Table 1.

Methods of measuring CME properties.

Property Method
Frequency of occurrence Count the number of observed CMEs occurring over a given time period.
Distance (height) Select an easily identifiable feature near the CME leading edge (some choose a common position angle) and measure its distance from the center of the Sun, calibrating to units of solar radii.
Speed (acceleration) Measure the distances of the same feature in multiple images and plot the distance-time distribution. A linear least-squares fit provides the speed; a second-order polynomial fit provides the acceleration.
Geometry Trace out the leading edge of the CME and calibrate to units of solar radii.

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