Presentation Abstract

Session: Upper Atmosphere
Presentation Number: P18.04
Title: Whither goes Cycle 24? A View from the Fe XIV Corona
Presentation Start: 6/13/2011 7:30:00 AM
Presentation End: 6/16/2011 8:30:00 AM
Authors: Richard C. Altrock1
1Air Force Research Lab..
Abstract: Solar Cycle 24 had a historically prolonged and weak start. Observations of the Fe XIV corona from the Sacramento Peak site of the National Solar Observatory showed an abnormal pattern of emission compared to observations of Cycles 21, 22, and 23 from the same instrument. The previous three cycles had a strong, rapid "Rush to the Poles" in Fe XIV. Cycle 24 displays a delayed, weak, intermittent, and slow "Rush" that is mainly apparent in the northern hemisphere. If this Rush persists at its current rate, evidence from previous cycles indicates that solar maximum will occur in approximately early 2013. At lower latitudes, solar maximum previously occurred when the greatest number of Fe XIV emission regions* first reached approximately 20° latitude. Currently, the value of this parameter at 20° is approximately 0.15. Previous behavior of this parameter indicates that solar maximum should occur in approximately two years, or 2013. Thus, both techniques yield an expected time of solar maximum in early 2013.
*annual average number of Fe XIV emission features per day greater than 0.19