# CHAPTER 3 ABSORPTION, EMISSION, REFLECTION, AND SCATTERING

Save this PDF as:

Size: px
Start display at page:

## Transcription

4 Absorption (Emission) Line Formation The Planck explanation of the continuous spectra of the blackbody was founded in the idea of quantization of available energy levels. Planck successfully explained the nature of radiation from heated solid objects of which the cavity blackbody radiator formed the prototype. Such radiation generates continuous spectra and is contrary to line spectra. However, when properly extended, the theory of quantization also led to the understanding of the line spectra of the atom. Let us investigate the development of the Bohr atomic model briefly. In 1913, Bohr postulated that: (a) the angular momentum of the electrons in their circular orbits about the nucleus are quantized, mvr = nh/2π, where m is the electron mass, v the velocity, r the radius, n the quantum number, and h Planck's constant; and (b) the atoms radiate (absorb) only when the electron makes a transition from one energy state to another state of lower (higher) energy, E n1 - E n2 = hf. The mechanical stability of the electron in a circular orbit about a proton is given by the Coulomb force offset by the centrifugal force e 2 mv 2 =, r r 2 where e is the electron charge. The total energy of the electron n th state is given by 1 e 2 E n = mv 2-2 r 2π 2 me 4 1 = -. h 2 n 2 Therefore, the frequency of the emission (absorption) lines in the hydrogen spectrum is given by or 2π 2 me f = ( - ) h n 2 n f = K ( - ), 2 2 n 2 n 1 where K = 3.28 x Hz. Monochromatic emission is practically never observed. Energy levels during energy transitions are normally changed slightly due to external influences on atoms and molecules, and due to the loss of energy in emission. As a consequence, radiation emitted during repeated energy transitions is non-monochromatic and spectral lines are caused by: (1) the damping of vibrations of oscillators resulting from the loss of energy in emission (the broadening of lines in this case is considered to be normal); (2) the perturbations due to collisions between the absorbing molecules

6 3-6 with the reduced mass of the vibrating system M 1 M 2 µ =. M 1 + M 2 The energy levels can be shown to have the form of the Planck postulate E m = (m + 2) hf o, m = 0, 1, 2,... where the additional 2 is a consequence of solving the Schroedinger wave equation for a harmonic oscillator. The vibrational energy levels of a diatomic molecule are shown in Figure 3.2, the upper energy levels are not equally spaced since the actual energy well is wider than the parabolic approximation and hence these energy levels are closer together than the lower levels. The rotational spectra appears as fine structure of the combined electronic and vibrational lines. The kinetic energy of rotation of the nuclei about their common centre of mass is readily solved with the Schroedinger equation and the following energy levels emerge: h 2 E J = J (J + 1), J = 1, 2, 3,... 8π 2 µ R o 2 These rotational energies are very small, and therefore, lines of the pure rotation spectrum are in the far infrared or microwave regions of the spectrum. The total energy of a molecule is given by E = E electronic + E vibration + E rotation. The typical separation between the lowest state and the first excited state is about 2 to 10 ev for electronic energies, about.2 to 2 ev for vibration energies and about 10-5 to 10-3 ev for rotation energies. Note that 1 ev = 1.6 x J which corresponds to emission at a wavelength of 1.24 µm. Figure 3.3 illustrates this schematically. Each transition involving a change in electron energy produces a whole series of emission or absorption lines, since many combinations of changes in vibration and rotation energy are possible. If such a system of lines is observed under low resolution conditions, it appears to be a band with practically a continuous distribution of frequencies. With higher resolution the individual lines can be resolved and the energy differences measured. In this way, the energies of the vibrational states and of the rotational states can be measured. It is apparent that in the higher vibrational states the average internuclear distance R is larger because of the asymmetry of the binding energy curve. This fact produces a higher moment of inertia µr 2 when the vibrational quantum number is large and a correspondingly smaller separation in the rotational energy levels. Thus, precision measurement of the rotational levels as a function of vibrational quantum number permits the study of the asymmetry of the binding energy curve; it is this asymmetry that is responsible for the thermal expansion of molecules. 3.7 Summary of the Interactions between Radiation and Matter One basic type of interaction between radiation and matter can be summarized by a photon transferring all of its energy to an atom or a molecule and thus being removed from the radiation field. The energy of the photon raises an electron to a higher energy level or a molecule to higher rotational or vibrational states. This increase in energy of the receiving atom or molecule can be released in several different ways.

