Blown Away!
Grade Levels: 6-12
Subject: Earth Science – Atmospherics
Teaching methodology: Open inquiry
Author: Tom Baker, tbaker@ukans.edu/tbaker@kancrn.org

Abstract:  This lesson uses ArcView GIS to correlate the seasonal position of the jet stream with location and intensity of tornadic activity in the United States.
ArcView Skills:
Turning themes on and off.
Conducting theme-on-theme selections
	Querying data from a theme
ArcView Source Files:
	/arcview31/esridata/world/latlong.*
	/arcview31/esridata/world/world30.*
	/arcview31/esridata/usa/states.*
	K12lib_5/gisdata/tornadoes/tornadoes.* 
A PDF format document from George Dailey (ESRI) is included within the data directory as meta data describing the original tornado data file that was used to create the monthly themes.
	K12lib_5/gisdata/elev48/elev48.*
	
	US Jet Stream seasonal average themes were recreated from digital and print 
material from the National Weather Service (http://www.nws.noaa.gov).  The location of the Jet Stream has been visually extrapolated and does not represent an algorithmic average in seasonal Jet Stream fluctuations.
	
Background:  Since records of tornado activity first began in 1916, scholars and researchers have studied the “hows and whys” of tornado development.  Within the past few decades it has been found that tornadoes typically require three conditions for formation.  
1.	A northerly flow of warm, moist air from the Gulf of Mexico
2.	A cool, dry air mass descending from Canadian regions
3.   A jet stream wind exceeding speeds of 150 mph

The US jet stream is a large mass of swift moving air that travels across the United States from West to East in seasonal patterns.  To the north of the jet stream lies cool Canadian air pushing the US jet stream south and toward the East.  From the Gulf of Mexico, warm moist air is pushing north and east against the Jet Stream (in a Counter Clockwise motion).  These two opposing air masses from Canada and Mexico are constantly struggling, pushing the US jet stream south and north as either air mass gains or looses energy from the rest of the atmosphere.

If we are to pay careful attention to the spatial relationship of the US jet stream and tornado location and intensity, we may see a correlation between the them.  It is this relationship that students will explore in this lesson.

Extensions/Conclusion:
1.	What effects may cause answers to questions #4 and #6 to be smaller than actual occurrences?
2.	If a typical US Winter jet stream has a speed of 130km/hr and a typical US Summer jet stream speed has a speed of 85 km/hr, why do we find more tornadoes and more intense tornadoes (based on Fujita) during the summer months?
3.	Can we obtain enough information from the monthly tornado layers and seasonal jet stream layers to support claims that jet stream position is significantly related to tornado development, location or intensity?
4.	Add the theme, Elev48 to the Blown Away ArcView project (located on ESRI’s Schools and Libraries CD at \gisdata\ELEV48\E;ev48.shp).  How does the elevation relate to the location of recorded tornadoes?  What other topographic effects may play a role in storm development?

Name:____________________________________  Date:_____________ Hour:_______

Since records of tornado activity were first kept in 1916, scholars and researchers have studied the “hows and whys” of tornado development.  Within the past few decades it has been found that tornadoes typically require three upper atmospheric conditions for formation. 
1.	A northerly flow of warm, moist air from the Gulf of Mexico
2.	A cool, dry air mass descending from Canadian regions
3.   A jet stream wind exceeding speeds of 150 mph

The region in the continental US where cold, dry winds from Canada meets warm, moist air from the Gulf of Mexico forms the US jet stream.  Scientists believe that the US jet stream serves as a likely indicator of tornado position and intensity.  In the activity below, try to refute or support this scientific theory using a Geographic Information System.
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Visual Survey: Observing data for patterns

Conduct a brief visual survey of the map and the themes available.  Experiment with the monthly tornado average themes by turning each month’s theme on, one at a time.

