Pierre De Mey-Frémaux

Pierre De Mey-Frémaux
French National Centre for Scientific Research | CNRS · LEGOS

Ph.D.

About

131
Publications
20,609
Reads
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2,730
Citations
Citations since 2016
22 Research Items
866 Citations
2016201720182019202020212022050100150
2016201720182019202020212022050100150
2016201720182019202020212022050100150
2016201720182019202020212022050100150
Additional affiliations
January 1985 - present
French National Centre for Scientific Research
Position
  • Directeur de Recherches
January 1985 - present
Laboratoire d'Etudes en Géophysique et Óceanographie Spatiales
Position
  • Directeur de Recherches
February 1983 - December 1984
Harvard University
Position
  • PostDoc Position
Education
September 1980 - January 1983
Sorbonne Université
Field of study
  • Ocean sciences
October 1977 - June 1980
Ecole Nationale des Ponts et Chaussées
Field of study
  • Civil engineering
September 1975 - June 1977
Lycée Faidherbe
Field of study
  • Classes préparatoires aux Grandes Ecoles

Publications

Publications (131)
Article
Full-text available
We study the daily to interannual variability of the Red River plume in the Gulf of Tonkin from numerical simulations at high resolution over 6 years (2011–2016). Compared with observational data, the model results show good performance. To identify the plume, passive tracers are used in order to (1) help distinguish the freshwater coming from diff...
Article
The regional and coastal ocean, as a complex interface area where land, hydrology, atmosphere, and ocean interact, concentrates a wide range of actors dealing with increasing socioeconomic and environmental issues. Under the pressure of the impacts of climate change, forecasting the coastal ocean remains a key challenge. The International Coastal...
Article
In this article, Part 1 of a two-part series, we run and evaluate the skill of a regional physical-biogeochemical stochastic ocean model based on NEMO. The domain covers the Bay of Biscay at 1/36° resolution, as a case study for open-ocean and coastal shelf dynamics. We generate ensembles of uncertainties from assumptions related to errors in the a...
Article
In this Part 2 article of a two-part series, observations based on satellite missions were used to evaluate the empirical consistency of model ensembles generated via stochastic modelling of ocean physics and biogeochemistry. A high-resolution Bay of Biscay configuration was used as a case study to explore the model error subspace in both the open...
Poster
Full-text available
The representation of ocean model errors is required in ensemble-based data assimilation methods. In this study, we assess ocean model uncertainties in a high-resolution Bay of Biscay configuration, using atmospheric ensembles and stochastic ocean simulations. The atmospheric ensemble consists of 50 members produced by the European Centre for Mediu...
Article
We downscaled a free ensemble of a regional, parent model to a high-resolution coastal, child ensemble in the Bay of Biscay. The child ensemble was forced at the open boundaries by the parent ensemble, and locally by perturbing the winds. By comparing ensembles generated by each of these forcings perturbations separately and combined we were able t...
Poster
Full-text available
Monitoring and Predicting Regional to Coastal Sea Level: Towards Comprehensive Observing and Modeling Systems
Article
Full-text available
Operational oceanography can be described as the provision of routine oceanographic information needed for decision-making purposes. It is dependent upon sustained research and development through the end-to-end framework of an operational service, from observation collection to delivery mechanisms. The core components of operational oceanographic...
Article
Full-text available
Operational oceanography can be described as the provision of routine oceanographic information needed for decision-making purposes. It is dependent upon sustained research and development through the end-to-end framework of an operational service, from observation collection to delivery mechanisms. The core components of operational oceanographic...
Article
Full-text available
A major challenge for managing impacts and implementing effective mitigation measures and adaptation strategies for coastal zones affected by future sea level (SL) rise is our limited capacity to predict SL change at the coast on relevant spatial and temporal scales. Predicting coastal SL requires the ability to monitor and simulate a multitude of...
Article
Full-text available
Integration of observations of the coastal ocean continuum, from regional oceans to shelf seas and estuaries/deltas with models, can substantially increase the value of observations and enable a wealth of applications. In particular, models can play a critical role at connecting sparse observations, synthesizing them, and assisting the design of ob...
