Solar Terrestrial Activity ReportSolar Terrestrial Activity Report

Last update December 5, 2002 at 03:50 UTC.
[Solar and geomagnetic data - last 4 weeks (updated daily)]
[Solar wind and electron fluence charts (updated daily)]
[Solar cycles 21-23 (last update December 2, 2002)]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22 and 23 (last update December 2, 2002)]
[Graphical comparison of cycles 10, 13, 17, 20 and 23 (last update December 2, 
2002)]
[Historical solar and geomagnetic data charts 1954-2002 (last update October 13, 
2002)]
[Archived reports (last update December 1, 2002)]
Recent activity
The geomagnetic field was quiet to active on December 4. Solar wind speed ranged 
between 406 and 467 km/sec.
Solar flare activity was moderate. Solar flux was 148.7, the planetary A index 
was 12 (STAR Ap - based on the mean of three hour ap indices: 13.3).
Three hour interval K indices: 22333432 (planetary), 12323332 (Boulder).
The background x-ray flux is at the class B4 level.
At midnight there were 8 spotted regions on the visible disk, 2 of which have 
not yet been numbered. Only 1 flare, an M class event, was recorded during the 
day.
Region 10203 decayed and was spotless by midnight.
Region 10205 decayed and could become spotless today.
Region 10207 decayed slowly and quietly.
Region 10208 was quiet and decayed in the trailing spot section. Several spots 
emerged in the leading spot section and a magnetic delta structure formed there. 
An M class flare is possible.
Region 10209 was quiet and stable.
Region 10212 developed early in the day, then decayed slowly and quietly.
Region 10213 did not change much and was quiet with the exception of the 
unexpected M flare. Flare: M2.5/2N at 22:49 UTC. This event was associated with 
a weak type IV, a strong type II radio sweep and a small CME.
Spotted regions not yet numbered by SEC:
[S41] A new region emerged in the northwest quadrant during the afternoon. 
Location at midnight: N12W13.
[S42] A new region emerged early in the day in the southeast quadrant. Initially 
many spots were visible, then the region began to decay and only a few small 
spots could be observed at midnight. Location at midnight: S10E18.
Coronal mass ejections (CMEs)
December 2-4: No obviously geoeffective CMEs noted.
Coronal holes
Coronal hole history (starting late October 2002)
Compare today's report with the situation one solar rotation ago: -1 day 27 days 
ago +1 day
The southernmost part of an extension of the northern polar coronal hole may 
have been in a geoeffective position on December 4. A slowly developing trans 
equatorial coronal hole was in a geoeffective position on December 4.

Processed SOHO EIT 284 image at 19:06 UTC on December 4. Any black areas on the 
solar disk are likely coronal holes.
Forecast
The geomagnetic field is expected to be quiet to unsettled on December 5-6 and 
quiet to active on December 7-8. Long distance medium wave (AM) band propagation 
along east-west paths over high and upper middle latitudes is fair to 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 continuum 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
      102022002.11.24  N12W64  plage 
      102032002.11.263N07W340010BXOnow spotless 
      102042002.11.27  N16W51  plage 
      102052002.11.2752N20W290020CROclassification was BXO
      at midnight 
      102062002.11.27 S27W48  plage 
      102072002.11.271513S19W210210EAO  
      102082002.11.292631N10E080140EAIbeta-gamma-delta 
      102092002.11.30115S19E070120CSO  
      102112002.12.02 S08W22  plage 
      102122002.12.02911N13E490180DAO
      102132002.12.0354N14E640090CAO
      S41emerged on
      2002.12.04 3N12W130010CRO
      S42emerged on
      2002.12.04 2S10E180010AXX
      Total spot count:7471
      SSN:144151

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
      2001.11210.6106.5115.5 (+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)
      2002.05178.4120.8108.8 (-1.7)
      2002.06148.788.3(106.4 predicted, -2.4)
      2002.07173.599.9(102.8 predicted, -3.6)
      2002.08183.6116.4(99.6 predicted, -3.2)
      2002.09175.8109.3(96.6 predicted, -3.0)
      2002.10167.097.5(93.1 predicted, -3.5)
      2002.11168.795.0(87.8 predicted, -5.3)
      2002.12147.6 (1)17.1 (2)(83.5 predicted, -4.3)

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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