Physics of the Lower Troposphere

Meteo 596 – Fall 2019
Physics of the Lower Troposphere 

  • Instructor: George S. Young
    • E-Mail:
    • Office hours: Office – 620 Walker – By appointment 
  • TA: None

Prerequisites: None

Course Expectations 


Students can demonstrate understanding of the physics by which the earth’s surface interacts with the lower troposphere 


Students can demonstrate the ability to apply lower tropospheric physics to problems in the atmospheric sciences 

Course Content: 

1) Basic characteristics of the boundary layer – 1 Week

  • Definition of the atmospheric boundary layer.
  • Vertical structure of the atmospheric boundary layer
  • Virtual potential temperature and ABL thermodynamic stability.
  • The atmospheric boundary layer (ABL) diurnal cycle
  • Taylor’s hypothesis. 

2) Statistical properties of boundary layer turbulence – 1 Week

  • Variances, covariances, correlations, time lags, and distributions of boundary layer turbulence in stable and unstable conditions.
  • The spectrum of atmospheric turbulence
  • Turbulence decomposition and Reynolds averaging.
  • Turbulent fluxes and stresses
  • Limits in our ability to numerically simulate the ABL.

3) Surface fluxes – 2 Weeks

  • Diel cycle of momentum, heat, and moisture fluxes, radiative fluxes.
  • The surface energy balance and the Bowen ratio.
  • Surface flux relationships including bulk aerodynamic flux estimates.
  • Sea surface fluxes (the Charnock equation).
  • Radiative fluxes (shortwave, IR, and their interaction with surface, vapor and clouds).
  • The Penman-Monteith equation.
  • The influence of plants and soil on the surface energy balance. 

4) Governing equations applied to the ABL – 1.5 Weeks

  • Simplifications of the governing equations for the ABL (including horizontal homogeneity and Reynolds Postulates.
  • Flux formulation in the governing equations.
  • The closure problem and covariance terms in the governing equations.
  • Eddy diffusivity and mixing lengths.
  • First order closure.
  • Higher order closure approaches. 

5) Applications of simplified governing equations for the ABL – 1.5 Weeks

  • Vertical structure of the boundary layer.
  • Mean variables, fluxes.
  • Flux divergences and ABL property time rates of change.
  • Entrainment fluxes.
  • Dispersion of scalars and dispersion modeling: The Gaussian plume model 

8) ABL modeling – part I – 0.5 Weeks

  • Quantification of entrainment fluxes.
  • Mixed layer model. 

6) Dynamic stability, TKE – 2 Weeks

  • Flux and variance equations.
  • Turbulent kinetic energy budget.
  • Richardson number and Obukhov Length.
  • Stability regimes.
  • Atmospheric spectra, separation of scales, the inertial subrange. 

7) Similarity theory – 1.5 Weeks

  • Surface layer similarity.
  • Radix layer similarity.
  • Monin-Obukhov scaling.
  • Link back to eddy diffusivity.
  • Log wind profile.
  • Displacement height and roughness length.
  • Diabatic wind profile
  • Mixed layer similarity, other similarity regimes 

8) ABL modeling – part II – 0.5 Weeks

  • Ekman spiral.
  • TKE model.
  • Large eddy simulation. 

9) Convective and stable boundary layers – 1 Week

  • Diurnal cycle of surface winds, temperature, moisture, TKE sources.
  • Temporal evolution of ABL depth, entrainment.
  • Low-Level Nocturnal Jet. 

10) Clouds and the ABL – 1 Week

  • Cumulus-topped boundary layers.
  • Trade-wind Cumulus-topped boundary layers.
  • Stratocumulus-topped boundary layers. 

11) Organized flows – 1.5 Weeks

  • Sea-breeze, drainage flow
  • Mountain breezes, gravity waves, roll instability.
  • Flow over complex terrain. 


Class times and places:

  • 620 Walker Building
  • By appointment


Assessment Tools

  • Required written/oral assignments
    • 7 written homework assignments
  • Examination policy
    • Midterm Exam
    • Final Exam
  • Grading policy

The homework count for 50% of the course grade, midterm exam 25%, final exam 25%

    Academic integrity: This course follows the Penn State defines academic integrity as "the pursuit of scholarly activity in an open, honest and responsible manner." Academic integrity includes "a commitment not to engage in or tolerate acts of falsification, misrepresentation, or deception." In particular, the University defines plagiarism as "the fabrication of information and citations; submitting other's work from professional journals, books, articles, and papers; submission of other student's papers, lab results or project reports and representing the work as one's own." Penalties for violations of academic integrity may include course failure. To learn more, see Penn State's "Plagiarism Tutorial for Students."

Preliminary Assignment Schedule (subject to change

Homework due every 2 weeks.  Midterm at mid semester and final exam Monday of Finals week.

University Policies 

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.


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.

Weather Delays

Campus emergencies, including weather delays, are announced on Penn State News and communicated to cell phones, 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

For this course, we recommend the minimum technical requirements outlined on the Dutton Institute Technical Requirements page (, including the requirements listed for same-time, synchronous communications. If you need technical assistance at any point during the course, please contact the ITS Help Desk (


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.


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 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:

Accessible Syllabus

Notes: Any syllabus posted online (e.g. a Word/PDF file or an online syllabus) should make destinations clickable links such as is done throughout this page. Also, in order to comply with Penn State Policy AD69(Accessibility of Penn State Web Pages,, PDF documents cannot be the sole source of presenting online information. Such documents include syllabi, homework assignments, and scanned notes. 

Disclaimer Statement

Please note that the specifics of this Course Syllabus can be changed at any time, and you will be responsible for abiding by any such changes. Changes to the syllabus shall also be given to the student in written (paper or electronic) form.