Precipitation Physics


Meteo 597: Precipitation Physics

Spring 2020

Instructor: Prof. Matt Kumjian
Office: 513 Walker Building
Phone: 814-863-1581

Class Website:

Lecture: TR, 12:05 - 1:20 pm; 126 Walker Building

Office Hours: TBD; by appointment; or when my door is open!

Required Text: None

Optional/Supplementary Texts: 

  • Microphysics of Clouds and Precipitation by H. R. Pruppacher and J. D. Klett
  • A Short Course in Cloud Physics by R. R. Rogers and M. K. Yau
  • Physics and Chemistry of Clouds by D. Lamb and J. Verlinde. Get it online here or at the University Book Store. Be sure to check out the errata here!

Note: any required readings from these optional texts will be provided. These books are available at the EMS Library. You can also download the entire PDF of Pruppacher and Klett through the university library here. 

Pre-requisites: None officially, though METEO 437/533 are strongly encouraged.

Grading: Your final grade* will be based on the following:

  • Modules 35%
  • Natural Laboratory Experiments 35%
  • Journal Club 30%

Note: there is a 10% day-1 reduction in the grade for assignments turned in late.

*Final letter grades will be determined based on the overall distribution of scores at the end of the semester.  

Modules: You will have regularly assigned "modules" to practice and apply concepts presented through lecture or in papers. The modules will include computer programming (e.g., developing simple process models), analysis of real precipitation data, and idealized calculations. Part of the rationale for assigning these modules is to help you develop skills and awareness of data sources needed for your research and careers.

Natural Laboratory Experiments: We will hopefully take advantage of any precipitation the atmosphere gives us this semester to get some hands-on experience with taking precipitation measurements! This idea itself is a bit of an experiment, so we'll see how this goes. The experiments will be more involved than modules, and as such will have more time available to complete. There will be ~2 or 3 throughout the semester, focusing on rain and snow. A shorter bonus experiment will be made available in the event of more exotic precipitation types! (#PrayForHail)

Journal Club: As part of this class, we will be reading key papers from the literature on precipitation physics. During certain weeks, a portion of one class will be devoted to discussion of these papers. Student groups will lead the discussions by putting together a powerpoint presentation. The rest of the class will submit at least 3 questions/discussion points about the paper to help facilitate the discussion, and are expected to participate. Your Journal Club grade will be based on the following: 

  • Group Presentation (15%): Groups of ~3 students will work together on a presentation covering the key points of the assigned paper. The presentation itself should be ~20 minutes or less to facilitate time for discussion. It is up to each group to divvy up the workload, but each student should focus on important processes in the study (i.e., don't just present the "methods" section). I may solicit input from each group member on the others' contributions to ensure there are no freeloaders! 
  •  Questions/Participation (10%): For each paper, you will submit ≥ ≥ 3 questions or discussion points you had about the paper based on your reading. These will be submitted prior to class via Canvas. You are also expected to participate in the class discussion. This is to ensure that everyone is engaged in the reading and digestion of the material in the papers.
  • Quality of Questions/Participation (5%): Think of this as "glory points"! Showing up and submitting questions will get you your 10%, but high-quality questions or participation are necessary to get these marks. In other words, I expect insightful or thoughtful questions and comments, not just superficial stuff ("The lines in the plot are too thin.")  

Course Objectives and Intents:

This course is designed to provide graduate students with diverse backgrounds a foundation in, and an overview of, the physics of precipitation in the atmosphere. Our understanding of precipitation will develop naturally through examinations of the fundamental physical processes operating across a wide variety of scales, readings and discussions of key papers in the scientific literature, and hands-on precipitation measurements and analysis.  

Course Topics Include:

The importance of precipitation in weather and climate; physical properties of precipitation particles (or hydrometeors), including rain, snow, ice pellets, graupel, and hail; precipitation formation mechanisms; the growth and multiplication of hydrometeors; hydrometeor phase changes; hydrometeor interactions and associated physical processes (e.g., collision-coalescence, collisional breakup, aggregation, riming, shedding) and results of these interactions (e.g., electrification and lightning); role of precipitation in storm evolution; precipitation hazards; representations of precipitation in numerical models. Other topics will be included given student interest and/or time. 


Students who do not meet the prerequisites after being informed in writing by the instructor may be dis-enrolled during the first 10-day free add-drop period ( If you have not completed the listed prerequisites, then promptly consult with the instructor if you have not done so already. Students who re-enroll after being dis-enrolled according to this policy are in violation of item 15 on the Student Code of Conduct ( 

Academic Integrity:

Academic integrity is the pursuit of scholarly activity in an open, honest, and responsible manner, and is a basic guiding principle for all academic activity in the College. As such, all are expected to act with personal integrity, respect for other students’ dignity, rights, and property, and to help create and maintain an environment in which all can succeed through the fruits of their efforts. Academic integrity includes a commitment not to engage in or tolerate acts of falsification, misrepresentation, or deception. Such acts of dishonesty violate the fundamental ethical principles of the EMS community and compromise the worth of work completed by others. The full college policy on academic integrity can be found here.

Simply put, don’t cheat. This includes but is not limited to copying, plagiarism, self- plagiarism, etc., all of which can result in a 0 on the assignment and/or an F or XF grade in the course. Ultimately, it negatively affects you: imagine the future disappointment of employers, family, and friends when you turn out to have severe inadequacies as a precipitation physicist. If you struggle with material, come see me or others for help

Campus Emergencies and Inclement Weather:

Campus emergencies, including weather delays, are announced on Penn State News ( and communicated to mobile devices, email, the Penn State Face- book page, and Twitter via the PSU Alert System (to sign up, please see https://psualert. 

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. 

Accommodation 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. 

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


 This course abides by the Penn State Attendance Policy E-11, and Conict Exam Policy 44-35. Please also see the 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 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 Aairs (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 available from the Registrar's Office: at least one week prior to the activity.

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 

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.

Additionally, I am "Safe Zone" trained and welcome students who need a safe space to contact me at any time.

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. 

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.