Last major update issued on March 22, 2004 at 04:40 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 11, 2004)]
The geomagnetic field was quiet to active on March 21. Solar wind speed ranged between 396 and 461 km/sec.
Solar flux measured at 20h UTC on 2.8 GHz was 111.2. The planetary A
index was 13 (STAR Ap - based on the mean of three hour interval ap indices: 13.4).
Three hour interval K indices: 33343232 (planetary), 33222333 (Boulder).
The background x-ray flux is at the class B2 level.
At midnight there were 4 spotted regions on the visible disk. The solar flare activity level was low. A total of 4 C class events was recorded during the day. A C6.2 flare was observed at the southwest limb at 09:52 UTC, its source was probably in region 10576.
Region 10574 decayed slowly and quietly. There is a single small patch of positive polarity in the central western part
of the region, otherwise the region is magnetically fairly simple structured.
Region 10577 was quiet and stable.
Region 10578 decayed slowly but still has a minor chance of producing a small M flare. Flares:
C1.0 at 01:17, C1.43 at 16:34 and C1.1 at 20:33 UTC.
Spotted region not numbered by NOAA/SEC:
[S375] This region was first observed on March 19, was spotless the next day and reemerged with a single small spot on
March 21. Location at midnight: S11E60.
March 19-21: No partly or fully earth directed CMEs 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, poorly defined coronal hole (CH85) in the northern hemisphere was in a geoeffective position on March 20. The southernmost parts of a coronal hole (CH86) in the northern hemisphere were in a geoeffective position on March 16-17.
Processed SOHO/EIT 284 image at 00:12 UTC on March 18. The darkest areas on the solar disk are likely coronal holes.
The geomagnetic field is expected to be quiet to unsettled on March 22-23 and quiet to active on March 24 under the influence of a weak high speed stream from coronal hole CH85.
Long distance low and medium frequency (below 2 MHz) propagation along east-west paths over high and upper middle latitudes is fair. Propagation along long distance north-south paths is fair to poor. [Trans Atlantic propagation conditions are currently monitored every night on 1470 kHz. Dominant stations tonight: Radio Vibración (Venezuela) and WLAM Lewiston ME. North American stations were noted on a number of frequencies, particularly above 1350 kHz].
| 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.
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 |
|---|---|---|---|---|---|---|---|
| 10573 | 2004.03.12 | S12W46 | plage | ||||
| 10574 | 2004.03.16 | 20 | 22 | S04E01 | 0100 | ESI | beta-gamma |
| 10575 | 2004.03.17 | S18W54 | plage | ||||
| 10577 | 2004.03.17 | 1 | 2 | N00E27 | 0040 | HSX |
area was 0070 at midnight |
| 10578 | 2004.03.18 | 14 | 24 | N15E34 | 0180 | EAO | beta-gamma |
| S375 | visible on 2004.03.19 |
1 | S11E60 | 0000 | AXX | ||
| Total spot count: | 35 | 49 | |||||
| SSN: | 65 | 89 | |||||
| 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 | 106.4 (1) | 43.1 (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.
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