7 3-7 One mechanism is for the activated molecule to collide with another molecule, and to drop back into a lower energy state; the energy thus freed becomes kinetic energy of the molecules and corresponds to warming the gas. This is absorption. The photon is permanently lost or attenuated from the radiation field. A second mechanism for release of the energy increase is the spontaneous transition of the molecule (in about one nanosecond) into its original state by emitting a photon which is identical to the absorbed one except for its direction of propagation. This is scattering, where the photon remains part of the radiation field but the direct beam is attenuated. A third mechanism is the activated molecule releases its energy spontaneously but in two stages. Two photons with different lower energies result; the sum of the energies of the two photons equals the energy of the absorbed photon. The direct beam is attenuated; the original photon has been replaced by two photons at longer wavelengths and is no longer part of the radiation field. This is Raman-scattering. Other mechanisms for energy release are fluorescence and phosphorescence. These occur when the energy is not released spontaneously, but after relaxation times of nanoseconds to hours. Another basic type of interaction involves the conversion of molecular kinetic energy (thermal energy) into electromagnetic energy (photons). This occurs when molecules are activated by collisions with each other and the activation energy is emitted as photons. This is emission. 3.8 Beer's Law and Schwarzchild's Equation In the absence of scattering, the absorption of parallel beam radiation as it passes downward through a horizontal layer of gas of infinitesimal thickness dz is proportional to the number of molecules per unit area that are absorbing radiation along the path. This relationship can be expressed in the form da λ = - di λ / I λ = - k λ ρ sec φ dz, where ρ is the density of the gas and φ is the zenith angle. Here absorbed monochromatic radiance is expressed as an incremental amount of depletion of the incident beam. di λ and dz are both negative quantities, so da λ is positive. The product ρ sec φ dz is the mass within the volume swept out by a unit cross-sectional area of the incident beam as it passes through the layer, as pictured in Figure 3.4. The absorption coefficient k λ is a measure of the fraction of the gas molecules per unit wavelength interval that are absorbing radiation at the wavelength in question. k λ is a function of composition, temperature, and pressure of the gas within the layer. It has units of square metres per kilogram, which makes the product k λ ρ dz dimensionless. Integrating from z up to the top of the atmosphere yields ln I λ - ln I λ = sec φ k λ ρ dz. z Taking the anti-log of both sides and assuming k λ is independent of height, where I λ = I λ exp (- k λ u), u = sec φ ρ dz. z

9 3-9 radiance of the radiation passing upward through it: dl λ = - (L λ - B λ ) k λ ρ sec φ dz. This expression, known as Schwarzchild's equation, is the basis for computations of the transfer of infrared radiation. For an isothermal gas, with constant k λ, this may be integrated to obtain (L λ - B λ ) = (L λo - B λ ) exp (- k λ u), where L λo is the radiance incident on the layer from below. This expression shows that L λ should exponentially approach B λ as the optical thickness of the layer increases. For a layer of infinite optical thickness the emission from the top is B λ regardless of the value of L λo ; that is to say, such a layer behaves as a blackbody. It is often useful to transform the height variable z to pressure p through the hydrostatic equation and the definition of mixing ratio q = ρ/ρ a where ρ and ρ a are the density of gas and air respectively, g ρ dz = - q dp. Thus, the optical depth becomes p u(p) = sec φ q g -1 dp, o and the monochromatic transmittance (the probability that a photon of wavelength l leaving pressure level p will reach the top of the atmosphere) is given by p -1 τ λ (p) = exp [ - sec φ k λ g q dp ]. o 3.9 Atmospheric Scattering Scattering is a physical process by which a particle in the path of an electromagnetic wave continuously abstracts energy from the incident wave and re-radiates that energy in all directions. Therefore, the particle may be thought of as a point source of the scattered energy. In the atmosphere, the particles responsible for scattering cover the sizes from gas molecules (~10-8 cm) to large raindrops and hail particles (~1 cm). The relative intensity of the scattering pattern depends strongly on the ratio of particle size to wavelength of the incident wave. If scattering is isotropic, the scattering pattern is symmetric about the direction of the incident wave. A small anisotropic particle tends to scatter light equally into the forward and backward directions. When the particle becomes larger, the scattered energy is increasingly concentrated in the forward directions. Distribution of the scattered energy involving spherical and certain symmetrical particles may be quantitatively determined by means of the electromagnetic wave theory. When particles are much smaller than the incident wavelength, the scattering is called Rayleigh scattering. For particles whose sizes are comparable to or larger than the wavelength, the scattering is customarily referred to as Mie scattering. Rayleigh scattering indicates that the intensity scattered by air molecules in a specific direction is inversely proportional to the fourth power of the wavelength. A large portion of solar energy, lying between the blue to red portion of the visible spectrum, is Rayleigh scattered by the atmosphere. Blue light (λ µm) has a shorter wavelength than red light (λ µm).

