Solar Terrestrial Activity Report

Last update December 8, 2002 at 04:35 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 unsettled to active on December 7. Solar wind speed ranged between 428 and 630 km/sec under the influence of a coronal stream.

Solar flare activity was low. Solar flux was 151.1, the planetary A index was 16 (STAR Ap - based on the mean of three hour ap indices: 17.6).
Three hour interval K indices: 33343333 (planetary), 43333233 (Boulder).

The background x-ray flux is at the class B5 level.

At midnight there were 11 spotted regions on the visible disk, 4 of which have not yet been numbered. A total of 2 C class flares were recorded during the day. A C2.1 event at 10:00 UTC could not be traced to any of the visible regions.

Region 10207 was quiet and stable.
Region 10208 decayed quickly and could become spotless today. 
Region 10209 lost its trailing spots again while no changes were observed for the leading penumbra.
Region 10212 lost several of its smaller spots, the main penumbra was mostly unchanged. 
Region 10213 decayed and lost more than half of its penumbral area. If the current rate of decay persists, the region will become spotless tomorrow.
Region 10214 developed further in the trailing spots section. C class flaring is likely and there is a chance of a minor M class flare. Flare: C1.0 at 18.51 UTC. 
Region 10215 developed slowly. The single penumbra appears to be splitting into two.

Spotted regions not yet numbered by SEC:
[S43] A new region emerged in the southeast quadrant on December 6. The region decayed slowly on Dec.7 and had only a single small spot left by the end of the day. Location at midnight: S08E03.
[S44] A new region emerged in the southwest quadrant on December 7. Location at midnight: S24W24.
[S45] A new region emerged at the northeast limb. Location at midnight: N11E70.
[S46] A new region was rotating into view at the southeast limb late on December 7. Location at midnight: S20E80.

Coronal mass ejections (CMEs)

December 5-6: 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: 28 days ago 26 days ago 25 days ago

A slowly developing trans equatorial coronal hole was in a geoeffective position on December 4. A small, decaying, recurrent coronal hole in the southern hemisphere could rotate into a geoeffective position on December 10.

Processed SOHO EIT 284 image at 19:06 UTC on December 7. Any black areas on the solar disk are likely coronal holes.

Forecast

The geomagnetic field is expected to be quiet to active on December 8 and quiet to unsettled on December 9-10. 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)
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.

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 region Date numbered SEC
spot
count
STAR
spot
count
Location at midnight Area Classification Comment
10203 2002.11.26   N07W73     plage
10205 2002.11.27     N20W67     plage
10206 2002.11.27   S27W74     plage
10207 2002.11.27 1 1 S18W67 0060 HSX  
10208 2002.11.29 4 2 N09W38 0060 DAO area was near 0010 at
midnight, classification
was BXO
10209 2002.11.30 6 1 S20W39 0060 FAO classification was HAX
at midnight
10211 2002.12.02   S08W61     plage
10212 2002.12.02 12 12 N13E08 0090 DAO
10213 2002.12.03 2 4 N14E24 0040 CAO  
10214 2002.12.05 9 13 N13W55 0110 DAO beta-gamma
10215 2002.12.05 2 3 S18E46 0080 HSX  
S42 emerged on
2002.12.04
  S10W21     plage
S43 emerged on
2002.12.06
  1 S08E03 0000 AXX
S44 emerged on
2002.12.07
  4 S24W24 0030 CAO
S45 emerged on
2002.12.07
  3 N11E70 0020 CAO
S46 visible on
2002.12.07
  3 S20E80 0060 DAO
Total spot count: 36 47
SSN: 106 157

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
2001.11 210.6 106.5 115.5 (+1.5)
2001.12 235.1 132.2 114.6 (-0.9)
2002.01 226.6 114.1 113.5 (-1.1)
2002.02 205.0 107.4 114.7 (+1.2)
2002.03 179.5 98.4 113.4 (-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 (106.4 predicted, -2.4)
2002.07 173.5 99.9 (102.8 predicted, -3.6)
2002.08 183.6 116.4 (99.6 predicted, -3.2)
2002.09 175.8 109.3 (96.6 predicted, -3.0)
2002.10 167.0 97.5 (93.1 predicted, -3.5)
2002.11 168.7 95.0 (87.8 predicted, -5.3)
2002.12 148.3 (1) 29.1 (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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