

[0010] Preliminarily processing the ocean observation data to obtain profile distribution data of geopotential temperature and geopotential density at each station;

[0011] Performing multi-point sliding average processing on the profile distribution data of the potential temperature and potential density of each station in the vertical direction to filter out noise and high-frequency signals to obtain filtered data;

[0012] Based on the filtered data, plotting the distribution of cross-section salinity, potential temperature and potential density with depth;

[0013] Based on the cross-section salinity, potential temperature and potential density distribution diagram with depth, marking the isolines of cross-section salinity, potential temperature and potential density;

[0014] Select the area with consistent distribution of contour lines and calculate the angle between the contour lines and the horizontal line;

[0015] The angle is expressed as an angle, divided by 90 degrees, and dimensionally converted to a unit value to obtain an evaluation index for evaluating the intensity of upwelling.

[0016] Optionally, the straight section of the target area is a longitudinal section, a latitudinal section, or an observation section in which sea surface observation stations are connected in a straight line.

[0017] Optionally, based on the evaluation index, the upwelling intensity is evaluated in the following manner:

[0018] When the evaluation index is greater than 0, one side of the evaluation sea area is upwelling;

[0019] When the evaluation index is less than 0, one side of the evaluation sea area is a downwelling;

[0020] When the evaluation index is closer to 0 in the range of -1 to 1, the upwelling or downwelling is evaluated as weak;

[0021] When the evaluation index is closer to 1 in the range of -1 to 1, the upwelling is evaluated as strong;

[0022] When the evaluation index is closer to -1 in the range of -1 to 1, the downwelling is evaluated as strong.

[0023] Optionally, select an area with uniform distribution of contour lines and calculate the angle between the contour lines and the horizontal line, including:

[0024] Select two seawater microclusters of the same volume, which are located on the same isovalue line, have the same seawater salinity, potential temperature, potential density, and have the same mass.

[0025] The potential energy of seawater microclusters is determined by the following formula:

[0026] mgh=mw 2 / 2;

[0027] Where, m is the mass of seawater microclusters, g is the acceleration due to gravity, w is the vertical velocity of seawater microclusters, h To increase the height;

[0028] Based on the potential energy of the seawater microclusters, the calculation formula for determining the vertical flow velocity of the seawater microclusters is:

[0029] ;

[0030] Based on the calculation formula of the vertical flow velocity of the seawater micro-group, the lifting height is calculated when the vertical flow velocity of the seawater micro-group is known. h ;

[0031] Based on the calculated lift height h , calculate the angle between the contour line and the horizontal line using the following formula:

[0032] ;

[0033] Where, is the angle between the contour line and the horizontal line, is the horizontal distance between two seawater microclusters.

[0034] Optionally, calculate the potential temperature using the following formula:

[0035] ;

[0036] Where, , T is the observed seawater temperature, S is the observed seawater salinity, p is the observed seawater pressure data, is the potential temperature, is the vertical gradient of seawater temperature.

[0037] Optionally, the method of performing multi-point sliding average processing on the profile distribution data of the potential temperature and potential density of each station in the vertical direction includes performing 5-point, 7-point or 9-point sliding smoothing processing in the vertical direction.

[0038] Optionally, based on the filtered data, the observation data of each observation station on the observation section are horizontally interpolated in the section direction according to the interpolated depth and horizontal distance, with a horizontal resolution of 1 km, and a distribution map of section salinity, potential temperature and potential density with depth is drawn.

[0039] Optionally, the ocean observation data is preliminarily processed to obtain profile distribution data of potential temperature and potential density at each station, including: performing horizontal interpolation processing on the observation data of each observation station on the observation section in the section direction, with a horizontal resolution of 1 km.

[0040] Optionally, the absolute value of the angle between the contour line and the horizontal line is less than 90 degrees.

[0041] Optionally, the angle resolution of the angle between the contour line and the horizontal line is 0.1 degrees.

[0042] Alternatively, a more accurate evaluation method can be used to calculate the different station positions on the cross section using the following formula i At , the angle between the contour line and the horizontal line is:

[0043] ;

[0044] Where, For different positions i The angle between the contour line at and the horizontal line is, is the horizontal distance between two seawater micro-clusters, thus providing more accurate assessment details. For standing position i The height at which seawater particles are lifted due to upward movement.

