Last major update issued on March 14, 2005 at 03:45 UTC.
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The geomagnetic field was quiet to unsettled on March 13. Solar wind speed ranged between 328 and 360 km/sec. The effects from CH151 arrived late in the day and the geomagnetic field is unsettled to active early on March 14.
Solar flux measured at 20h UTC on 2.8 GHz was 113.8. The planetary
A
index was 6 (STAR Ap - based on the mean of three hour interval ap
indices: 6.1).
Three hour interval K indices: 10012223 (planetary), 10013333 (Boulder).
The background x-ray flux is at the class B2 level.
At midnight there were 3 spotted regions on the visible solar disk. The solar flare activity level was low. A total of 5 C class events was recorded during the day.
Region 10741 developed with several new spots emerging. Flares: C1.2 at 08:18,
C1.0 at 12:50 and C1.1 at 15:01 UTC.
Region 10742 developed slowly while the positive and negative polarity areas further increased their separation.
Flares: C1.0 at 08:30 and C1.5 at 15:17 UTC.
Region 10743 was quiet and stable.
March 11-13: No obvious fully or partly Earth directed CMEs were observed.
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 (CH151) was in a geoeffective position on March 10. This coronal hole has developed somewhat over the last rotation. A recurrent coronal hole (CH152) in the northern hemisphere will likely rotate to a geoeffective position on March 14. This coronal hole appears to have decayed somewhat over the last rotation.
Processed SOHO/EIT 284 image at 13:06 UTC on March 11. The darkest areas on the solar disk are likely coronal holes.
The geomagnetic field is expected to be quiet to active on March 14 due to effects from CH151. Quiet conditions are likely again on March 15-16 while CH152 could cause unsettled to active conditions on March 17-18.
| 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) 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.
Long distance low and medium frequency (below 2 MHz) propagation along east-west paths over high and upper middle latitudes is poor to very poor. Propagation along long distance north-south paths is poor. Trans Atlantic propagation conditions are normally monitored every night on 1470 kHz. Dominant station tonight: Radio Vibración with a weak signal. Although propagation in general was poor, most of the stations heard were from Newfoundland (590, 620, 710, 740 and 930 kHz).
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 spot count |
STAR spot count |
Location at midnight | Area | Classification | Comment |
|---|---|---|---|---|---|---|---|
| 10741 | 2005.03.04 | 7 | 7 | N12W57 | 0060 | DAO | |
| 10742 | 2005.03.07 | 37 | 34 | S05W12 | 0340 | EAI | |
| 10743 | 2005.03.09 | 3 | 2 | S07E24 | 0250 | HKX | classification was HSX at midnight, area 0200 |
| S524 | visible on 2005.03.10 |
N10E37 | spotless | ||||
| Total spot count: | 47 | 43 | |||||
| SSN: | 77 | 73 | |||||
| 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) |
| 2004.01 | 114.1 | 37.3 | 52.0 (-2.8) |
| 2004.02 | 107.0 | 45.8 | 49.3 (-2.7) |
| 2004.03 | 112.0 | 49.1 | 47.1 (-2.2) |
| 2004.04 | 101.2 | 39.3 | 45.5 (-1.6) |
| 2004.05 | 99.8 | 41.5 | 43.9 (-1.6) |
| 2004.06 | 97.4 | 43.2 | 41.7 (-2.2) |
| 2004.07 | 119.1 | 51.0 | 40.3 (-1.4) |
| 2004.08 | 109.6 | 40.9 | 39.2 (-1.1) |
| 2004.09 | 103.1 | 27.7 | (37.4 predicted, -1.8) |
| 2004.10 | 105.9 | 48.4 | (35.2 predicted, -2.2) |
| 2004.11 | 113.2 | 43.7 | (33.3 predicted, -1.9) |
| 2004.12 | 94.5 | 17.9 | (31.0 predicted, -2.3) |
| 2005.01 | 102.2 | 31.3 | (28.3 predicted, -2.7) |
| 2005.02 | 97.2 | 29.1 | (25.9 predicted, -2.4) |
| 2005.03 | 90.8 (1) | 17.7 (2) | (24.1 predicted, -1.8) |
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.
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