Detection of Moroccan coastal upwelling fronts in SST images using the microcanonical multiscale formalism

• Algorithm for detection of thermal upwelling fronts in SST images is presented.
• The algorithm makes use of the singularity exponents.
• The singularity exponents are computed in a microcanonical framework.
• Performance of the algorithm is compared to an automatic algorithm for satellite edge detection.
• The algorithm is applied and validated by an oceanographer over 92 SST images.

Nonlinear signal processing using the Microcanonical Multiscale Formalism (MMF) is used to the problem of detecting and extracting the upwelling fronts in coastal region of Morocco using Sea Surface Temperature (SST) satellite images. The algorithm makes use of the Singularity Exponents (SE), computed in a microcanonical framework, to detect and analyze the critical transitions in oceanographic satellite data. The objective of the proposed study is to develop a helpful preprocessor that transforms SST images into clean and simple line drawing of upwelling fronts as an input to a subsequent step in the analysis of SST images of the ocean. The method is validated by an oceanographer and it is shown to be superior to that of an automatic algorithm commonly used to locate edges in satellite oceanographic images. The proposed approach is applied over a collection of 92 SST images, covering the southern Moroccan Atlantic coast of the years 2006 and 2007. The results indicate that the approach is promising and reliable for a wide variety of oceanographic conditions.