The Dry Valleys region in Antarctica is known as the coldest, windiest, driest place on Earth. Beacon Valley is famous for its katabatic winds which can routinely knock fit adults and PolarTREC teachers to the ground. This lesson was created by PolarTREC teacher Jacquelyn Hams who experienced the cold and the full force of the winds in 2008. The weather data was acquired from an anemometer (an instrument that measures wind speed) in Beacon Valley, Antarctica and provided courtesy of Sean MacKay of Boston University.
At the end of this lesson, students will be able to:
Define and calculate the wind chill factor
Identify a katabatic wind and discuss how it influences temperature.
Construct a graph by hand or by using Excel software (optional).
Teachers: Teachers should complete a general meteorology lecture that includes content on wind chill and katabatic winds.
Teachers and students: Read the British Antarctic Survey school handout "Antarctic Climate", Resource C2 – Factors Influencing Antarctic Climate (attached).
Read the PolarTREC 2008 Ancient Buried Ice in Antarctica journal - 19 November 2008 A Mighty Wind. (http://www.polartrec.com/node/7204)
Open the National Weather Service Windchill Website http://www.nws.noaa.gov/om/windchill/index.shtml
Scroll to the bottom of the site to the "Windchill Calculator"
Enter the temperature in degrees Celsius and wind speed in mph provided for the first date (Nov. 17) on the Beacon Valley Weather Data Assignment and select "Calculate Wind Chill".
Enter the Wind chill temperature in degrees Celsius on the Beacon Valley Weather Data Chart. The first value is completed on the assignment as an example.
Option: Calculate wind chill mathematically using the conversion formulas provided below.
Conversion Formulas: Formula for wind chill temperature: Wind Chill (ºF) = 35.74 + 0.6215T - 35.75(V0.16) + 0.4275T (V0.16) T=Air Temperature in Fahrenheit V=wind speed in mph
Formula for converting temperatures from Fahrenheit to Celsius: Tf = (9/5)Tc+32 Tc = (5/9)(Tf-32)
Repeat Step 3 entering the Beacon Valley temperature and wind data into the computer calculator for each of the dates until the chart is completed.
Have the students complete a graph of temperature in degrees Celsius vs. wind chill temperature in degrees Celsius. Option: Depending on grade level, students can practice computer skills by using Excel to complete the graphing portion of this lesson. An Excel data table is provided in the attachments.
Suggested questions: (teachers may edit or change)
1. What is the wind chill factor and how it is calculated?
2. What was the average temperature decrease due to the wind chill factor in Beacon Valley?
3. What are katabatic winds?
4. What effect did the katabatic winds have on the temperature in Beacon Valley?
There are local winds that affect temperatures in different parts of the country/world. How do the local winds in your area affect the temperature? How fast are the winds compared to katabatic winds? Here are some examples of local winds to use for comparison.
Southern California teachers may use the "Santa Ana Winds" for comparison, which blow from the desert at exceptional speeds.
For coastal communities, temperatures may vary with onshore vs. offshore winds. Is there a change with the seasons?
National Weather Service Windchill website http://www.nws.noaa.gov/om/windchill/index.shtml
"Antarctic Climate" Resource C2 – Factors Influencing Antarctic Climate, British Antarctic Survey.
The completed assignment will be assessed using the attached grading rubric.
Lesson created by Jacquelyn Hams with data provided courtesy of Sean MacKay of Boston University. Contact Jacquelyn Hams at Los Angeles Valley College, hamsje [at] lavc.edu