58357 - Atmospheric Physics and Meteorology

Learning outcomes

At the end of the course, the student: - applies the knowledge of electromagnetism and quantum physics to the processes of absorption and emission of radiation by solids and gases; - knows the energy balance of the planet, energy exchanges with external space and the measures that are used to determine them, as well as their intrinsic limitations; - knows the conservation laws that underlie the dynamics and thermodynamics of the atmosphere and the main forms of instability; - knows the characteristics and properties of gravity waves, baroclines and Rossby waves; - will know the main types of numerical forecasting models of the weather and the problems related to the parametrizations used; - uses the acquired knowledge to interpret data measured by sensors for the study of the atmosphere and to interpret the output of weather forecasting models ; - uses the lecturer's texts and lecture notes written in English and acquires skills in communication on the subject, becoming aware of the English terminology in use; - develops simple models (thermodynamics, greenhouse effect) during exercises; - prepares a report at the end of the exercises and discuss it during the final test.

Course contents

The course is organized in 2 modules, the first concerning the Synoptic Meteorology and introduction to Weather Forecasts, and the second on Atmospheric Physics and Meteorology.

Module 1 is structured as follows.

Introduction to synoptic meteorology;

Atmospheric thermodynamics:

- Hypsometric equation

- Adiabatic processes and Dry Adiabatic Lapse Rate

- Wet processes

- Thermodynamic diagrams 

- Static thermal stratification: neutral, stable and unstable

- Conditional and convective instability

- Convective inhibition (CIN)

- Convective Available Potential Energy (CAPE)

Dynamics of synoptic systems:

- Synoptic systems

- Equation of motion in vector form and in various coordinate systems

- Equation of continuity

- Equation for energy

- Scale analysis of the equations of motion

- Scale analysis of the continuity equation

- Vertical motions

- Equation for pressure tendency

- Solutions of the equations for the gradient wind; inertial wind; cyclostropic wind

- Geostrophic approximation

Elements of synoptic meteorology:

- Fronts: definition and characteristics

- Cyclones: definitions and characteristics

- Extra-tropical cyclones

- Mediterranean cyclones

- Time maps and their interpretation

Module 2 is structured as follows:

Radiative transfer in atmosphere: basic definitions

• Electromagnetic spectrum
• Sun solid angle
• Monochromatic and total radiance and irradiance

Il Sole

• Sun luminosity and solar constant
• Solar spectrum
• Natural variation of solar total irradiance

Black body and thermodynamic equilibrium

• Maxwell Boltzmann distribution
• Derivation of the Planck’s equation
• Features of the black body model
• Local thermodynamic equilibrium in the atmosphere

Absorption and emission of radiation in the atmosphere

• The law of absorption
• Monochromatic transmissivity
• Measures of solar radiation from the ground
• Emission: Schwarzschild’s equation

Energy balance 1-D models

• Spherical albedo
• Radiative equilibrium of a planet
• Greenhouse effect
• Energy storage
• Radiative equilibrium in a grey atmosphere
• Runaway greenhouse

Global energy balance

• Trenberth plot
• Latitudinal mean distribution of radiative fluxes
• Mean energy balance at the surface

During the course there will be 2 laboratory exercises (2 hours each). Laboratory 1: interpretation of a radiosounding
Laboratory 2: reading weather maps.

Readings/Bibliography

The lecture notes (in English) of the teacher are available online.
The lecture notes also contain an extensive bibliography.

Atmospheric Science, an introductory survey. John M. Wallace and Peter V. Hobbs, second edition Academic Press 2006.

Teaching methods

Frontal lectures with extensive use of multimedia materials.
Classroom exercises with active student intervention.
More complex exercises on the climate in equilibrium conditions and on the thermodynamics of the atmosphere are carried out during the course.

Assessment methods

The verification is entrusted to a single oral examination for the two modules, consisting of a discussion on the laboratory activities and in free questions on the topics of the program.

Teaching tools

PC and video projector.
More complex classroom activities can be performed on a PC or with a personal notebook.

Office hours

See the website of Federico Porcù