13 3-13 surface. Energy emitted from the earth, on the contrary, is absorbed largely by carbon dioxide, water vapour, and ozone in the atmosphere as evident in Figure 3.7. Trapping of thermal infrared radiation by atmospheric gases is typical of the atmosphere and is, therefore, called the atmospheric effect. Solar radiation is referred to as shortwave radiation because solar energy is concentrated in shorter wavelengths with its peak at about 0.5 µm. Thermal infrared radiation from the earth's atmosphere is referred to as longwave radiation because its maximum energy is in the longer wavelength at about 10 µm. The solar and infrared spectra are separated into two spectral ranges above and below about 4 µm, and the overlap between them is relatively insignificant. This distinction makes it possible to treat the two types of radiative transfer and source functions separately and thereby simplify the complexity of the transfer problem Atmospheric Absorption Bands in the Infrared Spectrum Inspection of high resolution spectroscopic data reveals that there are thousands of absorption lines within each absorption band. The fine structure of molecular absorption bands for the cm -1 is due to water vapour, and for the cm -1 region it is due to carbon dioxide. The optically active gases of the atmosphere, carbon dioxide, water vapour, and ozone are all triatomic molecules. Figure 3.9 shows the absorption spectra for H 2 O and CO 2. Spectroscopic evidence indicates that the three atoms of CO 2 form a symmetrical straight line array having the carbon atom in the middle flanked by oxygen atoms in either side. Because of linear symmetry it cannot have a static electric dipole moment. Figure 3.10a shows the three normal modes of vibration of such a configuration. The symmetrical motion v 1 should not give rise to an electric dipole moment and, therefore, should not be optically active. The v 1 vibration mode has been identified in the Raman spectrum near 7.5 µm. In the v 2 vibration mode, the dipole moment is perpendicular to the axis of the molecule. The 15 µm band represents this particular vibration. The band is referred to as a fundamental because it is caused by a transition from the ground state to the first excited vibrational state. Another fundamental corresponding to the v 3 vibration mode is the 4.3 µm band, which appears at the short-wave edge of the blackbody curve of atmospheric temperatures. The water molecule forms an isosceles triangle which is obtuse. Figure 3.10b shows the three normal modes of vibration for such a structure. The 6.3 µm band has been identified as the v 2 fundamental. The two fundamentals, v 1 and v 3, are found close together in a band near 2.7 µm, i.e., on the shortwave side of the infrared spectral region. The band covering the region from 800 to 400 cm -1 shown in Figure 3.7 represents the purely rotational spectrum of water vapour. The water molecule forms an asymmetrical top with respect to rotation, and the line structure of the spectrum does not have the simplicity of a symmetrical rotator such as found in the CO 2 molecule. Close inspection shows that the absorption lines have no clear-cut regularity. The fine structure of the 6.3 µm band is essentially similar to that of the pure rotational band. In the region between the two water vapour bands, i.e. between about eight and 12 µm, the so-called atmospheric window, absorption is continuous and is primarily due to water vapour. Absorption by carbon dioxide is typically a small part of the total in this region. The overlap of water vapour with ozone in this region is insignificant in the computations of cooling rates since water vapour is important mainly in the lower atmosphere, while cooling due to ozone takes place primarily in the stratosphere and higher. The ozone molecule is of the triatomic nonlinear type (Figure 3.10b) with a relatively strong rotation spectrum. The three fundamental vibrational bands v 1, v 2, and v 3 occur at wavelengths of 9.066, 14.27, and µm, respectively. The very strong v 3 and moderately strong v 1 fundamentals combine to make the well-known 9.6 µm band of ozone. The v 2 fundamental is well-

15 3-15 Table 3.1 Reflectance (in percent) of various surfaces in the spectral range of solar radiation (using the US Standard Atmosphere of 1976) Bare soil Sand, desert Grass Forest Snow (clean, dry) Snow (wet, dirty) Sea surface (sun angle) > 25 < 10 Sea surface (low sun angle) Table 3.2 Composition of the Atmosphere (from the US Standard Atmosphere of 1976) Permanent Constituents Variable Constituents Constituent % by volume Constituent % by volume Nitrogen (N 2 ) Water vapour (H 2 O) Oxygen (O 2 ) Ozone (O 3 ) 0-12x10-4 Argon (Ar) Sulfur dioxide (SO 2 ) x10-4 Carbon dioxide (CO 2 ) Nitrogen dioxide (NO 2 ) x10-4 Neon (Ne) 18.18x10-4 Ammonia (NH 3 ) x10-4 Helium (He) 5.24x10-4 Nitric oxide (NO) x10-4 Krypton (Kr) 1.14x10-4 Hydrogen sulfide (H 2 S) x10-4 Xenon (Xe) 0.089x10-4 Nitric acid vapour (HNO 3 ) Trace Hydrogen (H 2 ) 0.5x10-4 Methane (CH 4 ) 1.5x10-4 Nitrous oxide (N 2 O)1 0.27x10-4 Carbon monoxide (CO)1 0.19x Concentration near the earth's surface.

16 3-16 Figure 3.1: Schematic for reflectance, absorptance, and transmittance in a layer of gases. Figure 3.2: Vibrational energy levels of a diatomic molecule.

17 3-17 Figure 3.3: Energy levels of a diatomic molecule. Every level of electronic + vibrational energy has rotational fine structure, but this structure is illustrated only for the n = 2 states. Figure 3.4: Depletion of an incident beam of unit cross-section while passing through an absorbing layer of infinitesimal thickness.

18 3-18 Figure 3.5a: Size parameter a as a function of incident radiation and particle radius. Figure 3.5b: Scattering area coefficient K as a function of size parameter for refractive indices of (solid curve) and (dashed curve).

19 3-19 Figure 3.6: Spectral irradiance distribution curves related to the sun: (1) the observed solar irradiance at the top of the atmosphere (after Thekaekara, 1976); and (2) solar irradiance observed at sea level. The shaded areas represent absorption due to various gases in a clear atmosphere. O3 CO2 H20 CO2 Figure 3.7: Earth-atmosphere emitted radiances overlaid on Planck function envelopes.

20 3-20 Figure 3.8a: Atmospheric transmission characteristics showing the major absorption bands. Figure 3.8b: Atmospheric transmission characteristics and the associated remote sensing technologies.

21 3-21 Figure 3.9: Absorption spectrum of the water vapour rotational band (beyond 18 µm) and the carbon dioxide band (near 15 µm) at high spectral resolution. Figure 3.10: Normal modes of a linear (a) and triangular (b) molecules.

22 3-22 Figure 3.11: Atmospheric transmittance in the microwave region of the spectrum as a function of frequency. Figure 3.12: Spectral regions used for remote sensing of the earth atmosphere and surface from satellites. ε indicates emissivity, q denotes water vapour, and T represents temperature.

