Radiation and Climate

METEO 436: Radiation and Climate (Fall 2019)

Instructor: Eugene Clothiaux  Email:  
Office Hours: 
Su  02:00 - 03:00 PM (Room 529 Walker)
Tu  02:00 - 03:00 PM (Room 529 Walker)                                                 

Teaching Assistant: Branden Katona  Email:  
Office Hours: 
By Appointment 

Class Meeting Times and Locations:
Monday, Wednesday and Friday 09:05-09:55 PM; Room 103 Walker 

Course Designation in Curriculum: Choice of 1 of 3 Courses Required for the Major 

Support Services Available: None 

Brief Course Description from University Bulletin

From Browse Course Catalog on LionPath:

“This course covers radiation and how it interacts with the atmosphere and earth's surface to drive motions in the atmosphere. The fundamentals of radiative transfer at the molecular level, including absorption, scattering, transmission, and emission of radiation by matter, are discussed and applied to help describe the earth's energy budget. Crucial to understanding these processes in the atmosphere are the interactions of radiation with water in the vapor, liquid, and solid states. Applications of radiative transfer to the understanding of seasons and of climate and climate change are presented as well.” 

Prerequisites and Concurrent Courses:

METEO 300 is a prerequisite for this course while METEO 431 must at least be concurrent with this course. Mathematics through differential equations is a necessity for this course. A basic understanding of atmospheric thermal physics and classical electromagnetic theory is helpful, though all ideas pertinent to this course will be introduced within it.

Students who do not meet these prerequisites may be disenrolled according to Administrative Policy C-5 if they do not have the proper prerequisite override. Students who add the course after being disenrolled according to this policy are in violation of Item 15 on the Student Code of Conduct:

Required Textbooks and Recommended Textbooks:

The course closely follows the content in

Fundamentals of Atmospheric Radiation by Craig Bohren and Eugene Clothiaux

Conceptual Approach to Atmospheric Radiation edited by Eugene Clothiaux

as it is hard to ignore the ideas that one has written about in a textbook. 

Assistance with Textbooks:

Penn State honors and values the socioeconomic diversity of our students. If you require assistance with the costs of textbooks for this course, contact the Office of Student Care and Advocacy (120 Boucke Building, 863-4926, For additional need related to socioeconomic status please visit

Reserve Materials (EMS Library in the Deike Building):

  • C.F. Bohren Clouds in a Glass of Beer
  • C.F. Bohren What Light Through Yonder Window Breaks?
  • R.M. Goody and Y.L. Yung Atmospheric Radiation (2nd Edition)
  • K.N. Liou An Introduction to Atmospheric Radiation (2nd Edition)
  • G.W. Petty A First Course in Atmospheric Radiation (2nd Edition)
  • M.L. Salby Physics of the Atmosphere and Climate (2nd Edition)
  • G.L. Stephens Remote Sensing of the Lower Atmosphere
  • G.E. Thomas and K. Stamnes Radiative Transfer in the Atmosphere and Ocean
  • J.M. Wallace and P.V. Hobbs Atmospheric Science: An Introductory Survey (2nd Edition)
  • J.A. Coakley and P. Yang Atmospheric Radiation: A Primer with Illustrative Solutions
  • Wendisch and P. Yang Theory of Atmospheric Radiative Transfer 

Internet Materials and Links: None 

Course Objectives/Outcomes:

Meteorology Courses Objectives and Outcomes printable document contains a link to the Course objectives and outcomes listed below. 

Course Objectives:

  1. Students can demonstrate how radiative processes are related to atmospheric structure and phenomena (relate to program objectives 1 and 2)
  2. Students can demonstrate the ability to apply atmospheric radiative principles quantitatively to atmospheric problems (relate to program objectives 1 and 3)

Course Outcomes:

  1. Students can demonstrate knowledge of absorption, emission, and scattering properties along with the equations for radiance, irradiance, and solid angle (relate to program outcomes b and c)
  2. Students can demonstrate a basic grasp of the integro-differential form of the radiative transfer equation by providing a physical interpretation (relate to program outcome b)
  3. Students can solve the integro-differential form of the radiative transfer equation for simplified atmospheres such as attenuation-only with no scattering (relate to program outcome b and d)
  4. Students can demonstrate the use of simplified solutions of the integro-differential form of the radiative transfer equation to basic remote sensing of the atmosphere (relate to program outcomes a and d)

Students can show the link of atmospheric irradiance to atmospheric heating and cooling (relate to program outcome b) 

Course Expectations:

All students will come to class prepared to discuss the course material at hand. Students are allowed to work on homework problems together. But, students must write-up their homework solutions on their own and have complete mastery of what it is that they have written. Students must meet the deadlines for the homework assignments. Habitual tardiness in turning in the homework will lead to a loss of points but only after a warning from the instructor.