Article
Full-text available
We generate ocean biogeochemical model ensembles including several kinds of stochastic parameterizations. The NEMO stochastic modules are complemented by integrating a subroutine to calculate variable anisotropic spatial scales, which are of particular importance in high-resolution coastal configurations. The domain covers the Bay of Biscay at 1/36...
Article
This paper reviews the historical development of concepts and practices in the science of ocean predictions. It begins with meteorology, which conducted the first forecasting experiment in 1950, followed by wind waves, and continuing with tidal and storm surge predictions to arrive at the first successful ocean mesoscale forecast in 1983. The work...
Article
Full-text available
In parallel to the ever increasing activities and population in the coastal regions, and to the critical growth of the associated stresses on the coastal environment, the need for monitoring and forecasting of currents and marine parameters in the coastal and shelf seas is becoming more pressing (e.g. De Mey et al. 2009; De Mey and Kourafalou 2014)...
Conference Paper
Full-text available
Ocean model uncertainties arise on a range of spatiotemporal scales from the formulation of forecast models themselves and erroneous surface-lateral boundary forcings. In the past two decades, successful applications of advanced ocean data assimilation methods have led to an increased interest in their estimation. This study is based on a Copernicu...
Poster
Full-text available
The work is based on stochastic modelling of ocean physics and biogeochemistry in the Bay of Biscay, on an identical sub-grid configuration of the IBI-MFC system in its latest CMEMS operational version V2.
Article
Designing optimal observation networks in coastal oceans remains one of the major challenges towards the implementation of future efficient Integrated Ocean Observing Systems to monitor the coastal environment. In the Bay of Biscay and the English Channel, the diversity of involved processes (e.g. tidally-driven circulation, plume dynamics) require...
Article
In this paper, the adaptive filtering theory, recently proposed and developed the authors of present work [1-9] for stochastic, encountered in the field of data as simulation in meteorology and oceanography, is reviewed. Several important questions on numerical estimation og the gain matrix, model reduction, structural choices for the gain, filter...
Article
In the Bay of Biscay and the English Channel, in situ observations represent a key element to monitor and to understand the wide range of processes in the coastal ocean and their direct impacts on human activities. An efficient way to measure the hydrological content of the water column over the main part of the continental shelf is to consider shi...
Article
A twin-experiment is carried out introducing elements of an Ensemble Kalman Filter (EnKF), to assess and correct ocean uncertainties in a high-resolution Bay of Biscay configuration. Initially, an ensemble of 102 members is performed by applying stochastic modelling of the wind forcing. The target of this step is to simulate the envelope of possibl...
Article
Full-text available
The marine environment plays an increasingly important role in shaping economies and infrastructures, and touches upon many aspects of our lives, including food supplies, energy resources, national security and recreational activities. Global Ocean Data Assimilation Experiment (GODAE) and GODAE OceanView have provided platforms for international co...
Article
Full-text available
The value of global (e.g. altimetry, satellite sea-surface temperature, Argo) and regional (e.g. radars, gliders, instrumented mammals, airborne profiles and biogeochemical) observation-types for monitoring the mesoscale ocean circulation and biogeochemistry is demonstrated using a suite of global and regional prediction systems and remotely-sensed...
Article
Full-text available
Recent advances in Coastal Ocean Forecasting Systems (COFS) are discussed. Emphasis is given to the integration of the observational and modeling components, each developed in the context of monitoring and forecasting in the coastal seas. These integrated systems must be linked to larger scale systems toward seamless data sets, nowcasts and forecas...
Article
Full-text available
The advancement of Coastal Ocean Forecasting Systems (COFS) requires the support of continuous scientific progress addressing: (a) the primary mechanisms driving coastal circulation; (b) methods to achieve fully integrated coastal systems (observations and models), that are dynamically embedded in larger scale systems; and (c) methods to adequately...
Article
This study aims to explore the robustness of the mixed-layer heat budget as estimated from an eddy-permitting model with respect to uncertainties in atmospheric forcing. We illustrate how statistics from an ensemble can be used in a first step towards the calculation of error bars of any simulated quantity, such as the mixed-layer heat budget. The...
