Events

Turbulència de submesoescala a la capa de barreja

16 February 2018
12:15
Location: 
Sala d'Actes
Given by: 
Dr. Jordi Isern-Fontanet
Position at: 
Departament d'Oceanografia Física i Tecnològica, Institut de Ciències del Mar

Resum

Satellite infrared radiometers have unveiled the existence of distinct turbulence regimes in the upper ocean. These regimes have different contributions on the vertical transport of nutrients, heat, and climatically important gases between the oceanic upper layers and the ocean interior; and contain information about the dynamics in the mixed layer. The main difficulty is to define descriptors able to univocally identify such turbulence regimes and quantify the dynamical characteristics of the upper ocean. In this study, we have investigated the capability of different descriptors to characterize turbulence regimes from the observations of infrared Sea Surface Temperatures (SST) provided by the AATSR sensor (Envisat). First, data have been divided into granules adapted to the observed cloud coverage with a maximum size of 512 by 512 pixels (i.e. 512 km by 512 km). These granules have been classified into two groups: one characterized by the presence of submesoscale instabilities (∼ 5-10 km) and one characterized by the presence of vortices and filaments. Then, for all the granules of each group we have explored the statistical and geometrical properties of SST using spectral analysis and the curvature of SST fronts completed with the analysis of the multifractal properties of SST images obtained from singularity analysis. Results have shown that both groups of images were characterized by similar spectral slopes. On the contrary, the characteristics of the singularity spectra of both groups were different indicating different inttermitencies and allowing to identify the distinct dynamical regimes.

 

Breu biografia

Jordi Isern Fontanet (Banyoles 1975, Catalonia) is a ComFuturo researcher. He graduated in Physics at Universitat de Barcelona. He developed his PhD at the Institut de Ciències del Mar (CSIC) and get his PhD in Applied Physics from the Universitat Politècnica de Catalunya in 2003. JIF was enroled as a postdoctoral scientist in the Laboratoire de Physique des Océans (Ifremer, 2005-2006) funded by a Spanish grant from the Spanish Ministry of Science and in the Laboratoire d’Ocenographie Spatiale (Ifremer, 2006-2008) funded by a Marie Curie Grant (EIF, FP6). In 2008 he got a Ramón y Cajal contract from the Spanish Ministry of Science and joined the Institut Català de Ciències del Clima in Barcelona, where he led the Ocean Dynamics and Climate group. In October 2014 he joined the Institut de Ciències del Mar (CSIC). His main interests are the dynamics of the ocean's upper layers, the characterization of ocean turbulence, the quantification of the associated horizontal and vertical fluxes and the understanding of their role in Earth's climate. To this end the approach he mainly follows consists on the systematic application of recent theoretical results to ocean and atmospheric observations such as remote sensing data. This approach is complemented with the analysis of numerical simulations. In addition to his interest on general processes, he is very interested in the understanding of the Mediterranean area.