[0045] Optionally, for a sea area composed of multiple sections, the following formula is used to calculate the different sections j , and different stations on the cross section i At , the angle between the contour line and the horizontal line is:

[0046] ;

[0047] Where, for j cross section, i The angle between the contour line at the station and the horizontal line, forj cross section, i The horizontal distance between two seawater micro-clusters at the station, For cross section j Position i The height at which seawater micro-clusters are lifted due to upward movement can provide more accurate assessment details.

[0048] The beneficial effects of the present invention are:

[0049] The present invention calculates geopotential temperature and geopotential density based on actual seawater temperature and salinity cross-section observation data. Without a network connection, the present invention measures the inclination angles of the contour lines of seawater salinity, geopotential temperature, and geopotential density on the cross-section, selects the maximum value of the three angles as a parameter for evaluating upwelling intensity, and non-dimensionalizes the angles to obtain an upwelling intensity index. The advantages of the present invention are that, when the ship is offline, only observation data is used to calculate the dimensionless index of the contour line inclination angles, allowing quantitative assessment of the intensity of seawater upwelling from a single cross-section observation; multiple observations of the same cross-section can yield a time series of upwelling intensity changes; and observations of multiple cross-sections in a single sea area can yield the distribution of upwelling intensity in that area. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1 The flow chart of a method for observing and evaluating ocean upwelling intensity according to an embodiment of the present invention is shown. Figure 1 .

[0051] Figure 2 The flow chart of a method for observing and evaluating ocean upwelling intensity according to an embodiment of the present invention is shown. Figure 2 .

[0052] Figure 3 A schematic diagram showing the working principle of an observation and evaluation method for ocean upwelling intensity according to an embodiment of the present invention is shown; w is the rising speed of seawater micro-mass A1, is the density of seawater, the solid line is the isopycnic line, h is the vertical distance that the seawater micro-mass A1 rises relative to A2 under the action of the upward movement, l is the horizontal distance between seawater microclusters A1 and A2, is the angle between the contour line and the horizontal line, a is the horizontal auxiliary line, and b is the auxiliary line parallel to the inclined density line.

[0053] Figure 4 A schematic diagram of an example of calculating the eastward upwelling intensity index according to an embodiment of the present invention is shown, wherein (a) is a graph showing the distribution of seawater potential temperature with depth; (b) is a graph showing the distribution of seawater salinity with depth; and (c) is a graph showing the distribution of seawater potential density with depth. DETAILED DESCRIPTION

[0054] The following describes the embodiments of the present invention through specific examples. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments. The details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the following embodiments and features in the embodiments can be combined with each other unless they conflict.

[0055] The specific implementation of the present invention is further described in detail below with reference to the accompanying drawings and examples.

[0056] Example 1:

[0057] Figure 1 The flow chart of a method for observing and evaluating ocean upwelling intensity according to an embodiment of the present invention is shown. Figure 1 ,like Figure 1 As shown, an embodiment of the present invention provides an observation and evaluation method for the intensity of ocean upwelling, which includes steps S10 to S70, which are described in detail as follows.

[0058] S10. Acquire ocean observation data from multiple stations on a straight line section of the target area; wherein the ocean observation data includes seawater whole layer temperature and salinity profile data.

[0059] In this embodiment, the salinity profile data includes but is not limited to seawater salinity data and potential density data, and the seawater layer temperature includes but is not limited to potential temperature data and seawater rapid temperature data.

[0060] In some embodiments, the straight section of the target area is a longitudinal section, a latitudinal section, or an observation section in which sea surface observation stations are connected in a straight line.

[0061] In some embodiments, the length of the observation section is 50 to 200 kilometers.

[0062] S20. Preliminary processing is performed on the ocean observation data to obtain profile distribution data of geopotential temperature and geopotential density at each station.

[0063] In some embodiments, the station refers to an observation station, and the number of stations should be greater than or equal to three stations to ensure sufficient ocean observation data.

[0064] In some embodiments, the number of stations exceeds ten stations.

[0065] In some embodiments, the spacing between stations is 2 to 20 kilometers.

[0066] S30, performing multi-point sliding average processing on the profile distribution data of the potential temperature and potential density of each station in the vertical direction to filter out noise and high-frequency signals to obtain filtered data.

[0067] In some embodiments, the method of performing multi-point sliding average processing on the profile distribution data of the potential temperature and potential density of each station in the vertical direction includes performing 5-point, 7-point or 9-point sliding smoothing processing in the vertical direction.

[0068] S40. Based on the filtered data, draw a distribution diagram of cross-section salinity, potential temperature, and potential density with depth.

