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The blue area surrounding the white-to-yellow-to-red oval area of these plots does not have any significance except to show the geographic extent of the data observations used to produce the plots. (The blue color does not signify greater auroral activity than the surrounding black color.) The red arrow on the plot points toward the noon meridian.

This display of the statistical auroral oval includes a presentation of the actual auroral energy input observations that were used to estimate the hemispheric power and the level of auroral activity. This presentation shows the track of the satellite over the polar region. The length of the solid line indicates that amount of energy into the atmosphere that was observed at that point along the satellite track. The scales in the 4 corners of the plot may be used to convert the line length to actual energy flux. The length of the dotted line is an indication of the energy of the electrons that are flowing into the atmosphere to produce the aurora. A line of two dots represents a very low energy of about 100 eV, a length of 16 dots a high energy. Both the solid and dotted lines are plotted every 16-seconds or about 100 km along the satellite track.

Normalization factor (n)
A normalization factor of less than 2.0 indicates a reasonable level of confidence in the estimate of power. The more the value of n exceeds 2.0, the less confidence should be placed in the estimate of hemispheric power and the activity level.

The process to estimate the hemispheric power, and the level of auroral activity, involves using this normalization factor which takes into account how effective the satellite was in sampling the aurora during its transit over the polar region. A large (> 2.0) normalization factor indicates that the transit through the aurora was not very effective and the resulting estimate of auroral activity has a lower confidence. In order for users to assess the confidence in a given estimate of auroral power, we now report the numerical value of the normalization factor in our web pages.