TRACKING A PERFECT STORM
Magnetosphere
Scientists measure the strength and direction of Earth's field with sensitive instruments called magnetometers. Scientists put 'magnetic observatories' all over the world, but most are in the polar regions of Earth where the field is known to change rapidly.
One observatory you use is at Baker Lake in Canada. You see the graph from May 29.
After a calm day a rather large disturbance occurred starting about 13:00 UT. This plot shows the strength and direction of the magnetic field at Baker Lake, Canada. These plots show the X (northward), Y (eastward) and Z (vertical downward) components of the magnetic field. Universal Time (UT) is used. Notice that the field is pretty steady in the early part of the day. Late in the day the field varies by 1000 nanoTeslas (nT) or more.
It is important to check other observatories to see if they recorded a disturbance, too. You check Alaska.
These lines also show components of the magnetic field. Again, the field is steady early in the day of May 29 and shows large variations late in the day.
The Kp index is the easiest way to find out if there is a disturbance in the Earth’s magnetic field and how severe the disturbance was. The Kp index combines the disturbances in the Earth’s magnetic field measured at 9 separate observatories in North America. The Kp ranges from 0-3 (steady), 4 (mild disturbance), and 5-9 (severe disturbance) The Kp plot for late in the day of May 29 climbs steadily to a large disturbance of 8.
A quick look at the ACE (Advanced Composition Explorer) data confirms that there was a significant disturbance in space. ACE is 1 million miles from Earth and can measure the strength and direction of the magnetic field of the coronal mass ejection as it reaches Earth. A strong, negative field will affect the Earth’s field. A strong, negative field existed for several hours at the end of May 29 (the 149th day of the year).
This was a fairly powerful storm. But, because of your Space Weather Alert, there was little damage to power grids or satellites. Electric power companies were able to monitor their systems to prevent burnout. The government and communications companies were able to monitor satellites and shut down sensitive systems if needed. You have done a great job – and there are a few hours left for you to go outside and see if you can see an aurora!
like the one in the photograph taken by Bob Sandy of Roanoke County, Virginia about 10:00pm, May 29, 2003
It is always interesting to find out how extensive the aurora display was. After all you can only see the aurora where you are. The GUVI (Global Ultraviolet Imager) instrument on board the TIMED (Thermosphere*Ionosphere*Mesosphere Energetics and Dynamics) satellite provides images showing how intesnse the aurora was and where it was seen. Unfortunately, you have to wait a few days for the data to be processed. Here are two images from GUVI. The one on the left is from about 2:00 am EST on May 29.
The image on the left is from about 9:00 pm EST on May 29. Red and orange colors on the night side of Earth indicate auroras. Since 2:00am and 9:00 pm are during the night, observers in the United States and Canada could see aurora. The intense red over southern Canada in the early morning suggests that observers in the Northern U.S. could see aurora. In the evening of May 29 the intense red extends south into New York state and Pennsylvania.
Solar storms don’t happen every day. But now you are ready to monitor the Sun through the Student Observation Network module “Tracking a Solar Storm”. You might be the one to issue a Space Weather Alert for the next solar storm.
- NASA Official: Dr. James Thieman
- Project Manager: Don Robinson-Boonstra
- Website Manager: Bryan Stephenson