Exploiting oceanographic satellite data to study the small scale coastal dynamics in a NE Atlantic open embayment

An approach to the processing and analysis of oceanographic satellite data is presented suitable for its use in coastal areas. Satellite images of a small (300 km2) open embayment in the NW of the Iberian Peninsula (Seno de Corcubión) are used to study a decade of time series of three important oceanographic variables: sea surface temperature (SST), chlorophyll a concentration ([Chlo]) and turbidity (K490). Their interannual and seasonal trends, together with the regional variability, are assessed using a Generalized Linear Model (GLM). We identify seasonal upwelling–downwelling processes, on top of interannual trends that show that coastal dynamics is not directly driven by the oceanic trend. To study spatial patterns the study area was divided in subareas; these subareas show significant differences among them in seasonal as well as in interannual scales. Using this information, some oceanographic hypotheses were tested based on the statistical significance of the variable residual dependencies: a possible relationship between SST and turbidity (found to be not significant in the study area), and the presence of short-term upwelling events reported by other researchers in this geographical region (not found statistically significant either). A database and an oceanographic atlas summarizing all the information used in the analyses have been generated and can be freely visualized online and downloaded.

Research highlights►This work shows how oceanographic satellite images can be used to study coastal areas ►GLMs are used in a spatiotemporal study using satellite derived SST, [Chlo] and K490 ►GLM reports an SST negative trend caused by local sea dynamics in the coastal area ►GLM describes seasonal upwelling events that exist in the surrounding coastal areas ►Statistical tests discard any increase of SST due to turbidity in this area