Course Attendance:

This course abides by the Penn State Attendance Policy E-11:, and Conflict Exam Policy 44-35: Please also see Illness Verification Policy:, and Religious Observance Policy: Students who miss class for legitimate reasons will be given a reasonable opportunity to make up missed work, including exams and quizzes.  Students are not required to secure the signature of medical personnel in the case of illness or injury and should use their best judgment on whether they are well enough to attend class or not; the University Health Center will not provide medical verification for minor illnesses or injuries. Other legitimate reasons for missing class include religious observance, military service, family emergencies, regularly scheduled university-approved curricular or extracurricular activities, and post-graduate, career-related interviews when there is no opportunity for students to re-schedule these opportunities (such as employment and graduate school final interviews).  Students who encounter serious family, health, or personal situations that result in extended absences should contact the Office of the Assistant Vice President for Student Affairs (AVPSA) and Student Care and Advocacy for help:  Whenever possible, students participating in University-approved activities should submit to the instructor a Class Absence Form:, at least one week prior to the activity.

Course Sick Days Policy:

The bottom line is very simple: Please never come to a class when running a fever! Contact the Instructor via email letting the Instructor know that you will miss class because of illness. When you are feeling better and return to class, meet with the Instructor in order to develop a plan of action for making up all missed assignments. 

Grading and Examination Policy:

For a summary of General and Final Examination Policies 44-10 and 44-20 and alternative assessment practices, please see Examination Policy Summary: and General and Final Exam Policies:

Required Written Assignments:

The only written assignments for this course will be homework assignments. The homework assignments must be completed according to course expectations listed above. Homework assignments will compose 25% of the final course grade. 

Examination Policy:

There will be two non-final exams, each worth 25% (for a total of 50%) of the final course grade, and a final exam worth 25% of the final course grade. The final exam will be given during the official exam slot scheduled for this course. The non-final exams will be given at appropriate times during the semester at a time agreed upon by all. 

Grading Policy:

There will be no grade curving and the grading scale is as follows: A: 92.5-100.0; A-:90.0-92.5; B+: 87.5-90.0; B: 82.5-87.5; B-:80.0-82.5; C+: 77.5-80.0: C: 70.0-77.5; D: 50.0-70.0; F: < 50.0. For the final course grade the instructor may throw out poor exam questions, adjust the percentages that homework and exams count, and/or adjust the grading scale above. This will be done in the same way for all students and only in such a way as to help each student’s overall course grade. No student will receive a grade less than what is based on the homework (25%), non-final exams (50%), and final exam (25%) percentages and using the grading scale above. 

Academic Integrity Statement:

Students in this class are expected to write up their homework sets individually and to work the exams on their own. Class members may work on the homework sets in groups, but then each student must write up the answers separately. Students are not to copy homework or exam answers from another person's paper and present them as their own. Students who present other people's work as their own will receive at least a 0 on the assignment and may well receive an F or XF in the course depending upon the circumstances. Please see: Earth and Mineral Sciences Academic Integrity Policy:, which this course adopts. To learn more, see Penn State's "Plagiarism Tutorial for Students."

Course Copyright:

All course materials students receive or to which students have online access are protected by copyright laws. Students may use course materials and make copies for their own use as needed, but unauthorized distribution and/or uploading of materials without the instructor’s express permission is strictly prohibited. University Policy AD 40, the University Policy Recording of Classroom Activities and Note Taking Services addresses this issue. Students who engage in the unauthorized distribution of copyrighted materials may be held in violation of the University’s Code of Conduct, and/or liable under Federal and State laws.

For example, uploading completed labs, homework, or other assignments to any study site constitutes a violation of this policy.

Accommodations for Students with Disabilities:

Penn State welcomes students with disabilities into the University's educational programs. Every Penn State campus has an office for students with disabilities. The Student Disability Resources (SDR) website provides contact information for every Penn State campus: ( For further information, please visit the Student Disability Resources website (

In order to receive consideration for reasonable accommodations, you must contact the appropriate disability services office at the campus where you are officially enrolled, participate in an intake interview, and provide documentation: If the documentation supports your request for reasonable accommodations, your campus’s disability services office will provide you with an accommodation letter. Please share this letter with your instructors and discuss the accommodations with them as early in your courses as possible. You must follow this process for every semester that you request accommodations.

