Last major update issued on June 3, 2005 at 04:15 UTC.
[Solar and
geomagnetic data - last month (updated daily)]
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electron fluence charts (updated daily)]
[Solar cycles 21-23
(last update May 6, 2005)]
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[Graphical comparison
of cycles 21, 22 and 23 (last update May 6, 2005)]
[Graphical
comparison of cycles 2, 10, 13, 17, 20 and 23 (last update May 6, 2005)]
[Historical solar and
geomagnetic data charts 1954-2004 (last update February 1, 2005)]
[Archived reports
(last update May 15, 2005)]
The geomagnetic field was quiet to unsettled on June 2. Solar wind speed ranged between 350 and 436 km/sec. Solar wind speed increased slowly after noon as a weak low speed stream from CH168 became the dominant source.
Solar flux measured at 20h UTC on 2.8 GHz was 93.3. The planetary
A
index was 7 (STAR Ap - based on the mean of three hour interval ap
indices: 7.4).
Three hour interval K indices: 22221223 (planetary), 22232223 (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 single C class event was recorded during the day.
Region 10769 still has a few small spots, but could become spotless any day.
Region 10772 decayed slowly with most of the decay occurring in the leader spots. Flare:
C1.3 at 23:05 UTC.
Region 10773 was mostly unchanged and quiet.
May 31- June 2: No obvious fully or partly potentially geoeffective 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 small coronal hole (CH168) in the southern hemisphere was in an Earth facing position on May 29. A large, recurrent coronal hole (CH169) in the northern hemisphere will rotate into an Earth facing position on June 1-3.
Processed SOHO/EIT 284 image at 01:06 UTC on June 3. The darkest areas on the solar disk are likely coronal holes.
The geomagnetic field is expected to be quiet to unsettled on June 3. Sometime on June 4 a high speed stream from CH169 is likely to arrive causing unsettled to minor storm conditions. These conditions will continue on June 5 and most of June 6. Quiet to unsettled is likely on June 7-8
| 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 very poor. Propagation along long distance north-south paths is fair to good. Trans Atlantic propagation conditions are normally monitored every night on 1470 kHz. Dominant station tonight: Radio Cristal del Uruguay. On other frequencies quite a few stations from Argentina were audible with the most interesting station on 1590 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 |
|---|---|---|---|---|---|---|---|
| 10767 | 2005.05.21 | 1 | S09W85 | 0000 | AXX | rotated out of view | |
| 10769 | 2005.05.28 | 1 | 3 | S10E15 | 0010 | AXX | classification was BXO at midnight |
| 10770 | 2005.05.29 | N12W52 | plage | ||||
| 10771 | 2005.05.30 | 1 | N23W72 | 0010 | AXX | spotless | |
| 10772 | 2005.05.31 | 13 | 12 | S17E23 | 0110 | DAI | beta-gamma |
| 10773 | 2005.06.01 | 3 | 5 | S12E63 | 0140 | DAO | area was 0100 at midnight |
| Total spot count: | 19 | 20 | |||||
| SSN: | 69 | 50 | |||||
| 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) |
| 2004.04 | 101.2 | 39.3 | 45.5 (-1.6) |
| 2004.05 | 99.8 | 41.5 | 43.8 (-1.7) |
| 2004.06 | 97.4 | 43.2 | 41.6 (-2.2) |
| 2004.07 | 119.1 | 51.1 | 40.2 (-1.4) |
| 2004.08 | 109.6 | 40.9 | 39.2 (-1.0) |
| 2004.09 | 103.1 | 27.7 | 37.5 (-1.7) |
| 2004.10 | 105.9 | 48.0 | 35.9 (-1.6) |
| 2004.11 | 113.2 | 43.5 | 35.3 (-0.6) |
| 2004.12 | 94.5 | 17.9 | (34.8 predicted, -0.5) |
| 2005.01 | 102.2 | 31.3 | (32.8 predicted, -2.0) |
| 2005.02 | 97.2 | 29.1 | (30.4 predicted, -2.4) |
| 2005.03 | 89.9 | 24.8 | (28.8 predicted, -1.6) |
| 2005.04 | 86.0 | 24.4 | (26.9 predicted, -1.9) |
| 2005.05 | 99.3 | 42.6 | (24.3 predicted, -2.6) |
| 2005.06 | 95.1 (1) | 5.5 (2) | (22.8 predicted, -1.5) |
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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