Understanding Doppler radar radial velocity fields

This page authored by Aryeh J. Drager, University of Nebraska-Lincoln.

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Formative assessment GeoClick question using a classroom response system ("clickers"). Can be used to reveal students' spatial understanding. Students are shown this diagram and are given the following instructions: "This is a Doppler velocity image corresponding to a supercell thunderstorm. If the storm is rotating counter-clockwise, then where is the radar located? Click on a location where the radar could be located."

Used this activity? Share your experiences and modifications

Learning Goals

Content: Students will be able to interpret Doppler velocity radar maps.
Spatial skills category: This activity engages students in perspective taking.

Context for Use

This activity is used as a formative assessment in an introductory-level severe weather class for non-majors during a lecture about interpreting Doppler radar radial velocity data. Displaying the results after administering the question provides students and instructor immediate feedback about what students have understood.

Description and Teaching Materials

Start by introducing the concepts of Doppler radar and radial velocity.

To do this, introduce the first image on this NWS page illustrates* the radial component of the wind and how it translates on Doppler velocity images https://www.weather.gov/jetstream/vel

*Note: This image is not accessible for students with color-blindness

To demonstrate how a radar antenna is rotated to collect data, share this NSF video of the Doppler on Wheels: https://www.youtube.com/watch?v=jsDcQryQm3Q

After preparing students, engage them in the scaffolded questions described below and presented in the slides. Note: One of the slides uses a radar antenna icon with the radar antenna facing right. Point out to students that the radar is constantly rotating and that the direction for an icon is not relevant to the question.

PowerPoint slides for GeoClick Radial Velocity (PowerPoint 2007 (.pptx) 3MB Oct27 21)

PDF slides for GeoClick Radial Velocity (Acrobat (PDF) 7.9MB Oct27 21)

Teaching Notes and Tips

Scaffolding: The GeoClick question (last slide) asks students to work backwards, which is difficult! In order to prepare students, it is helpful to go through the constant-wind and rotation-with-radar-location-given examples.

The PowerPoint/PDF slides below contain a set of multiple-choice clicker questions. The multiple-choice questions are intended to help orient students to looking at Doppler velocity images (you might want to find and present some real-world Doppler velocity images as well).


This question is useful for students to self-assess their answer relative to other students in the class. The web-based system can display student responses in a heat map image that highlights the most common answers. In most systems it is possible to designate a region for the correct answer, but receiving a right-wrong answer is likely less useful than engaging students in peer discussion if the students' responses do not converge on one region. In general, the correct answer is that the radar is located to the south of the rotation signal at the center of the image.

References and Resources

General introduction to radial velocity: https://www.weather.gov/jetstream/vel

Persistent link to the above site: https://web.archive.org/web/20210707213711/https://www.weather.gov/jetstream/vel

NSF YouTube video of the Doppler on Wheels: https://www.youtube.com/watch?v=jsDcQryQm3Q

LaDue, N.D. and Shipley, T.F. (2018). Click-on-Diagram Questions: A New Tool to Study Conceptions using Classroom Response Systems. Journal of Science Education and Technology, 27(6), 492-507.