Sylvie Malardel

Sylvie Malardel
European Center For Medium Range Weather Forecasts · Research Department

Doctor of Philosophy

About

44
Publications
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1,991
Citations

Publications

Publications (44)
Article
Full-text available
The ReNovRisk-Cyclone program aimed at developing an observation network in the south-west Indian ocean (SWIO) in close synergy with the implementation of numerical tools to model and analyze the impacts of tropical cyclones (TC) in the present and in a context of climate change. This paper addresses the modeling part of the program. First, a uniqu...
Article
Full-text available
Tropical cyclone (TC) monitoring and forecast in the South West Indian Ocean (SWIO) basin remain challenging, notably because of the lack of direct observations. During the 2018–2019 cyclone season, S-1 Sentinel SAR images were acquired, as part of the ReNovRisk-Cyclone research program, giving access to unprecedented detailed TC wind structure des...
Article
Full-text available
The evolution of tropical cyclone activity under climate change remains a crucial scientific issue. Physical theory of cyclogenesis is limited, observational datasets suffer from heterogeneities in space and time, and state-of-the-art climate models used for future projections are still too coarse (∼100 km of resolution) to simulate realistic syste...
Article
Full-text available
In order to contribute to ongoing efforts on tropical cyclone (TC) forecasting, a new, convection‐permitting, limited‐area coupled model called AROME‐Indian Ocean (AROME‐IO) was deployed in the Southwest Indian Ocean basin (SWIO) in April 2016. The skill of this numerical weather predicting system for TC prediction is evaluated against its coupling...
Article
Full-text available
In order to contribute to ongoing efforts on tropical cyclone (TC) forecasting, a new, convection‐permitting, limited‐area coupled model called AROME‐Indian Ocean (AROME‐IO) was deployed in the Southwest Indian Ocean basin (SWIO) in April 2016. The skill of this numerical weather predicting system for TC prediction is evaluated against its coupling...
Article
The resolution of the European Centre for Medium‐range Weather Forecast (ECMWF) integrated forecast system (IFS) is expected to reach 5 km in the coming decade. Assumptions in the parametrisation of deep convection such as that all of the compensating environmental flow occurs in the grid column, i.e. the convective and environmental mass flux canc...
Article
Full-text available
We present a nonhydrostatic finite-volume global atmospheric model formulation for numerical weather prediction with the Integrated Forecasting System (IFS) at ECMWF and compare it to the established operational spectral-transform formulation. The novel Finite-Volume Module of the IFS (henceforth IFS-FVM) integrates the fully compressible equations...
Article
Full-text available
We present a nonhydrostatic finite-volume global atmospheric model formulation for numerical weather prediction with the Integrated Forecasting System (IFS) at ECMWF, and compare it to the established operational spectral-transform formulation. The novel Finite-Volume Module of IFS (henceforth IFS-FVM) integrates the fully compressible equations us...
Article
Full-text available
Tropical cyclones are some of the most devastating natural hazards and the “three beasts”—Harvey, Irma, and Maria—during the Atlantic hurricane season 2017 are recent examples. The European Centre for Medium-Range Weather Forecasts (ECMWF) is working on fulfilling its 2016–25 strategy in which early warnings for extreme events will be made possible...
Book
Weather and climate models include complex representations of dynamics (fluid motions) and physics (e.g. radiative transfer, chemistry, cloud processes) that span timescales from fractions-of-a-second to millennia. The coupling of these processes is complex and difficult to represent. This workshop will address challenges in the development of adva...
Article
Numerical weather, climate, or Earth system models involve the coupling of components. At a broad level, these components can be classified as the resolved fluid dynamics, unresolved fluid dynamical aspects (i.e., those represented by physical parameterizations such as subgrid-scale mixing), and nonfluid dynamical aspects such as radiation and micr...
Article
Middle atmospheric lidar temperature observations conducted above Sodankylä, Finland (67.4N, 26.6E), during December 2015 are compared to two estimates of the atmospheric state computed by the integrated forecast system (IFS) of the European Centre for Medium-Range Weather Forecasts (ECMWF). The first set corresponds to an hourly sampling of the mi...
Article
Full-text available
Members in ensemble forecasts differ due to the representations of initial uncertainties and model uncertainties. The inclusion of stochastic schemes to represent model uncertainties has improved the probabilistic skill of the ECMWF ensemble by increasing reliability and reducing the error of the ensemble mean. Recent progress, challenges and futur...
Article
Full-text available
A stratocumulus-to-cumulus transition as observed in a cold air outbreak over the North Atlantic Ocean is compared in global climate and numerical weather prediction models and a large-eddy simulation model as part of the Working Group on Numerical Experimentation "Grey Zone" project. The focus of the project is to investigate to what degree curren...
Article
Full-text available
Geophysical models of the atmosphere and ocean invariably involve parameterizations. These represent two distinct areas: a) Subgrid processes which the model cannot (yet) resolve, due to its discrete resolution, and b) sources in the equation, due to radiation for example. Hence coupling between these physics parameterizations and the resolved flui...
Article
The paper examines horizontal wind variance (kinetic energy spectra) and available potential energy spectra in simulations conducted with a state-of-the-art global numerical weather prediction (NWP) model: the Integrated Forecasting System (IFS) of the European Centre for Medium-Range Weather Forecasts. The formulation of the spectral energy budget...
Technical Report
