CN-121997791-A - Identification method of offshore ocean front based on Lagrange particle statistics

Abstract

The invention provides a method for identifying a near-shore ocean front based on Lagrangian particle statistics, which belongs to the technical field of marine environment numerical simulation and comprises the steps of constructing a target sea area hydrodynamic model to simulate a water body flowing state, tracking Lagrangian particles according to the constructed target sea area hydrodynamic model to obtain distribution information of the particles in time and space, analyzing relative dispersion of the obtained distribution information of the particles in time and space, counting and analyzing the change characteristics of the particles in time to obtain the spatial distribution characteristics of the relative dispersion, and identifying and calibrating the position of the ocean front by utilizing the spatial distribution characteristics of the relative dispersion. The invention combines Lagrange particle tracking technology with relative dispersion analysis, is used for identifying front structures such as near-shore promontory front, river mouth front, land frame front and the like, and realizes accurate prediction and identification of ocean front.

Inventors

• SONG CHUNYAN
• ZHANG QIONG
• CHEN YONG
• XI QI
• XIU CHANGJUN
• SHI XIAN
• LI LI
• LI YUAN
• GUO RUIQING

Assignees

• 中国石油化工股份有限公司
• 中国石油化工股份有限公司胜利油田分公司

Dates

Publication Date

20260508

Application Date

20241108

Claims (10)

1. 1. A method for identifying an offshore ocean front based on lagrangian particle statistics, the method comprising: constructing a target sea area hydrodynamic model to simulate the water body flowing state; Carrying out Lagrange particle tracking according to the constructed target sea area hydrodynamic model, and obtaining the distribution information of particles in time and space; Carrying out relative dispersion analysis on the acquired distribution information of the particles in time and space, and counting and analyzing the change characteristics of the particles along with time to acquire the spatial distribution characteristics of the relative dispersion; And identifying and calibrating the position of the ocean front by utilizing the spatial distribution characteristics of the relative dispersion.
2. 2. The method of claim 1, wherein constructing a target sea area hydrodynamic model to simulate a water flow state comprises constructing a target sea area hydrodynamic model based on FVCOM.
3. 3. The method of identifying a near shore ocean front based on lagrangian particle statistics according to claim 2, wherein the target sea area hydrodynamic model employs Sigma coordinates.
4. 4. The method of identifying a near shore ocean front based on lagrangian particle statistics according to claim 1, wherein said lagrangian particle tracking based on the constructed target sea area hydrodynamic model comprises employing the following formula as the equation of motion of particles in a flowing body of water: where x represents the position vector of the particle at time t and u (x, t) is the velocity vector.
5. 5. The method of claim 4, wherein the step of performing lagrangian particle tracking based on the constructed target sea hydrodynamic model comprises approximating an update of particle positions using a fourth-order lagrangian-base method: wherein the particles are in time The position of (2) is The particles are at The position of (2) is 。
6. 6. The method of claim 1, wherein the relative dispersion analysis for the acquired distribution information of the particles in time and space comprises constructing a relative dispersion field.
7. 7. The method of claim 6, wherein the relative dispersion field is calculated by the following formula: Wherein, the For the initial moment of the release of the particles, Representing the time interval over which the device is to be operated, Is that Time particle At the position where the water is to be located, Is at Time of day , , , The particle is located.
8. 8. The method of claim 7, wherein forward integration of the constructed relative dispersion field generates a forward relative dispersion field and backward integration of the constructed relative dispersion field generates a backward relative dispersion field.
9. 9. The method of claim 1, wherein using the spatial distribution characteristics of the relative dispersion to identify and scale the location of the ocean front comprises using a Canny image edge detection algorithm to identify the location of the ocean front.
10. 10. The method for identifying a near shore ocean front based on lagrangian particle statistics of claim 9, wherein the identifying the location of the ocean front using the Canny image edge detection algorithm comprises: preprocessing to remove noise; calculating gradients to obtain the intensity and direction of the pixel gradients; performing non-maximum suppression and thinning edges; Threshold detection is carried out, and strong and weak edges are distinguished; trailing edge tracking, connecting edge segments.

