A Note on NOAA SEC Active Region Numbers
From the SEC daily "solar region summary:"
This message is for users of the NOAA/SEC Space
Weather Operations sunspot region numbers. As you
may have noticed, region number 10000 was assigned
on June 14. Space Weather operations is going
through the sequence of Region numbers as 9998,
9999, 0000, 0001, and so on. SEC's product text
discussions of the active regions will ignore the
leading zeroes (for example, we will say 'Region
number 5' rather than Region number '0005'). However,
the Geoalert product, the Region Report product, as
well as the USAF and ISES data exchange codes will
preserve the 4 digit format. The necessity of using
four digits is for operational purposes only. For
historical purposes all regions beyond Region 9999
will be understood to be in a series of region numbers
10000 and higher.