Campus Emergencies, Including Weather Delays

Campus emergencies, including weather delays, are announced on Penn State News: http:/ and communicated to cellphones, email, the Penn State Facebook page, and Twitter via PSUAlert (Sign up at:  

Reporting Bias-Motivated Incidents

Penn State takes great pride to foster a diverse and inclusive environment for students, faculty, and staff.  Acts of intolerance, discrimination, or harassment due to age, ancestry, color, disability, gender, gender identity, national origin, race, religious belief, sexual orientation, or veteran status are not tolerated ( and can be reported through Educational Equity via the Report Bias webpage. 

Counseling and Psychological Services

Many students at Penn State face personal challenges or have psychological needs that may interfere with their academic progress, social development, or emotional wellbeing.  The university offers a variety of confidential services to help you through difficult times, including individual and group counseling, crisis intervention, consultations, online chats, and mental health screenings.  These services are provided by staff who welcome all students and embrace a philosophy respectful of clients’ cultural and religious backgrounds, and sensitive to differences in race, ability, gender identity and sexual orientation.  Services include the following: 

Counseling and Psychological Services at University Park  (CAPS): 814-863-0395
Counseling and Psychological Services at Commonwealth Campuses
Penn State Crisis Line (24 hours/7 days/week): 877-229-6400
Crisis Text Line (24 hours/7 days/week): Text LIONS to 741741

Penn State E-mail Accounts

All official communications from Penn State are sent to students' Penn State e-mail accounts. Be sure to check your Penn State account regularly, or forward your Penn State e-mail (see to your preferred e-mail account, so you don't miss any important information.

Deferred Grades

If you are prevented from completing this course within the prescribed amount of time for reasons that are beyond your control, it is possible to have the grade deferred with the concurrence of the instructor, following Penn State Deferred Grade Policy 48-40 ( To seek a deferred grade, you must submit a written request (by e-mail or U.S. post) to the instructor describing the reason(s) for the request. Non-emergency permission for filing a deferred grade must be requested before the beginning of the final examination period. It is up to the instructor to determine whether or not you will be permitted to receive a deferred grade. If permission is granted, you will work with the instructor to establish a communication plan and a clear schedule for completion.  If, for any reason, the course work for the deferred grade is not complete by the assigned time, a grade of "F" will be automatically entered on your transcript.

Military Personnel

Veterans and currently serving military personnel and/or spouses with unique circumstances (e.g., upcoming deployments, drill/duty requirements, disabilities, VA appointments, etc.) are welcome and encouraged to communicate these, in advance if possible, to the instructor in the case that special arrangements need to be made.

Technical Requirements

One must have access to email, pencils and paper. From time to time one may need to make use of a computer to perform a calculation or to put together a presentation in some electronic format. 


The term "Netiquette" refers to the etiquette guidelines for electronic communications, such as e-mail and bulletin board postings. Netiquette covers not only rules to maintain civility in discussions, but also special guidelines unique to the electronic nature of forum messages. Please review some general Netiquette guidelines that should be followed when communicating in this course. 

Disruptive Behavior

Behavior that disrupts normal classroom activities will not be tolerated, in accordance with Items 9 and 14 in the Student Code of Conduct. This includes in-class use of cell phones for non-coursework related topics.


In the case of an emergency, we will follow the College of Earth and Mineral Sciences Critical Incident Plan (  In the event of an evacuation, we will follow posted evacuation routes and gather at the Designated Meeting Site.  Evacuation routes for all EMS buildings are available at  For more information regarding actions to take during particular emergencies, please see the Penn State Emergency Action Guides

Mandated Reporting Statement

Penn State’s policies require me, as a faculty member, to share information about incidents of sex-based discrimination and harassment (discrimination, harassment, sexual harassment, sexual misconduct, dating violence, domestic violence, stalking, and retaliation) with Penn State’s Title IX coordinator or deputy coordinators, regardless of whether the incidents are stated to me in person or shared by students as part of their coursework.  For more information regarding the University's policies and procedures for responding to reports of sexual or gender-based harassment or misconduct, please visit Penn State's Office of Sexual Misconduct and Prevention & Response website.

Additionally, I am required to make a report on any reasonable suspicion of child abuse in accordance with the Pennsylvania Child Protective Services Law

Diversity, Inclusion, and Respect

Penn State is “committed to creating an educational environment which is free from intolerance directed toward individuals or groups and strives to create and maintain an environment that fosters respect for others” as stated in Policy AD29 Statement on Intolerance. All members of this class are expected to contribute to a respectful, welcoming and inclusive environment and to interact with civility.