Description

Identification method of offshore ocean front based on Lagrange particle statistics Technical Field The invention relates to the technical field of marine environment numerical simulation, in particular to a method for identifying a near-shore ocean front based on Lagrange particle statistics. Background Ocean fronts refer to narrow transition zones between two or more bodies of water that differ significantly in characteristics, which can be described by the horizontal gradients of elements such as temperature, salinity, density, color, chlorophyll, etc. Common ocean fronts are estuary fronts, shallow sea fronts, rising fronts, land frame slope fronts, and west boundary fronts. Particularly, the composite material is applied to coastal fronts, cape heads, base fronts and the like in offshore, has important application in a plurality of fields such as offshore fishery, marine environment protection and the like, and is widely paid attention by people in the marine field. The identification technology of the ocean front mainly comprises the following steps: First, spatial distribution of environmental elements is obtained by remote sensing or field survey data, whereby concentration gradients of the environmental elements are analyzed to determine the location and intensity of the front. However, satellite remote sensing and marine surveys have limitations in space-time resolution, and it is difficult to capture small-scale or fine fronts. Second, the frontal dynamics can be better explored by numerical modeling techniques. For example, liu et al （Variation in the Current Shear Front and its Potential Effect on Sediment Transport Over the Inner Shelf of the East China Sea in Winter[J].Journal of Geophysical Research: Oceans, 2018, 123）, in combination with observation and numerical modeling methods, studied the characteristics of the ocean current shear front of the east Asian inland frame, the mechanism of change and its potential impact on water and sand transport and the muddy area of the inland frame. For ocean front detection or prediction, in the prior art, as CN117217073A discloses a method for extracting a front of a black tide extension body below the sea surface and a method for calculating, predicting and analyzing the trend of the front, the problem of accurately extracting the front of the black tide extension body front is solved, as CN113484860A discloses a method and a system for detecting the ocean front of an SAR image based on Doppler central abnormality in liquid, the speed characteristics of the ocean front are fully utilized, the problems of ocean front detection and false detection based on amplitude images are solved, the accuracy of ocean front detection of the SAR image is improved, and CN114187553A discloses a ocean front detection method for fusing scSE and Mask R-CNN networks. Current detection or prediction techniques for ocean fronts are based primarily on the perception of the spatial-temporal distribution of environmental elements and determine the ocean fronts as gradients of the environmental elements. However, these techniques have certain limitations in identifying small-scale ocean fronts, and it is difficult to accurately obtain small-scale environmental element distributions, so that the frontal phenomenon is difficult to detect. The nature of the ocean front determines the tendency of matter to accumulate near the front, and the ocean front forms a barrier to the transport of matter across the front. Thus, the ocean front can be revealed by statistics of the mass transport path. The Lagrange particle tracking method is used as a research means of marine substance transportation, and can quickly and effectively identify marine phenomena by simulating and tracking the track and behavior of particles near a ocean front. In recent years, statistical analysis based on Lagrangian particle trajectories has been actively advanced in revealing ocean flow dynamics, mass transfer mechanisms, mixing processes, and the like. The method can be divided into single particle statistical analysis, double particle statistical analysis and multi-particle statistical analysis according to the number difference of particles in an analysis and statistics unit. Therefore, how to effectively identify the offshore ocean front according to Lagrange particle statistics in a targeted manner is a technical problem to be solved urgently. Disclosure of Invention Aiming at the problems, the invention provides a method for identifying the offshore ocean front based on Lagrangian particle statistics in order to improve the accuracy and speed of identifying the ocean front. The invention provides a method for identifying a near-shore ocean front based on Lagrange particle statistics, which comprises the following steps: constructing a target sea area hydrodynamic model to simulate the water body flowing state; Carrying out Lagrange particle tracking according to the constructed target sea area hydrodyna