23 3-23 Figure 3.13: Infrared atmospheric absorption (top) and earth surface emissivity for some surfaces (bottom).

### NATS 101 Section 13: Lecture 6. The Greenhouse Effect and Earth-Atmosphere Energy Balance

NATS 101 Section 13: Lecture 6 The Greenhouse Effect and Earth-Atmosphere Energy Balance FOUR POSSIBLE FATES OF RADIATION: 1.Transmitted 2. Reflected 3. Scattered 4. Absorbed The atmosphere does ALL of

### Lecture 2: Radiation/Heat in the atmosphere

Lecture 2: Radiation/Heat in the atmosphere TEMPERATURE is a measure of the internal heat energy of a substance. The molecules that make up all matter are in constant motion. By internal heat energy, we

### Blackbody radiation. Main Laws. Brightness temperature. 1. Concepts of a blackbody and thermodynamical equilibrium.

Lecture 4 lackbody radiation. Main Laws. rightness temperature. Objectives: 1. Concepts of a blackbody, thermodynamical equilibrium, and local thermodynamical equilibrium.. Main laws: lackbody emission:

1. Radiative Transfer Virtually all the exchanges of energy between the earth-atmosphere system and the rest of the universe take place by radiative transfer. The earth and its atmosphere are constantly

### ESCI 107/109 The Atmosphere Lesson 2 Solar and Terrestrial Radiation

ESCI 107/109 The Atmosphere Lesson 2 Solar and Terrestrial Radiation Reading: Meteorology Today, Chapters 2 and 3 EARTH-SUN GEOMETRY The Earth has an elliptical orbit around the sun The average Earth-Sun

### Overview. What is EMR? Electromagnetic Radiation (EMR) LA502 Special Studies Remote Sensing

LA502 Special Studies Remote Sensing Electromagnetic Radiation (EMR) Dr. Ragab Khalil Department of Landscape Architecture Faculty of Environmental Design King AbdulAziz University Room 103 Overview What

### Solar Energy. Outline. Solar radiation. What is light?-- Electromagnetic Radiation. Light - Electromagnetic wave spectrum. Electromagnetic Radiation

Outline MAE 493R/593V- Renewable Energy Devices Solar Energy Electromagnetic wave Solar spectrum Solar global radiation Solar thermal energy Solar thermal collectors Solar thermal power plants Photovoltaics

### The Earth s Atmosphere

THE SUN-EARTH SYSTEM III The Earth s Atmosphere Composition and Distribution of the Atmosphere The composition of the atmosphere and the way its gases interact with electromagnetic radiation determine

### Corso di Fisica Te T cnica Ambientale Solar Radiation

Solar Radiation Solar radiation i The Sun The Sun is the primary natural energy source for our planet. It has a diameter D = 1.39x10 6 km and a mass M = 1.989x10 30 kg and it is constituted by 1/3 of He

### Infrared Spectroscopy: Theory

u Chapter 15 Infrared Spectroscopy: Theory An important tool of the organic chemist is Infrared Spectroscopy, or IR. IR spectra are acquired on a special instrument, called an IR spectrometer. IR is used

### Interactions Between Electromagnetic Wave and Targets

Interactions Between Electromagnetic Wave and Targets Electromagnetic radiation wavelength λ, frequency ν and the velocity υ have the following relation. λ = υ/ν by: Dr. Kiyoshi Honda Space Technology

### Treasure Hunt. Lecture 2 How does Light Interact with the Environment? EMR Principles and Properties. EMR and Remote Sensing

Lecture 2 How does Light Interact with the Environment? Treasure Hunt Find and scan all 11 QR codes Choose one to watch / read in detail Post the key points as a reaction to http://www.scoop.it/t/env202-502-w2

### Further Modification of JB s criticism of the FM Paper in E & E

Further Modification of JB s criticism of the FM Paper in E & E This is a shortened and updated version of my criticism of FM s paper [THE STABLE STATIONARY VALUE OF THE EARTH S GLOBAL AVERAGE ATMOSPHERIC

### The Nature of Electromagnetic Radiation

II The Nature of Electromagnetic Radiation The Sun s energy has traveled across space as electromagnetic radiation, and that is the form in which it arrives on Earth. It is this radiation that determines

### where h = 6.62 10-34 J s

Electromagnetic Spectrum: Refer to Figure 12.1 Molecular Spectroscopy: Absorption of electromagnetic radiation: The absorptions and emissions of electromagnetic radiation are related molecular-level phenomena

### Lecture 1. The nature of electromagnetic radiation.

Lecture 1. The nature of electromagnetic radiation. 1. Basic introduction to the electromagnetic field: Dual nature of electromagnetic radiation Electromagnetic spectrum. Basic radiometric quantities:

### Light as a Wave. The Nature of Light. EM Radiation Spectrum. EM Radiation Spectrum. Electromagnetic Radiation

The Nature of Light Light and other forms of radiation carry information to us from distance astronomical objects Visible light is a subset of a huge spectrum of electromagnetic radiation Maxwell pioneered

### Radiation Transfer in Environmental Science

Radiation Transfer in Environmental Science with emphasis on aquatic and vegetation canopy media Autumn 2008 Prof. Emmanuel Boss, Dr. Eyal Rotenberg Introduction Radiation in Environmental sciences Most

