99515 - EARTH OBSERVATION FOR CLIMATE SCIENCE

Conoscenze e abilità da conseguire

Satellite earth observation is an essential tool that allows a global and integrated view of the whole earth system, allowing quantitative measurements of a large number of relevant geophysical parameters including essential climate variables. In this courses, the students will learn the main capabilities of current satellite earth observing system and the main techniques used for the derivation of key products concerning the earth's atmosphere and surface properties. Practical exercises on satellite data analysis will be proposed during the classes.

Contenuti

Modulo 1

Satellite measurements of LW and SW radiance fields (theory)
• Effective Bi-Directional Reflectance Function
• Surface spectral signatures at sw
• Brightness temperature
• Refractive index of liquid and solid surfaces
• Surface emissivity at lw

2 Detection of snow and vegetation (theory and practice)
• Normalized difference snow index
• Partially snow covered pixel, dirty snow
• Ice surface temperature
• Vegetation index
• Leaf Area index and Enhanced VI
• Atmospheric perturbations on snow and vegetation index: Aerosols, water vapor, Rayleigh scattering, thin cirri

3 Water vapor and surface temperature (theory and practice)
• Precipitable water vapor from sw channels
• Split window techniques: Land surface temperature
• Absorption and emission of radiation by sea water
• Sea Surface temperature from infrared radiometers

4 Fire detection (theory and practice)
• The 4 microns band
• Temperature sensitivity
• Multichannel threshold and contextual algorithms
• Normalized burn ratio

5 RGB techniques (theory and practice)
• The process of creating RGB: examples
• Meteosat RGBs: natural, airmass, dust
• Detecting oil spills

6 Detection of clouds from passive measurements (theory and practice)
• The full radiative transfer equation and the cloud parameters
• Detection of thin cirrus clouds
• Cloud phase derivation: techniques
• Cloud altitude: co2 slicing and sorting
• Nakajima-King method for cloud OD and Reff

7 Detection of aerosols from passive methods (theory and practice)
• Radiative transfer equation in single scattering approximation
• Aerosol reflectance over black and reflective surfaces
• Global aerosol optical depth

8 Sounder data (theory)
• The information content in the high spectral resolution measurements
• Inversion techniques for derivation of gas and temperature profile
• Optimal estimation, the role of the a-priori information
• Detection of volcanic ash and outgas
• Example from IASI

Modulo 2

Basics of satellite orbits and sensor parameters:

Geostationary and low Earth orbits

Parameters: Pixel, Field of view, dwell time

Scanning techniques: whiskbroom and pushbroom sensors

Sensor noise: NeSR, NeDT, SNR

Resolution: temporal, spatial, spectral, radiometric

Dataset and products:

Climate Data Records

Copernicus Services

The Earth’s atmosphere and surface in the microwave spectrum:

RTE in the microwave

Absorption and emission of gases

Properties of water vapour and particles

Surface emissivity

Microwave active sensors:

radar equation

ground based and space-borne systems

Techniques to estimate precipitation rates with passive sensors:

The GPM constellation

Statistical and physical methods

Blended techniques

Techniques to estimate snow/ice parameters:

microwave emission from snow and glacier ice

Techniques to estimate soil moisture:

microwave emission from wet soil

space gravimetry

Validation of satellite products

 

Testi/Bibliografia

Materiale presentato a lezione, articoli selezionati e documenti

Metodi didattici

I docenti svolgeranno i 6 cfu di lezioni frontali con ausilio di proiettore e/o alla lavagna.

Gli argomenti trattati prevedono una parte teorica che sarà seguita da esercitazioni con ausilio di semplici codici di lettura, visualizzazione ed analisi di dati satellitari (utilizzando il linguaggio MATLAB). 

Modalità di verifica e valutazione dell'apprendimento

La verifica dell'apprendimento avverrà attraverso una prova orale atta a valutare il raggiungimento degli obiettivi principali del corso:

* la comprensione delle leggi fondamentali che regolano il trasporto radiativo in atmosfera e la loro applicazione alla misura

* la comprensione delle principali metodologie di misura satellitare

* la capacità di interpretare dati e prodotti derivati da misure da satellite riguardanti la superficie e l'atmosfera

La prova orale copre l'intero programma svolto, prevede un voto finale in 30esimi ed avrà durata di circa 1 ora.

Strumenti a supporto della didattica

Gli studenti avranno a loro disposizione:

* Appunti delle lezioni (formato elettronico pdf)

* Articoli scientifici utili all'approfondimento di alcune tematiche

* Un pacchetto software (MATLAB) per l'analisi dati da satellite e dati specifici

* Bibliografia e referenze

Orario di ricevimento

Consulta il sito web di Tiziano Maestri

Consulta il sito web di Federico Porcù