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Head of section : Olivier THUAL Professor Emeritus at Toulouse INP, IMFT (Institute of Fluid Mechanics) and CERFACS (European Centre for Research and Advanced Training in Scientific Computing).

Space Environment

Encyclopédie environnement - Environnement spatial Terre et météorologie de l'espace -

Space weather and its consequences on Earth

05-01-2025

Our Sun is the guarantor of life on Earth. We have known since the 1980s that it is also responsible for a heap of electrical,…

Encyclopedie Environnement - energies solaires - couverture

Solar energies

05-01-2025

Sun radiation is commonly referred to as solar energy, limiting this energy to visible radiation. But the Sun sends us energy in many forms: radiation…

Encyclopédie environnement - magnétosphère - couverture

The magnetosphere: under the influence of the Earth and the Sun

05-01-2025

The magnetosphere is the interface between the interplanetary environment and the upper Earth’s atmosphere. It is a vast region evolving under the control of the…

upper atmosphere - haute atmosphere

The upper atmosphere

07-03-2024

This article should be read in conjunction with The Atmosphere and the Earth’s Gas Envelope. It differs, however, by extending the description of the atmosphere above…

Gaseous envelope of the Earth

Encyclopédie environnement - atmosphère -température selon altitude

Earth’s atmosphere and gaseous envelope

05-01-2025

The Earth is surrounded by a gaseous domain, commonly referred to as the atmosphere, although, etymologically, this name is only justified for the lowest and…

Encyclopédie environnement - couleur du ciel - colors sky

The colours of the sky

05-01-2025

Why is the sky blue, clouds white, grey, or black? Why are the sunsets red? Why is the night black? Where do rainbows come from?…

Encyclopédie environnement - halos atmosphériques - couverture

Atmospheric halos

05-01-2025

In the Earth’s atmosphere, light often offers a spectacle that can be appreciated simply by looking at the sky with the naked eye. In a…

Atmospheric circulation

Encyclopédie environnement - circulation atmosphérique - couverture

Atmospheric circulation: its organization

05-01-2025

The only driver of atmospheric circulation is sunlight. Under the constraints of gravity, Archimedes’ thrust and Coriolis’ force due to the Earth’s rotation, temperature differences…

Encyclopédie environnement - alizés -

The key role of the trade winds

05-01-2025

The meteorology of tropical regions, marked by trade winds and their effects, is particularly capricious. In the vicinity of the land or sea, the lightening…

Encyclopédie environnement - jet streams

Jet streams

05-01-2025

MOREAU René, FLOR Jan-Bert

Jet streams, major winds that flow from west to east in the atmosphere, can be explained by analogy with the rotation of skaters on ice.…

gisement-eolien-production-electricite

From wind energy to electricity generation

05-01-2025

The challenge of emitting less and less CO2 in order to limit global warming calls for the design of a low-carbon electricity mix in which…

impacts production électricité éolienne

Impacts of wind power generation. What is the balance sheet in 2020? What is the outlook?

05-01-2025

As part of the electricity mix in many countries, wind electrical power is generated by thousands of wind farms spread over the continents and more…

Meteorological phenomena

Encyclopédie environnement - cyclones tropicaux - couverture

Tropical Cyclones: development and organization

05-01-2025

Tropical cyclones extract their energy from the heat stored in the tropical oceans and transform it into fierce winds, devastating rains, monstrous waves that devastate…

Tropical Cyclones: impacts and risks

05-01-2025

As the ruins of Tacloban in the Philippines show, after the passage of Typhoon Hayan in November 2013, cyclones, together with earthquakes, are the most…

storms - thunderstorms - orages

Thunderstorms: electricity in the air

05-01-2025

RISI Camille, ROUX Frank

Thunderstorms are made up of clouds called cumulonimbus. A combination of phenomena (updraft of moist and warm air, condensation, evaporation, downdrafts of cool air) causes…

Encyclopédie environnement - tornades - couverture

Tornadoes: powerful devastating eddies

05-01-2025

The strongest winds on Earth are due to tornadoes, causing devastation unmatched by any other phenomenon where they strike. The thunderstorms that give rise to…

Inversion layer, fog and other curiosities of the lower atmosphere

05-01-2025

How can we explain that in February-March, in the presence of a beautiful anticyclone, it is warmer at altitude than at the bottom of the…

What’s happening in the clouds?

