Solar Terrestrial Activity Report

Last major update issued on March 11, 2004 at 03:50 UTC.

[Solar and geomagnetic data - last month (updated daily)]
[Solar wind and electron fluence charts (updated daily)]
[Solar cycles 21-23 (last update March 2, 2004)]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22 and 23 (last update March 2, 2004)]
[Graphical comparison of cycles 2, 10, 13, 17, 20 and 23 (last update March 2, 2004)]
[Historical solar and geomagnetic data charts 1954-2003 (last update January 16, 2004)]
[Archived reports (last update March 3, 2004)]

Recent activity

The geomagnetic field was unsettled to major storm on March 10. Solar wind speed ranged between 608 and 908 km/sec under the influence of a strong high speed stream from coronal hole CH84.

Solar flux measured at 20h UTC on 2.8 GHz was 112.6. The planetary A index was 40 (STAR Ap - based on the mean of three hour interval ap indices: 41.8).
Three hour interval K indices: 56645334 (planetary), 55534334 (Boulder).

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

At midnight there were 3 spotted regions on the visible disk. Solar flare activity was very low. No C class events was recorded during the day. 

Region 10569 was quiet and stable
Region 10570 developed significantly as positive polarity flux emerged at the southeast and northeast edges of the large leading penumbra. There is currently a magnetic delta structure in the southeastern part of this penumbra. An M class flare is possible.
New region 10571 emerged on a coronal island inside coronal hole CH84 on March 8 and was numbered two days later by SEC.

Coronal mass ejections (CMEs)

March 8-10: 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 large recurrent trans equatorial coronal hole (CH84) was in a geoeffective position on March 7-11.

Processed SOHO/EIT 284 image at 01:06 UTC on March 11. The darkest areas on the solar disk are likely coronal holes.


The geomagnetic field is expected to be unsettled to minor storm with occasional major storm intervals on March 11-14 due to a high speed stream from coronal hole CH84.

Long distance low and medium frequency (below 2 MHz) propagation along east-west paths over high and upper middle latitudes is very poor. Propagation along long distance north-south paths is fair. [Trans Atlantic propagation conditions are currently monitored every night on 1470 kHz. Dominant stations tonight: Radio Cristal del Uruguay with a good signal and Radio Vibración (Venezuela) which had a poor to fair signal. Occasionally an unidentified station from Brazil with a soccer game was noticed. On 1510 kHz WWZN Boston was observed with a poor to fair signal for a long time. On other frequencies there were mostly stations from Brazil and Argentina].

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
10569 2004.03.04 3 2 S12W54 0030 BXO classification was HSX
at midnight
10570 2004.03.05 21 25 S14E20 0730 FKO beta-gamma-delta
10571 2004.03.10 2 2 S14W13 0010 BXO formerly region S369
S367 emerged on
    S13W39     plage
Total spot count: 26 29
SSN: 56 59

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)
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 61.8 (-3.2)
2003.08 122.1 72.7 60.0 (-1.8)
2003.09 112.2 48.7 (58.9 predicted, -1.1)
2003.10 151.7 65.5 (56.2 predicted, -2.7)
2003.11 140.8 67.3 (53.5 predicted, -2.7)
2003.12 114.9 46.5 (50.9 predicted, -2.6)
2004.01 114.1 37.2 (46.7 predicted, -4.2)
2004.02 107.0 46.0 (42.1 predicted, -4.6)
2004.03 103.5 (1) 17.1 (2) (39.7 predicted, -2.4)

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 some of these solar data sources. All time references are to the UTC day. Comments and suggestions are always welcome.

[DX-Listeners' Club]