Ingrid Puillat

Algerian Eddies lifetime can near 3 years

The Algerian Current (AC) is unstable and generates mesoscale meanders and eddies. Only anticyclonic eddies can develop and reach diameters over 200 km with vertical extents down to the bottom (f3000 m). Algerian Eddies (AEs) first propagate eastward along the Algerian slope at few kilometers per day. In the vicinity of the Channel of Sardinia, a few AEs detach from the Algerian slope and propagate along the Sardinian one. It was hypothesized that AEs then followed a counter-clockwise circuit in the eastern part of the basin. Maximum recorded lifetimes were known to exceed 9 months. Within the framework of the 1-year Eddies and Leddies Interdisciplinary Study off Algeria (ELISA) experiment (1997–1998), we exhaustively tracked two AEs, using mainly an f3-year time series of NOAA/AVHRR satellite images. We show that AEs lifetimes can near 3 years, exceeding 33 months at least. We also confirm the long-lived AEs preferential circuit in the eastern part of the Algerian Basin, and specify that it may include several loops (at least three). D 2002 Elsevier Science B.V. All rights reserved.

HF Radar Activity in European Coastal Seas: Next Steps toward a Pan-European HF Radar Network

High Frequency radar (HFR) is a land-based remote sensing instrument offering a unique insight to coastal ocean variability, by providing synoptic, high frequency and high resolution data at the ocean atmosphere interface. HFRs have become invaluable tools in the field of operational oceanography for measuring surface currents, waves and winds, with direct applications in different sectors and an unprecedented potential for the integrated management of the coastal zone. In Europe, the number of HFR networks has been showing a significant growth over the past ten years, with over 50 HFRs currently deployed and a number in the planning stage. There is also a growing literature concerning the use of this technology in research and operational oceanography. A big effort is made in Europe towards a coordinated development of coastal HFR technology and its products within the framework of different European and international initiatives. One recent initiative has been to make an up-to-date inventory of the existing HFR operational systems in Europe, describing the characteristics of the systems, their operational products and applications. This paper offers a comprehensive review on the present status of European HFR network, and discusses the next steps towards the integration of HFR platforms as operational components of the European Ocean Observing System, designed to align and integrate Europe’s ocean observing capacity for a truly integrated end-to-end observing system for the European coasts.

Advanced Spectral Analysis and Cross Correlation Based on the Empirical Mode Decomposition: Application to the Environmental Time Series

In marine sciences, time series are often nonlinear and nonstationary. Adequate and specific methods are needed to analyze such series. In this letter, an application of the empirical mode decomposition method (EMD) associated to the Hilbert spectral analysis (HSA) is presented. Furthermore, EMD-based time-dependent intrinsic correlation (TDIC) analysis is applied to consider the correlation between two nonstationary time series. Four temperature time series obtained from automatic measurements in nearshore waters of the Réunion island are considered, recorded every 10 min from July 2011 to January 2012. The application of the EMD on these series and the estimation of their power spectra using the HSA are illustrated. The authors identify low-frequency tidal waves and display the pattern of correlations at different scales and different locations. By TDIC analysis, it was concluded that the high-frequency modes have small correlation, whereas the trends are perfectly correlated.

From ESONET multidisciplinary scientific community to EMSO novel European research infrastructure for ocean observation

Environmental and climate changes are crucial challenges for sustainable living because of their significant impact on the Earth system and the important consequences for natural resources. Oceans have a primary role in these changes as they regulate heat flux, greenhouse gases and climate whilst harboring many different life forms and resources. Understanding processes in the marine environment is of paramount importance for any prediction of short-, intermediate- and long-term global change.

Open-Sea Observatories: A New Technology to Bring the Pulse of the Sea to Human Awareness

Historically, observation in Marine Science was mainly based on in situ measurements made mainly over ship surveys and shore measurements. Unfortunately, ship surveys can only be episodic, and are constrained by weather and by the constant rise of ship-time cost. As the data provided by non-communicating moorings are stored in the measurement system, a ship intervention is needed to recover both the mooring and the data after several acquisition months. Further to the rather successful mediumand short-term deployment of these traditional devices, scientists have expected the development of long-term observations and permanent marine system-monitoring tools so as to gain more insight into the observed processes. By providing additional information, satellite technology can partly solve this gap between the reality and expectations. However, even though satellite images provide information over a large time frame (from minutes to years) and a wide range of spatial resolutions (from metres to thousands of kilometres), they only cover the upper layer of the sea. An Open-Sea Observatory is a complementary tool that allows one to make, in the water column and on the seafloor, long-term measurements of many environmental parameters and to acquire them in real-time, or near real-time. In addition to this real-time data transmission, these systems permit remote intervention by humans when needed, and thus can be considered as 2-way communicating devices. Because of these two characteristics, observatories are innovative systems that bring internet to the ocean and make the ocean reality visible to the human eye. According to our definition of an Open-Sea observatory, other very useful observation tools such as gliders, floats, repeated profiler transects, etc. will not be considered in this chapter to only focus on such ocean observatories. Observatory initiatives have been spreading worldwide since the 1990s. In Europe, several initiatives started twenty years ago so as to upgrade free-fall systems from the sea surface (the so-called “landers”) to make them 2-way communicating and to develop bottom

