Solar Terrestrial Activity Report

Report for January 19 issued on January 20, 2003 at 03:20 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 13, 2003)]

Recent activity

The geomagnetic field was quiet to active on January 18. Solar wind speed ranged between 359 and 478 km/sec as a coronal stream began to dominate the solar wind. The source of this coronal stream is likely the northwesternmost extension of the southern polar coronal hole.

Solar flux measured at 20h UTC on 2.8 GHz was 137.4. The planetary A index was 12 (STAR Ap - based on the mean of three hour interval ap indices: 13.1).
Three hour interval K indices: 22334322 (planetary), 22334323 (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 has not yet been numbered by SEC/NOAA. Solar flare activity was very low. No C class flares were recorded.

Region 10250 developed slowly as new spots emerged south of the largest penumbra.
Region 10251 decayed slowly and quietly.
Region 10254 decayed slowly and quietly with the trailing penumbra losing area.

Region 10255 was split off from region 10251 on January 12 by SEC/NOAA. This split was doubtful even then and it is currently obvious that it was a premature decision.
Region 10256 was split off from region 10254 on January 12 by SEC/NOAA. Regions 10254 and 10256 make up one bipolar region with the negative polarity area in the west and the positive area to the east. It remains to be seen if SEC will merge the "two" regions again.

Region 10257 lost area in the main penumbra, however, a few small spots emerged.
Region 10258 was quiet and stable.
Region 10259 decayed slowly and quietly.
Region 10260 developed slightly and was quiet.

Spotted regions not numbered by SEC/NOAA:
[S75] A new region emerged in the southwest quadrant north of region 10254. Location at midnight: S06W32.
[S76] A new region emerged in the northwest quadrant. Location at midnight: N26W31.

Coronal mass ejections (CMEs)

January 16-18: 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

An extension of the southern polar coronal hole was in a geoeffective position on January 18, a northwestern extension may have been in a geoeffective position on January 16. A large trans equatorial coronal hole has split off from the southern polar coronal hole and will be in a geoeffective position on January 18-22.

Processed SOHO EIT 284 image at 19:06 UTC on January 18. Any black areas on the solar disk are likely coronal holes.

Forecast

The geomagnetic field is expected to be quiet to active until January 26 due to coronal streams, occasional minor storm intervals are possible. 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
spot
count
STAR
spot
count
Location at midnight Area Classification Comment
10247 2003.01.06 4   S14W88 0030 CSO actually spotless
10250 2003.01.07 8 12 S27W63 0140 DAO  
10251 2003.01.07 2 1 S14W63
(SEC:
S13W55)
0010 AXX classification was HSX
at midnight, area 0080,
region 10255 included
10252 2003.01.09     S03W60     plage
10254 2003.01.10 1 6 S15W32
(SEC:
S14W37)
0090 HAX location corrected,
classification was ESO
at midnight, area 0120.
STAR spot count
includes region 10256.
10255 2003.01.12 2   S13W67 0110 HAX split off from region
10251
10256 2003.01.12 6   S16W25 0020 CSO split off from region
10254. Only positive
polarity spots.
10257 2003.01.13 6 7 N16W48 0020 CSO  
10258 2003.01.14 2 2 N07W01 0080 HAX  
10259 2003.01.14 14 15 N10E12 0070 DAO  
10260 2003.01.15 3 4 N14E40 0030 HAX  
S75 2003.01.18   3 S06W32 0010 BXO  
S76 2003.01.18   1 N26W31 0010 HRX  
Total spot count: 48 51
SSN: 148 141

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)
2003.01 155.5 (1) 92.0 (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]