A New Upwelling Index for the Moroccan Atlantic Coast for the Period between 1982-2021

Being a component of the Eastern Boundary Upwelling (EBU) ecosystem, Morocco's Atlantic coast presents high biological production throughout the year, with seasonal variations in upwelling dynamics. This characterization reflects the inherent nature of EBU's ecosystems. In this work, we develop a novel methodology to compute a new upwelling index based on the analysis of sea surface temperature (SST) images. Our new upwelling index is not only simple to calculate but also efficient. Indeed, it is limited only to the upwelling region, which has allowed the improvement of the quantification and analysis of the seasonal and interannual variability of the upwelling dynamics. The new proposed upwelling index is based on the application of a recent segmentation method that allows for the monitoring of upwelling dynamics using satellite observations. The proposed upwelling index is applied to a 40-year database of weekly SST images covering the period from 1982 to 2021, and the results are used to analyze seasonal and interannual variations of the upwelling in the region.

Automated summary

This article introduces the seasonal variations in upwelling dynamics along Morocco's Atlantic coast and develops a new methodology to compute an upwelling index based on sea surface temperature analysis. The proposed index is simple, efficient, and improves the analysis and quantification of seasonal and interannual variations.