67111 - Planetary Atmospheres

Learning outcomes

At the end of the course the Student has a basic knowledge of the fundamentals of Planetary Sciences and is able to analyze the planetary atmospheres as physical systems. The Student learns the phenomenology and equations governing the fundamental physical processes occurring in the planetary atmospheres in the Solar System.  The Student is able to interpret simple models of greenhouse effect and to link climatic patterns with orbital parameters of Planets.

Course contents

1) Introduction What is a planet and why a planet is round and smooth. The planets and minor bodies of the solar system. The Solar System in the context of exoplanetary systems. Formation of the Solar System. Comets, meteorites and origins of the Moon. main properties of the Sun and their evolution, in the context of the interaction with the planets. Solar constant, insolation. Radiative equilibrium of a planet.

2) Main characteristics of the Earth and Planets atmosphere Composition and chemical evolution: secondary atmosphere. Mass escape mechanisms (Jeans Escape). Mean thermal structure. The Stratosphere and the role of the Ozone layer. Thermal vertical profile of internal and external planets and Titan.

3)  Thermodynamics of the Atmosphere Air parcel concept. The gas laws applied to the real atmospheres. Hydrostatic balance and hypsometric equation. Dry air: adiabatic processes and lapse rate. Diabatic processes and diabatic stratification. 

4) Hydrostatic Stability Buoyancy force and vertical velocities. Static stability and the Brunt Vaisala frequency. Categories of static stability for dry air and convection. Auto-convective gradient.   

5) Water Vapour and Condensed Phases in the Atmosphere Water vapour saturation pressure and phase changes. Adiabatic lapse rate for saturated air (pseudo-adiabats). Condensed states in atmospheric planets: clouds and hazes.

6) Radiative Transfer and greenhouse effect models Electromagnetic spectrum. Solid angle and main radiometric quantities. Black body radiance and its fundamental laws. Kirchhoff's law. The differential equation of the radiative transfer for absorbing and emitting processes. Schwarzschild's solution for a plane parallel atmosphere. Greenhouse 1-d model. Greenhouse parameter. The Venus case and the Sandstrom theorem. Radiative equilibrium in a plane parallel and grey atmosphere. Runaway green-house effect (Venus, Earth and Mars). Time radiative constants. Global energy budgets for multiple planets. 

7) Atmospheric Dynamics Fundamental fluid dynamics. Eulerian and lagrangian formalism. Equation of motion in a rotating reference frame. Scale analysis of the momentum conservation equation: geostrphic balance, cyclosptrophic balance, and gradient wind. Thermal wind and its applicability. Zonal and meridian circulation. Hadley Cell. Characteristics and peculiarities of the atmospheric dynamic of Jovian planets, Venus, Mars, Earth, and Titan: observations and simplified theoretical models. 

Readings/Bibliography

Lissauer & de Pater: Fundamental Planetary Science, Cambridge University Press

T. Maestri. Planetary Atmospheres. Reperibile direttamente dal docente.

Sanchez-Lavega, Agustin. An Introduction to Planetary Atmospheres, Taylor & Francis Group.

F.W. Taylor: Planetary atmospheres. Oxford

Introduction to Dynamic Meteorology, J. R. Holton, Academic Press

Teaching methods

The teacher will cover the course program (for a total of 6 ects) by discussing material shown with the video projector and with the help of blackboard. Simple problems and questionnaires will be solved and discussed during the classes to facilitate the understanding of the most theoretical part of the course. It is foreseen the discussion of some of the most recent scientific outcomes concerning the topics of the course.

Assessment methods

The verification of the student's learning occurs through an oral test that will evaluate the achievements of the main objectives of the course:

*) understanding the physical laws regulating a planet and its evolution 

*) interpreting simplified physical model applied to a complex system 

*) ability to identify the main parameters affecting and determining the thermal structure of an atmosphere


The oral test will cover the whole course program.  

The student has the possibility to discuss a brief oral/written research of his own choice concerning a specific topic.  

The oral test will last at about 1 hour and 15 minutes.

Teaching tools

The following items will be available to the Students:       
* Lectures notes (on paper and/or electronics).    
* Scientific articles useful for the investigation of specific research lines.    
* Software algorithms for the numerical solution of specific problems.   
* Bibliography and references

Links to further information

https://solarsystem.nasa.gov

Office hours

See the website of Leonardo Testi

See the website of Laura Sandra Leo