Parametric Model for Eddies‐Induced Sound Speed Anomaly in Five Active Mesoscale Eddy Regions

Mesoscale eddies are ubiquitous in the ocean. Their acoustic properties have attracted considerable research attention. However, the three‐dimensional structure for eddy‐induced sound speed anomalies has remained obscure, hindering further understanding of the impact of eddies on acoustic propagation. To solve this problem, a region‐dependent parametric model for eddy‐induced sound speed anomaly (SSA) structure is established by performing a composite analysis based on abundant profiles measured by Argo floats and the corresponding satellite altimetry data. The parametric SSA model can be applied to fast reconstruct the underwater sound speed (SS) field of the eddy based only on the intensity and radius of the eddy. A comparison with a surveyed eddy shows that the errors of the reconstructed SSA are 2.36 m/s (8.33%) in strength and 37 m (9.37%) in core depth. The reconstructed SS field is employed to study the sound propagation characteristics in the presence of a cyclonic eddy with the ray‐tracing method. The results show that the parametric model can advance eddy‐acoustic effect research in the case of observation data shortages. Plain Language Summary Mesoscale eddies are coherent rotating oceanic systems that can generate markedly different water masses from ambient water, as well as underwater sound propagation. At present, the acoustic effect of mesoscale eddies has not been exhaustively studied due to the shortage of field experiments. As a useful effort to address this problem, a region‐dependent parametric model for eddy‐induced sound speed anomalies is established on the basis of abundant profiles measured by Argo floats and sea surface observation data from satellites. The proposed model can achieve the fast reconstruction of the eddy‐induced underwater sound speed (SS) field, only requiring the surface characteristics of mesoscale eddies. The reconstructed and surveyed SSs have relatively good consistency. The work promotes the understanding of underwater sound propagation in the presence of mesoscale eddies. Key Points The region‐dependent structure of the sound speed anomaly (SSA) induced by mesoscale eddies is parametrized The three‐dimensional SSAs induced by the mesoscale eddies are reconstructed The parametric SSA model is validated through a field experiment