Solar Terrestrial Activity ReportSolar Terrestrial Activity Report

Last update November 21, 2002 at 03:40 UTC. Minor update posted at 10:32 UTC.
[Solar and geomagnetic data - last 4 weeks (updated daily)]
[Solar wind and electron fluence charts (updated daily)]
[Solar cycles 21-23 (last update November 2, 2002)]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22 and 23 (last update November 2, 2002)]
[Graphical comparison of cycles 10, 13, 17, 20 and 23 (last update November 2, 
2002)]
[Historical solar and geomagnetic data charts 1954-2002 (last update October 13, 
2002)]
[Archived reports (last update November 9, 2002)]
Recent activity
The geomagnetic field was quiet to active on November 20. Solar wind speed 
ranged between 353 and 494 km/sec. A disturbance began influencing the 
geomagnetic field around noon. Solar wind density and speed increased as early 
as 10:30 UTC at ACE. The total field of the interplanetary magnetic field 
increased gradually in strength from 23h UTC and became very strong early on 
Nov.21. Although a coronal stream is still the most likely possibility, this 
disturbance may have other sources than a coronal hole.
Solar flare activity was moderate. Solar flux was 159.1, the planetary A index 
was 17 (STAR Ap - based on the mean of three hour ap indices: 18.5).
Three hour interval K indices: 33132444 (planetary), 32231444 (Boulder).
The background x-ray flux is at the class B7 level.
At midnight there were 7 spotted regions on the visible disk, 1 of which has not 
yet been numbered. A total of 10 C and 1 M class events were recorded during the 
day.
Region 10191 decayed slowly and is rotating over the southwest limb. Flares: 
C1.1 at 04:50 and C1.0 at 15:25 UTC.
Region 10195 decayed slowly and quietly.
Region 10197 added a few small spots and was otherwise unchanged and quiet.
Region 10198 did not change much. The magnetic delta in the huge leading 
penumbra disappeared, however, there is a weak delta in a trailing penumbra. 
Flares: C1.7 at 01:46, C1.4 at 03:12, C1.3 at 11:24, C3.9 at 16:33, an impulsive 
M1.4 at 18:07, C1.6 at 19:29 and an impulsive C5.2 at 23:56 UTC.
New region 10199 emerged in the northeast quadrant on Nov.19 and was numbered on 
Nov.20.
New region 10200 rotated into view at the east limb early in the day.
Spotted regions not yet numbered:
[S32] A bipolar region emerged just northwest of the leading penumbra of region 
10198 late on Nov. 18 and developed slowly on Nov.19 and 20. Location at 
midnight: S16E03.
Comment added at 10:32 UTC on November 21: The unusually strong coronal stream 
in progress caused severe to very severe geomagnetic storming during the 06-09h 
UTC interval with the 3-hour planetary A index reaching 144 (as far as I can 
recall this is the highest 3-hour ap value associated with a coronal stream 
disturbance, at least since the years prior to the last sunspot minimum). Solar 
wind speed has levelled out just below 700 km/sec. Active to major storming is 
likely for the remainder of the day.
Coronal mass ejections (CMEs)
November 18-20: No obviously geoeffective CMEs noted.
Coronal holes
A trans equatorial coronal hole, possibly an extension of the southern polar 
coronal hole, was in a geoeffective position on November 18.

Enhanced SOHO EIT 284 image at 19:05 UTC on November 20 . The black areas on the 
solar disk are coronal holes.
Forecast
The geomagnetic field is expected to be unsettled to major storm on November 21 
and unsettled to minor storm on Nov.22 under the influence of a coronal stream. 
Long distance medium wave (AM) band propagation along east-west paths over high 
and upper middle latitudes is poor to very poor.
      Coronal holes (1)Coronal mass ejections (2)M and X class flares (3)


1) Effects from a coronal hole could reach Earth within the next 5 days.
2) Material from a CME is likely to impact Earth within 96 hours.
3) There is a possibility of either M or X class flares within the next 48 
hours.
Green: 0-20% probability, Yellow: 20-60% probability, Red: 60-100% probability.
Active solar regions (Recent map)

Composite image based on a SOHO/MDI image and overlaid by a coronal hole image. 
Region numbering has been included.
Data for all numbered solar regions according to the Solar Region Summary 
provided by SEC/NOAA. Comments are my own, as is the STAR spot count (spots 
observed at or just prior to midnight) and data for regions not numbered by SEC 
or where SEC has observed no spots.
      Solar regionDate numberedSEC
      spot
      countSTAR
      spot
      countLocation at midnightAreaClassificationComment
      101912002.11.0871S18W810200FAOarea was 0040 in
      an HAX group at
      midnight 
      101932002.11.12  S02W84  plage 
      101942002.11.13  S17W51  plage 
      101952002.11.1375S17W110190EAO  
      101972002.11.1425N24W060310HHX  
      101982002.11.153024S18E150580FKCbeta-gamma-delta
      SEC spot number
      includes region S32 
      101992002.11.2034N27E130030AXXformerly region S33,
      classification was HRX
      at midnight 
      102002002.11.2011N00E710060HSXlatitude appears to
      be S02 rather than
      N00  
      S32emerged on
      2002.11.18 6S16E030040DAO  
      Total spot count:5046
      SSN:110116

Monthly solar cycle data
      MonthAverage solar
      flux at EarthInternational sunspot numberSmoothed sunspot number
      2000.04184.2125.5120.8
      cycle 23 sunspot max. 
      2000.07202.3170.1119.8
      2001.10207.6125.5114.0 (-0.1)
      2001.11210.6106.5115.5 (+1.5)
      2001.12235.1132.2114.6 (-0.9)
      2002.01226.6114.1113.5 (-1.1)
      2002.02205.0107.4114.7 (+1.2)
      2002.03179.598.4113.4 (-1.3)
      2002.04189.8120.7110.5 (-2.9)
      2002.05178.4120.8(109.0 predicted, -1-5)
      2002.06148.788.3(107.0 predicted, -2.0)
      2002.07173.599.9(103.6 predicted, -3.4)
      2002.08183.6116.4(100.2 predicted, -3.4)
      2002.09175.8109.3(96.4 predicted, -4.8)
      2002.10167.097.5(92.3 predicted, -4.1)
      2002.11180.9 (1)120.4 (2)(87.0 predicted, -5.3)

1) Running average based on the daily 20:00 UT observed solar flux value at 2800 
MHz.
2) Unofficial, accumulated value based on the Boulder (SEC/NOAA) sunspot number. 
The official international sunspot number is typically 25-45% less.
This report has been prepared by Jan Alvestad. It is based partly on my own 
observations and interpretations, and partly on data from sources noted in solar 
links. Comments and suggestions are always welcome.


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