81828 - FONDAMENTI DI FISICA DELL'ATMOSFERA E METEOROLOGIA

Course Unit Page

  • Teacher Rolando Rizzi

  • Learning modules Rolando Rizzi (Modulo 1)
    Federico Porcù (Modulo 2)

  • Credits 6

  • SSD FIS/06

  • Teaching Mode Traditional lectures (Modulo 1)
    Traditional lectures (Modulo 2)

  • Language Italian

  • Course Timetable from Sep 26, 2018 to Dec 20, 2018

Academic Year 2018/2019

Learning outcomes

At the end of the course the student has acquired the basic knowledge of the long term mean properties of the atmosphere and of the basic equations of fluid dynamics. The laws of thermodynamics are applied to a gaseous fluid with phase changes. The equations of atmospheric motion are introduced with applications to some aspects of synoptic meteorology of mid-latitude weather systems with the aid of meteorological chart and satellite imagery. The fundamental radiative processes are introduced to interpret observations from space and to justify the simple planetary energy budget that introduces to the greenhouse effect.

Course contents

Module 1: Atmospheric physics 3 CFU (24 hours)

Properties of the mean atmosphere. Introductory notes on processes that influence the behaviour of the atmosphere. On atmospheric science and meteorology.

Spatial distribution of measuring stations. Mean atmospheric composition. The vertical mean structure of the atmosphere. Meridional cross-sections of zonal temperature and zonal wind. Beyond the average.

Complements of thermodynamics. Thermodynamics of dry air. the first law of thermodynamics. Adiabatic processes and potential temperature. Humidity parameters. Thermodynamic diagrams. Hydrostatic stability of unsaturated air. Saturated behaviour and the release of latent heat. Pseudo-adiabatic process and the Equivalent Potential Temperature. Convective Available Potential Energy (CAPE). Stability exercises with using thermodynamic diagrams (six hours)..

Radiative processes. Basic radiometric definitions. Emission and scattering processes.

An introduction to remote sensing. Satellite orbit geometry and Kepler ’ s laws. Classification of weather satellites. Geostationary satellites and orbit properties. Polar satellites and orbit properties. Introducing Meteosat Second Generation.

Simple models of planetary energy balance. Global energy balance model for a planet without atmosphere. A climate model with one atmospheric layer and a surface layer. Global mean atmospheric energy balance.

 

Module 2: Atmospheric physics 3 CFU (24 hours)

Spatial and temporal scales. Basic concepts of atmospheric fluid dynamics (Knudsen Number, air parcel, eulerian and lagrangian views, total derivative).

Navier-Stokes equation, viscous and inertial forces. Qualitative sketch on transport phenomena. Reynolds number and regimes, linearity and non-linearity, examples. Mass conservation equation with eulerian and lagrangian approach.

Equation of motion on a rotating system: scale analysis.

Simple equilibrium configurations: inertial motion, geostrophic motion (with and without friction), example of finite difference method.

Gradient wind, role of pressure gradient in the evolution of baric systems. Cyclostrophic wind, Rossby Number.

Isobaric and isentropic coordinates, thermal wind. Barotropicity and baroclinicity. Horizontal divergence and vertical motion (application to global circulation).

Fronts: pressure, temperature and winds across frontal surfaces. Sketch of extra-tropical cyclone structure. Examples on meteorological charts.

Fronts and cyclones in meteorological satellite imagery: conveyor belt, dry intrusion, warm sector, gust fronts, squall lines.

Basic introduction to weather forecast: nowcasting, NWP, data assimilation, ensamble forecast. Available global products (ERA, NCEP, Globo), and regional (bolam, moloch).

The Earth’s climate system: definitions, observation and trends.

Readings/Bibliography

Lecture notes of both modules are available online. They contain an extensive bibliography.

Atmospheric Science, An introductory survey. John M. Wallace e Peter V. Hobbs, Second Edition, Academic Press 2006.

Holton, J.R., An Introduction to Dynamic Meteorology (4th Ed.) Elsevier-Academic Press, New York (2004), pp 535.

Teaching methods

Frontal lectures with ample use of multimedial material.

Exercise are done with active intervention by the students.

Assessment methods

Final examination is common to both modules. It consists of  questions on the arguments presented during the lectures that require an oral presentation and discussion by the student and may require the solution of exercises.

Teaching tools

Notebook and projector.

Office hours

See the website of Rolando Rizzi

See the website of Federico Porcù