Affiliation:
1. Department of Applied Physics, Faculty of Marine and Environmental Sciences, Marine Research Institute (INMAR), International Campus of Excellence of the Sea (CEI-MAR), University of Cadiz, 11510 Cadiz, Spain
2. Plataforma Oceánica de Canarias, 35214 Telde, Spain
Abstract
The Antarctic Intermediate Water (AAIW), one of the most important global intermediate water masses, spreads over the world ocean. Its propagation limit at the Northeast Subtropical Atlantic is characterized by its encounter with the Mediterranean Water (MW), which presents dissimilar thermohaline properties. Previous studies of the AAIW in this region have been based on traditional oceanographic cruise observations, which were later complemented by observations using autonomous systems such as ARGO floats. However, these observations present limitations for the study of processes occurring at mesoscale and smaller scales. In this study, we used high-resolution observations made by cutting edge platforms such as underwater gliders. Specifically, a meridional glider section realized in spring 2016 between the islands of Madeira and Gran Canaria has been used. The temperature, salinity and dissolved oxygen minima have allowed the detection of the AAIW signal north of the Canarian archipelago and significantly westward from its main northward propagation pathway in this region. The results of this work have shown that the encounter of AAIW and MW generates thermohaline intrusions or interleaving layers. It is suggested that double diffusion processes may play a role in the development of these structures, which may be important for water masses mixing and, therefore, in determining the northward spreading boundary of AAIW. The use of the high-resolution glider observations combined with other data products is essential for the study of water masses and dynamics when relevant processes have a wide range of scales.
Funder
Optimising and Enhancing the Integrated Atlantic Ocean Observing Systems (AtlantOS) project
Vulnerability of Littoral Cultural Heritage to environmental agents: impact of Climate Change (VOLICHE) project
Subject
Ocean Engineering,Water Science and Technology,Civil and Structural Engineering