Solar Terrestrial Activity Report

Last major update issued on January 19, 2004 at 04:30 UTC.

[Solar and geomagnetic data - last month (updated daily)]
[Solar wind and electron fluence charts (updated daily)]
[Solar cycles 21-23 (last update January 4, 2004)]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22 and 23 (last update January 4, 2004)]
[Graphical comparison of cycles 2, 10, 13, 17, 20 and 23 (last update January 4, 2004)]
[Historical solar and geomagnetic data charts 1954-2003 (last update January 16, 2004)]
[Archived reports (last update January 9, 2004)]

Recent activity

The geomagnetic field was quiet to active on January 18. Solar wind speed ranged between 527 and 690 km/sec under the influence of a high speed stream from coronal hole CH76.

Solar flux measured at 20h UTC on 2.8 GHz was 119.5. The planetary A index was 18 (STAR Ap - based on the mean of three hour interval ap indices: 18.5).
Three hour interval K indices: 24433344 (planetary), 14423333 (Boulder).

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

At midnight there were 6 spotted regions on the visible disk. Solar flare activity was moderate. A total of 3 C and 1 M class events was recorded during the day.

Region 10537 rotated partly out of view at northwest limb. Flares: C1.4 at 13:57 and C3.7 at 20:03 UTC.
Region 10540 developed significantly in the trailing spot section where two magnetic delta structures formed as several areas of negative polarity emerged in the southern part of the positive polarity field. M class flares are likely and there is a chance of a major flare. Flares: impulsive M1.4/1N (associated with a moderate type II radio sweep) at 00:17 and C1.4 at 21:44 UTC.
Region 10541 decayed slowly and was quiet. This region could become spotless today.
Region 10542 reemerged with a single spot.

Spotted regions not numbered by NOAA/SEC:
[S333] This is a quickly emerging region to the east of region 10542. There is not much separating the opposite polarity fields in the leading spot section. If the region continues to develop at the current rate, M class flares will soon become a possibility. Location at midnight: N08E35.
[S334] This region emerged to the west of region 10540 on January 18. Location at midnight: S12W13.

Coronal mass ejections (CMEs)

January 18: The M1 flare in region 10540 early in the day was associated with a partial halo CME observed mostly off of the southern limbs and the south pole. It is uncertain if there are any earth directed parts of this CME.

January 17: The major M5 flare in region 10540 was associated with a partial halo CME observed off of the southern limbs and the south pole. It is uncertain if there are any earth directed parts of this CME.

January 16: No partly or fully earth directed 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 coronal hole (CH76) was in a geoeffective position on January 13-17.

Processed SOHO/EIT 284 image at 01:06 UTC on January 19. The darkest areas on the solar disk are likely coronal holes.


The geomagnetic field is expected to be quiet to active on January 19-20 due to a high speed stream from coronal hole CH76. Quiet to unsettled is likely on January 21-23.

Long distance low frequency (below 2 MHz) propagation along east-west paths over high and upper middle latitudes is poor. Propagation along long distance north-south paths is poor. [Trans Atlantic propagation conditions are currently monitored every night on 1470 kHz. Dominant stations tonight: Radio Cristal del Uruguay and Radio Rafaela (Argentina). On the northwesterly EWE a few east coast US and Canadian stations were noted].

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. When the high speed stream has arrived the color changes to green.
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 NOAA/SEC. 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. SEC active region numbers in the table below and in the active region map above are the historic SEC/USAF numbers.

Active region Date numbered SEC
Location at midnight Area Classification Comment
10537 2004.01.06 3 2 N04W83 0050 CAO  
10540 2004.01.12 36 34 S14E02 0330 FKO beta-gamma-delta
classification was FAI
at midnight, area 0470
10541 2004.01.15 3 1 S10W44 0010 BXO classification was HRX
at midnight
10542 2004.01.16   2 N09E23
0010 HRX  
S333 emerged on
  10 N08E35 0040 DAO  
S334 emerged on
  2 S12W13 0000 AXX  
Total spot count: 42 51
SSN: 72 111

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)
2002.12 157.2 80.8 82.0 (-3.2)
2003.01 144.0 79.7 80.8 (-1.2)
2003.02 124.5 46.0 78.3 (-2.5)
2003.03 131.4 61.1 74.0 (-4.3)
2003.04 126.4 60.0 70.1 (-3.9)
2003.05 115.7 55.2 67.6 (-2.5)
2003.06 129.3 77.4 65.0 (-2.6)
2003.07 127.7 83.3 (62.0 predicted, -3.0)
2003.08 122.1 72.7 (59.4 predicted, -2.6)
2003.09 112.2 48.7 (57.5 predicted, -1.9)
2003.10 151.7 65.6 (54.7 predicted, -2.8)
2003.11 140.8 67.2 (52.0 predicted, -2.7)
2003.12 114.9 47.0 (49.4 predicted, -2.6)
2004.01 119.0 (1) 39.7 (2) (45.3 predicted, -4.1)

1) Running average based on the daily 20:00 UTC observed solar flux value at 2800 MHz.
2) Unofficial, accumulated value based on the Boulder (NOAA/SEC) sunspot number. The official international sunspot number is typically 30-50% less.

This report has been prepared by Jan Alvestad. It is based partly on my own observations and analysis, 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]