Multi-segment least-square fitting method for calculating the eigenvalues of oceanic meteoroid

Abstract

The invention discloses a method for calculating the eigenvalue of the ocean jump layer by the least square fitting of multi-line segments. The method comprises the following steps: (1) establishing adata section structure model composed of four line segments A, B, C and D; (2) determining the best intersection point a, b, c of A, B, C, D segments by combining critical value and least square method; (3) according to the measured data of depth, depth difference and depth of a, b, c, the eigenvalue of oceanic jump layer, i. E. the depth, thickness and strength of jump layer, being calculated. Embodiments of the present invention show that the method can be applied to deep sea area, the thermocline inflection point of the continental shelf slope break area and the shallow sea area is accurately determined, and the described thermocline structure is in good agreement with the actual section structure. The method for calculating the thermocline eigenvalue does not need to change the thermocline evaluation standard or replace the calculation method according to the water depth, and has the characteristics of high automatic identification rate of the marine thermocline.

Description

technical field [0001] The invention relates to the field of marine scientific research and application, in particular to a calculation method for the characteristic value of the physical oceanographic layer. Background technique [0002] The cline is one of the important physical phenomena in the ocean, which has a direct impact on fishery production, marine resource development and submarine activities, and is an important part of physical oceanography research. Oceanoclines can be divided into thermoclines, haloclines, microclines and sonic layers according to the elements. In the analysis of the cline, the cline depth (D), cline strength (r) and cline thickness (H) are usually used as the characteristic values ​​to describe the cline. "Marine Survey Specifications" (GB / T 12763.7-2007) defines the eigenvalues ​​of the cline as: "The points A and B with the largest curvature on the vertical distribution curve of an element (called "inflection points" by custom) are called...

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Problems solved by technology

However, this method has two outstanding problems in practical application: (1) In deep sea areas (water depth > 200m) and shallow sea areas (water depth ≤ 200m) using two different levels of discrimination standards, which will cause the difference between shallow sea and deep sea The intersection causes the discontinuity of the cline; (2) The temperature profile data observed by CTD equipment shows that there will be multiple water layers with a vertical gradient greater than the critical value and not necessarily continuous. How to identify and merge the cline requires Human Subjective Judgment

However, this combined method of calculating the eigenvalues ​​of the cline with different methods in the deep sea area and the shallow sea area, the consistency of the results of the calculated eigenvalues ​​of the cline is questionable, and at the same time it adds the prerequisite of distinguishing the water depth, which is not conducive to the study of the cline. Automatic identification of

[0007] To sum up, there are problems in the existing calculation methods of the eigenvalues ​​of the cline, such as inconsistent evaluation criteria for shallow and deep clines, discontinuity of cline analysis results in the continental shelf slope break area, and poor automatic recognition of clines.

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