### Earth s Energy Balance & the Greenhouse Effect

Earth s Energy Balance & the Greenhouse Effect Outline: The Earth s Energy Balance: Electromagnetic Spectrum: Ultraviolet (UV) Visible Infrared (IR) Blackbody Radiation Albedo (reflectivity) Greenhouse

### The Greenhouse Effect

The Greenhouse Effect The Greenhouse Effect Solar and terrestrial radiation occupy different ranges of the electromagnetic spectrum, that we have been referring to as shortwave and longwave. The Greenhouse

### 5. The Nature of Light. Does Light Travel Infinitely Fast? EMR Travels At Finite Speed. EMR: Electric & Magnetic Waves

5. The Nature of Light Light travels in vacuum at 3.0. 10 8 m/s Light is one form of electromagnetic radiation Continuous radiation: Based on temperature Wien s Law & the Stefan-Boltzmann Law Light has

### Heating & Cooling in Molecular Clouds

Lecture 8: Cloud Stability Heating & Cooling in Molecular Clouds Balance of heating and cooling processes helps to set the temperature in the gas. This then sets the minimum internal pressure in a core

### Greenhouse Effect and the Global Energy Balance

Greenhouse Effect and the Global Energy Balance Energy transmission ( a a refresher) There are three modes of energy transmission to consider. Conduction: the transfer of energy in a substance by means

### Chapter 2. The global energy balance. 2.1 Planetary emission temperature

Chapter 2 The global energy balance We consider now the general problem of the radiative equilibrium temperature of the Earth. The Earth is bathed in solar radiation and absorbs much of that incident upon

### 2 Absorbing Solar Energy

2 Absorbing Solar Energy 2.1 Air Mass and the Solar Spectrum Now that we have introduced the solar cell, it is time to introduce the source of the energy the sun. The sun has many properties that could

### I ν = λ 2 I λ. λ<0.35 µm F λ =0 0.70 µm <λ<1.00 µm F λ =0.2 Wm 2 µm 1. λ>1.00 µm F λ =0. F λi 4λ i. i 1

Chapter 4 4.12 Remote sensing in the microwave part of the spectrum relies on radiation emitted by oxygen molecules at frequencies near 55 ghz. Calculate the wavelength and wavenumber of this radiation.

### Electromagnetic Radiation (EMR) and Remote Sensing

Electromagnetic Radiation (EMR) and Remote Sensing 1 Atmosphere Anything missing in between? Electromagnetic Radiation (EMR) is radiated by atomic particles at the source (the Sun), propagates through

### - the total energy of the system is found by summing up (integrating) over all particles n(ε) at different energies ε

Average Particle Energy in an Ideal Gas - the total energy of the system is found by summing up (integrating) over all particles n(ε) at different energies ε - with the integral - we find - note: - the

### 2. Molecular stucture/basic

2. Molecular stucture/basic spectroscopy The electromagnetic spectrum Spectral region for atomic and molecular spectroscopy E. Hecht (2nd Ed.) Optics, Addison-Wesley Publishing Company,1987 Spectral regions

### MCQ - ENERGY and CLIMATE

1 MCQ - ENERGY and CLIMATE 1. The volume of a given mass of water at a temperature of T 1 is V 1. The volume increases to V 2 at temperature T 2. The coefficient of volume expansion of water may be calculated

### COLLEGE PHYSICS. Chapter 29 INTRODUCTION TO QUANTUM PHYSICS

COLLEGE PHYSICS Chapter 29 INTRODUCTION TO QUANTUM PHYSICS Quantization: Planck s Hypothesis An ideal blackbody absorbs all incoming radiation and re-emits it in a spectrum that depends only on temperature.

### ENERGY & ENVIRONMENT

Greenhouse molecules, their spectra and function in the atmosphere by Jack Barrett Reprinted from ENERGY & ENVIRNMENT VLUME 16 No. 6 2005 MULTI-SCIENCE PUBLISING C. LTD. 5 Wates Way, Brentwood, Essex CM15

### Physics 9e/Cutnell. correlated to the. College Board AP Physics 1 Course Objectives

Physics 9e/Cutnell correlated to the College Board AP Physics 1 Course Objectives Big Idea 1: Objects and systems have properties such as mass and charge. Systems may have internal structure. Enduring

### A Theoretical Analysis of the Effect of Greenhouse Gases in the Atmosphere

A Theoretical Analysis of the Effect of Greenhouse Gases in the Atmosphere Michael Hammer A presentation to The Lavoisier Group s 2007 Workshop Rehabilitating Carbon Dioxide held in Melbourne on 29-30

### 8.1 Radio Emission from Solar System objects

8.1 Radio Emission from Solar System objects 8.1.1 Moon and Terrestrial planets At visible wavelengths all the emission seen from these objects is due to light reflected from the sun. However at radio

### Take away concepts. What is Energy? Solar Energy. EM Radiation. Properties of waves. Solar Radiation Emission and Absorption

Take away concepts Solar Radiation Emission and Absorption 1. 2. 3. 4. 5. 6. Conservation of energy. Black body radiation principle Emission wavelength and temperature (Wein s Law). Radiation vs. distance

### Solar Flux and Flux Density. Lecture 3: Global Energy Cycle. Solar Energy Incident On the Earth. Solar Flux Density Reaching Earth

Lecture 3: Global Energy Cycle Solar Flux and Flux Density Planetary energy balance Greenhouse Effect Vertical energy balance Latitudinal energy balance Seasonal and diurnal cycles Solar Luminosity (L)

