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GEOG 372 February 2 2009

GEOG 372 February 2 2009. Instructor Dr. Christopher Neigh NASA Goddard Space flight Center Building 33 Room F120 Telephone: 301 614 6681 UMD office: TBD E-mail: cneigh@gmail.com. Christopher S. Neigh Office Hours: Mon/Wed 11:00 to 12:00 am or by appointment

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GEOG 372 February 2 2009

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  1. GEOG 372February 2 2009

  2. Instructor Dr. Christopher Neigh NASA Goddard Space flight Center Building 33 Room F120 Telephone: 301 614 6681 UMD office: TBD E-mail: cneigh@gmail.com

  3. Christopher S. Neigh Office Hours: Mon/Wed 11:00 to 12:00 am or by appointment Do not hesitate to contact me for an appointment!!!!!

  4. Course Textbook • Campbell, J.B., Introduction to Remote Sensing, 4th edition, The Gulford Press, 2007.

  5. Class Web Page All class materials will be placed on the Department of Geographies Courses Webpage: http://www.geog.umd.edu/ Click onto Academics/Course Information/ Course Materials/GEOG 372

  6. Summary of Remote Sensing Courses in the Department of Geography GEOG 372 – Introduction to Remote Sensing GEOG 472 – Principles of Remote Sensing GEOG671 (GEOG 609): Remote sensing instrumentation and observing systems GEOG672: Physical principles of remote sensing and land surface characterization Geog 788A – Seminar in Remote Sensing

  7. Course Goals • Provide the student with a basic understanding of the science and technology of remote sensing • Provide a strong foundation for GEOG 472 • Enable the student to understand the differences between the various satellite remote sensing systems that are in existence today • Enable the student to differentiate between the different types of information products generated from data collected by these systems

  8. Course Structure • Two lectures per week • Readings assigned for most lectures • One lab per week • Most labs will be written up and graded • Additional work outside of the lab will be required to complete lab assignments

  9. Evaluation of Students • 4 Pop quizzes – each 2.5% (10% total) • 2 hourly exams - each 20% (40% total) • Comprehensive final exam – 25% • Laboratory Exercises – ~3% each (25% total) • Test Grading Policy – One abnormally low score (out of three) will be partially discounted

  10. Exams • Each exam will cover 1/3 of course material • Final exam will also include material from entire course • Only cover material presented in Lecture, but readings provide important supplemental material for student • Exam dates • 25 February (normal class time) • 08 April (normal class time) • Final, will notify asap

  11. Grading – Lab Exercises • Each lab exercise is worth 10 points and is due at the beginning of the next lab period • Lab exercises turned in late will not receive full credit

  12. Late Lab Exercises • Up to 4 days late – 8 points maximum • 5 to 7 days late – 5 points maximum • 8 to 14 days late – 2 points maximum • > 14 days late – 0 points

  13. SyllabusLecture/Hourly Exam Schedule and Assigned Readings (Subject to Change) Week Date Lecture Topic Reading Part I Remote Sensing Basics 1 26-Jan 1 Introduction to Remote Sensing Ch 1 28-Jan University Closed2 02-Feb 2 Principles of EM radiometry and basic EM Theory Ch 2 04-Feb Principles of EM radiometry and basic EM Theory II3 09-Feb 3 Atmospheric influences on EM Radiation I 11-Feb 4 Photographic Systems/Image Interpretation Ch 3,54 16-Feb 5 The Digital Image I Ch 4,10 18-Feb The Digital Image II5 23-Feb 6 Applications with areal and space photography 25-Feb Exam 1 26-Feb Lab 1 Introduction to ENVI – manipulation of digital imagery

  14. Lecture 2 The Basics of Electromagnetic RadiationFebruary 2nd 2009

  15. Reading Assignment • Campbell, Chapter 2 Unless otherwise noted, all images in this lecture are from • Jensen, J.R., Remote Sensing of the Environment - An Earth Resource Perspective, 544 pp., Prentice Hall, Upper Saddle River, NJ, 2000.

  16. The electromagnetic (EM) spectrum

  17. EM Spectrum Regions Used in Remote Sensing  = EM radiation wavelength • Ultraviolet (  < 0.4 m) • Visible ( 0.4 m <  < 0.7 m) • Reflected IR ( 0.7 m <  < 2.8 m) • Emitted (thermal) IR ( 2.4 m <  < 20 m) • Microwave ( 1 cm <  < 1 m)

  18. Lecture Topics • Types of thermal energy transfer • Models of EM radiation/energy • Particle Model Photon absorption, excitation, de-excitation • Wave Model Characteristics of EM waves Polarization, speed of light, wavelength, frequency • Laws governing EM radiation • Stephan-Boltzman Law • Planck’s Formula • Wien Displacement Law • Remote sensing in the visible and reflected infrared region of the EM spectrum • Descriptors of EM radiation • Radiant flux • Radiant flux density – irradiance and exitance • Radiation budget equation • Reflection • Absorption • Transmission

  19. Types of Thermal Energy Transfer • Energy is the ability to do work • There are three ways to transfer thermal energy from one place or object to another • Conduction • Convection • Radiation

  20. Conduction – transfer of energy through collisions of atoms or molecules

  21. Convection - physically moving the molecules/atoms from one place to another

  22. Radiation – Emission or transfer of energy in the form of electromagnetic waves or particles

  23. Lecture Topics • Types of thermal energy transfer • Models of EM radiation/energy • Particle Model Photon absorption, excitation, de-excitation • Wave Model Characteristics of EM waves Polarization, speed of light, wavelength, frequency • Laws governing EM radiation • Stephan-Boltzman Law • Planck’s Formula • Wien Displacement Law • Remote sensing in the visible and reflected infrared region of the EM spectrum • Descriptors of EM radiation • Radiant flux • Radiant flux density – irradiance and exitance • Radiation budget equation • Reflection • Absorption • Transmission

