Fine-scale sea surface temperature fronts in wintertime in the northern South China Sea

Abstract

This study presents finer structures and inter-seasonal evolutions of sea surface temperature (SST) fronts in wintertime in the northern South China Sea (SCS) by applying an entropy-based edge detection method to 7-year (2001–2007) satellite-derived SST images with a grid size of 1 km. From monthly mean maps of SST front, six significant SST fronts were defined in the northern SCS. This study not only reveals the earlier defined frontal bands, but also provides finer structures and gradient variability of the fronts. One front alongside Luzon Island (the Philippines), which was undetected by a gradient-based method in previous studies, is well defined by the entropy-based method used in the present study. This result suggests that the gradient-based method might not be appropriate for front detection in coastal waters or marginal seas, but using SST data of lower spatial resolution SST data might not be suitable to describe the detailed structure of short or small fronts through the sophisticated edge detection methods.