Below is a note forwarded to me by John Sumption from Jan Janssens. For those who do not know him, Jan runs a very comphrehensive solar tracking website here.
Jan included the caveat:
This topic’s sure to start another heated discussion on the solar blogs
So I’m happy to oblige by posting it here. Jansen makes some good points about the possible first month that cylce 24 spots exceed cycle 23 spots. But when you are in a deep minimum like this one, it is hard to pinpoint the transition, because next month may bring the reverse condition. He writes:
Prior to August 2008, only 3 SC24-sunspot groups appeared. This was in January, April and May. During these 3 months, SC23-activity was higher than SC24-activity. Based on the NOAA-numbering, there were respectively (SC23 to SC24) 2 to 1, 2 to 1, and 4 to 1 sunspotgroups visible.
In August, there were no sunspotgroups numbered by NOAA. However, on 21-22 August “something” was visible well enough to be seen by several observers and to prompt the SIDC to give a (preliminary) non-zero sunspotnumber for those days.
This group had a SC24-polarity but appeared on a moderate latitude of 15 degrees. Based on previous cycle transits, it is not unusual that some “early” new cycle groups appear this low. If one considers this as a sunspotgroup and belonging to SC24, then August was the month during which SC24-activity outnumbered SC23 activity.
However, if one adheres strictly to the NOAA-numbering, then September ***might*** be that month. I stress “might”, because -unless some group appears tomorrow or tuesday- the score will still be 1 to 1: On September 11th, NOAA did number an even tinier group than the August one, and it was a SC23 group (NOAA 1001). SC24-activity then wins on “points”, because the Wolfnumbers for 22-23 September produced by NOAA 1002 (SC24) were higher than the NOAA 1002 Wolfnumber.
Last but not least, I want to emphasize that SC24-activity will be considered higher than SC23’s when its smoothed group (or Wolf) number exceeds that of the old cycle. This might happen in the coming months (or whenever her Majesty the Sun feels up to it ;-)