### Energy Pathways in Earth s Atmosphere

BRSP - 10 Page 1 Solar radiation reaching Earth s atmosphere includes a wide spectrum of wavelengths. In addition to visible light there is radiation of higher energy and shorter wavelength called ultraviolet

### CHAPTER 2 Energy and Earth

CHAPTER 2 Energy and Earth This chapter is concerned with the nature of energy and how it interacts with Earth. At this stage we are looking at energy in an abstract form though relate it to how it affect

### lecture 3: The greenhouse effect

lecture 3: The greenhouse effect Concepts from Lecture 2 Temperature Scales Forms of Heat Transfer Electromagnetic Spectrum Planck Law Stefan-Boltzmann Law Inverse Square Law Reflectivity or Albedo Solar

### Chapter 5 Light and Matter: Reading Messages from the Cosmos

Chapter 5 Light and Matter: Reading Messages from the Cosmos Messages Interactions of Light and Matter The interactions determine everything we see, including what we observe in the Universe. What is light?

### Chapter 16 Heat Transfer. Topics: Conduction Convection Radiation Greenhouse Effect/Global Warming

Chapter 16 Heat Transfer Topics: Conduction Convection Radiation Greenhouse Effect/Global Warming Radiation Every object at a temperature above absolute zero is an emitted of electromagnetic radiation

### We know the shape of the solar spectrum. Let s consider that the earth atmosphere is 8000 km thick.

We know the shape of the solar spectrum. How is this spectral shape and irradiance of the solar light affected by the earth s atmosphere? Let s consider that the earth atmosphere is 8000 km thick. The

### Clouds and the Energy Cycle

August 1999 NF-207 The Earth Science Enterprise Series These articles discuss Earth's many dynamic processes and their interactions Clouds and the Energy Cycle he study of clouds, where they occur, and

### Plenary 2. All you need to know about Greenhouse Gases. Outline

Plenary 2. All you need to know about Greenhouse Gases Outline What drives the Climate? What are Greenhouse Gases and the Greenhouse Effect? How the changes in GHG concentrations produce global warming/climate

### Raman Scattering Theory David W. Hahn Department of Mechanical and Aerospace Engineering University of Florida (dwhahn@ufl.edu)

Introduction Raman Scattering Theory David W. Hahn Department of Mechanical and Aerospace Engineering University of Florida (dwhahn@ufl.edu) The scattering of light may be thought of as the redirection

### The greenhouse effect and global warming

CA1. The greenhouse effect and global warming. Vicky Wong Page 1 of 7 The greenhouse effect and global warming The sun produces radiation mainly in the ultraviolet (UV), visible (vis) and infrared (IR)

### Lecture 3: Greenhouse gasses:

The Atmosphere Lecture 3: Greenhouse gasses: Absorption and emission of radiation by greenhouse gasses The atmospheric energy balance and the greenhouse effect The vertical structure of the atmosphere

### a) species of plants that require a relatively cool, moist environment tend to grow on poleward-facing slopes.

J.D. McAlpine ATMS 611 HMWK #8 a) species of plants that require a relatively cool, moist environment tend to grow on poleward-facing slopes. These sides of the slopes will tend to have less average solar

### EARTH S ATMOSPHERE AND ITS SEASONS

EARTH S ATMOSPHERE AND ITS SEASONS Provided by Tasa Graphic Arts, Inc. for Earthʼs Atmosphere and Its Seasons CD-ROM http://www.tasagraphicarts.com/progeas.html 1.The Importance of Weather (wx) The U.S.

### Symmetric Stretch: allows molecule to move through space

BACKGROUND INFORMATION Infrared Spectroscopy Before introducing the subject of IR spectroscopy, we must first review some aspects of the electromagnetic spectrum. The electromagnetic spectrum is composed

### Greenhouse Effect and Radiative Balance on Earth and Venus

Venus Exploration Advisory Group Greenhouse Effect and Radiative Balance on Earth and Venus Dave Crisp November 5, 2007-1- Venus and Earth: An Unlikely Pair Most theories of solar system evolution assume

### Absorption by atmospheric gases in the IR, visible and UV spectral regions.

Lecture 6. Absorption by atmospheric gases in the IR, visible and UV spectral regions. Objectives: 1. Gaseous absorption in thermal IR. 2. Gaseous absorption in the visible and near infrared. 3. Gaseous

### The Atmospheres of Different Planets

UMEÅ UNIVERSITY October 12, 2010 Department of Physics Space Physics Project The Atmospheres of Different Planets Amir Asadpoordarvish amas0004@student.umu.se Contents Introduction... 2 1. Mercury... 2

### Today s Lecture: Radiation Hartmann, Global Physical Climatology (1994), Ch. 2, 3, 6 Peixoto and Oort, Ch. 4, 6, 7

Today s Lecture: Radiation Hartmann, Global Physical Climatology (1994), Ch. 2, 3, 6 Peixoto and Oort, Ch. 4, 6, 7 5 The climate system 1. Introduction 2. Atmosphere 3. Ocean 4. Land, biosphere, cryosphere

### Emission Temperature of Planets

Emission Temperature of Planets The emission temperature of a planet, T e, is the temperature with which it needs to emit in order to achieve energy balance (assuming the average temperature is not decreasing

