Solar Terrestrial Activity Report

Last update issued on February 8, 2003 at 03:40 UTC.

[Solar and geomagnetic data - last 4 weeks (updated daily)]
[Solar wind and electron fluence charts (updated daily)]
[Solar cycles 21-23 (last update February 2, 2003)]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22 and 23 (last update February 2, 2003)]
[Graphical comparison of cycles 10, 13, 17, 20 and 23 (last update February 2, 2003)]
[Historical solar and geomagnetic data charts 1954-2002 (last update January 27, 2003)]
[Archived reports (last update February 3, 2003)]

Recent activity

The geomagnetic field was quiet to active on February 7. Solar wind speed ranged between 447 and 559 km/sec under the influence of a coronal stream.

Solar flux measured at 20h UTC on 2.8 GHz was 147.3. The planetary A index was 13 (STAR Ap - based on the mean of three hour interval ap indices: 13.4).
Three hour interval K indices: 32234333 (planetary), 32223332 (Boulder).

The background x-ray flux is at the class B3 level.

At midnight there were 9 spotted regions on the visible disk, 2 of which have not yet been numbered by SEC/NOAA. Solar flare activity was low. Only 1 C class event was recorded during the day.

Region 10274 was mostly quiet and stable. Flare: Long duration C1.0 peaking at 16:28 UTC.
Region 10276 decayed quickly. At the current rate of decay this region will become spotless within 2 days.
Region 10277 developed slowly and quietly.
Region 10278 decayed further and was quiet.
Region 10280 decayed slowly and quietly.
Region 10281 was mostly quiet and unchanged.
New region 10282 emerged in the northeast quadrant, then decayed and was spotless again before early evening. This region was first spotted on February 5, then became spotless on February 6.
New region 10283 emerged in the northeast quadrant on February 6 and was numbered the next day. The region developed slowly on Feb.7.

Spotted regions not yet numbered by SEC/NOAA:
[S87] A new region emerged north of region 10274 on January 31. Initially it was not clear if this was a separate region and the spots were associated with region 10274. The region developed quickly on February 2 and it became obvious that regions 10274 and S87 were separate bipolar regions. Slow decay has been observed since February 4. Location at midnight: S04W66.
[S90] A new region emerged in the southeast quadrant on February 4. Location at midnight: S16E30.

Coronal mass ejections (CMEs)

February 5-6: No obviously geoeffective CMEs observed. (Images covering February 7 not yet available.)

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

No obvious coronal holes are currently approaching geoeffective positions.

Processed SOHO EIT 284 image at 01:06 UTC on February 8. Any black areas on the solar disk are likely coronal holes.

Forecast

The geomagnetic field is expected to be quiet to unsettled on February 8-11. Long distance medium wave (AM) band propagation along east-west paths over high and upper middle latitudes is very poor, propagation along north-south paths 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)

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
spot
count
STAR
spot
count
Location at midnight Area Classification Comment
10274 2003.01.28 3 1 S07W59
(SEC:
S05W63)
0100 CSO classification was HSX
at midnight.
location corrected.
SEC spot count
includes that of region
S87
10276 2003.02.01 31 20 S13W01 0090 ESI  
10277 2003.02.04 1 9 S19E25 0020 HRX classification was DAO
at midnight, area 0040
10278 2003.02.04 21 18 N18E40 0130 DAO  
10279 2003.02.05     S13W25     plage
10280 2003.02.06 9 8 S07E16 0040 DSO  
10281 2003.02.06 1 1 S14E60 0050 HAX  
10282 2003.02.07 4   N12E35 0020 BXO formerly region S93
now spotless
10283 2003.02.07 3 3 N01E52 0040 CSO formerly region S97
classification was DSO
at midnight, area 0070
S86 emerged on
2003.02.02
  S18W74     plage
S87 emerged on
2003.01.31
  1 S04W66 0030 HSX split off from region
10274
S88 emerged on
2003.02.04
    S08W27     plage
S90 emerged on
2003.02.04
  2 S16E30 0010 BXO  
S96 emerged on
2003.02.06
    S03W21     now spotless
Total spot count: 73 63
SSN: 153 153

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 99.6 102.7 (-3.5)
2002.08 183.6 116.4 (99.7 predicted, -3.0)
2002.09 175.8 109.6 (96.7 predicted, -3.0)
2002.10 167.0 97.5 (93.2 predicted, -3.5)
2002.11 168.7 95.0 (88.0 predicted, -5.2)
2002.12 157.2 81.6 (83.6 predicted, -4.4)
2003.01 144.0 79.5 (80.6 predicted, -3.0)
2003.02 136.7 (1) 23.5 (2) (75.5 predicted, -5.1)

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.


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