Conference Paper
Full-text available
In this study, a Data Assimilative (DA) twin experiment is implemented with the aim to provide the "best" estimate of the coastal ocean state via ensemble methods. The work uses a coastal configuration of NEMO in the Bay of Biscay, following the activities of LEGOS/CNRS and Mercator Ocean teams within the European MyOcean2 project. In a first step,...
Article
This study is aimed at exploring the errors of a regional model of the Bay of Biscay, a regional zoom of the IBI configuration of the ocean model NEMO, with the ultimate objective of guiding the choice and implementation of a data assimilation system in that region. An ensemble experiment was carried out by randomly perturbing winds along a base of...
Chapter
Full-text available
Starting in the mid-2000s, GODAE (Global Ocean Data Assimilation Experiment) fully embraced the importance of coastal ocean “intermediate users” for coastal applications. To address this need, the Coastal and Shelf Seas Working Group (CSSWG, 2006-2008) was established with the mission to bridge global and coastal prediction strategies by quantifyin...
Conference Paper
Full-text available
An important factor of any Data Assimilation (DA) scheme is the estimation of the background error covariances. This study is linked to the design of a DA system, based on the ensemble Kalman Filter and the ocean model NEMO. The work is part of the Research and Development activities of LEGOS/CNRS and Mercator-Ocean French teams within the European...
Article
Full-text available
This work describes the design and validation of a high-resolution (1/36 •) ocean forecasting model over the "Iberian–Biscay–Irish" (IBI) area. The system has been set-up using the NEMO model (Nucleus for European Modelling of the Ocean). New developments have been incorporated in NEMO to make it suitable to open-as well as coastal-ocean modelling....
Article
Full-text available
The Iberia-Biscay-Ireland (IBI) system serves one of the 7 MyOcean "Monitoring and Forecasting Centres". A high resolution simulation covering the IBI region is set-up over July 2007–February 2009. The NEMO (Nucleus for European Modelling of the Ocean) model is used with a 1/36° horizontal resolution and 50 z-levels in the vertical. New development...
Article
At present, several high-resolution models are widely used in coastal ocean configuration with prediction purposes. In this context the choice of the ad hoc data assimilation (DA) method, that will ensure the "best" estimate of the ocean state through a combination of model forecast and observations, is decisive and it needs to be assessed on a cas...
Article
Full-text available
A high resolution simulation covering the Iberia–Biscay–Ireland (IBI) region is set-up over July 2007–February 2009. The NEMO model is used with a 1/36° horizontal resolution on 50 z -levels in the vertical. It is forced by the astronomical potential and atmospheric forcing fields which consist of 3-hourly ECMWF analyses. Initial hydrographic condi...
Article
Full-text available
Eddy properties in the Bay of Biscay are studied from 15 years of reprocessed along-track altimeter data using a wavelet-based analysis. Associated spatial scales vary from 60 km in the inner bay to 130 km offshore, with amplitudes also increasing offshore. These characteristics are not correctly represented in standard gridded products, which are...
Chapter
Full-text available
Altimetry missions in the last 16 years (TOPEX/Poseidon, ERS-1/2, GFO, Jason-1 and ENVISAT) and the recently-launched Jason-2 mission have resulted in great advances in deep ocean research and operational oceanography. However, oceanographic applications using satellite altimeter data have become very challenging over regions extending from near-sh...
Article
The structure and dynamics of errors in a 3D coastal model of the Catalan sea is characterized through stochastic modelling. Wind forcing and large scale circulation are identified as the main sources of model errors. Ensemble simulations perturbing the wind field and the model initial and open boundary conditions are performed. The dispersion of m...
Conference Paper
As a first step towards the set-up of a data assimilation system based on the Ensemble Kalman Filter (EnKF), we explore the space-time structure of the influence functions of sea surface temperature (SST) observations using stochastic modeling. Our ultimate goal is to constrain our ocean circulation model with high resolution SST products and altim...