[0069] In some embodiments, based on the filtered data, the observation data of each observation station on the observation section are horizontally interpolated in the section direction according to the interpolated depth and horizontal distance, with a horizontal resolution of 1 kilometer, and a distribution map of section salinity, potential temperature and potential density with depth is drawn.

[0070] S50. Based on the cross-section salinity, potential temperature and potential density distribution diagram with depth, mark the isovalue lines of cross-section salinity, potential temperature and potential density.

[0071] S60: Select an area where the contour lines are uniformly distributed, and calculate the angle between the contour lines and the horizontal line.

[0072] In some embodiments, selecting an area with uniform distribution of contour lines and calculating the angle between the contour lines and the horizontal line includes:

[0073] Select two seawater microclusters of the same volume, which are located on the same isovalue line, have the same seawater salinity, potential temperature, potential density, and have the same mass.

[0074] The potential energy of seawater microclusters is determined by the following formula:

[0075] mgh=mw 2 / 2;

[0076] Where, m is the mass of seawater microclusters, g is the acceleration due to gravity, w is the vertical velocity of seawater microclusters, h To increase the height;

[0077] Based on the potential energy of the seawater microclusters, the calculation formula for determining the vertical flow velocity of the seawater microclusters is:

[0078] ;

[0079] Based on the calculation formula of the vertical flow velocity of the seawater micro-group, the lifting height is calculated when the vertical flow velocity of the seawater micro-group is known.h ;

[0080] Based on the calculated lift height h , calculate the angle between the contour line and the horizontal line using the following formula:

[0081] ;

[0082] Where, is the angle between the contour line and the horizontal line, is the horizontal distance between two seawater microclusters.

[0083] Optionally, calculate the potential temperature using the following formula:

[0084] ;

[0085] Where, , T is the observed seawater temperature, S is the observed seawater salinity, p is the observed seawater pressure data, is the potential temperature, is the vertical gradient of seawater temperature.

[0086] In some embodiments, a more accurate evaluation is performed on different positions on the cross section by calculating the following formula for different positions on the cross section: i At , the angle between the contour line and the horizontal line is:

[0087] ;

[0088] Where, For different positions i The angle between the contour line at and the horizontal line is, is the horizontal distance between two seawater micro-clusters, thus providing more accurate assessment details. For standing position i The height at which seawater particles are lifted due to upward movement.

[0089] In some embodiments, for a sea area composed of multiple sections, the following formula is used to calculate the sea area of ​​different sections: j , and different stations on the cross section i At , the angle between the contour line and the horizontal line is:

[0090] ;

[0091] Where, for j cross section, i The angle between the contour line at the station and the horizontal line, for j cross section, iThe horizontal distance between two seawater micro-clusters at the station, For cross section j Position i The height at which seawater micro-clusters are lifted due to upward movement can provide more accurate assessment details.

[0092] S70. Express the angle in degrees and divide it by 90 degrees to perform dimensionless processing to remove the unit, so as to obtain an evaluation index for evaluating the upwelling intensity.

[0093] In some embodiments, the absolute value of the angle between the contour line and the horizontal line is less than 90 degrees, and the angular resolution of the angle between the contour line and the horizontal line is 0.1 degrees.

[0094] In some embodiments, the dimensionless de-unitization process is performed by expressing the angle in radians, that is, dividing by 90 degrees to obtain a radian value, and the radian value is in the range of [-1, 1].

[0095] In some embodiments, based on the evaluation index, the upwelling intensity is evaluated as follows:

[0096] When the evaluation index is greater than 0, one side of the evaluation sea area is upwelling;

[0097] When the evaluation index is less than 0, one side of the evaluation sea area is a downwelling;

[0098] When the evaluation index is closer to 0 in the range of -1 to 1, the upwelling or downwelling is evaluated as weak;

[0099] When the evaluation index is closer to 1 in the range of -1 to 1, the upwelling is evaluated as strong;

[0100] When the evaluation index is closer to -1 in the range of -1 to 1, the downwelling is evaluated as strong.

