Radiative Transfer Christian Mätzler & Jaro Ricka

Radiative Transfer

• Christian Mätzler & Jaro Ricka

• Institute of Applied Physics

• Spring Semester 2009

Contents

• Introduction

• The Radiative Transfer Equation

• Solutions Without Volume Scattering

• A Simple Case With Scattering

• Random Walk and Diffusion (under construction)

• Single and Multiple Scattering (under construction)

• Monte Carlo Methods (under construction)

• Lorenz-Mie Scattering on Spheres

• Polarised Radiative Transfer (under construction)

• Special Interests ???

1 Introduction: 1.1 Historical Overview

• Radiative transfer is a tool for

• - astronomy and astrophysics,

• - remote sensing of the earth surface atmosphere and ocean,

• - assessment of the light and heat transport in the natural (climate, hydrosphere, meteorology, biosphere)

• - technical (paint, paper, textile, architecture, imaging, medicine)

• - cognitive human environment (e.g. in art).

• Radiative transfer describes the emission, propagation, scattering and absorption of (thermal) radiation.

• Almost everything we know about the universe and a lot about our environment has been brought to men by radiation. Thus radiative transfer is as old as vision.

Introduction: Historical Overview

• Today's knowledge on (thermal) radiation is based - among others - on

• Willebrod Snell (1591-1626)

• Friedrich Wilhelm Herschel (1738-1822)

• Josef von Fraunhofer (1787-1826)

• Augustin Fresnel (1788-1827)

• Robert Bunsen (1811-1899)

• Gustav Robert Kirchhoff (1824-1887): Application of the first and second laws of thermodynamics let Kirchhoff formulate a law on radiation in 1860, stating that under local thermodynamic equilibrium the emissivity of a given object is equal to its absorptivity.

• James Clark Maxwell (1831-1879) stated that magnetism, electricity, and light are different manifestations of the same fundamental laws.

• Max Planck (1858-1947) found a function that describes the spectral shape of thermal radiation, giving a key to a new area of physics, quantum theory, by the introduction of the constant h.

• Albert Einstein (1879-1955) first understood the Planck function as a photon signature.

Introduction: Historical Overview

Introduction: Historical Overview

Introduction: Historical Overview

Introduction: Historical Overview

Introduction: Historical Overview

Introduction: Historical Overview

Introduction: Historical Overview

Introduction: Historical Overview

Introduction: Historical Overview

Introduction: Historical Overview

Introduction: Historical Overview

Introduction: Historical Overview

Introduction: Historical Overview

Introduction: Historical Overview

Introduction: Historical Overview

Introduction: Historical Overview

Introduction: Historical Overview