### Dr. Muhammad Asif Hanif, Department of Chemistry, University of Agriculture, Faisalabad, Pakistan

Incoming solar energy is largely in the visible region of the spectrum. The shorter wavelength blue solar light is scattered relatively more strongly by molecules and particles in the upper atmosphere,

### Intended Learning Outcomes

An Introduction to Thermal Radiation This problem provides an introduction to thermal and atmospheric physics. Intended Learning Outcomes By the end of this activity students should be able to: Use basic

### Physics Open House. Faraday's Law and EM Waves Change in the magnetic field strength in coils generates a current. Electromagnetic Radiation

Electromagnetic Radiation (How we get most of our information about the cosmos) Examples of electromagnetic radiation: Light Infrared Ultraviolet Microwaves AM radio FM radio TV signals Cell phone signals

Blackbody radiation derivation of Planck s radiation low 1 Classical theories of Lorentz and Debye: Lorentz (oscillator model): Electrons and ions of matter were treated as a simple harmonic oscillators

### Application Note AN4

TAKING INVENTIVE STEPS IN INFRARED. MINIATURE INFRARED GAS SENSORS GOLD SERIES UK Patent App. No. 2372099A USA Patent App. No. 09/783,711 World Patents Pending INFRARED SPECTROSCOPY Application Note AN4

### Principle of Thermal Imaging

Section 8 All materials, which are above 0 degrees Kelvin (-273 degrees C), emit infrared energy. The infrared energy emitted from the measured object is converted into an electrical signal by the imaging

### Radiative Convective Equilibrium and the Greenhouse Effect

Radiative Convective Equilibrium and the Greenhouse Effect Weston Anderson September 19, 2016 Contents 1 Introduction 1 2 Basics of radiation 1 3 Emission temperature of earth 2 3.1 Radiative equilibrium........................

### Copyrighted Material. 1 Basics of Climate. The climate s delicate, the air most sweet. William Shakespeare, A Winter s Tale

1 Basics of Climate The climate s delicate, the air most sweet. William Shakespeare, A Winter s Tale To appreciate the role of the ocean in climate, we need to have a basic understanding of how the climate

### Chapter 8 Molecules. Some molecular bonds involve sharing of electrons between atoms. These are covalent bonds.

Chapter 8 Molecules (We have only three days for chapter 8!) 8.1 The Molecular Bond A molecule is an electrically neutral group of atoms held together strongly enough to behave as a single particle. A

### Chapter 24. Wave Optics

Chapter 24 Wave Optics Wave Optics The wave nature of light is needed to explain various phenomena. Interference Diffraction Polarization The particle nature of light was the basis for ray (geometric)

### Greenhouse Effect Mechanism and Radiative Forcing

Greenhouse Effect Mechanism and Radiative Forcing How does radiative energy balance help determine Earth s climate? How does the greenhouse effect work? What is radiative forcing? References AR4 Ch. 2

### III. Radiation and the Greenhouse Effect

III. Radiation and the Greenhouse Effect A. The electromagnetic spectrum consists of radiation we can see (visible light, the colors of the rainbow), radiation we can feel (the infrared), radiation we

### Energy Transport. Focus on heat transfer. Heat Transfer Mechanisms: Conduction Radiation Convection (mass movement of fluids)

Energy Transport Focus on heat transfer Heat Transfer Mechanisms: Conduction Radiation Convection (mass movement of fluids) Conduction Conduction heat transfer occurs only when there is physical contact

### Experiment #5: Qualitative Absorption Spectroscopy

Experiment #5: Qualitative Absorption Spectroscopy One of the most important areas in the field of analytical chemistry is that of spectroscopy. In general terms, spectroscopy deals with the interactions

Blackbody Radiation References 1) R.A. Serway, R.J. Beichner: Physics for Scientists and Engineers with Modern Physics, 5 th Edition, Vol. 2, Ch.40, Saunders College Publishing (A Division of Harcourt

Lecture 8: Radiation Spectrum The information contained in the light we receive is unaffected by distance The information remains intact so long as the light doesn t run into something along the way Since

### D.S. Boyd School of Earth Sciences and Geography, Kingston University, U.K.

PHYSICAL BASIS OF REMOTE SENSING D.S. Boyd School of Earth Sciences and Geography, Kingston University, U.K. Keywords: Remote sensing, electromagnetic radiation, wavelengths, target, atmosphere, sensor,

### Quantum Mechanics I Physics 325. Importance of Hydrogen Atom

Quantum Mechanics I Physics 35 Atomic spectra and Atom Models Importance of Hydrogen Atom Hydrogen is the simplest atom The quantum numbers used to characterize the allowed states of hydrogen can also

### Indiana's Academic Standards 2010 ICP Indiana's Academic Standards 2016 ICP. map) that describe the relationship acceleration, velocity and distance.