[0101] Example 2:

[0102] Figure 2 The flow chart of a method for observing and evaluating ocean upwelling intensity according to an embodiment of the present invention is shown. Figure 2 ,like Figure 2As shown, an embodiment of the present invention provides an observation and evaluation method for the intensity of ocean upwelling, which includes: obtaining seawater temperature and salinity profile data of a plurality of stations on a straight line section of a target area; performing preliminary processing on the ocean observation data to obtain the profile distribution of the potential temperature and potential density of each station; performing a 5-point sliding average on the data of each station in the vertical direction to filter out noise and high-frequency signals; drawing a cross-section salinity, potential temperature, and potential density distribution diagram with depth; marking the contour lines of the above parameters; selecting an area with consistent contour line distribution, calculating the angle between the contour line and the horizontal line, and selecting the maximum angle of the isoline inclination of the salinity, potential temperature, and potential density parameters; expressing the angle as an angle, dividing it by 90 degrees, and performing dimensionless processing to remove the unit to obtain an evaluation index for evaluating the intensity of upwelling. This observation and evaluation method for the intensity of ocean upwelling can directly use the cross-section observation data to quantitatively evaluate the strength of the upwelling in a single observation using numerical values. If multiple observations are performed, the evaluation index can also reflect the changes in the intensity of the upwelling.

[0103] In this embodiment, the intensity of upwelling is assessed based on the inclination angles of the depth-dependent contour lines for salinity, geopotential temperature, and geopotential density. If the salinity contour line has the largest inclination angle on a section, the upwelling region is primarily controlled by seawater salinity and has a significant amount of exogenous freshwater input. If the geopotential temperature contour line has the largest inclination angle on a section, the upwelling process is primarily controlled by seawater temperature, with relatively low amounts of exogenous freshwater input. If the geopotential density contour line has the largest inclination angle on a section, the upwelling process is primarily controlled by seawater density, with both seawater temperature and salinity controlling the process.

[0104] In some embodiments, it is also possible to use only the rapid temperature observation profile obtained from one cross-sectional observation to establish an upwelling intensity assessment parameter based on seawater temperature. For ships far away from land that cannot perceive the upwelling or falling state of seawater in the sea area where the ships are located, an upwelling intensity assessment index is provided to provide a basis and reference for ship decision-making.

[0105] like Figure 3 The figure shows the working principle of the observation and evaluation method of ocean upwelling intensity. The seawater on the left side of the cross section rises, resulting in the hydrological parameters of the seawater, such as the potential density of the seawater. , contour uplift, seawater potential density The elevation height of the contour line is h , hydrological parameters include seawater salinity, potential temperature, and potential density. Take seawater microclusters of the same volume, and in order to distinguish two seawater microclusters, Figure 2 A1 and A2 are used to represent two seawater microclusters, and the horizontal distance between the two seawater microclusters is l Since the contour lines are the same, the salinity, potential temperature, and potential density of the two seawater microclusters are the same, that is, the mass of the two seawater microclusters is mThe result of the upward movement is that the gravitational potential energy of the seawater micro-mass A1 increases, and the potential energy increases to mgh ,in g is the acceleration due to gravity. The upward kinetic energy of the seawater particles is mw 2 / 2, the increase in potential energy of seawater microclusters is the conversion of their kinetic energy, so

[0106] mgh=mw 2 / 2;

[0107] Where, w is the vertical velocity of seawater microclusters.

[0108] The vertical velocity of seawater microclusters can be obtained from the above formula:

[0109] ;

[0110] The angle of the elevation of the hydrological parameter contour lines caused by the upward movement of fluid particles is the potential density The angle between the contour line and the horizontal line is calculated using the following formula:

[0111] ;

[0112] Where, is the angle between the contour line and the horizontal line. In a simplified case, the angle parameter can be quickly obtained by measuring the angle between the horizontal auxiliary line a and the auxiliary line b parallel to the inclined isodensity line.

[0113] In an exemplary embodiment, a specific example of an observation and evaluation method based on the intensity of ocean upwelling is given. This specific example uses the seawater temperature, salinity, and density profile observed by a ship on the east side of Hainan Province as an example to evaluate the intensity of upwelling. Figure 4 As shown, the left side of the observation section is closer to land, the right side is closer to the open sea, and the bottom section is the seabed. The horizontal axis is distance from the coast, and the vertical axis is the distribution of observed hydrological parameters (seawater potential temperature, seawater salinity, and seawater potential density) with depth. The ship observed hydrological parameter profiles at 15 stations along this section.

[0114] Since the distribution of isopycnals is relatively consistent, a single angle is used here to evaluate the strength of upwelling during the observation period. Figure 2 , this specific example is implemented by the following steps 1 to 12.

