Formative Assessment 3: Orographic Effect

Part 1: Calculating Relative Humidity

Instructions

For each problem below, calculate the correct numerical answer. In order to receive full credit, you must show all your work.

Questions

Follow the trajectory of the air mass at the following locations in the image below, and use the plot of water content to calculate the relative humidity at each:

1. Starting point as the air mass comes onshore
2. Halfway up the Sierra Nevada mountains
3. At the crest of the Sierras
4. In the low area just East of the Sierras

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Orographic sequence animation
Base Map from Google Earth, inset by Mike Arthur (Penn State)

Worksheet

Download the worksheet (Microsoft Word 2007 (.docx) 1MB Mar28 17)to be used to submit your assessment.

Submitting your Answers

Bring your hand-written answers to class. Make sure your calculations are written neatly enough that another person can understand them.

Scoring and Rubric

Each problem will earn a maximum of 5 points, as described in the rubric below.

Part 2: Topography and the Orographic Effect

Instructions

Answer each question in 2-3 complete sentences. Consider each question carefully and be sure to provide a complete answer.

Questions

1. Look at the map of U.S. mean annual precipitation (Figure 7). Note two areas where it rains a lot, and explain why – are there mountains there? If so, which mountains?
2. Do the same for two dry areas.
3. Are there any particular population centers that seem poorly situated based on the distribution of precipitation in the U.S.? Explain your logic.
4. Where is your hometown? What is the average annual precipitation in your hometown? Where do you think the water originates (i.e., from where does it evaporate to become atmospheric water vapor before it returns to the surface as precipitation)? Where do you suppose it ultimately ends up after it falls (i.e., which ocean)?

Submitting your answers

Bring your written answers to class. If they are hand-written, be sure your writing is legible. If your handwriting is not clear, please type and print your answers.

Scoring and Rubric

Each answer will earn a maximum of 5 points, as described in the rubric below.