  24. What is EM Radiation? Two models have been developed to describe EM radiation or energy • Particle Model of EM Energy – describes how EM radiation interacts with matter • Wave Model of EM Energy – describes how EM radiation is propagated, e.g., how it moves through space

  25. Lecture Topics • Types of thermal energy transfer • Models of EM radiation/energy • Particle Model Photon absorption, excitation, de-excitation • Wave Model Characteristics of EM waves Polarization, speed of light, wavelength, frequency • Laws governing EM radiation • Stephan-Boltzman Law • Planck’s Formula • Wien Displacement Law • Remote sensing in the visible and reflected infrared region of the EM spectrum • Descriptors of EM radiation • Radiant flux • Radiant flux density – irradiance and exitance • Radiation budget equation • Reflection • Absorption • Transmission

  26. EM Radiation Particle Model -Radiation from Atomic Structures Einstein discovered that when light (EM radiation) interacts with matter, it behaves like it is composed of photons • Photons carry energy and momentum, i.e., particle like properties • Thus, light is considered to be a unique type of matter

  27. Important components of the Particle Model of EM Radiation • When EM energy strikes an atom, excitation occurs, e.g., thermal energy from the EM energy (e.g., a photon) is absorbed by the atom, the atom is warmed, and an electron in the atom gains enough energy to obtain a higher orbit • When atom cools down, it can do so by releasing EM energy – this process is called de-excitation – it releases a photon of EM energy

  28. Lecture Topics • Types of thermal energy transfer • Models of EM radiation/energy • Particle Model Photon absorption, excitation, de-excitation • Wave Model Characteristics of EM waves Polarization, speed of light, wavelength, frequency • Laws governing EM radiation • Stephan-Boltzman Law • Planck’s Formula • Wien Displacement Law • Remote sensing in the visible and reflected infrared region of the EM spectrum • Descriptors of EM radiation • Radiant flux • Radiant flux density – irradiance and exitance • Radiation budget equation • Reflection • Absorption • Transmission

  29. EM radiation can be thought of as the propagation through space of two wave fields – an electrical wave field and a magnetic wave field

  30. Polarization • Polarization refers to the relative orientation of the electrical field of an EM wave • Horizontal polarization - an EM wave that is parallel to the earth’s surface • Vertical polarization - an EM wave that is perpendicular to the earth’s surface

  31. Active Microwave (RADAR) systems control the polarization of both the transmitted and received microwave EM energy Figure 9.6 from Jensen

  32. The Electromagnetic Wave • EM energy travels with the speed of light, c, • Within a vacuum c = 3 x 108 m sec-1

  33. EM Radiation is created whenever an electrical charge is accelerated • Two characteristics of EM waves Wavelength () – depends on the length of time over which the electrical charge is accelerated – distance between two wave crests Frequency () depends on the number of accelerations per second – how many waves per unit time are being generated

  34. EM Frequency () • Frequency is expressed in hertz (Hz), where one hertz is one cycle or wavelength per second • Shorter wavelengths have higher frequencies • Longer wavelengths have lower frequencies

  35. Microwave remote sensing systems are often defined by the frequency of the EM radiation MHz = 1 million Hz (106 Hz) GHz = 1 billion Hz (109 Hz)

  36. Relationship between c, , and c =   = c /   = c /  - In visible, near IR, and thermal IR remote sensing, wavelength () is used to describe a system In microwave remote sensing, frequency () is often used to describe a system

  37. Example – What is the frequency () of EM energy with a wavelength () of 6 cm (= .06 m = 6 x 10-2 m)  = c /  = (3 x 108 m sec-1) / (6 x 10-2 m)  = 0.5 x 1010 cycles/sec = 5 x 109 Hz = 5 GHz

  38. Lecture Topics • Types of thermal energy transfer • Models of EM radiation/energy • Particle Model Photon absorption, excitation, de-excitation • Wave Model Characteristics of EM waves Polarization, speed of light, wavelength, frequency • Laws governing EM radiation • Stephan-Boltzman Law • Planck’s Formula • Wien Displacement Law • Remote sensing in the visible and reflected infrared region of the EM spectrum • Descriptors of EM radiation • Radiant flux • Radiant flux density – irradiance and exitance • Radiation budget equation • Reflection • Absorption • Transmission

  39. Emittance • Emittance refers to the ability of the surface to emit radiant energy

  40. All matter that has a temperature above 0 degree Kelvin (-273 degrees C or -459 degrees F) are emitting EM radiation across the entire EM spectrum (e.g., at all wavelengths/frequencies) The temperature of the matter defines the characteristics of the EM radiation

  41. Stefan-Boltzmann Law* • The amount of EM radiation (M) emitted from a body in Watts m-2 can be calculated as M =  T4 where  is a constant and T4 is the temperature in degrees Kelvin *Know this formula

  42. Degrees Kelvin = Degrees C (centigrade) + 273

  43. Planck’s formula** • Spectral emittance – S() S() = 2 h c2 / [5 (ech /  kT – 1)] Where h is Planck’s constant And k is the Stephan-Boltzman constant **you don’t have to know this formula

  44. Planck’s formula gives basic shape of emittance curves Stephan Boltzman Law predicts how much total energy is emitted Note how total energy drops dramatically as temperature decreases Note how the wavelength where maximum emittance occurs increases as temperature decreases

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