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With the objective to develop and maintain one of the most advanced and flexible modelling infrastructures in Europe for operational, global NWP applications, recent advances and future challenges are described. A particular challenge arises from the need to achieve computationally and energy efficient solutions for operating global, complex, high-...
Article
Convection-permitting limited-area models based on the same spectral semi-implicit semi-Lagrangian (SL) techniques which are used in the ECMWF global model, are run operationally in several countries of the ALADIN/HIRLAM consortium. Forecasters reported a general tendency for these models to produce overestimated precipitation and unrealistic diver...
Technical Report
Full-text available
A case of orographically enhanced, extreme precipitation which led to extensive flooding in Central Europe is investigated. The ECMWF Integrated Forecasting System (IFS) provided good forecasts of the location of the heaviest precipitation on the northern side of the Alps but underestimated the magnitude. As a result, streamflow predictions for the...
Article
Full-text available
Introduction The Atmosphere The atmosphere, like the ocean, is a stratified fluid highly influenced by the rotation of the Earth. But, unlike the ocean, the atmosphere is a mixture of gases known as air The composition of the gas layer around the Earth has evolved very slowly since the time of its formation. Thanks to the appearance of life about 3...
Article
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In numerical weather prediction and climate models, planetary boundary-layer (PBL) clouds are linked to subgrid-scale processes such as shallow convection. A comprehensive statistical analysis of large-eddy simulations (LES), obtained for warm PBL cloud cases, is carried out in order to characterize the distributions of the horizontal subgrid cloud...
Article
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The FLOHOF field campaign took place in the period July 21 to August 24, 2007 on and in the surroundings of Hofsjökull glacier in Central Iceland. During the campaign, 18 automatic weather stations (AWS) recording temperature, humidity, wind speed, wind direction, pressure, and precipitation were deployed on and around the glacier. In addition, atm...
Article
After six years of scientific, technical developments and meteorological validation, the Application of Research to Operations at Mesoscale (AROME-France) convective-scale model became operational at Mé téo-France at the end of 2008. This paper presents the main characteristics of this new numerical weather prediction system: the nonhydrostatic dyn...
Article
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For numerical weather prediction models and models resolving deep convection, shallow convective ascents are subgrid processes that are not parameterized by classical local turbulent schemes. The mass flux formulation of convective mixing is now largely accepted as an efficient approach for parameterizing the contribution of larger plumes in convec...
Article
Clouds are a major element for the hydrological cycle and the Earth climatic system. In the atmosphere, the water can exist under three phases: water vapour, liquid water and ice. Each of them has a different impact on atmospheric processes such as the formation of precipitation or the radiative budget. A good representation of clouds is a quality...
Article
Clouds are a major element for the hydrological cycle and the Earth system. In the atmosphere, the water can exist under three phases (water vapour, liquid water and ice) which have a different impact on atmospheric processes. A good representation of clouds is a quality condition for all numerical weather forecast models such as the operational mo...
Article
Full-text available
The french AROME project at METEO-France aims at developping a new Numerical Weather Prediction system that is planned to be used operationnally by 2008. This system is designed for very short range forecast in order to improve the forecast of mesoscale phenomena and extreme weather events. The AROME numerical model, which will run at 2-3 km horizo...
Article
The french AROME project at METEO-France aims at developping a new Numerical Weather Prediction system that is planned to be used operationally by 2008. This system is designed for very short range forecast in order to improve the forecast of mesoscale phenomena and extreme weather events. The AROME numerical model, which will run at 2- 3 km horizo...
Article
Full-text available
The feasibility of the recently proposed concept of adaptive observations is tested on a typical case of poorly forecast North Atlantic cyclogenesis. Only numerical tools are employed, no special observations. Although based on simulated data, this study addresses both theoretical and practical problems of adaptive observations. In the first stage...
Article
A subsynoptic instability with dominant barotropic signature has been found to be a possible mechanism for the development of frontal waves. Linear semigeostrophic calculations of the growth rate of waves developing along a front exhibiting a low-level potential vorticity band are here compared with the results of similar experiments made with a pr...
Article
Linear, semi-geostrophic (SG) theory reveals the instability of steady fronts with low-level potential vorticity anomalies. Joy and Thorpe (1990) have shown in this context the most unstable normal modes to have sub-synoptic wavelenghts. The present study uses a primitive equation (PE) model to construct, at these wavelenghts and along the same fro...
Article
Thesis (Ph. D.)--University of Reading, 1994.

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Project (1)
Project
ReNovRisk-CYCLONES focuses on meteorological and oceanographic impacts of tropical cyclones (TC) of the South-West Indian Ocean (SWIO) in both current and future climates. It aims to improve knowledge and forecasting of TC in order to better anticipate their effects on inhabited islands of the SWIO and East coast of Africa, from the present time until 2100. ReNovrisk-CYCLONES is funded by EU and Reunion Regional Council under the frame of the INTERREG-V Indian Ocean 2014-2020 research program.