Solar Terrestrial Activity Report

Last update December 4, 2002 at 04:00 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 unsettled on December 3. Solar wind speed ranged between 439 and 547 km/sec.

Solar flare activity was low. Solar flux was 145.9, the planetary A index was 11 (STAR Ap - based on the mean of three hour ap indices: 12.3).
Three hour interval K indices: 33233332 (planetary), 23233322 (Boulder).

The background x-ray flux is at the class B4 level.

At midnight there were 7 spotted regions on the visible disk. A total of 2 C class events was recorded during the day.

Region 10203 reemerged with a couple of small spots.
Region 10205 was quiet and stable.
Region 10207 decayed substantially and lost many spots.
Region 10208 lost a few small spots and the magnetic delta observed one day earlier. A minor M class flare is still possible. Flare: C8.3 at 08:18 UTC.
Region 10209 decayed slowly and quietly.
Region 10212 developed a few spots north of the dominant penumbra. Flare: C1.2 at 13:06 UTC.
New region 10213 rotated into view at the northeast limb.

Coronal mass ejections (CMEs)

December 1-3: 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

A coronal hole in the northern hemisphere and a developing trans equatorial coronal hole will move into a geoeffective position on December 4.

Processed SOHO EIT 284 image at 19:06 UTC on December 3. Any black areas on the solar disk are likely coronal holes.

Forecast

The geomagnetic field is expected to be quiet to unsettled on December 4-6. A coronal stream could begin influencing the geomagnetic field on Dec.7. Long distance medium wave (AM) band propagation along east-west paths over high and upper middle latitudes is poor and slowly improving.

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
10202 2002.11.24  1   N12W51 0000 AXX spotless all day
10203 2002.11.26   2 N06W20 0020 BXO
10204 2002.11.27     N16W39     plage
10205 2002.11.27 5 2 N20W16 0020 CSO  
10206 2002.11.27   S27W35     plage
10207 2002.11.27 18 8 S19W06 0240 EAO  
10208 2002.11.29 24 17 N11E22 0120 EAI beta-gamma
10209 2002.11.30 6 4 S19E20 0110 ESO  
10211 2002.12.02   S08W09     plage
10212 2002.12.02 8 9 N14E62 0180 DAO
10213 2002.12.03 3 4 N15E79 0070 CSO
Total spot count: 65 46
SSN: 135 116

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)
2002.12 147.2 (1) 12.5 (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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