Solar Terrestrial Activity Report

Last update January 5, 2003 at 05:00 UTC.

[Solar and geomagnetic data - last 4 weeks (updated daily)]
[Solar wind and electron fluence charts (updated daily)]
[Solar cycles 21-23 (last update 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 1, 2003)]

Recent activity

The geomagnetic field was quiet to active on January 4. Solar wind speed ranged between 473 and 654 km/sec under the influence of a coronal stream. Solar wind speed peaked before noon and decreased for the remainder of the day as the coronal stream subsided. 

Solar flux measured at 20h UTC on 2.8 GHz was 143.0. The planetary A index was 13 (STAR Ap - based on the mean of three hour interval ap indices: 14.8).
Three hour interval K indices: 44223332 (planetary), 33223332 (Boulder).

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

At midnight there were 8 spotted regions on the visible disk, 3 of which have not yet been numbered. Solar flare activity was low. A total of 5 C class events were recorded during the day.

Region 10239 decayed further and had only a single tiny spot left at the end of the day.
Region 10241 decayed and was spotless by late evening.
Region 10242 developed further. A few small negative polarity areas emerged inside the trailing positive polarity area. There is currently no magnetic delta structure, however, a delta could form today if the current development continues. A minor M class flare is possible.
Region 10243 developed slowly and has only a minor chance of producing an M class flare. Flares: C1.0 at 08:13 and C1.4 at 11:32 UTC.
Region 10244 developed slowly. A minor M class flare is a remote possibility. Flares: C1.9 at 09:03 and C1.3 at 17:03 UTC.
Region 10245 developed slowly and quietly.

Spotted regions not yet numbered by SEC/NOAA:
[S66] A new region emerged northeast of region 10239. Location at midnight: S06W37. Unfortunately and confusingly SEC/NOAA decided to reuse region number 10240.
[S67] A new region emerged in the southeast quadrant to the east northeast of region 10244. Location at midnight: S15E55.
[S68] A new region emerged late in the day halfway between regions 10242 and 10245. Location at midnight: N02E45.

Coronal mass ejections (CMEs)

January 2-4: 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 will rotate into a geoeffective position on January 6-7.

Processed SOHO EIT 284 image at 19:06 UTC on January 4. Any black areas on the solar disk are likely coronal holes.

Forecast

The geomagnetic field is expected to be quiet to unsettled on January 5-8 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 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. 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
10234 2002.12.24     N19W73     plage 
10238 2002.12.28   N09W76     plage
10239 2002.12.29 2 1 S09W43 0020 HRX classification was AXX
at midnight, area 0000
10240 2002.12.30 1 S08W30 0010 HRX actually spotless
location corrected
see region S66 below
10241 2003.01.02 3   S24W66 0030 DRO now spotless
10242 2003.01.02 18 31 S08E33 0180 DAI beta-gamma
area approx. 0250
at midnight
10243 2003.01.03 13 21 S19W47 0150 DAO area approx. 0220
at midnight
10244 2003.01.03 9 16 S23E40 0140 DAO  
10245 2003.01.03 1 2 N11E59 0110 HAX  
S66 emerged on
2003.01.04
  10 S06W37 0030 CAO  
S67 emerged on
2003.01.04
  3 S15E55 0010 AXX  
S68 emerged on
2003.01.04
  1 N02E45 0000 AXX  
Total spot count: 47 85
SSN: 117 165

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)
2003.01 128.5 (1) 11.2 (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. Comments and suggestions are always welcome.


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