05-01-2025

Fog, cumulonimbus, cirrus clouds… Clouds are present in the atmosphere at very different altitudes and have a wide variety of characteristics in terms of shape,…

Monsoons

05-01-2025

Monsoons govern the climate of much of the tropics, where billions of people live. After months of winter drought, the long-awaited summer rains restore water…

dew

Dew

05-01-2025

Everyone knows or has experienced dew, when the ground and plants are wet on the morning of a clear, calm night or when water runs…

Atmospheric observations

observation meteorologique annees 1950 - meteo 1950 - meteorological observations

Meteorological observations over the past centuries

05-01-2025

PEPIN Marie-Hélène

Meteorology has been a constant concern of humankind. The first writings are rich in meteorological descriptions, such as that of the Flood, the most shared…

meteo - observation meteo - capteur meteo

Ground weather observations: what is measured and what is done with it?

05-01-2025

How is the state of the atmosphere characterized in ground-based weather stations? What quantities are measured and with which sensors? For several decades, the meteorological…

Weather forecast

Encyclopédie environnement - prévision météorologique - couverture

Introduction to weather forecasting

05-01-2025

BOUGEAULT Philippe

What time will we have next weekend? What are the risks of storms, thunderstorms and heat waves in the coming days? Meteorological services are now…

Weather forecasting models

05-01-2025

MALARDEL Sylvie

This article presents the basic principles of numerical atmospheric modelling. First, it explains how to move from general and continuous equations of fluid mechanics to…

Encyclopédie environnement -modèles biosphère, hydrosphère, cryosphère - couverture

Biosphere, hydrosphere and cryosphere models

05-01-2025

BALSAMO Gianpaolo

This article presents the importance of taking into account the Earth’s surfaces in Numerical Weather Forecasting, a step towards a more complete representation of the…

Encyclopédie environnement - données météorologique - meterological data

Assimilation of meteorological data

05-01-2025

DESROZIERS Gérald

Meteorological observation tools (satellites and ground stations) provide a very large amount of meteorological data, which must be processed to establish the state of the…

The ensemble forecasting

05-01-2025

BOUTTIER François

Ensemble forecasting is the tool used to make probabilistic weather forecasts. It is both an alternative and a complement to deterministic weather forecasting that has…

Encyclopedie environnement - prevision saisonniere - couverture

The seasonal forecast

05-01-2025

This article shows how the numerical models used for numerical weather prediction can be used to provide information on the weather over the next few…

Encyclopedie environnement - prevision immediate -

Nowcasting

07-03-2024

MOISSELIN Jean-Marc

Weather radars and satellites have long provided the main input data for nowcasting. Extrapolation methods based on recent movements of clouds and precipitating areas provided…

Encyclopédie environnement - prévisionniste - forecaster

The role of the forecaster

05-01-2025

GILLET-CHAULET Bruno

The common predictionist name commonly refers to the meteorologist responsible for developing weather forecasts. This article describes the functions of a forecaster in 2016, as…

Artificial intelligence for weather forecasting

05-01-2025

Artificial intelligence (AI), and in particular deep learning methods using neural networks, has been successfully exploited in numerous applications in recent years. Weather forecasting is…

Air quality

Air pollution

05-01-2025

Air pollution is multiple and old. They have consequences not only for human health but also for the biosphere, in particular the planet’s vegetation, atmosphere…

smog new delhi - pollution air - encyclopedie environnement

Outdoor air pollution: keys to understand, inform and prevent

05-01-2025

GUIDOTTI Sylvie, PITHON Marion

Outdoor air quality is now a major challenge for society. This article aims to clarify the phenomena involved in air pollution episodes and describe their…

Parmelia sulcata - lichens - lichens foliacé - biosurveillance- pollution atmosphérique - encyclopedie environnement

Plants and lichens sentinels of air quality

05-01-2025

Air pollution has effects on health and the environment. The impact of pollutants on terrestrial ecosystems can be monitored and assessed by observing plants, mosses…

Encyclopédie environnement - feux de végétation - wildfires

Understanding and preventing wildfires

05-01-2025

MORVAN Dominique

Improving policies to prevent and reduce fire risk in the natural environment and in peri-urban areas requires a thorough understanding of the factors that will…

pollution - smog - particules polluantes

Air pollution particles: what are they?

05-01-2025

Particulate matter is a major component of air pollutants. They are considered to be one of the main causes of pollution-related mortality. Their finely divided…

wood combustion - particles - air particles - fog pollution - smog - pollution

Diesel engines and wood combustion in charge

05-01-2025

Fine particles (PM 2.5), one of the major components of air pollution, are believed to be responsible for a large number of deaths in France…