Subsurface circulation and mesoscale variability in the Algerian subbasin from altimeter-derived eddy trajectories

Algerian eddies are the strongest and largest propagating mesoscale structures in the Western Mediterranean Sea. They have a large influence on the mean circulation, water masses and biological processes. Over 20 years of satellite altimeter data have been analyzed to characterize the propagation of these eddies using automatic detection methods and cross-correlation analysis. We found that, on average, Algerian eddy trajectories form two subbasin scale anticlockwise gyres that coincide with the two Algerian gyres which were described in the literature as the barotropic circulation in the area. This result suggests that altimetry sea surface observations can provide information on subsurface currents and their variability through the study of the propagation of deep mesoscale eddies in semienclosed seas. The analysis of eddy sea level anomalies along the mean pathways reveals three preferred areas of formation. Eddies are usually formed at a specific time of the year in these areas, with a strong interannual variability over the last 20 years.This work was supported by LaCaixa fundation through the MedClic project. The SLA data were generated by DUACS and distributed by AVISO (ftp://ftp.aviso.oceanobs.com).Peer Reviewe

Heavy Guadalquivir River discharge detection with satellite altimetry: The case of the eastern continental shelf of the Gulf of Cadiz (Iberian Peninsula)

© 2015 COSPAR. Published by Elsevier Ltd. All rights reserved. In situ water levels in the Guadalquivir River estuary mouth show the effect of strong river freshwater discharges on the monthly means of the sea level on a yearly basis. Accurate altimeter products oriented toward coastal zones are increasing the number of potential applications at different spatiotemporal scales. The present work is focused on the analysis of the sea-level variability in the eastern shelf of the Gulf of Cadiz (between North Africa and the southwestern side of the Iberian Peninsula), adjacent to the Guadalquivir River estuary. Sixteen years (1994-2009) of along-track and standard AVISO maps of sea-level anomalies (SLAs) have been used to generate a new high-resolution product with increased spatiotemporal resolution. The use of a bathymetry constraint and smaller correlation scales in the methodology developed to generate high-resolution altimeter products improves the characterization of the mesoscale signals in the coastal strip adjacent to the estuary due to strong river freshwater discharges. This has been confirmed by the analysis of along-track SLA data in the vicinity of the estuary. The daily evolution (2 weeks) of the sea level obtained in the event of December 2009 might be related to the river plume extension observed by optical Moderate Resolution Imaging Spectrometer (MODIS) images. The spatiotemporal distribution of the altimeter tracks available in the study area might compromise the mapping capabilities to capture coastal and fine-scale features.This work has been partially supported by the ALCOVA Project (CTM2012-37839) funded by the Spanish Ministerio de Economía y Competitividad and FEDERPeer Reviewe

Design of experiments

Design of numerical experiments assimilating in situ physical and BGC observations to assess and enhance their impact in CMEMS ocean monitoring and forecasting systems

On the seasonality of eddies in the Western Mediterranean Sea: answers with altimetry and modeling.

Trabajo presentado en la EGU General Assemby 2013, celebrada del 7 al 12 de abril de 2013 en Viena (Austria)Eighteen years of weekly SLA merged maps in the Western Mediterranean are analyzed using the new method proposed by Chelton et al. (2011) to identify and track mesoscale eddies. The method has been adapted to take into account the specificity of the Mediterranean basin. Results are similar to the global ocean results with a radius smaller due to a smaller Rossby radius. The areas of intense rotational speed and amplitude of eddies are similar to the areas of intense eddy kinetic energy calculated from altimetry sea level anomalies. Eddies propagation speed shows a wide range of values without a clear preferred direction. Nevertheless, eddies seems to propagate following the main currents. Temporal analysis of the number of eddies per day is made focusing on the annual and semiannual variability. This annual and semi-annual cycle is analyzed using a regional model of the Mediterranean Sea and studying the interaction with atmospheric forcingsPeer reviewe

The Mediterranean analysis and forecasting physical system for the Copernicus Marine Service: description and skill assessment

The Mediterranean Analysis and Forecasting System is a numerical ocean prediction system that operationally produces analyses and 10 days forecasts of the main physical parameters for the entire Mediterranean Sea and its Atlantic Ocean adjacent areas. The system is composed by the hydrodynamic model NEMO (Nucleus for European Modelling of the Ocean) 2-way coupled with the third-generation wave model WW3 (WaveWatchIII) and forced by ECMWF (European Centre for Medium-range Weather Forecasts) atmospheric fields. The forecast initial conditions are produced by a 3D variational data assimilation system which considers a daily assimilation cycle of Sea Level Anomaly, vertical profiles of Temperature and Salinity from ARGO and ship CTDs and heat flux corrections with satellite SST. The system has been recently upgraded in the framework of the Copernicus Marine Environment Monitoring Service (CMEMS) by increasing the grid resolution from 1/16 to 1/24 degree in the horizontal, thus becoming fully mesoscale resolving and from 72 to 141 vertical levels, by increasing the number of fresh water river inputs and by updating the data assimilation scheme. The model has a non-linear explicit free surface and the forecast is forced by surface pressure, interactive heat, momentum and water fluxes at the air-sea interface. The focus of this work is to present the latest modeling system upgrades and the related improvements achieved by showing the model skill assessment including comparison with independent (insitu coastal moorings) and quasi-independent (insitu vertical profiles and satellite) datasets.PublishedHalifax, Nova Scotia, Canada4A. Oceanografia e clim

Mediterranean Sea Analysis and Forecast (CMEMS MED-Currents 2016-2019)

INGVPublished4A. Oceanografia e clim

Mediterranean Sea Analysis and Forecast (CMEMS MED-Currents 2016-2019)

Copernicus Marine Environment Monitoring ServicePublished4A. Oceanografia e clim

Medclic: the Mediterranean in one click

Medcli