For additional information, see:

Course Content 

What a Practicing Meteorologist Needs to Know 

  • Radiation and Matter
    • The Big Picture (Sources of Radiation)
      • Accelerated Charges
      • Importance of Dipoles in Earth System Radiation
    • Repartitioning of Energy within Matter
    • Quantized Internal Energy States of Matter
    • Simple matter
      • Single lines with widths and strengths
    • Simple matter under increasing pressures
      • Changes in single line parameters
    • Complex matter
      • Multiple and merged lines forming continuum emission across all wavelengths
      • Planck Function Radiation
    • Probability of Energy States within Matter
      • The Planck Function
  • Integro-differential Form of the Radiative Transfer Equation
    • Radiance (185-191)
      • Power (185-186)
      • Solid Angle (186-188)
      • Definition of Radiance
      • Invariance of (191-192)
    • Irradiance (206-211)
      • Connection to Radiance
      • Definition of Irradiance
    • Building the Radiative Transfer Equation
      • Attenuation/Extinction Term
        • Absorption and Scattering Coefficients (51-66, 60-66)
        • From Coefficients to the Attenuation Term
      • Emission Term (4-15)
        • Absorptivity and Emissivity [Kirchhoff's Law (14-15)]
        • Planck Function
          • Temperature Dependent
        • Emission Term
          • Planck Function and Absorptivity/Emissivity
    • Dependent
      • Scattering Term
        • Scattering Phase Function (293-295)
  • Heating Rates (58-59, 212)
    • From Radiances to Irradiances
    • From Irradiances to Heating Rates
  • Multiple Scattering: Elementary (Section 5.2)
    • Visualizing the Radiation Field
  • Some Nomenclature
    • Optical Thickness (256)
    • Mean Free Path (253-254)
    • Single-scattering Albedo (254-257)
    • Asymmetry Parameter (254-257)
    • Brightness and Color Temperature (21)
    • Wavenumbers (or Inverse Centimeters) (79)
  • Properties of Matter: A First Look
    • Building One's Intuition: Simple Sorts of Calculations
  • Properties of Matter
    • Overview of Particle Concentrations and Cross Sections (91-94)
    • Wavelength Dependence of Molecular Scattering (Fig. 2.12)
    • Wavelength Dependence of Molecular Absorption (Fig. 2.12)
    • Wavelength Dependence of (Spherical) Particle Scattering (Fig. 3.9, Fig. 3.11)
    • Wavelength Dependence of (Spherical) Particle Absorption (Fig. 3.9)
  • Multiple Scattering: The Full Monte (Chapter 6)

Digging Deeper into the Properties of Matter (The Why of Things)

  • To Cohere or Not to Cohere (or, Why Clouds are So Important to Climate) 
  • Classical Electromagnetic Theory
    • From Radiation as Energy Bundles to Radiation as Waves (129-134)
    • Charges and Electric Fields
    • Moving Charges and Magnetic Fields
    • The Lorentz Force
    • Maxwell's Equations (Yikes!)
    • Response of Matter to Electric Fields
    • Response of Matter to Magnetic Fields
    • Four Consequences of Maxwell's Equations
      • Speed of Light
      • Plane Electromagnetic Wave Solutions in Infinite Media (129-134, 141-142, 158-165)
      • The Poynting Vector (Irradiance) (185-186)
      • Production of Radiation by Accelerated Charges
        • Dipoles
  • Why Matter Scatters and Absorbs Radiation the Way It Does
    • Scattering and Absorbing Properties of Molecules
      • Scattering by Air Molecules (128, 151-155)
      • Scattering Phase Function of Molecules
      • Absorption by Air Molecules (66-74, 76-84, 125-129)
        • Radiatively Active and Inactive Molecules (80-84)
        • State Populations and the Structure of Absorption (95-102)
        • Absorption Line Strengths, Shapes and Widths (102-105)
    • Scattering and Absorbing Properties of Particles
      • Small Particles
      • Large Particles
      • Complex indices of refraction
      • Scattering by Spherical Water Particles (165-175)
        • Coherence Effects (134-141, 146-148, 148-151)
        • Small and Large Particle Limits (168-169, 169, 170-172, 172-175)
      • Absorption by Spherical Water Particles (110-115)
        • Small and Large Particle Limits