[0115] Step 1. Select the observation section: Draw a straight line on the chart. The straight line should be 50 to 200 kilometers long. The line can be in the longitudinal direction, the latitudinal direction, or any other direction. If near the continental shelf, the line should be perpendicular to the coastline or perpendicular to the seabed isobath.

[0116] Step 2. Obtain observation stations: On the above-selected observation section, select about 10 stations with a station spacing of 5 km to 20 km.

[0117] Step 3. Obtain observation data: At the selected observation station, use instruments to quickly obtain the seawater temperature and salinity distribution data with depth at the station.

[0118] Step 4: Calculation of potential hydrological parameters: Calculate the potential temperature and potential density based on the seawater temperature and salinity observed at each observation station on the above observation section. The potential temperature is calculated as follows:

[0119] ;

[0120] Where, , T is the observed seawater temperature, S is the observed seawater salinity, p is the observed seawater pressure data, is the potential temperature, is the vertical gradient of seawater temperature.

[0121] Step 5. Vertical interpolation of potential hydrological parameters: Linearly interpolate the seawater salinity, potential temperature, and potential density of each of the above observation stations in the vertical direction. The processed data are evenly spaced in the vertical direction, and the general spacing should be 1 meter, or one hundredth of the total observation depth.

[0122] Step 6: Vertical Sliding Average of Potential Hydrological Parameters: Perform a vertical sliding average of the vertically interpolated seawater salinity, geopotential temperature, and geopotential density at each observation station. This sliding average is typically performed over five points, but can also be performed over seven or nine points. The specific number of sliding averages depends on the water depth. Deeper waters require more sliding averages, while shallower waters require fewer.

[0123] Step 7. Horizontal interpolation of the cross section: Interpolate the above observation stations in the horizontal direction with a horizontal resolution of 1 km and interpolate the corresponding hydrological parameters.

[0124] Step 8: Draw the distribution of hydrological parameters along the cross section with depth: Draw the contour line cross section of the above observation data, as shown in the following example: Figure 4 The seawater potential temperature ( Figure 4 (a)), seawater salinity ( Figure 4 (b)), seawater potential density ( Figure 4 (c) Contour map.

[0125] Step 9: Divide the above motion diagnosis range: for the seawater potential temperature to be diagnosed ( Figure 4(a)), seawater salinity ( Figure 4 (b)), seawater potential density ( Figure 4 In (c), the scope of diagnosis is divided according to actual needs, such as Figure 4 , divided into three areas: A, B and C.

[0126] If a more accurate angle is required, the angles of adjacent stations can be solved to obtain the distribution of the angle of upwelling intensity on the horizontal section.

[0127] Step 10, measure the contour angle: the seawater potential temperature in the above-mentioned A, B, and C areas ( Figure 4 (a)), seawater salinity ( Figure 4 (b)), seawater potential density ( Figure 4 For the contour lines in (c), measure the inclination angle of the contour lines. For example, to assess the inclination of the contour lines in Area B toward the shelf, select the horizontal auxiliary line (dashed line) and measure the angle of the contour lines in Area B relative to the horizontal auxiliary line. Rotate the horizontal auxiliary line counterclockwise to obtain the angle of the contour line. An angle of 45° is considered positive when rotated counterclockwise. The left side of Area B indicates upward movement.

[0128] Similarly, it can be seen that there is basically no upward movement in area A, and because the contour line angle in area C is 5°, the upward movement is much smaller than the upward movement of the sea water in area B.

[0129] Step 11: Dimensionless upwelling index: Divide the above angle value by 90°, then the upwelling index of area B is 0.5, area A is 0, and area C is 0.05.

[0130] For a more refined assessment of the upwelling index, the upwelling index can be calculated at different depths or even at different horizontal distances.

[0131] Step 12, time series of upwelling index: by conducting multiple cross-section observations in the same sea area, the time series of upwelling index can be obtained.

[0132] It should be noted that when drawing contour maps of hydrological parameters from multiple cross-section observations, the scales of the horizontal and vertical axes should be kept the same.

[0133] The above embodiments are only used to illustrate the present invention, and are not intended to limit the present invention. Ordinary technicians in the relevant technical field may make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, all equivalent technical solutions also fall within the scope of the present invention. The scope of patent protection of the present invention should be defined by the claims.

