Magnetic Storms

When a solar storm hits Earth, most of its affects are invisible, but if you know how to look for them, you can find them even here on the ground!

Scientists operate observatories all over the world to carefully measure Earth's magnetism. These observatories record changes in Earth's magnetic field as solar storms shake the field. Scientists keep track of the storminess by using the data to create a number called the 'Kp index'. This number ranges from 0 to 9 and is largest for the most severe storms.

Below you will see a table of the Kp index for the month of March, 2001 for the magnetic observatory at Dixon Island (Online Details)which is located at latitude 73.5 North and longitude 80.4 West. The first column is the day of the month. The 'Time of Day' columns give the Kp index reading every three hours.

For example, the first row is for March 1. The value of the Kp index at 9:00 PM was '3'.

-------------------------------------------------------------------------
		 	--------------Time of Day----------------------
Day        Station    3:00  6:00  9:00  Noon  3:00 6:00  9:00  Midnight
-------------------------------------------------------------------------

01      Dixon Island   5     3     2     1     1     5     3     3
02      Dixon Island        No Data Available for this day
03      Dixon Island   5     3     2     5     5     6     7     4
04      Dixon Island   3     4     5     5     6     6     7     7
05      Dixon Island   8     6     4     4     3     4     3     4
06      Dixon Island   3     4     2     3     2     4     6     5
07      Dixon Island   3     4     3     3     3     7     4     3
08      Dixon Island   2     2     3     3     2     5     5     5
09      Dixon Island   3     2     -     3     6     6     3     2
10      Dixon Island   3     2     3     3     1     5     6     2
11      Dixon Island   1     2     1     2     2     2     2     3
12      Dixon Island   1     1     2     4     5     5     6     7
13      Dixon Island   3     3     3     5     5     3     3     5
14      Dixon Island   4     2     3     3     4     3     4     4
15      Dixon Island   1     1     2     1     2     3     4     4
16      Dixon Island   4     2     3     3     4     3     4     4
17	Dixon Island   1     1     1     2     2     5     6     3
18      Dixon Island   4     3     3     4     4     5     4     6
19      Dixon Island   5     2     3     3     6     6     5     6
20      Dixon Island   7     6     4     4     9     6     6     5
21      Dixon Island   4     4     2     3     2     3     2     2
22      Dixon Island   2     2     2     2     3     6     5     6
23      Dixon Island   5     5     5     6     7     6     5     5
24      Dixon Island   3     3     4     4     5     4     5     2
25      Dixon Island   2     3     3     4     3     2     4     4
26      Dixon Island   1     2     1     3     4     2     5     2
27      Dixon Island   5     3     3     4     4     5     6     8
28      Dixon Island   4     3     5     7     6     7     3     6
29      Dixon Island   6     4     6     5     5     6     4     4
30      Dixon Island   4     3     4     4     4     5     5     5
31      Dixon Island   8     9     9     6     5     9     9     6


  1. How many days of observations are recorded?
  2. On March 9th at 9:00 AM, what would you predict that Kp might have been?
  3. What is the median Kp index for the month of March?
  4. What is the mode Kp index for the month of March?
  5. What percentage of the time was Kp higher than 5?
  6. What percentage of the time was Kp higher than 7?
  7. What was the stormiest day of the month?
  8. How long, in hours, does a typical storm event last?
  9. Do small storms (Kp = 5 or 6) last longer or shorter times than severe storms (kp = 8 or 9)?
  10. What is the average Kp index for March 30th?
  11. What is the average Kp index for the month of March?
  12. Which days would have been good for aurora observing?
  13. It takes 1 day for you to travel to a place where you could view an aurora. How well could you have used the Kp index to predict when to start your journey so that you would arrive during an auroral display?