1.	How would you describe the locations and concentrations of tornadoes in the US during the winter months?  Turn on tornado themes for January – March separately.
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2.	How would you describe the locations and concentrations of tornadoes in the US 
      during Spring?  Turn on tornado themes for April – June separately.
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3.	How would you describe the locations and concentrations of tornadoes in the US 
      during Summer and Fall?  Turn on tornado themes for July – December separately.
________________________________________________________________________________________________________________________________________________________________________________________________________________________

Image Analysis: Theme-on-theme selections

Turn on the US Winter Jet Stream and January Tornadoes theme (be sure all other tornado and jet stream themes are off).  Do you see any pattern between the US jet stream and tornado occurrence?  To help find an answer, we will do a theme-on-theme selection around the US Winter jet stream of 200 miles and then tabulate the number of monthly tornadoes that fall within the region. 

Make the January Tornadoes theme active by clicking once on the label.  Then 
1.  Go to the pull-down menu “Themes” and choose “Select By Theme” 
	2.  In the first pull-down box select “Are Within Distance Of”
	3.  In the second box you should select “Winter JetStream”
	4.  In the third box (which only appears after you set your first box) you should type  
	     “200” without the quotations.
4.	Finally, press the button “New Set”

5.	The box will now disappear, but tornadoes falling within 200 miles of the jet stream should be yellow.
6.	  Press the  “Open Theme Table” button.   This table displays data for the active theme (January tornadoes).  You can find a count of how many tornadoes are selected beneath the “Save” button (Example: 234 of 345 selected).  This means that 234 tornadoes fall within 200 miles on either side of the January Jet Stream.

7.	To calculate a percentage, divide the number of selected tornadoes by the total number of tornadoes.

4.   What percentage of January tornadoes fall within 200 miles of the Winter Jet Stream?
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1.	What percentage of May tornadoes fall within 200 miles of the Equinox Jet Stream?
					__________________________________

2.	What percentage of August tornadoes fall within 200 miles of the US Summer jet stream?							
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7.   Based on the information just recorded, what can you say about how tornadoes and the US jet stream relate?  
________________________________________________________________________________________________________________________________________________________________________________________________________________________

Finding data beneath the surface: Querying tables

To find out more information, we can search through the data tables and determine how intense the Tornadoes within 200 miles of the US jet stream were by looking at the assigned Fujita scale.  To obtain more information, we must conduct a “query” of the data we selected above.  

To identify characteristics of pre-selected data:
1.	Do another theme-on-theme selection of January tornadoes as we did before.  
2.	  Press the “Open Theme Table” button.  Notice the highlighted records.
3.	  Press the “Query Builder” icon.  It looks like a hammer and question mark.
4.	Make sure the checkbox “Update Values” is checked.
5.	In the left window, you will see a list of all the information types.  Scroll down the list and double click on “Fujita”.  Notice Fujita should now appear in the box at the bottom of the window.
6.	In the top middle of the box, there are many signs and words.  These are mathematical and logical operators.  Use the Equal to or greater than sign (“>=”).  Click it once.  It should also appear in the window.
7.	Finally, the available values of the Fujita information type appear in the upper right window.  Double click “3”.

8.	We can now ask the database, what January Tornadoes within 200 miles of the US Winter jet stream have a Fujita value equal or greater than three?  Press the “Select from Set” button.
9.	Close the Query builder window.
10.	Record the number of selected records and total records.  Remember, the number of selected records should be smaller than what you started with.

8.   What percentage of January Tornadoes (within 200 miles of the winter jet stream) have a Fujita value equal to or greater then three?
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1.	What percentage of May Tornadoes (within 200 miles of the winter jet stream) have a Fujita value equal to or greater then three? 
							_______________________

2.	 What percentage of August Tornadoes have a Fujita value equal to or greater then three?
_______________________
 
3.	What relationship do you see between the Fujita values of tornado intensity during January, May, and August?  What trends or patterns exist in the data?
_______________________________________________________________________________________________________________________________________________________________________________________________________________

12. What role does seasonal variation in the US jet stream have on tornado development?  How does this role reflect the original scientific theory proposed above?
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13. Are the tests we conducted completely reliable for supporting or refuting these scientific claims?  Why or why not?
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