Claims

1. A method for observing and evaluating the intensity of ocean upwelling, characterized in that: The method comprises: Acquire ocean observation data from multiple stations along a straight line section in the target area; wherein the ocean observation data includes seawater temperature and salinity profile data; Preliminarily processing the ocean observation data to obtain profile distribution data of geopotential temperature and geopotential density at each station; Performing multi-point sliding average processing on the profile distribution data of the potential temperature and potential density of each station in the vertical direction to filter out noise and high-frequency signals to obtain filtered data; Based on the filtered data, plotting the distribution of cross-section salinity, potential temperature and potential density with depth; Based on the cross-section salinity, potential temperature and potential density distribution diagram with depth, marking the isolines of cross-section salinity, potential temperature and potential density; Select the area with consistent distribution of contour lines and calculate the angle between the contour lines and the horizontal line; The angle is expressed as a degree and divided by 90 degrees to perform dimensionless processing to remove data units, thereby obtaining an evaluation index for evaluating upwelling intensity; The straight section of the target area is a longitudinal section, a latitudinal section or an observation section where the sea surface observation stations are connected in a straight line; Select areas with consistent distribution of contour lines and calculate the angle between the contour lines and the horizontal line, including: Select two seawater microclusters of the same volume, which are located on the same isovalue line, have the same seawater salinity, potential temperature and potential density, and have the same mass. The potential energy of seawater microclusters is determined by the following formula: ； Where, m is the mass of seawater microclusters, g is the acceleration due to gravity, w is the vertical velocity of seawater microclusters, h To increase the height; Based on the potential energy of the seawater microclusters, the calculation formula for determining the vertical flow velocity of the seawater microclusters is: ； Based on the calculation formula of the vertical flow velocity of the seawater micro-group, the lifting height is calculated when the vertical flow velocity of the seawater micro-group is known. h ; Based on the calculated lift height h , calculate the angle between the contour line and the horizontal line using the following formula: ； Where, is the angle between the contour line and the horizontal line, is the horizontal distance between two seawater microclusters.

2. The method for observing and evaluating the intensity of ocean upwelling according to claim 1, wherein: Based on the evaluation index, the upwelling intensity is evaluated as follows: When the evaluation index is greater than 0, one side of the evaluation sea area is upwelling; When the evaluation index is less than 0, one side of the evaluation sea area is a downwelling; When the evaluation index is closer to 0 in the range of -1 to 1, the upwelling or downwelling is evaluated as weak; When the evaluation index is closer to 1 in the range of -1 to 1, the upwelling is evaluated as strong; When the evaluation index is closer to -1 in the range of -1 to 1, the downwelling is evaluated as strong.

3. The method for observing and evaluating the intensity of ocean upwelling according to claim 1, wherein: The potential temperature is calculated using the following formula: ； Where, , T is the observed seawater temperature, S is the observed seawater salinity, p is the observed seawater pressure data, is degrees Celsius, is the vertical gradient of seawater temperature.

4. The method for observing and evaluating the intensity of ocean upwelling according to claim 1, wherein: The method of performing multi-point sliding average processing on the profile distribution data of the potential temperature and potential density of each station in the vertical direction includes performing 5-point, 7-point or 9-point sliding smoothing processing in the vertical direction.

5. The method for observing and evaluating the intensity of ocean upwelling according to claim 1, wherein: Based on the filtered data, the observation data of each observation station on the observation section are horizontally interpolated in the section direction according to the interpolated depth and horizontal distance, with a horizontal resolution of 1 km, and a distribution map of section salinity, potential temperature and potential density with depth is drawn.

6. The method for observing and evaluating the intensity of ocean upwelling according to claim 1, wherein: The method of preliminarily processing the ocean observation data to obtain the profile distribution data of the potential temperature and potential density of each station includes: performing horizontal interpolation processing on the observation data of each observation station on the observation section in the section direction, with a horizontal resolution of 1 km.

7. The method for observing and evaluating the intensity of ocean upwelling according to claim 1, wherein: The following formula is used to calculate the different station positions on the section i The angle between the contour line at and the horizontal line: ； Where, For different positions i The angle between the contour line at and the horizontal line is, is the horizontal distance between two seawater microclusters, For standing position i The height at which seawater particles are lifted due to upward movement.

8. The method for observing and evaluating ocean upwelling intensity according to claim 1, wherein: For a sea area composed of multiple sections, the following formula is used to calculate the j and different positions of the cross section i The angle between the contour line at and the horizontal line: ； Where, for j cross section, i The angle between the contour line at the station and the horizontal line, for j cross section, i The horizontal distance between two seawater micro-clusters at the station, For cross section j Position i The height at which seawater particles are lifted due to upward movement.

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