An article in the New Scientist says:
But Dr. Leif Svalgaard, one of the worlds leading solar physicists and WUWT’s resident solar expert has this to say:
Solar max is a slippery concept. One can be more precise and *define* solar max for a given hemisphere as the time when the polar fields reverse in the hemisphere. The reversals usually differ by one or two years, so solar max will similarly differ. The North is undergoing reversal right now, so has reached maximum. The South is lagging, but already the polar field is rapidly decreasing, so reversal may be only a year away. Such asymmetry is very common.
Here is a link to the evolution of the polar fields as measured at WSO:
And here’s data all the way back to 1966, note there has not been a crossing of the polar fields yet in 2012, a typical event at solar max:
Here is a link to a talk on this: http://www.leif.org/research/ click
on paper 1540.
Dr. Svalgaard adds:
Solar max happens at different times for each hemisphere. In the North we are *at* max right now. For the South there is another year to go, but ‘max’ for a small cycle like 24 is a drawn out affair and will last several years. To say that max falls on a given date, e.g. Jan 3rd, 2013, at UT 04:15 is meaningless.