Solar Terrestrial Activity Report

Last major update issued on January 4, 2008 at 04:45 UTC. The next update will be on January 7.

[Solar and geomagnetic data - last month (updated daily)]
[Solar wind and electron fluence charts (updated daily)
[Solar cycles 21-23 (last update October 4, 2007)]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22 and 23 (last update October 4, 2007)]
[Graphical comparison of cycles 2, 10, 13, 17, 20 and 23 (last update October 4, 2007)]
[Historical solar and geomagnetic data charts 1954-2006 (last update April 5, 2007)]
[Archived reports (last update October 3, 2007)]

Recent activity

The geomagnetic field was inactive on January 3. Solar wind speed ranged between 270 and 362 km/s.

Solar flux measured at 20h UTC on 2.8 GHz was 79.3. The planetary A index was 1 (STAR Ap - based on the mean of three hour interval ap indices: 0.8). Three hour interval K indices: 00000000 (planetary), 00100110 (Boulder).

The background x-ray flux is at the class A2 level.

At midnight there were 2 spotted regions on the visible solar disk. The solar flare activity level was very low. No C class events were recorded during the day.

Region 10980 decayed slowly and quietly.

Spotted regions not numbered by NOAA/SWPC:
[S716] This cycle 24 region emerged in the northeastern quadrant late on January 3. Location at midnight: N27E32

Coronal mass ejections (CMEs)

January 1-3: A full halo CME associated with a C1.2 LDE in region on January 2 may cause a flanking impact on January 5. The main part of the CME had a direction well away from Earth.

Coronal holes

Coronal hole history (since late October 2002)
Compare today's report to the situation one solar rotation ago: 28 days ago 27 days ago 26 days ago

A recurrent trans equatorial coronal hole (CH306) will likely rotate into an Earth facing position on January 4-5. A small coronal hole (CH307) in the northern hemisphere was in an Earth facing position on January 2.

Processed SOHO/EIT 195 image at 21:12 UTC on January 3. The darkest areas on the solar disk are likely coronal holes.

Propagation

Long distance low and medium frequency (below 2 MHz) propagation along paths north of due west over high and upper middle latitudes is good. Propagation on long distance northeast-southwest paths is poor.

Monitoring remarks from a location near N58E06: January 1: Good signals were noted on most TA frequencies in widespread conditions as even a few west coast stations surfaced. Several stations from México had strong signals as did 1570 HRRF.  The best Trans Atlantic propagation sector was 270-300 degrees.

Forecast

The geomagnetic field is expected to be quiet on January 4. On January 5 there is a significant chance of weak effects from the CME observed on January 2 and for weak coronal hole effects from CH307. January 7-9 will likely see effects from CH306 causing some unsettled and active intervals.

Coronal holes (1) Coronal mass ejections (2) M and X class flares (3)



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) Effects from a CME are likely to be observed at 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/SWPC. 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 SWPC or where SWPC has observed no spots. SWPC active region numbers in the table below and in the active region map above are the historic SWPC/USAF numbers.

Active region Date numbered SWPC
spot
count
STAR
spot
count
Location at midnight Area Classification Comment
10980 2007.12.31 3 2 S06E42 0020 HSX classification was AXX at midnight
S716 2008.01.03   1 N27E32 0000 AXX  
Total spot count: 3 3  
SSN: 13 23  

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)
2006.09 77.8 14.4 15.6 (+0.0)
2006.10 74.3 10.4 14.2 (-1.4)
2006.11 86.3 21.5 12.7 (-1.5)
2006.12 84.5 13.6 12.1 (-0.6)
2007.01 83.3 16.9 12.0 (-0.1)
2007.02 77.7 10.6 11.6 (-0.4)
2007.03 72.2 4.8 10.8 (-0.8)
2007.04 72.4 3.7 9.9 (-0.9)
2007.05 74.4 11.7 8.7 (-1.2)
2007.06 73.7 12.0 7.7 (-1.0)
2007.07 71.6 10.0 (7.2 predicted, -0.5)
2007.08 69.1 6.2 (6.7 predicted, -0.5)
2007.09 67.1 2.4 (6.7 predicted, +0.0)
2007.10 67.4 0.9 (7.2 predicted, +0.5)
2007.11 69.6 1.7 (7.8 predicted, +0.6)
2007.12 78.5 10.1 (8.1 predicted, +0.3)
2008.01 79.5 (1) 1.2 (2) (8.7 predicted, +0.6)

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/SWPC) sunspot number. The official international sunspot number is typically 30-50% lower.

This report has been prepared by Jan Alvestad. It is based partly on my own observations and analysis, and partly on data from some of these solar data sources. All time references are to the UTC day. Comments and suggestions are always welcome.


[DX-Listeners' Club]