Master WAPE Courses

Clouds, Aerosols and Precipitations

Hélène Chepfer
Jean-Claude Raut

This course is shared with other OACOS specialities

Clouds constitute the visible part of the water cycle in the atmosphere. They regulate precipitations and atmospheric water vapour, they interact with the surface and with pollution (e.g. by producing smog), they are one of the main modulators of the Earth temperature through their interaction with solar and telluric radiations. Aerosol particles play a significant role on air quality but also on climate through their interaction with radiation and clouds. Without aerosol particles, cloud formation in the atmosphere would not occur at the temperatures and relative humidities at which clouds are observed to exist.

This course provides key elements of aerosol, cloud and precipitation physics, from the small scale (the particles composing clouds) to the regional scale (a cloud system) and up to the global scales.  It includes:

- Origin and chemical composition of aerosols
- Spatial and vertical distributions of particles in the atmosphere
- Microphysics of aerosols: brownian motion, coagulation, condensation, deposition, cloud nucleation
- Optical properties of aerosols
- Aerosol radiative forcing: direct, semi-direct, indirect, impact on snow and ice surfaces
- Water in the atmosphere: thermodynamics of moist air
- Microphysics of warm clouds: formation and growth of cloud droplets
- Microphysics of cold clouds: formation and growth of ice crystals
- Precipitation processes: Rain and Snow
- Opical properties of clouds
- Effect of clouds on radiations
- Cloud feedbacks and link with climate sensitivity.

Hélène Chepfer is professor at Sorbonne Université and researcher at the Dynamic Meteorology Laboratory (LMD). Research interests: Clouds, Radiation, Remote sensing, Climate

Jean-Christophe Raut is associate professor at Sorbonne Université and researcher at LATMOS.
Research interests: Aerosols (microphysics and radiation), Mesoscale modelling, Arctic studies.