99081 - TRASFERIMENTO RADIATIVO: TEORIA E MODELLISTICA

Learning outcomes

At the end of the course the Student:

- knows the main physical processes governing the interaction between solar and terrestrial radiation with atmospheric and surface matter;

- knows the fundamentals laws of the radiative transfer in atmosphere. He learns the phenomenology and equations governing the physics of the radiative energy transfer by electromagnetic waves in a multiple scattering environment;

- is able to apply approximations to the radiative transfer general equation in order to interpret radiance fieldsin different regimes

- is able to implement numerical modelling techniques for radiative transfer algorithm;

- knows the basics of the satellite remote sensing and is capable to use geolocated calibrated radiances and create surface, atmospheric and cloud products for climate and meteorology;

- uses texts and lecture notes written in English and she/he is able to communicate about radiative transfer in atmosphere using the proper terminology

Course contents

1.Introduction, basic definitions

•Summary of the basics

•Radiometry and Photometry

2.Spectroscopy

•Molecular energy levels

•Electric dipole•Rotational transitions

•Vibrational transitions

•Line Shapes•

3.Thermodynamic equilibrium

•LTE e NLTE

•Schwarzchild equation

•Curve of growth

•Complex RI

4.Shortwave RT

•Absorption of sw radiation

•Ozone cycle

•Heating rates

5.Rayleigh scattering

•Overview of scattering

•Rayleigh scattering

•Airlight

6.RT equation and Scattering

•RT equation for MS events

•The Mie solution

•Stokes parameters

7.Cloud properties

•Single scattering properties of single particles

•Particle size distributions

•Optical properties of cloud and aerosols

8.Reflectance from surface and thin clouds/aerosols

•BDRF

•Albedo

•Single scattering approximation

•aerosols

9.Polarization and Radar-lidar equation

•Polarization of light

•Active sensors

•Depolarization ratio

10.Longwave RT

•IR absorption and weighting functions

•LbL computations

•LW cooling rates

•Cooling rates in presence of clouds

10.Principles of inversion methods

•Direct linear inversion

•IR inversion problems•optimal estimation•regularizations

11.Advanced topics in Radiative Transfer

•General form of the RT equation

•Legendre polynomial

•Azimuth independent solution

•Approximate solutions of the RTE

•Two-stream approximation

•Similarity principle and 𝛿-function approximation

Readings/Bibliography

* T. Maestri, lectures notes on radiative transfer and remote sensing

* K.N.Liou: An introduction to atmospheric radiation. Academic Press

* K.N.Liou: Radiation and cloud processes in the atmosphere. Oxford University Press

Teaching methods

The program content (6 ects) will be discussed by using both the blackboard and the video projector.

Simple problems will be solved during the classes (or suggested as homework) to facilitate the understanding of the theoretical part of the program. During the lessons, the student will implement in coded algorithm the solving equations of the multiple problems proposed.

Possibly, Satellite data will be made available to the students to facilitate the interpretation of remote sensing measurements.

Assessment methods

The assessment of the student's learnings is performed by an oral test which serves to evaluate the achievements of the main objectives of the course:

*) understanding the fundamental laws regulating the radiative transfer in atmosphere

*) the ability to implement numerical solution of the proposed problems

*) the ability to interpret satellite remote sensing data and products of atmosphere and surface

The test will cover the whole program. The student can start the test by discussing a written work concerning a specific topic of radiative transfer modelling. The oral test will last at about 1 hour.

Teaching tools

The following items will be available to the Students:

* Lectures notes (in pdf format).

* Scientific articles useful for the investigation of specific lines of research.

* Software algorithms (in MATLAB) for the numerical solution of specific problems.

 * Bibliography and references

Office hours

See the website of Tiziano Maestri