.1.1 Measure the motion of objects to understand.1.1 Develop graphical, the relationships among distance, velocity and mathematical, and pictorial acceleration. Develop deeper understanding through representations

### P R E A M B L E. The problem is run over one week with the following pattern: Facilitated workshop problems for class discussion (2 hours) Lecture

GREENHOUSE EFFECT AN INTRODUCTION TO THERMAL RADIATION P R E A M B L E The original form of the problem is the first part of a four week (15 credit) module in the IScience programme at the University of

### The Phenomenon of Photoelectric Emission:

The Photoelectric Effect. The Wave particle duality of light Light, like any other E.M.R (electromagnetic radiation) has got a dual nature. That is there are experiments that prove that it is made up of

### CHAPTER 12 ATOMS ONE MARK QUESTIONS WITH ANSWER. Ans: Electrons were discovered by J.J Thomason in the year 1897.

CHAPTER 12 ATOMS ONE MARK QUESTIONS WITH ANSWER 1. Who discovered electrons? Ans: Electrons were discovered by J.J Thomason in the year 1897. 2. What is the electric charge on an atom? Ans: At atom of

### - thus, the total number of atoms per second that absorb a photon is

Stimulated Emission of Radiation - stimulated emission is referring to the emission of radiation (a photon) from one quantum system at its transition frequency induced by the presence of other photons

### Chapter 04: Atmosphere and Surface Energy Balance. Energy Essentials Energy Balance in the Troposphere Energy Balance at Earth s Surface

Chapter 04: Atmosphere and Surface Energy Balance Energy Essentials Energy Balance in the Troposphere Energy Balance at Earth s Surface Energy Essentials Energy Pathways and Principles Energy Pathways

### Physics 202H - Introductory Quantum Physics I Homework #02 - Solutions Fall 2004 Due 5:01 PM, Monday 2004/09/27

Physics 0H - Introductory Quantum Physics I Homework #0 - Solutions Fall 004 Due 5:01 PM, Monday 004/09/7 [65 points total] Journal questions. Briefly share your thoughts on the following questions: What

### Boltzmann Distribution Law

Boltzmann Distribution Law The motion of molecules is extremely chaotic Any individual molecule is colliding with others at an enormous rate Typically at a rate of a billion times per second We introduce

### Wave Properties of Electromagnetic Radiation

Wave Properties of Electromagnetic Radiation Two options are available for analytical utility when an analyte interacts with a beam of electromagnetic radiation in an instrument 1. We can monitor the changes

### The Fundamentals of Infrared Spectroscopy. Joe Van Gompel, PhD

TN-100 The Fundamentals of Infrared Spectroscopy The Principles of Infrared Spectroscopy Joe Van Gompel, PhD Spectroscopy is the study of the interaction of electromagnetic radiation with matter. The electromagnetic

### Topics through Chapter 4

Topics through Chapter 4 3.5 The Doppler Effect: this is how we learn about the motions of objects in the universe, discover extraterrestrial planets, black holes at the centers of galaxies, and the expansion

### The Surface Energy Budget

The Surface Energy Budget The radiation (R) budget Shortwave (solar) Radiation Longwave Radiation R SW R SW α α = surface albedo R LW εσt 4 ε = emissivity σ = Stefan-Boltzman constant T = temperature Subsurface

### 1. Theoretical background

1. Theoretical background We consider the energy budget at the soil surface (equation 1). Energy flux components absorbed or emitted by the soil surface are: net radiation, latent heat flux, sensible heat

### 4.5 Orbits, Tides, and the Acceleration of Gravity

4.5 Orbits, Tides, and the Acceleration of Gravity Our goals for learning: How do gravity and energy together allow us to understand orbits? How does gravity cause tides? Why do all objects fall at the

### Global warming and its implications for conservation.

Global warming and its implications for conservation. 4. Greenhouse gasses and the lapse rate The layer model is a reasonable heuristic model, but it assumes that the atmosphere acts as a perfect blackbody

### Homework 2 Due Wednesday, July 19, 2006 Astronomy/EPS 12 The Planets

Homework 2 Due Wednesday, July 19, 2006 Astronomy/EPS 12 The Planets Chapter 4, Review and Discussion 11 - Why do excited atoms absorb and reemit radiation at characteristic frequencies? As described by

### ENERGY BALANCE AND GREENHOUSE EFFECT. D. Stahle, Global Change (ENDY/GEOG 5113)

ENERGY BALANCE AND GREENHOUSE EFFECT D. Stahle, Global Change (ENDY/GEOG 5113) Gedzelman, S.D., 1980. The Science and Wonders of the Atmosphere. Wiley, NY. Huschke, R.E., 1989. Glossary of Meteorology.

### Our Galaxy, the Milky Way

Our Galaxy, the Milky Way In the night sky, the Milky Way appears as a faint band of light. Dusty gas clouds obscure our view because they absorb visible light. This is the interstellar medium that makes

### CHAPTER 2: Electromagnetic Radiation Principles

CHAPTER 2: Electromagnetic Radiation Principles REFERENCE: Remote Sensing of the Environment John R. Jensen (2007) Second Edition Pearson Prentice Hall DETECTING THE REMOTE SIGNAL 1 Electromagnetic Energy

### Energy. Mechanical Energy

Principles of Imaging Science I (RAD119) Electromagnetic Radiation Energy Definition of energy Ability to do work Physicist s definition of work Work = force x distance Force acting upon object over distance

### Passive Remote Sensing of Clouds from Airborne Platforms

Passive Remote Sensing of Clouds from Airborne Platforms Why airborne measurements? My instrument: the Solar Spectral Flux Radiometer (SSFR) Some spectrometry/radiometry basics How can we infer cloud properties

### DO PHYSICS ONLINE FROM QUANTA TO QUARKS QUANTUM (WAVE) MECHANICS

DO PHYSICS ONLINE FROM QUANTA TO QUARKS QUANTUM (WAVE) MECHANICS Quantum Mechanics or wave mechanics is the best mathematical theory used today to describe and predict the behaviour of particles and waves.