Reconstruction Method of Ocean Front Model Based on Fuzzy Cluster Analysis of Sound Speed Profile

Abstract

Ocean fronts are mostly determined according to the horizontal temperature gradient, and various selection criteria may lead to different frontal zones. This study proposes a frontal zone delineation method based on sound speed profile. In this paper, the sound speed profile of the Kuroshio intrusion front in the Luzon Strait is classified via fuzzy cluster analysis based on transitive closure and fuzzy C-means algorithm. At the same time, considering that ocean fronts affect sound propagation, we verify the effectiveness of the two algorithms in terms of sound transmission loss. The results show that in different depth ranges, the effectiveness of the two algorithms differs in identifying the frontal zone. At depth below 300 m, the sound speed profile changes drastically, and fuzzy cluster analysis based on the transitive closure is more effective. At 300-700 m depth where the sound speed profile tends to be stable, the fuzzy Cmeans algorithm is more effective. At 700-1000 m depth near the SOFAR axis (the depth of the minimum sound speed), fuzzy cluster analysis based on the transitive closure is more effective. Finally, based on the sound speed profile, we combine both algorithms for the first time to obtain a three-layer geometric optimized structure of the Kuroshio intrusion front in the Luzon Strait. The classification of sound speed profiles via the two fuzzy cluster algorithms provides a new way to judge the frontal zone in different depth ranges and reconstruct geometric models of ocean fronts. INDEX TERMS Fuzzy cluster analysis, ocean front, sound speed profile, transmission loss.

Administrative Ethics Conflict and Governance of Grassroots Government Staff Under the Human Relationship Society

“…Take i = 2, j = 1 and substitute it into the formula to get f 21 = 0.839. Due to the huge amount of computation, the remaining values are calculated by C language programming, and the fuzzy similarity relationship matrix ( f αβ ) 11×11 is obtained ( Liu et al, 2021 ).…”

Ocean Front Reconstruction Method Based on K-Means Algorithm Iterative Hierarchical Clustering Sound Speed Profile

“…Considering the changing characteristics of the ocean front in different depth ranges, it is necessary to cluster sound speed profiles of the ocean front in different sea layers to reconstruct the geometric model of the ocean front, but there are few studies in this regard. Liu et al [16] divided the set of sound speed profiles of the Luzon Strait into three layers and clustered the sound speed profiles of each layer to reconstruct the three-layer structure of the Kuroshio intrusion front (KIF). Although it is a layered reconstruction method for the ocean front, the number of layers is fixed at the beginning, that is, the layering principle is not fully considered, so the results are completely related to the initial value of layering, and there is no means to optimize the layering through iteration.…”