Article
Full-text available
During the Global Ocean Data Assimilation Experiment (GODAE), numerical modeling and prediction in coastal and shelf seas benefited from development of state-of-the-art, data-assimilative, and data-validated large-scale models that can supply initial and boundary conditions to nested domains. Rather than attempting an exhaustive synthesis, this art...
Article
Full-text available
The development of coastal ocean modeling in the recent years has allowed an improved representation of the associated complex physics. Such models have become more realistic, to the point that they can now be used to design observation networks in coastal areas, with the idea that a “good” network is a network that controls model state error. To t...
Article
Full-text available
The impact of errors in atmospheric forcing on the behaviour of ocean models is a fundamental issue for ocean modellers and data assimilation and one that has yet to be fully addressed. In this study, we use a stochastic modelling approach with 50 7-months (September–March) primitive equation eddy permitting (1/4°) integrations. We investigate the...
Article
We propose a set of methodologies to test the performance of observational networks at measuring coastal ocean processes and constraining them in models. Ocean models in coastal areas have become more realistic, to the point that they can now be used to design observation networks, with the idea that a "good" network is a network that controls mode...
Article
Full-text available
The authors investigate the potential qualitative improvement brought by wide-swath, interferometry-based ocean altimetry measurements with respect to classical nadir altimeters in a coastal/shelf data assimilation system. In addition, particular attention is paid to roll errors, which could significantly reduce the expected benefits of wide-swath...
Article
Full-text available
The next decade will spawn new research activities that will build on the success of GODAE. The grand vision and key research challenge is to develop coupled initialisation systems of numerical weather prediction and eddy-resolving ocean models. These systems will contribute to and benefit from recent progress in earth systems modelling. With incre...
Conference Paper
Full-text available
The study presented here aims to assess the capabilities and the limits of the use of the GOCE geoid to improve the shelf and coastal ocean low frequency circulations. The approach consists in using advanced data assimilation techniques (namely, the Ensemble Kalman Filter analysis kernel from the SEQUOIA-BELUGA data assimilation platform – De Mey,...
Conference Paper
In order to assess the value of coastal and shelf seas models and the well-posedness of their configuration (including boundary specification using larger-scale models), observation networks can be set up. It seems natural to plan the new observations in areas and on variables for which model errors are expected to be largest (if they are made perm...
Conference Paper
Full-text available
Operational oceanography reached a new level with the publication of the first global forecast bulletin by the French group MERCATOR in October 2005. Since then, global ocean fields are available in real time not only for scientific studies but also for commercial or military applications. At a regional scale, the knowledge of the coastal dynamics...
Conference Paper
Full-text available
The purpose of this study is to assimilate various altimetry andtide-gauges data in the barotropic, free-surface, finite element model MOG2D, covering the Bay of Biscay and nested in a North East Atlantic domain. In a first step, we explore the errors sub-space of the model in presence of forcing uncertainties, and especially in presence of high fr...
Article
Full-text available
Conference Paper
The penetration of atmospheric forcing into the ocean is a fundamental issue in physical oceanography and climate change science. In this study, we use a ensemble method with fifty 7-months (September to March) primitive equation ° North Atlantic integrations to investigate the processes that control the vertical transmission of small atmospheric p...
Article
Full-text available
In the specific context of the barotropic free surface MOG2D model response to uncertainties in atmospheric forcing, the model forecast errors have been characterized by the use of an ensemble method; they appeared to be anisotropic, nonhomogeneous and non-stationary, evolving in the form of error regimes which are highly correlated to the growth o...
Conference Paper
The spatial and temporal resolution of satellite altimetry is usually well adapted to the sampling of the sea surface topography of the open ocean. However, the coastal ocean dynamics are much more complex, being characterized by a wide range of spatial and temporal scales, which are more difficult to observe with a single altimetric satellite. Thu...
Article
A technique, closely related to the breeding method, is described for sim- ulating prediction errors for components of the system state which is very simple to implement and requires only some in- tegrations of the numerical model. This technique is proposed for approximat- ing forecast errors covariance matrices (ECM) participating in construction...