Harmonization in the joint European research infrastructure network for coastal observatories - JERICO

The JERICO European research infrastructure (RI) is integrating diverse platform types such as fixed buoys, piles, moorings, drifters, FerryBoxes, gliders, HF radars, coastal cable observatories and the associated technologies dedicated to observe and monitor coastal European seas. The first steps of setting up, coordination and harmonization were done during 2011 to 2015 in the framework of FP7-JERICO (www.jericofp7.eu), a 4-year long infrastructure project co-funded by the European Commission with 27 partners from 17 European countries under the coordination of IFREMER. Next steps are driven in the H2020-JERICO-NEXT European project until 2019, involving 33 partners. The main objective of the JERICO consortium is to establish a Pan European approach for a European coastal marine observatory network. This is a dynamic activity going beyond a projects lifetime including continuous efforts towards harmonization in terms of design, operation, and maintenance, the evolution and extension of the current systems as well as the delivery of data and products to the users. Our scope here is to present the work done towards the harmonization of operation and maintenance methods, in FP7JERICO and the next steps in JERICO-NEXT. As a starting point of harmonization assessment, the priority was given to the most pressing issues like calibration and biofouling, while it is the first time that a Best Practice report on all phases of the system from first installation to operation and maintenance is attempted adopting a platform based approach.

Application of Hilbert-Huang decomposition to temperature and currents data in the Réunion island

In marine sciences, time series are often nonlinear and nonstationary. Their analysis faces new challenges and thus requires the implementation of adequate and specific methods. We use the Hilbert-Huang Transform (HHT) for the spectral analysis of high frequency sampled time series in near shore waters of the Réunion island, located in the Indian Ocean 700 km east of Madagascar. We focus particularly on automatic measurements of sea level fluctuations, temperature records and current data sets at four different stations in the island. We look at the contribution of different Intrinsic Mode Functions (IMFs) obtained by the Empirical Mode Decomposition (EMD) and also compare the Hilbert spectra with the wavelet spectra. The inertial wave and several low-frequency tidal waves are identified by the application of EMD. Furthermore, the authors investigate the cross-correlations between data at the different stations. Wavelet coherence and EMD based Time Dependent Intrinsic Correlation (TDIC) analyses are applied to consider the correlation between two nonstationary time series. By TDIC analysis, it was concluded that the high frequency modes have small correlation; whereas the trends are perfectly correlated. The results obtained by wavelet coherence are very similar, thus confirming that both approaches could be used for identification of main properties of marine environmental time series. The methodologies presented in this paper are general and thus can be applied on other time series from the environmental and oceanic sciences, where time series are complex with fluctuations over a large range of different spatial and temporal scales, from seconds to thousands of years.

Strategy for sustainability of the Joint European Research Infrastructure Network for Coastal Observatories - JERICO

The JERICO European research infrastructure (RI) is integrating several platform types i.e. fixed buoys, piles, moorings, drifters, Ferryboxes, gliders, HF radars, coastal cable observatories and the associated technologies dedicated to the observation and monitoring of the European coastal seas. The infrastructure is to serve both the implementation of European marine policies and the elucidation of key scientific questions through dedicated observation and monitoring plans. It includes observations of the physical, chemical and biological compartments and aims at a better integration of marine biology with physical and chemical oceanology, through specific interactions with other relevant ocean observing systems that provide complementary observations. The first phase of the implementation of JERICO encompasses setting up, coordination and harmonization, and were performed between 2011 and 2015 in the framework of FP7-JERICO (www.jerico-fp7.eu), a 4-year long infrastructure project co-funded by the European Commission, with 27 partners from 17 European countries under the coordination of IFREMER. The next 4-year phase is to be carried out through the H2020-JERICO-NEXT European project, starting in 2015 and involving 33 scientific and industrial partners. The main objective of the JERICO consortium is to establish a common approach for a pan-European coastal marine observatory network. This is a dynamic and long-lasting effort necessitating continuous work towards harmonization (i.e. design, operation, and maintenance), evolution and extension of the current systems as well as the delivery of data and products to the users. Success relies on a good coordination and follow-up between FP7-JERICO and JERICO-NEXT, and onwards, at both hardware and software levels. More specifically, the existing network and its possible evolution are continuously assessed taking in account the evolution of the user needs, the harmonization effort to be driven, the existing sensors and technologies, their upgrades for integration on dedicated platforms, also the accompanying of under development sensors and/or systems with involvement of providers and stakeholders when possible. Nevertheless, a major issue relates to the sustainability of the infrastructure, both at economical and governance levels, and the capability in integrating the latest technology while preserving the scientific value of the data. This paper briefly summarizes the work carried out in FP7-JERICO project and drafts strategic aspects of the JERICO-RI sustainability on the long-term. s. We will present the 6 priority scientific areas that are the drivers of JERICO-NEXT scientific strategy and the subsequent technology development to be implemented through dedicated Joint Research Activity Projects. Emphasis is put on how the consortium intends to address long term financial and legal governance structures for the sustainable implementation of JERICO-NEXT infrastructures, as well as access to the infrastructure and associated services and link to stakeholders such as relevant funding agencies and SMEs.