Robert Zimmerman’s article referenced in yesterday’s DDX asserts that “it appears that Solar Minimum has arrived.” based only on very frequent spotless days during the last six weeks.
More comprehensive physical evidence suggests its more likely that we’ve just begun a lengthy Deep Solar Minimum Phase — similar to late 2007 through late 2008 — that’s likely to last well into next year.
How did I reach that conclusion? An important solar physical event that precedes Solar Minimum (the date when Solar Cycle 24 transitions to Solar Cycle 25) hasn’t yet occurred. Solar polar magnetic field strength peaks at least a year before Solar Minimum.
While the north polar region reached peak field strength last year, the south polar region hasn’t yet peaked. This suggests that Solar Minimum is likely to occur next year at the earliest.