A Gaussian process regression-based sea surface temperature interpolation algorithm

The resolution of ocean reanalysis datasets is generally low because of the limited resolution of their associated numerical models. Low-resolution ocean reanalysis datasets are therefore usually interpolated to provide an initial or boundary field for higher-resolution regional ocean models. However, traditional interpolation methods (nearest neighbor interpolation, bilinear interpolation, and bicubic interpolation) lack physical constraints and can generate significant errors at land-sea boundaries and around islands. In this paper, a machine learning method is used to design an interpolation algorithm based on Gaussian process regression. The method uses a multiscale kernel function to process two-dimensional space meteorological ocean processes and introduces multiscale physical feature information (sea surface wind stress, sea surface heat flux, and ocean current velocity). This greatly improves the spatial resolution of ocean features and the interpolation accuracy. The eff ectiveness of the algorithm was validated through interpolation experiments relating to sea surface temperature (SST). The root mean square error (RMSE) of the interpolation algorithm was 38.9%, 43.7%, and 62.4% lower than that of bilinear interpolation, bicubic interpolation, and nearest neighbor interpolation, respectively. The interpolation accuracy was also significantly better in off shore area and around islands. The algorithm has an acceptable runtime cost and good temporal and spatial generalizability.