Abstract: This study reconstructs the three-dimensional dynamic temperature field in the Northwest Pacific Ocean using high-resolution satellite sea surface data and historical ocean temperature and salinity profile data based on the variational method. Compared to the Argo (Array for Real-time Geostrophic Oceanography) temperature profiles, the reconstructed temperature field effectively reproduces the vertical distribution of seawater temperature, particularly in the thermocline region, where the reconstructed results closely match the actual observed temperature profiles. Two typical mesoscale eddy cases were selected for analysis, where the reconstructed temperature field was used to examine the entire evolution process of the eddies, from generation to decay, and to display the dynamic changes in the vertical and horizontal distribution of temperature anomalies induced by the eddies. In particular, during the mature stage of the eddies, the intensity and vertical extent of the temperature anomalies reach their maximum, reflecting the significant impact of the eddies on the oceanic thermocline. By analyzing the distribution of temperature anomalies at different stages, the study reveals the evolution of the spatial structure of cold and warm cores and the anomalous regions. The results show that the method can effectively utilize satellite sea surface observations to reconstruct the underwater temperature structure and dynamic evolution of mesoscale eddies, providing valuable data support for understanding the role of mesoscale eddies in oceanic material and heat transport.

Key words: Variational Method, Three-Dimensional Temperature Structure, Mesoscale Eddy, Satellite Sea Surface information