Solar Terrestrial Activity Report

Last update January 7, 2003 at 03:15 UTC. Minor update posted at 08:24 UTC.

[Solar and geomagnetic data - last 4 weeks (updated daily)]
[Solar wind and electron fluence charts (updated daily)]
[Solar cycles 21-23 (last update January 1, 2003)]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22 and 23 (last update January 1, 2003)]
[Graphical comparison of cycles 10, 13, 17, 20 and 23 (last update January 1, 2003)]
[Historical solar and geomagnetic data charts 1954-2002 (last update October 13, 2002)]
[Archived reports (last update January 6, 2003)]

Recent activity

The geomagnetic field was quiet to unsettled on January 6. Solar wind speed ranged between 369 and 428 km/sec. 

Solar flux measured at 20h UTC on 2.8 GHz was 162.1. The planetary A index was 7 (STAR Ap - based on the mean of three hour interval ap indices: 7.8).
Three hour interval K indices: 22223332 (planetary), 12212222 (Boulder).

The background x-ray flux is at the class B8 level.

At midnight there were 9 spotted regions on the visible disk, 1 of which has not yet been numbered. Solar flare activity was low. A total of 4 C class events were recorded during the day. An optically unaccounted C2.9 event occurred at 14:29 UTC.

Region 10239 reemerged quickly with several spots after noon.
Region 10242 developed fairly quickly adding a significant amount of penumbra in all parts of the region. Although the region is not currently very complex, there is a chance of an M class flare.
Region 10243 decayed slowly and will be rotating over the southwest limb today and tomorrow. Flare: C1.0 at 08:17 UTC.
Region 10244 developed slowly and was mostly quiet. Flare: C2.7 at 09:43 UTC.
Region 10245 was mostly unchanged and quiet.
New region 10246 emerged in the northeast quadrant on January 5 and was numbered one day later. The region decayed slightly on Jan.6.
New region 10247 emerged quickly after noon near the southeast limb.

Spotted regions not yet numbered by SEC/NOAA:
[S66] A new region emerged to the northeast of region 10239 on January 4. The region was mostly unchanged on Jan.5 and decayed slowly on Jan.6. Location at midnight: S05W63. Unfortunately and confusingly SEC/NOAA decided to reuse region number 10240.
[S67] This region first emerged in the southeast quadrant on January 4, then decayed and became spotless the next day. A single spot reemerged just before midnight UTC on January 6.

Comment added at 08:24 UTC on January 7: Region 10244 was at center of an M1.0 event peaking at 07:50 UTC. This event may have involved a filament near the region, a filament which was quite active prior to the eruption. If there was a CME associated with this event, another update will be posted within a few hours.
Otherwise a new region will soon be rotating into view at the southeast limb. This region appears to be quite interesting and could have M class flare potential. 

Coronal mass ejections (CMEs)

January 4-6: No obviously geoeffective CMEs observed.

Coronal holes

Coronal hole history (since late October 2002)
Compare today's report with the situation one solar rotation ago: 28 days ago 27 days ago 26 days ago

A recurrent trans equatorial extension of the northern polar coronal hole was in a geoeffective position on January 6.

Processed SOHO EIT 284 image at 19:06 UTC on January 6. Any black areas on the solar disk are likely coronal holes.


The geomagnetic field is expected to be quiet to unsettled on January 7-8 becoming quiet to active on January 9-10 due to a coronal stream. Long distance medium wave (AM) band propagation along east-west paths over high and upper middle latitudes is fair.

Coronal holes (1) Coronal mass ejections (2) M and X class flares (3)
Coronal hole indicator CME indicator M and X class flare indicator

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. Compare to the previous day's image.

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 inside a few hours before midnight) and data for regions not numbered by SEC or where SEC has observed no spots.

Solar region Date numbered SEC
Location at midnight Area Classification Comment
10239 2002.12.29 3 4 S09W73
0020 BXO location corrected
area was 0060 at
midnight, classification
CAO then
10240 2002.12.30 3 S08W56
0010 CSO actually spotless
location corrected
see region S66 below
10242 2003.01.02 27 38 S08E03 0190 DAC beta-gamma
area approx. 0450
at midnight,
classification EAI
10243 2003.01.03 9 11 S19W73 0150 CAO classification was DAO
at midnight
10244 2003.01.03 13 15 S23E14 0090 CAO classification was DAO
at midnight,
area near 0140
10245 2003.01.03 2 3 N11E33 0030 HAX classification was CSO
at midnight,
area near 0060
10246 2003.01.06 3 3 N08E10 0010 CRO formerly region S70
classification was DRO
at midnight,
area was 0020
10247 2003.01.06 1 2 S17E73 0020 HSX classification was HAX
at midnight,
area was 0050
S66 emerged on
  2 S05W63 0020 CSO  
S67 emerged on
  1 S15E29 0010 HRX  
S68 emerged on
  N02E19     plage
S69 emerged on
  N13W12     plage
Total spot count: 61 79
SSN: 141 169

Monthly solar cycle data

Month Average solar
flux at Earth
International sunspot number Smoothed sunspot number
2000.04 184.2 125.5 120.8
cycle 23 sunspot max.
2000.07 202.3 170.1 119.8
2001.12 235.1 132.2 114.6 (-0.9)
2002.01 226.6 114.1 113.5 (-1.1)
2002.02 205.0 107.4 114.6 (+1.2)
2002.03 179.5 98.4 113.3 (-1.3)
2002.04 189.8 120.7 110.5 (-2.9)
2002.05 178.4 120.8 108.8 (-1.7)
2002.06 148.7 88.3 106.2 (-2.6)
2002.07 173.5 99.6 (102.1 predicted, -4.1)
2002.08 183.6 116.4 (98.5 predicted, -3.6)
2002.09 175.8 109.6 (95.5 predicted, -3.0)
2002.10 167.0 97.5 (92.0 predicted, -3.5)
2002.11 168.7 95.0 (86.7 predicted, -5.3)
2002.12 157.2 81.6 (82.4 predicted, -4.3)
2003.01 137.4 (1) 19.8 (2) (79.4 predicted, -3.0)

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. All time references are to the UTC day. Comments and suggestions are always welcome.

[DX-Listeners' Club]