Solar Terrestrial Activity Report

Last major update issued on January 12, 2004 at 03:30 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 October 15, 2003)]
[Archived reports (last update January 9, 2004)]

Recent activity

The geomagnetic field was quiet to active on January 11. Solar wind speed ranged between 518 and 723 km/sec. A high speed stream from coronal hole CH75 dominated the solar wind most of the day.

Solar flux measured at 20h UTC on 2.8 GHz was 118.5. The planetary A index was 17 (STAR Ap - based on the mean of three hour interval ap indices: 18.1).
Three hour interval K indices: 22344442 (planetary), 11444432 (Boulder).

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

At midnight there were 2 spotted regions on the visible disk. Solar flare activity was low. A total of 6 C class events was recorded during the day.

Region 10536 decayed slowly and lost the trailing spots. A minor M class flare is still possible. Flares: C1.0 at 03:18, C1.0 at 04:16, C1.6 at 07:21 and C1.7 at 19:04 UTC.
Region 10537 did not change much, the only development of some significance was that the two main penumbrae appear to be merging. There is still a magnetic delta in the central part of the region and a major flare is possible.  Flares: C1.1 at 10:13 and C1.8 at 18:34 UTC. 

Coronal mass ejections (CMEs)

January 11: A CME was observed off of the southeast limb during the evening, it is not likely to be geoeffective. 

January 9-10: 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) will rotate into a geoeffective position on January 13-14.

Processed SOHO/EIT 284 image at 19:06 UTC on January 11. The darkest areas on the solar disk are likely coronal holes.


The geomagnetic field is expected to be quiet to unsettled on January 12-15 with unsettled to minor storm conditions possible on January 16-17 because of a high speed stream from coronal hole CH76.

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 Rafaela (Argentina) and Radio Cristal del Uruguay on the southwesterly antenna, Radio Vibración (Venezuela) on the EWEs directed to the west and northwest. Lots of carriers noted on TA frequencies, the Newfoundland stations on 590 and 930 had fairly good signals].

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
10536 2004.01.01 22 24 S12W54 0480 EKC beta-gamma
classification was DKC
at midnight
10537 2004.01.06 11 17 N05E11 0210 DKC beta-gamma-delta
10538 2004.01.07     N05W43     plage
10539 2004.01.07     N09W24     plage
Total spot count: 33 41
SSN: 53 61

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)
2004.01 118.5 (1) 26.4 (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]