Using Landsat Image Series to Identify and Characterize Persistent Oceanographic Structures in a Dynamic Marine Protected Area (North of San Jorge Gulf, Argentinian Patagonia)

Abstract

Coastal oceanographic processes, like up- and downwelling, topographic fronts, etc., have consequences in biological communities. In some cases, these processes show up as surface structures observable in satellite imagery at different scales. In this work, we focus on the persistent structures observed in the coastal marine protected area of Parque Interjurisdiccional Marino-Costero Patagonia Austral (PIMCPA), one of the most relevant areas of the Argentine coast in terms of biodiversity and productivity. Using 80 Landsat-8 30 m-resolution images from the years 2017–2021, more than 20 structures were identified in the PIMCPA that appear consistently across seasons in approximately the same areas. We focus on four of them, those that are persistent and of medium scale, whose dimensions do not extend in most cases more than 10 km from their region of generation, and describe their location and shape in detail, and analyze their dependence on forcing variables such as tides, wind, bathymetry, and seasonality. Tidal currents prove to be the most significant variable in the formation and evolution of the structures described, above wind or seasonal stratification, which play only a secondary role.