75812 - Radiative Transfer and Remote Sensing

Learning outcomes

At the end of the course the Student 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 atmosphere.

The Student is able to use approximations to interpret the radiative transfer equation in different regimes. He also 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.

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
• Complex RI
• Curve of growth

4. Shortwave RT

• Absorption of sw radiation
• Ozono cycle
• Heating rates

5. Introduction to scattering

• Overview of scattering
• Rayleigh scattering
• Airlight

6. RT equation and Scattering

• RT equation for MS events
• The Mie solution
• Stokes parameters
• Polarization

7. Cloud properties

• Single scattering properties of single particles
• Particle size distributions
• Bulk properties

8. Reflectance from surface and thin clouds

• BDRF
• Albedo
• Single scattering approximation

9. Longwave RT

• IR absorption and weighting functions
• LbL computations
• LW cooling rates
• Cooling rates in presence of clouds

10. Advanced topics in RT

• General form of the RT equation
• Legendre polynomial
• Azimuth independent solution
• Two-stream approximation
• Similarity principle and 𝛿-function approximation

11. Radar-lidar equation

• Active sensors
• Depolarization

12. Satellites

• Orbits
• Sensor parameters
• GEO vs LEO

13. Observations from space

• Introduction
• Spectroradiometers (MODIS)
• Sounders (IASI)

14. Satellite data analysis

• Detection of snow
• Vegetation index
• T sensitivity and fires detection
• RGB
• Split window techniques: SST, LST
• Water vapor Column
• Cloud detection and properties

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 teacher will discuss the program content (6 ects) by using both the blackboard and the video projector.

Simple problems will be solved during the classes to facilitate the understanding of the theoretical part of the program. Simple optical experiments will also be demonstrated.

Satellite data will be made available to the students to facilitate the interpretation of remote sensing measurements. Satellite data will be visualised and simple graphical and mathematical operations will be performed to derive satellite products.

Assessment methods

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

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

*) 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 presenting a written work concerning a specific topic of satellite remote sensing. 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 for the numerical solution of specific problems.

* A data analysis software kit and satellite data

* Bibliography and references

Links to further information

https://www.eumetsat.int/website/home/index.html

Office hours

See the website of Tiziano Maestri